Drawings of s90 speakers. Speakers S90: technical specifications, diagram. DIY speakers. Advantages of new buildings

No matter what the snobs say, the Soviets were at the highest level. Even now they can bypass many modern beepers. And after appropriate modifications, even budget speaker systems from Yamaha cannot compare with them. And now we will look at the legendary Radiotehnika S90. This is a symbol Even abroad they noted the high quality of this (at one time). Therefore, it makes sense to consider these columns. Moreover, many people still use them to this day.

A little history

Radiotehnika S90 speakers were first released in the early eighties of the last century. They were produced by a plant located in Latvia, which became an additional incentive for citizens to buy them. Despite the rather high price, the speakers sold like hot cakes. People saved for a long time, did not eat enough, hiccupped them wherever possible. They even purchased used speaker systems. Just to decorate your closets with “Radio Engineering”.

Nowadays, many audiophiles are still chasing this speaker system. Speakers "Radio Engineering" are the dream of every connoisseur of high-quality sound. But now they can only be purchased on the secondary market. And it’s far from a fact that their condition will be acceptable (affect However, this acoustic system can give a head start to many modern speakers. And after appropriate modifications, it completely turns into Hi-End class acoustics. And this is a completely different level.

Appearance and Design

Looks impressive from Radiotekhnika. These are very large speakers. Each of them weighs about 15-20 kilograms. This is not to mention the fact that carrying them is not very convenient due to the bulky and bulky case. The front panel (like the entire body) is covered with veneer. There are several color combinations. The speakers are covered with a metal mesh. Only the tweeter is not covered with protection. This is, of course, good, but it does not have the best effect on the acoustic properties of the speakers. However, the design is quite acceptable. Much better than other speakers of “clumsy” Soviet production.

On the right side of the mid-frequency and high-frequency speakers there are two operating mode switches. It is unknown why they were placed here. A normal amplifier itself is capable of switching modes. And the job of speakers is to reproduce sound correctly. Nevertheless, Radiotehnika S90 has such switches. But during the finalization process they can be removed, because they have a very negative effect on the overall sound quality. But for those who appreciate retro and antiques, such proposals will seem blasphemous.

Specifications

So let's get down to the hard numbers. Normal speaker power is 35 watts. But these beauties can easily give out 90. That is why they were called “the neighbors’ nightmare.” However, to fully exploit them, stereo amplifiers of appropriate power are required. Only then will this speaker system really sound. The frequency range starts at 20 hertz and ends at 25,000 hertz. This wide range allows the speakers to reproduce almost all instruments quite reliably. The frequency response is quite acceptable for an acoustic system of this level. You can't expect any miracles from her. But the sound is quite decent.

Now comes the fun part - the woofer. This is the legendary "Din 75 GD". The thing is, of course, good, but it does not produce perfectly reliable bass. If the low-frequency speaker is at least something of itself, then the mid-frequency and low-frequency drivers, although they cope with their task, can not be called “kosher”. Ordinary paper bubbles. It would be much better to replace them with Kevlar or silk canopies during refurbishment. That's when the big speakers will start sounding. And it’s better to rewind the woofer, since in used speakers it often burns out due to “super-mega bass”.

Sound quality

As mentioned above, Radiotekhnika speakers with standard components cannot boast of very clean and correct sound. But the quality is enough for not very demanding listeners. The acoustic system copes well with instrumental music (light rock, jazz, blues), and the electronic system also works well. But heavy and other subgenres of great and terrible metal - not so much. That is, the speakers reproduce it as expected, but the woofer jerks so much that it could easily break. Especially when listening to those groups that often abuse the cardan on the kick drum.

The classics also go well. This is probably the only genre that the Radiotehnika S90 copes with very well. All instruments sound crystal clear. Nothing gets ahead of itself. Even audiophiles may enjoy listening to classics on these speakers. However, it is impossible to call this speaker system a Hi-End item. To achieve this level, the speakers will have to be modified. As standard, this is an average but confident Hi-Fi. But the Soviet people didn’t need more.

Amplifiers for S90

In order for passive acoustics to sound good, high-quality stereo amplifiers are also required. It should be noted that the “nineties” can only be driven and fully revealed by a very powerful amplifier. The Soviet vehicles "Brig" and "Odyssey" will cope with such work perfectly. These monsters are capable of getting everything out of the speakers. Amphiton U-001 will also do a good job. Just don’t even think about connecting this speaker system to the Vega 50U. The amplifier will immediately refuse to work even at minimum volume.

The ideal option for this speaker system is the Radiotekhnika amplifier. They were produced in huge quantities, with varying power and resistance. Therefore, finding such a thing on the secondary market is not a problem. There are more than enough amplifiers of this type suitable in terms of power. You can, of course, puzzle yourself and connect these speakers to a completely modern receiver like Yamaha. But then such a kit will go far beyond the “budget” scope. And such a decision is not worth the candle. It's like putting a Porsche engine into a Zaporozhets. It's possible, but there's no point.

Price S90

Now let's look at the most interesting quality of Radiotehnika S90. The price on the secondary market depends on the “kill” of the kit and its originality. Speakers in standard configuration and in decent condition will cost from 1000 to 2000 rubles. Depending on how good they look. Speakers with a whole internal system cost almost the same. You can even find ones that are barely used. It all depends on the seller himself and the level of awareness of the buyer. Speakers modified according to all the rules will cost more, since this is an acoustic system of a completely different class. They will cost about 3,000 rubles.

The Radiotekhnika amplifier will also cost about the same amount. Monsters like the Brig or Odyssey in perfect condition will cost around 15,000 rubles. But the problem is that finding them is almost impossible. In total, the approximate cost of the complete set will be approximately 6,000 rubles. Much better than an obscure Chinese speaker system for the same money. However, this is an approximate cost. It may vary depending on the degree of modification of the speaker system and its condition. But it still turns out to be much more profitable. And the sound quality will be at the same level.

Positive feedback from owners

Now let's look at the reviews about the Radiotehnika S90 speaker system. The amplifier is a separate topic, so we will not consider it here. So what will the owners say? Positive and negative reviews about these speakers go neck and neck. Competent audiophiles have long since finalized their “nineties” and therefore their reviews are laudatory panegyrics addressed to Soviet speakers. There is clear sound, clearly defined bass, wide range, versatility (for all genres) with some equalizer adjustment. Also an important advantage for many was the completely wooden body. And the power of these speakers is the talk of the town. Everyone noted this quality.

Negative reviews from owners

However, there are also snobs who are not satisfied with the sound quality of this speaker system. They note insufficient definition of mid and high frequencies (and this is true). The case, after so many years of use, is simply rattling. The subwoofer thumps out of place. But, comrades, any thing needs to be monitored and timely prevention carried out. This also applies to speakers. After the appropriate procedures, they will sound completely different. Dissatisfied S90 owners - take note!

Conclusion

Radiotehnika S90 is one of the most preferred budget options. It copes with its responsibilities much better than any modern acoustics from China, is highly customizable and can provide Hi-End class sound. What else does a music lover need to be happy?

Small housing volume for woofer. The consequence is a muttering of low frequencies.
The bass reflex is designed for a frequency of 20 Hz. The consequence is large low-frequency distortion.
Worst midrange speaker. The consequences are disgusting midrange and overtones.
Low resonance frequency of the tweeter. Consequences - "quacking", hissing.
The filter is designed taking into account the previous shortcomings. The consequence is that when modifying any unit, the filter must be changed.
The body is not rigid enough and is not “damped”. Consequences - vibrations, overtones, "barrel".
Etc. etc. ...

We study and dare

While drinking beer, we reach three truths. There are three ways:

Lightweight and effective.
Medium difficulty. More shamanism and snobbery. Some sound improvements compared to point 1.
Super complex, time consuming and super efficient. In reality, you are trying to make new speakers. It all depends on the quality of workmanship and musical flair. If nothing works out, then no one promised you anything.

Attention! Attention! Attention!

When carrying out all work, ensure that the phasing of the speakers is correct. If you have not encountered this yourself, invite a specialist - electronics!
Remaking the speaker 15 GD - 11A is an irreversible process. If you are not careful, the speaker has one path - to the trash can, and you have another - to the market.

The first way. Lightweight and effective.

Mid frequencies are the main emphasis. By reworking the speaker, we will make it work in piston mode, increase the upper limit frequency, remove overtones, increase sensitivity, improve directivity, and dampen it.
Let's move the speaker to the range of 31.5 Hz, instead of 20 Hz. There will be less muttering.
Let's suppress the resonance of the high-frequency head.
Let's quiet the sounds of the building

We buy a Soviet tennis ball from a store. Chinese and others are not suitable. They have different material. The ball should be exactly the same as in distant childhood for 8 kopecks. As a last resort, you can take it from friends or in the tennis sports section. We buy epoxy resin (a little, maybe 1 cm cube), glue (Super Cement, Mars, Argo, etc. - hard after hardening), a couple of simple pencils, any medical bandage and cotton wool.

Let's get creative. We saw the ball in half along the seam. The seam is visible to light. It is overlapped and 1 - 2 mm wide. You need to cut in the middle of the seam. I sawed with a Nev blade, having previously made notches on it with a sharpening stone. After sawing, align the cut line on sandpaper and sand the outer surface of the ball with fine sandpaper. If there are large deposits inside the seam area, then they also need to be removed. When working, the ball must be secured with plasticine on a Mars battery (a film case, a jar of fish food, etc., according to your imagination) at three points. That's enough. Plasticine is removed later either with a dry cloth or by wiping with gasoline. Once the surface of the ball has been treated, do not touch it with your hands. Grind the pencil leads on sandpaper.

Dilute epoxy resin with double the amount of hardener. Cover the surface of the ball with the thinnest layer. If necessary, excess glue can be removed with newsprint. Sprinkle with graphite and shake off excess. It is necessary to ensure that the white plastic of the ball does not show through the graphite. If it shows through, it means the layer of epoxy resin was small. Need to add. Once everything is done, let it harden.

Assembling a 3 KHz filter. To do this, we take a 4.7 Mf capacitor and a 0.6 mH inductor. You can take a capacitor from 4 to 7 mF and adjust the inductor to it. In order not to bother your head with unnecessary formulas, the simplest thing is that the product of the capacitor capacitance in microfarads and the inductance of the inductor in mH should be equal to 2.82. Let's say the capacitance of the filter capacitor is 6.6 μF (MBGO and MBM with a permissible deviation from the nominal value of ±10%), then the inductance of the coil is 2.82: 6.6 = 0.43 mH, (the winding contains 150 turns of PEV-1 0.8 wire , wound on a frame with a diameter of 22 and a length of 22 mm with a cheek diameter of 44 mm). Using these data, it is possible to assemble a circuit without an LC meter, since it is not the exact value that is important, but the “capture” of the resonant frequency, which has a certain spread. We attach the capacitor and inductor to a piece of fiberboard and solder one terminal of the coil to the terminal of the capacitor. We solder wires 40-50 cm long to the free terminals.

Let's disassemble the column. We remove the low-frequency speaker, the mid-frequency speaker, take out the glass from it, remove the high-frequency speaker, remove the decorative trim, remove the phase reflex (on some speakers you will have to unscrew the filter). We take half of the dried ball, polish it on the outside with suede or newsprint and glue it over the dust cap of the mid-range speaker head with hard glue. You need to make sure that there are no un-glued gaps between the edge of the ball and the cap and that the ball is glued exactly in the center. We do the same with the second midrange driver. Leave to dry.

We screw a homemade filter onto the back wall of the speaker (inside) opposite the tweeter. Solder the wires from the filter to the output of the high-frequency speaker. Which one goes where does not matter. We remove the connectors from the back wall of the speakers and solder the wire going from the amplifier directly to the filter. We saw off 10 cm from the phase reflex pipe along the center line with a hacksaw. We wrap the phase reflex pipe and the mid-frequency speaker glass with a layer of gauze and bandage it. It is necessary to check whether they will enter their nests after this procedure. If they do not fit, then reduce the layer of cotton wool and gauze. We check if there is cotton wool and gauze in the glass. Add if it’s not enough until it’s full. We dampen the mid-frequency speakers. To do this, we additionally cover their diffuser holders with foam rings made from 10x27x355 mm blanks. the ends of which are glued end-to-end with Moment glue. We cover the bottom and ceiling of the column from the inside with felt (batting, padding polyester, etc.). We wrap the wires with a bandage.

We place the bandage along the wire and twist it, wrapping it around the wire. It is convenient to secure the bandage with threads. Assembling the column. We coat all the perimeters of all speakers with plasticine. There is no need to wear protective nets, but only on the condition that there are no small children, the wife will not come in with a mop or vacuum cleaner, and that the speakers will not be transported. Turn on the speakers. We don't know right. We call our friends. Please bring your favorite recordings. Let's listen. We calm our friends down with beer. We note with mockery how useful the bucks spent on purchasing foreign rubbish would be to them.

The second way. Medium difficulty.

We do everything indicated in path 1, but do not collect the columns.

Let's improve the properties of the body and kill overtones and the "barrel"
Let's achieve better signal transmission
Housing sealing. Removing the influence of the body

So, let's go. Strengthen the rear wall of the case by placing two slats with a cross-section of 3x2cm. vertically along the entire length at a distance of 15-20 cm from each other symmetrically, and attaching them with screws to the back wall. Pre-treat the mounting area with epoxy. It is necessary to take into account the possibility of installing a phase reflex later. Between the rear and front walls we install a spacer rail at the level of the midrange head, taking into account the possibility of installing a glass. We coat all wall joints and corners from the inside with silicone glue such as "Bison" or plumbing silicone putty. We cover the entire body inside with felt (batting, padding polyester, etc.). It should not be thicker than 1.5 cm, so as not to greatly reduce the internal volume of the case.

We reject all proposals to replace 15 GD-11A with 6 GDSH-5. Ours is already “cool”, and such a replacement will lead to a loss of power, a decrease in the dynamic range (very dangerous) and you will have to greatly change the filter. So, when replacing 15 GD - 11A with 6 GDSh-5 for 35AS - 212, you will have to replace the following parts: L1 - 0.22mH, C2 - 1.0mF, C8 - 0.5mF, L4 - 0.1mH. New parameters have been specified. When using 6 GDSH - 5 - 4, you will also have to install an additional resistance in the circuit of this head at 4 Ohms. The appearance of the column also changes. Well, if you really want to, then you can. Next. Removing tone switches. Remove unnecessary resistors R (1, 2, 4, 5, 7, 8, 9, 11, 12). We replace the wires on the filter mounting with a copper wire with a diameter of 1.2 mm. We replace the wires going from the speakers to the filter with more traveling ones. For the low-frequency speaker - multi-core - with a cross-section of 2.5 - 3 mm square, for the mid-frequency - 2.5 mm square. For high frequency - 2 mm square. - single-core. All wires are soldered to the filter directly, rather than passing through previous speakers. The filter is installed at the bottom of the column. All wires are laid under a layer of felt. On the side walls.

The filter regulators are removed. In their place, we make wooden (chipboard, plywood) plugs according to the thickness of the body. We pour them onto the epoxy and sand them down. We cover the front panel with self-adhesive wood-look film to match the veneer of the speakers. Installing speakers. Low-frequency and mid-frequency through rubber gaskets. Rubber from window insulation, thin rubber medical hoses, silicone hoses (worse) are suitable. We treat the installed speakers around the perimeter with plasticine or non-hardening window putty (it resembles a bar of laundry soap and is cheap). Checking the sound. We're just fooling around. We push aside all sorts of “Pioner”, “Technics”, JAMO and ...

The third way. Super complex, time consuming and super efficient.

It’s a good idea to have the following instruments: an oscilloscope, an audio frequency generator, a digital multimeter, an LC meter. A person who doesn’t do repairs and assembly at home, of course, doesn’t have all this, but there is a way out - go to the workshop and ask to try on what you need, taking filters, heads, etc. with you. If they ask for payment for this, it will be purely symbolic. You can even order a filter. This, of course, will be more expensive. Let's begin. We take as a basis 35AC-212 with dimensions 710x360x285. It is desirable that the case be made of plywood, a woofer with a rubber surround, and a high-frequency speaker with a fiberglass dome. Let's sort everything out. We no longer need the midrange speaker. The housing needs to be increased to 100 liters for a woofer with a rubber surround. If the suspension is polyurethane foam, then up to 120 -130 liters. Our body is 70 liters.

There are two options:

Remove the front wall from the case, so that you can then use it for a matrix for the holes for the speakers in the newly manufactured case for 100 liters. The remains of the buildings make good boxes for potatoes and markoshka in the cellar.
You can try to build up the old body.

In the first case, you need to focus on the dimensions - 1100x360x350 and production in a furniture workshop according to your drawings, with abuse and quibbles about quality. We will consider the second way. So, you can try to get by with a little blood. We make it ourselves, or we order two boxes with tightly fitting walls and lids made of double 10-layer plywood with external dimensions - 380x360x285. We cut out identical holes approximately 270x210 in the bottom of the column and in the lid of the box. We cover the inside of the box with felt. After assembly it will be impossible to do this. We drill holes in the lid of the box and in the bottom of the column through which we fasten them together with bolts. The bolt heads should sink into the countersunk area. Add a little bit of shot - 10 kilograms of shot won't hurt, throw a gauze bag with cotton wool on top. We pre-fill the joint with epoxy with a normal content of hardener. We cover the joint with felt. The rest of the body movements are the same as in paths 1 and 2. Let’s take the mid-frequency head 30 GDS-1. You just need to check them - there are a lot of defects. Purely mechanical properties. Next. We measure f resonance of all speakers. You can use a felt-tip pen to sign directly on the magnets so as not to get confused and try everything on again.

It would be good if the resonance frequency of paired speakers did not differ greatly. If the speaker makes extraneous sounds at any of the audio frequencies, then it must either be cleaned or replaced if cleaning did not achieve normal operation. We calculate and make filters for our case. The fewer inductances, the better. We continue to work with the body. Remove excess resin at the joint. Let's polish it. We make two wooden boxes for filters. We will mount them on the back wall from the outside. We solder the wires from the amplifier directly to the filters. And we will drag the wires to the speakers through the fastenings of the speaker connectors. All wires are branded audiophile ones. Choose your own price category. There’s just no point in taking very expensive ones. It is better to convert the bass reflex to a frequency of 31.5 - 40 Hz. If the dome of the high-frequency head is made of lavsan, then, after removing the crosspiece, you need to coat the suspension and the outer third of the dome with perchlorovinyl. We cover the entire body with self-adhesive film. For the rest, see path 1 and path 2. With mandatory step-by-step verification - better - worse. The best method, if there is no obvious result, is blind listening.

Literature

Zhagirnovsky M., Shorov 8. Improving the sound of 35AC-1 and its modifications. - Radio, 1987, No. 8, p. 29, 30.
Shorov V. Improvement of loudspeaker heads. - Radio. 1986, no. 4, p. 39-41.
Aldoshina I., Voishvillo A. High-quality acoustic systems and emitters. - M.; Radio and communications. 1985.
Zhbanov V. Mechanical damping of diffusers. - Radio, 1988, No. 5, p. 41-43.
Maslov A. Once again about the modification of the loudspeaker 35AC-212 (S-90). - Radio, 1985. No. 1, P. 59.
Zhbanov V. About damping of dynamic heads. - Radio, 1987, No. 8, p. 31-34.
Gennady and Karen Arzumanov. On the issue of modernizing acoustic systems. Bulletin of A.R.F. No. 6" 2000

Reworking the S-90 filter

Having been an opponent of audiophilia as a simplification, after experiments I changed my point of view and now I’m even ready to sacrifice something for the sake of a small number of obstacles in the path of sound :). This is actually very important, even on the speakers discussed below. But this also forces you to sacrifice some things: high power and congestion of frequency bands.

I used the crossover below, broken down into pieces, for my s-90de with speakers: 30GD-2, 6GDSH-5-5, 3GD-2, where it plays simply wonderful with any genre of music. 3GD-2 (its worse analogue 6GDV-1-16) is a very old high-frequency speaker (my copy is from 1977) with a resonance frequency of as much as 4500 Hz (but there is an opinion that in this place it is quite calm), therefore the high frequency of the midrange section is HF is due precisely to this fact. However, most domestic tweeters have not gone far, so I consider this cut to be very good for them.

This filter will work great on good foreign mid-high-frequency speakers, which I tried myself :). But, of course, it needs to be changed taking into account everything new (including the frequency of the section) - taking the principle itself as a basis.

p.s. Still, we should not forget that everything in the world is not only relative, but also subjective :). In addition, at the moment I have absolutely no means of measuring the frequency response of my system - everything is adjusted by ear in the same room...

speakers

NC: Let's look at the generally good bass driver used in the s-90. 30GD-2 (75GDN-1-4) with a nominal resistance Z=4Ohm, sensitivity S=86dB (or dB/W*m) and frequencies F=30-1000Hz does not provide the best IFC (impedance-frequency characteristic:)) in the compartment with poor sound at frequencies above 500Hz.

Our cutoff will be at 500Hz. Ideally, to make this speaker work really well, you would cut off everything above 200Hz. After all, the main drawback of the 30GD-2 is that at these frequencies it mumbles (“sound from under the diffuser hood”) and plays very poorly. But to make such a low crossover frequency you need an excellent midrange speaker with a resonance frequency of no more than 70Hz.

MF: The standard mid-range driver 15GD-11 (20GDS-4-8), with parameters Z=8Ohm, S=89dB, F=200-5000Hz, does not stand up to any criticism either in terms of sound or the characteristics we need. Therefore, it needs to be replaced with the nice baby 6GDSh-5-4 (Z=4Ohm, S=92dB, F=150-12000Hz) which looks completely frivolous, but in fact turns out to be very good. In addition, it has the sizes we need, price (no more than $4!) and availability in Russia.
It should be noted the low power of the 6GDSH-5 (as a result, the inability to work at discos/parties) and bursts in some parts of the frequency range (“loudness”).

There were opinions that the 6GDSH-5 has poor directivity at high frequencies, which is why the stereo panorama is “unstable” at a relatively high section. It seemed to me that this was not so, so if there are problems, act according to the circumstances :).

HF: Any tweeter with parameters S=89-92dB and Z=16Ohm will do. It is important to note F (actually, the minimum operating frequency of the speaker) - it should not be more than 4500Hz, and the lower the better.
Structural dimensions and fastenings are selected on site using available means.

sensitivity

MF: To cut off the extra 7 dB (92-85 = 6), I suggest using the option of one resistor, which will avoid unnecessary elements in the circuit and at the same time reduce the ratings of the filter elements due to an increase in the speaker resistance. Resistor R2=4.3Ohm will give us a reduction of 6dB. The sensitivity is reduced by a resistor in the approximate ratio of 1 dB/0.7 Ohm. Coil L1 has its own resistance of 0.75 Ohm and will help us remove another 1 dB. Voila! :)

However, the disadvantage here is that there are no exact formulas and dependencies, and the values I gave appeared as a result of my personal feelings.

HF: We use the same method, selecting the desired resistor until the desired result is achieved. However, in this circuit there are no filter elements with a high intrinsic resistance, so resistor R1 must be taken with a margin of 1 dB. We also note that the volume of the high-frequency speakers relative to others in the system strongly characterizes its “inclinations” - for example, most listeners like a slightly muffled high-frequency sound (by about 1-2 dB), the system seems to be “softer”. What is important for domestic high-frequency speakers is not of the best quality :)). For heavier music, emphasizing the high frequencies may be more important.

It's nice to know that changing the sensitivity resistors within one unit (1 Ohm) has virtually no effect on the filter itself and the cutoff frequencies, which makes it possible to experiment.

But you shouldn't cross the 0.7 Ohm difference when experimenting with R2 - the L1 coil is much more sensitive to this change.

inductors

The most difficult thing. We urgently need to find ways to measure inductance, otherwise precise tuning will not work.

In the absence of a way to measure, I suggest the following: compare the coils by their own resistance, taking into account all design parameters. Theoretically, if all the factors influencing the inductance rating coincide (there are some very interesting ones - the density of turns, the content of iron impurities in the frame :)), then you can obtain the necessary inductance, as if “following a model”.

Despite everything, this method, it must be said, is very inaccurate. There is no difference between the inductance L2, for example, 1.5 mH and 1.27 mH in terms of resistance.

LF: I’ll give my parameters for a large coil (it also has “ears” on the sides): inner diameter of the ring: 35mm, outer: 70mm, coil height: 37mm, width of the winding area (height without sides): 30mm, wire thickness (copper, enameled ): 1mm. With these parameters, the coil's DC resistance (measured with a digital tester): 0.8 Ohm.
If these parameters are observed, you should get an inductance in the region of 1.0-1.6 mH, congratulations :).

You can wind the coil the “old fashioned” way, knowing how many turns you need to make. This has recently become known: for 1.27 mH, 210 turns of “manual” (not very neat) winding are required. In this case, for every 0.05 mH there are approximately 5 turns.

SC: The small coils should all be the same in frame; I took the one with the smallest inductance. Inner ring diameter: 12mm, outer: 32mm, coil height: 23mm, winding area width (height without edges): 18mm, wire thickness (copper, enameled): 0.5mm. Resistance: 0.7 Ohm, inductance 0.18-0.21 mH.

At 0.18 mH the number of turns is 127 pieces. At 0.21 mH - 136.

By the way, do not repeat the mistakes of the USSR assemblers, do not fasten small coils with screws inside - the inductance will change and nonlinearity will be added; attach with glue.

For those who measure themselves: it is useless to try to rewind a small coil with a thick wire from a large one, and you probably want to do this :). Even having completely wound the entire frame, I did not get an inductance of more than 0.1 mH.

At the same time, if you build a new optimal frame (see links, “Cec”), which is not as simple as it seems, then the coil’s own resistance will allow you to gain 1 dB to the speaker sensitivity - you will need to slightly calibrate the sensitivity resistors in front of the speakers.

If you try to find the same large frames somewhere else and wind the L1 coils with thick wire, then their resistance will be approximately 0.4 Ohm - also better.

p.s. I kindly ask you not to write me letters asking for help in calculating inductance on other frames and other values using this method. Assemble the “box” (see links), it is very easy and will solve all your problems with precise winding of coils.

capacitors

Everything is extremely simple. You need to find the same values for decent quality capacitors, you can read about the types here, and about resistors there, by the way. Capacitors can be combined (summed) in parallel (as well as reduced according to the resistance rule by connecting in series). If you have disassembled the s-90 filters, then you should already have a good set of necessary containers :).

Among the domestic ones, instead of the film K73-xx that you probably came across, I recommend trying the metal-paper MBxx - a “softer” sound. If funds are available and accessible, foreign MKPs are preferable (1uF ~ $1.1, domestic equivalent - k78).

The capacitors, of course, are non-polar and for a voltage of at least 40V. The quality of the elements in Zobel circuits is just as important.

Here you can experiment with changing the “color” of the system that the capacitors give. I recommend trying to bypass all capacitors (except those in the Zobel circuit) with small (around 0.1 µF) capacitors of other, usually higher quality, types. For example, polystyrene (k71-7) or mica (SGM) - the result is more detailed sound at mid-high frequencies and increases the transparency of the system. In addition, metal-paper (MBxx) capacitors give a slightly “muddy” sound. To bypass means to combine together in parallel :).

resistors

With a power of at least 2W, with less, overheating and a change in rating are possible. Among the domestic ones, MLT-2 can be used. PEV-10 from the s-90 kit are not the best, but they will reluctantly go... I recommend Chinese ceramics - they look like white teeth, they are large, they are inexpensively sold everywhere in radio stores (power up to 15 W), but the range of ratings is fully present.

In other matters, low-power MLT resistors also work well at non-disco power levels, at least in place of R1.

Please note that the value written on the resistor is not necessarily the same as what it actually is. I strongly recommend selecting resistors by measuring them with an ohmmeter/tester. The diagram shows clearly measured resistors.

When finalizing the speakers, it is highly recommended to place resistors R1 and R2 as close to the speakers as possible - directly on the terminals. This will greatly reduce the influence of the cable (which is after these resistors, but not before them) on the sound.
Zobel chains

The reason is that the impedance of the speaker is not constant and increases as the frequency response decreases. This effect occurs in all dynamic type heads without exception, regardless of the country and year of production. More precisely, the Zobel circuit (in my filter only a simplified version of it is used; full ones allow you to adjust the impedance at low frequencies, which is not always necessary) is necessary for the normal operation of the filter inductors, with a sufficiently large self-inductance of the speaker coil. Without a Zobel circuit, the operation of the inductor as a low-pass filter is grossly disrupted and filtering is practically not carried out at all (!).

LF: Elements R4 and C4. It is advisable to set C3 to more than 60 µF, but even this is sufficient for a crossover frequency of 500 Hz. R4 is equal to 4.3 Ohm.

Compare the ICHH of 30GD-2 without and with Zobel. The graphs are approximate, but there you can see the tuning frequency of the s-90 bass reflex - the second huge rock on the left, before 100Hz :).

SC: ICHH 6gdsh-5. You can try smoothing above 3 kHz with Zobel R3, C3. For this, 10-20 µF and an 8.0 Ohm resistor are enough.

Important: a Zobel circuit on the midrange is required for the normal operation of this crossover. Without it, the “new lightweight filter” showed its complete inconsistency in the midrange and high frequencies.

HF: Due to the low inductance of the speaker's own coil and the cutoff at low frequencies, the circuit is irrelevant.

filter

In all frequency sections, a passive all-pass filter of the first order is used with an attenuation of 6 dB per octave (frequency change by a factor of two), Butterworth approximation. Actually, the filter itself was calculated by the JBL Speaker Shop program and slightly adjusted manually :)).

LF: Low pass filter. As you can already understand, the cutoff frequency is 500 Hz (for 30GD-2/75GDN-1-4, lower is desirable, but was chosen as a compromise to 6GDSH-5). Provided by element L2, speaker load, coupled with a simplified Zobel correction circuit.

Midrange: Bandpass filter. The lower part (C2) is matched with the low-pass filter and is tuned to a cutoff frequency of 500 Hz based on considerations of the resonant frequency of the 6GDSh-5. The upper part (L1) is matched with the high-pass filter and is tuned to 7500Hz, which allows for a broadband speaker structure, coupled with Zobel.
Both parts are loaded at 8 ohms (4 ohms from 6GDSH-5-4 + 4 ohms from R2).

HF: High pass filter. The frequency is matched to the upper part of the midrange filter and operates at 7500Hz, which avoids problems associated with the high frequency of the main resonance of domestic high-frequency speakers. Load 21 Ohm (16 Ohm speaker + 5 Ohm from R1).

All speakers are switched on in phase, which has a lesser effect on the phase characteristics of the system.

scheme

Electrical circuit diagram. Click to enlarge :).

The arrow on the right shows the “sound input” from the amplifier. The dotted lines are bi-wiring (the low-pass and mid-high-frequency sections of the filter are connected to each other in parallel at the amplifier - plus the low-pass with the plus of the mid-range and high-frequency to the plus of the amplifier, the minuses are the same).

The gray numbers in brackets above the filter elements indicate their load. The gray numbers with an "r" in front of them are the element's own resistance. Gray marks -1dB - loss of speaker sensitivity on the elements.

Next to the speakers, their important characteristics are briefly written out; below are the frequencies at which the bands/links intersect.

Inductance in mH, capacitance in µF, resistance in Ohm. After assembling the filter, the nominal speaker impedance for the amplifier remains 4 ohms.

A version of the “new lightweight” filter for s-90 clones, more precisely for Orbit 35AC-016. Speakers: 10gdv-2-16, 6gdsh-5-4, 75gdn-1-4 - a fairly common set.

27120

Modernization of S-90 speakers by replacing standard cabinets with labyrinthine design of bass speakers

Upgrade of the S-90 labyrinth design by stuffing the corners with cotton wool and sticking them on the inner surface of the wool blanket
At first, only the frontal knees of the labyrinth were covered with wool, then the side surfaces too
Ready labyrinth S-90 with inner surfaces covered with wool

Remaking the most famous speakers of the USSR Radiotekhnika S-90

Alexander Rogozhin came up with the know-how of how to convert the Radiotekhnika S-90 speakers, most well known to most Russian-speaking people, into labyrinthine housings. The article is devoted to the most widespread and for more than 20 years considered the standard acoustics of the Soviet period, which in its first generation was called 35AS-1. And Rogozhin proposes to make speakers from 35AC-1 (Radio Engineering S-90) with the name “Cheap, loud and super-bass”!

Ode to speakers Radiotekhnika S-90 (35AC-1)

There is no person who speaks Russian, Ukrainian, Belarusian, who at least once in his life has not heard the famous Soviet Radiotekhnika S-90 speakers, or has not had one of their modifications produced in the mezzanine, in the closet, at home or on the hacienda more than 30 years. You can think whatever you want about their sound, appearance, rubber speakers, but in fact these are the MOST common “People’s” speakers in the vast expanses of the former USSR. Even now, tens of thousands of them work in the systems of music lovers, who feel sorry to throw them away because Compared to the branded “remake” they play very, very well.

If a person is faced with a choice on which speakers to listen to music on: with bass, loudly, and for ridiculous money, then despite all the disadvantages of the Radio Engineering S-90, they have practically no competitors, and even less so before. In the late USSR, in addition to S-90 speakers, of course, “clones” appeared, taken from the best foreign samples, for example, Electronics 100AC063 or 75AC-063. But they were very expensive and not widely used; they could not compete in popularity with the S-90 acoustics. It was basically impossible to get three full-fledged bands with the same power as the S-90, a 10-inch woofer and almost nothing from any other speakers. This is even more relevant now.

Tens of thousands of these speakers still work in the rooms of young and not so young people who do not have the opportunity to carry out complex projects on expensive imported dynamic heads. For obvious reasons, many of our compatriots are in no hurry to abandon the Radiotekhnika S-90 acoustics. They are not eager to run to the store and buy beautiful branded speakers, which for the most part differ from the S-90 only in appearance, which often cannot be said about their sound.

And yet, we all love listening to music; we all have a good mood when we want to turn it on “to the fullest.” Everyone loves high-quality bass, without which almost any music loses its foundation and most of its emotions. Many styles of music without bass are generally impossible to listen to, because... without it, the lion's share of important musical information is lost. The soul asks UUUH! And low frequencies are actually a very delicate thing; in order to sound adequately and make an impression, they require large speakers, cabinets and power. But even with all this (in large speakers like the S-90), the bass often turns out to be buzzy, drawn out and indistinct, and does not give us the “buzz” that it is supposed to give. We quickly get tired of such bass and start turning the tone control knobs or switching the equalizer modes on the receiver. And instead of getting pleasure, you get annoyed and think about the imperfections of this mortal world... Almost all music lovers and owners of these acoustics, in particular, have found themselves in this situation more than once.

Low Frequency Problems S-90

The reason that over the past 30 years, owners of the Radiotekhnika S-90 acoustics and its numerous modifications are not satisfied with its sound and are somehow trying to cope with this problem lies in several reasons. The main problem with the S-90 speakers, confirmed by repeated research by specialists, is an error made when designing the low-frequency design of the 30GD-2 speaker. Having entered the series, the error led to the fact that the potential for high-quality reproduction of low frequencies, originally inherent in the Radiotekhnika S-90 model and its modifications, is not realized even by 20-30% of the possible ones.

A huge number of S-90 owners, almost from the moment they appeared on sale in the 80s until today, have been trying to improve the low frequencies of these speakers by conjuring with filters, altering the bass reflex pipes, strengthening the original housings and filling them with anything.

Dear music lovers! I urge you to stop doing nonsense, because... this is absolutely useless... The S-90 speakers from the factory have a housing with a volume of only 45 liters - NOT corresponding to the optimal operating mode of the 30GD-2, 75GDN1-4 speaker installed in it. You can even trim it with the roots of rare species and cover it with porous rubber on all sides - it will still NOT work correctly.

That is, the question of radically improving the performance of these speakers at low frequencies, no matter how regrettable it may be, is that the question of replacing the housing arises in full force.

The task is somewhat complicated by the fact that over 30 years a huge number of modifications of the 35AC-1 speakers with 30GD2/75GDN1-4 (8) low-frequency speakers have been released, which have a wide range of parameters. In the new enclosures, this problem has been largely resolved and allows speakers from the earliest releases to the latest to feel correct. The setup of new enclosures is “stretched” and allows you NOT to specifically select low-frequency speakers.

Mid Frequency ProblemsS-90

Almost all owners of s-90 speakers note unpleasant overtones and greater unevenness of output at mid frequencies, which become especially noticeable at medium and high volumes. All grandiose projects to remake filters by installing expensive imported capacitors, replacing wires, resistors, etc. as well as options for gluing halves of a tennis ball onto the diffuser of mid-frequency heads, etc. fail.

The main reason for the unsatisfactory sound at mid frequencies is not the 15GD-11 speaker at all, but its acoustic design. This “glass” covering the midrange head from behind has a tiny volume and is the second mistake made by the engineers who designed the S-90 speakers. The “glass” of the mid-frequency head 15GD-11 (20GDS...) has everything wrong, from the volume and configuration to the internal design. When replacing the housing of the s90 speakers with the correct one from the point of view of the design of the woofer, the mid-frequency speaker should also be designed accordingly.

Of course, replacing the “minuscule” standard glass with an acoustic design that is optimal in volume and shape will not make the 15GD11 head a different speaker, but will give it the opportunity to do what it can do initially.

What you can get

As a result, the updated S-90 speakers will sound radically different not only at low, but also at medium frequencies. There are a large number of attempts on the Internet to remake S-90 speakers with the goal of “deceiving everyone” and turning them into studio monitors. Attempts concern everything except replacing the main “weak point” - the body, and most often turn out to be failures. While keeping the S-90 speaker cabinets unchanged, to radically change the sound, you need to change the speakers to modern ones or design three-way speakers from scratch, which most music lovers do not dare to do.

I suggest leaving the original set of S-90 speakers untouched. Their value lies in the minimum budget and, no matter how clever you look, their performance has been proven over decades of operation in the harshest conditions.

What these speakers have that can be fundamentally improved is to “get the most out of their speakers.” To do this, you need to make an acoustically correct housing for the original set of speakers and filters. As a result, you can reach a fundamentally new level of sound quality from these speakers without spoiling anything.

As a bonus, you don’t have to throw away the old cases and, if necessary, the “stock” S-90s can be put back together and sold to some lover of authentic speakers made in the USSR.

Problems with native boxesS-90

The wrong amount of low-frequency design does not provide the required level of pressure on the low frequencies;
Non-optimal bass reflex tuning frequency leads to uneven bass response and poor bass quality;
The type of low-frequency design “bass reflex” in combination with a “tight” speaker on a rubber surround leads to an extended and monotonous “hum” at low frequencies, instead of a clear impact bass;
Phase-inverted acoustic design leads to significant unevenness of sound pressure at low frequencies in the room, and places demands on obtaining high power from the amplifier;
The weak walls of the S-90 speaker boxes lead to a loss of efficiency at low frequencies and produce noticeable overtones when operating at high volumes;
Poor sealing of the boxes prevents even the low-frequency design that the S-90 speakers have in the stock version from working;
The extremely small volume of the cap of the mid-frequency head 15GD11 (20GDS-) leads to “squeezing” of the mid-frequency dynamics;
Non-optimal damping of a small-volume midrange box leads to noticeable overtones and “nasality” in the midrange;
The shape and dimensions of the S-90 speaker cabinets in the stock version require their installation on furniture, which leads to a “wobbly position” of the speakers, resonance of the furniture at high volumes and, ultimately, to deterioration in the sound of low frequencies;
The “low-profile” shape of the speaker housing requires installation on specialized stands for acoustics, which ultimately increases the cost of the system. Installing the 35AC-1 speakers on the floor leads to a lack of high frequencies and an incorrect scene.

Advantages of new buildings

The design of the low-frequency head is a quarter-wave labyrinth with its radical advantages at low frequencies over a bass reflex (detailed description here);
The optimally calculated frequency and quality factor of the quarter-wave resonator tuning provide a wide band and optimal level of low frequencies;
The highest rigidity of the box gives the highest possible efficiency, clean, elastic and biting sound at low frequencies;
The high-volume, hard-box midrange driver produces a lively, open midrange and clear vocals;
The placement of the midrange and high-frequency speakers on the front panel, maintaining the distances to the cabinet walls according to the “golden ratio” principle, reduces diffraction phenomena on vocals and high frequencies and makes the sound much more comfortable;
With the new enclosures, the acoustics transform into a classic floor-standing design with midrange and high-frequency speakers optimally positioned in height;
The speakers have narrower and taller front panels than standard S-90s and do not require any stands. The appearance of the speakers is improved many times over.

Manufacturer: Riga Radio Plant named after. A. S. Popova.

Purpose: speaker systems are designed for high-quality sound reproduction as part of household electronic equipment.

Specifications:

3-way floorstanding speaker with bass reflex

Frequency range: 25 – 25000 Hz

Frequency response unevenness in the range 100-8000 Hz: ±4 dB

Sensitivity in the range 100-8000 Hz: 89 dB

Resistance: 8 ohms

Minimum impedance value: 7.6 ohms

Rated power: 35W

Maximum (nameplate) power: 90 W

Short-term power: 600 W

Installed speakers:

Dimensions (HxWxD): 710x360x285 mm

Description:

The acoustic system is similar except for the midrange speaker; the S-100F is installed with MAXID magnetic fluid. The speakers have two smooth playback level controls for midrange and treble. Adjustment limits are from 0 to -6 dB in the ranges of 500-5000 Hz and 5000-20000 Hz. In the “-6 dB” position the signal is weakened by 2 times. The speakers have LED indication of speaker overloads.

The body is made in the form of a rectangular non-separable box made of chipboard, veneered with valuable wood veneer. The wall thickness is 16 mm, the front panel is plywood 22 mm thick. At the joints of the housing walls, elements are installed on the inside that increase the strength and rigidity of the housing.

The heads are each framed with decorative black plates with four mounting holes. The midrange head is isolated on the inside from the total volume of the housing by a special plastic casing in the shape of a truncated cone. The LF head is located on the front panel along a vertical axis, and the MF and HF heads are shifted relative to this axis to the left. In the upper corner of the front panel there are overload indicators, and in the lower part there is a rectangular bass reflex hole, measuring 108x35 mm and tuning frequency 25 Hz. The nameplate on the midrange and treble regulators shows the frequency response curve and the manufacturer's logo. In addition, the front panel has bushings for attaching a decorative frame with fabric. On the rear wall, in the lower part, a block with terminals and a nameplate are attached. The set includes grills with acoustically transparent fabric.

The internal volume of the speaker is 45 liters. To reduce the impact on the frequency response of sound pressure and the sound quality of the speaker resonances of the internal volume of the housing, it is filled with a sound absorber, which is mats of technical wool, covered with gauze.

Inside the case, on one board, there are electrical filters that ensure separation of the speaker bands. The frequency section between LF/MF is 750±50 Hz, between MF/HF - 5000±500 Hz. The design of the filters and the overload indication unit uses resistors such as BC, MLT, SP3-38B, S5-35I, PPB, capacitors such as MBGO-2, K50-12, K75-11 and inductors on plastic cast frames.