S90 high and low pass filter circuits. Speakers S90 diagram, description. What you can get

Rated power... 35 W

Nominal electrical resistance... 4 Ohm

Frequency range... 31.5-20000 Hz

Nominal sound pressure... 1.2 Pa

Overall dimensions of the speaker... 360x710x285 mm

Speaker weight no more than... 30 kg

S-90 is a classic of Soviet column construction. According to the manual, the S-90 speaker system is designed for high-quality reproduction of sound programs in combination with various types of household radio equipment.

Well, for the early 80s these were truly outstanding speakers with high sound quality. However, foreign speaker construction is developing, and already at the beginning of the new century, the sound of the S-90 is perceived differently.

High frequencies sound disgusting, there is simply NO mids! And if we talk about bass, then a similar effect will be when placing a healthy bass player in a large kick drum... The lows drone on in black. It is impossible to listen to D&B style music; IDM also hits the ears. What can we say about classics and calm music. After an hour or two of listening, my ears begin to hurt (however, my head and stomach hurt no less). Despite these shortcomings, many people buy these speakers.

All of the following applies to Radiotechnika S-90a (AC35-212) speakers. This is one of the very first releases (and one of the best), the characteristic features are 2 controls on the front panel, the tweeters and midrange are shifted from the center, the speakers are paired, the resistance is 4 Ohms. However, the meaning of the modification and the modification itself can easily be applied to other S-90 (S-90b, S-90F, etc.), their analogues (Orbit, Amphiton, etc.), as well as to homemade speakers . The main criterion is the presence of 3 bands (speakers) and a bass reflex. The modification of speakers with a closed cabinet (i.e. without a bass reflex) is somewhat different, I will write about this later. And one more thing - there are many options for improvement, so in some places I will describe 2 methods. You will choose the most suitable one yourself..
I will not write a list of necessary materials - in most cases, everyone uses what is most available at the moment.

1) Disassembly

We take one speaker and place it on the floor with its back wall (this is the most convenient way to remove the speakers). Using a figured screwdriver, unscrew the 6 bolts securing the decorative plastic trim from the bottom of the column. Using a flat-head screwdriver, unscrew 4 bolts and remove the decorative nameplates from the speakers and the protective grilles.

Next, you will need a heated soldering iron! Then we unscrew the 4 bolts securing the woofer and carefully lift one side of it and remove it from the housing. We unsolder the wires (you can, of course, mark which one was soldered where - but it’s better to then check the diagram and solder it 100% correctly) and put it aside. We take out the midrange speaker from the housing (it was secured with a nameplate) along with the glass in which it stands. Unsolder it and put it to the woofer. We take out the HF (tweeter) - it was also attached with a nameplate and unsolder it. If there is no mark on it at one of the terminals (+), we mark which wire was soldered where, then we look where it goes according to the diagram and find “+”. We put it with the other speakers.

Be careful with diffusers! The speakers can only be grasped by the magnet or diffuser holder supports!!!
Unscrew the 4 screws on the bass reflex and carefully remove it from the housing. It is held on by sealant, the main thing here is not to use excessive force - it may break! We take out 2 “sausages” of cotton wool from the body (if it is there). We unscrew and remove the filter from the housing (it can be either on an iron chassis or on a wooden plank). The wires going to it can be cut off with wire cutters (they still need to be replaced early). That's all with disassembly! Now we need to finalize and assemble.

2) Modification of the case - it is advisable to strengthen the back side of the case with wooden slats (attached with screws and epoxy). It is also necessary to place a wooden spacer in the center of the speaker (between the rear wall and the front) at the level of the midrange glass. (the main thing is to pay attention to the possibility of then installing a bass reflex!!!) This is necessary to reduce vibrations of the body - turn it up loud and put your hand on it - the body shakes! You also need to check the tightness of the housing at the joints and, if necessary, coat the joints with epoxy glue or sealant.

3) Refinement of the filter: You will need a diagram.

The point is to remove switches from the circuit, replace the wires with audio made of oxygen-free copper, solder the speakers directly to the filter, solder the lead wire directly to the filter and shorten the signal path

In the absence of finances, you can also supply suitable copper ones from the Soviet Union. The point of selecting wires is to have a multi-core wire for the woofer, the larger the better (but not less than 2.5 mm2, and it’s bad to solder more than 4 mm2), for the midrange you can have a multi-core of at least 1.5 mm2, and for the high frequency - a single-core of at least 1 mm2 (I recommend using a core from a twisted pair cable of the fifth category for + and -). It should be said that the selection of wires is a delicate matter. There are still fierce discussions about the choice of wire for speakers. I express my personal opinion. I advise you not to skimp and buy at least the cheapest audio cable! The sound quality greatly depends on it! Take my word for it.

I also highly recommend remounting all the filter parts on a small piece of plywood/wood, so that you can place the filter on the bottom of the speaker, next to the bass reflex. This is important (especially if the filter is mounted on an iron plate). The inductors should be attached to the new board not with iron screws, but with something plastic or mounted on epoxy. So, we replace all the wires on the filter board - we install it directly to the outputs of the capacitors, removing the contact plates from them.

I will not give the sequence for replacing the wires. As well as tips on where to solder the wires from the bass, midrange and treble. I hope you figure it out :). If you can’t cope, invite a knowledgeable person (one who can distinguish a capacitor from a resistor will do). As a last resort, write to me by e-mail [email protected]. We're done with the filter - put it aside.

4) Hull damping:

The point is to, if possible, absorb and dissipate all standing waves inside the housing. The criterion for choosing a material is that the denser and thicker it is (felt), the better it absorbs; the thinner and lighter it is (sintepon), the worse it is. The best way to make a pancake is to coat the body with sound-absorbing mastic (automotive mastic will do), then glue a layer of felt under 1 cm + the low-frequency part with another such layer and stick chaotically pieces of felt on top. They also recommend covering it with a layer of material for kitchen hoods - I don’t know, I haven’t seen it. I did this myself - everything is upholstered with 1.5 cm felt + the bottom part is another 1.5 cm + pieces. The sound absorber must be glued throughout the entire inside of the housing. After installing the first layer of felt, I recommend placing a filter board (with wires soldered to it) and a bass reflex port on the bottom of the speaker (otherwise you won’t be able to put it in later!), placing the remaining layers of sound absorber while closing the filter. and also wrap the bass reflex with a sound absorber (the main thing is not to cover the internal section of the pipe and maintain direct access from the bass diffuser to the bass reflex). It is necessary to look at the internal volume of the case - you cannot reduce it excessively - it will affect the depth of the bass! The body is finished.

By the way, I advise those who want to find household felt, about 1.5 cm thick.

5) Midrange speaker and its glass.

I highly recommend replacing the standard 15GD-11A (or its clone) with a broadband 6-GDSH-5-4 or 6-GDSH-5-8. The difference between them is that the first has a resistance of 4 ohms, and the second has 8 ohms. Accordingly, when installing 6-GDSH-5-8, the filter does not need to be changed, and when installing 6-GDSH-5-4, put a 4 Ohm large resistor (6-10 W) power. Resistor R3 (4.3 Ohm) from the midrange divider (columns 35AC212) is just suitable for this. Don't worry about losing power with this swap! You will only benefit in sound quality. The method has already been tested on many S-90s, there are no negative reviews, the power has not decreased. Moreover, competitors for the 6-GDSh-5 still need to be looked for (even among foreign analogues). And this is when the cost of a pair of these broadband speakers (new!) is $4-6. They have only one minus - appearance. Although I like it :).

For the midrange you need to make a PAS. This means covering the windows of the diffuser holder on the back of the speaker with a layer of foam rubber 0.5-0.8 cm thick. Quilted batting will also work. It is convenient to cut a strip of foam rubber 4-5 cm wide and a length equal to slightly less than the perimeter of the speaker, sew it and stretch it over the windows (for 15GD-11A). Then sew with threads to the supports. We made a PAS (be sure to do it - it degrades the quality factor, which is vital for almost all Soviet midranges used in the S-90 15GD11, and even more so!) - you can install the glass and speaker in place. Insert the glass into the body and wrap the outside in 2-3 layers of a good, dense sound absorber. It is convenient to cut off a boot boot that is suitable in height and width from a felt boot, place it in the body, and then place a glass of midrange in it. The inside of the glass also needs to be covered with a layer of sound absorber (felt is just right). The purpose of such damping is to eliminate the influence of the low-frequency head on the midrange. Then you need to put fluffy cotton wool in the glass and you can put the midrange speaker in place. First check that its phasing is correct.

When you connect a 1.5V AA battery + to + the speaker, a - to - , the diffuser moves forward. Checking phasing is important! We solder the wires to it (+ according to the diagram to + on the speaker) and place them in the housing through the rubber gasket, between the midrange and the glass. Rubber 2-3mm thick. It is convenient to use window rubber insulation made in the form of hollow tubes and with a self-adhesive side.

We install the speaker, seal it with plasticine and screw it on top with a nameplate, placing rubber gaskets on the screws between it and the speaker. It is better not to install a protective grille - it spoils the sound. Have you seen good imported speakers with grilles on the speakers? When installing 6-GDSH-5 under the nameplate, you will need to put rubber gaskets about 1 cm thick on the screws.

More about the midrange speaker. If you don’t want to install another midrange driver, you can modify the old one, for example like this. Although if you have a speaker with a rubber, rather than fabric, surround, it’s better to go for the 6GDSH!

6) Vata:

This sweet word is cotton wool... It greatly affects both the overall sound and the bass in particular! So one day I reduced its amount by half. The speakers began to emit not bass, but some kind of hum...

So, we sew a couple of gauze bags (35 cm by 35 cm) and fill them with cotton wool from the 2 sausages that were removed from the body, so that almost the entire sausage goes into the first bag, and less than half of the second into the second bag. Fluff the cotton wool. We place these bags in the upper part of the case under the slot for

HF and next to the midrange glass. We fluff the remaining half of the cotton sausage and simply throw it on the bottom of the column, on the filter wrapped in felt. In my opinion, this is the best placement of cotton wool in these columns.

7) HF head.

Solder according to the diagram. We put it into the body through a rubber gasket and screw it on top with a nameplate. We also don’t install a protective grille!
Uhh... A hell of a job has been done, but there is very little left! Let's continue.

8) woofer.

We solder it (it is advisable to check the phasing, as well as the midrange) and place it through a rubber gasket (required!), fasten it with bolts, again through rubber washers and seal it with plasticine sealant. We put a nameplate on top.

9)End of assembly.

We install the plastic front, tighten all the bolts and wipe the front panel.

Yes - a few little things (quite important!): run the wires to the HF and MF under a layer of sound absorber, and wrap them around the LF; carefully check the phasing, keep in mind that the bass and midrange in the S-90 are connected in antiphase; be sure to place the speakers on rubber pads; remove all parts from the plates of the disconnected HF and MF dividers, and cover them with a sound absorber; don't skimp on wires; remove the grilles; do not suffocate the volume; the bass reflex pipe must communicate freely with the surface of the speaker diffuser; gauze is clamped inside the bass reflex pipe - it is needed there; Place the speakers on spikes (for example like this); It is better to immediately solder the connecting cable to the filter; it is much cheaper than buying good connectors.

27122

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, or Belarusian, who has not heard the famous Soviet Radiotekhnika S-90 speakers at least once in his life, or who has not had one of their modifications produced in 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 vastness 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 the 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 widespread; 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 buzzing, 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 this 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 decorate it with the root 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 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.

One thing that can be fundamentally improved about these speakers 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 “bass reflex” type of low-frequency design in combination with a “tight” speaker on a rubber surround leads to an extended and monotonous “hum” at low frequencies, instead of a clear striking 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 turn 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.

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 hotcakes. 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. Listening to classics on these speakers may well please even audiophiles. 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). After so many years of use, the case 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?

Modification of 35AC-212 (S-90) with original speakers and switches.

According to the prospectus of the 90s, the Riga Radio Plant mass-produced two models of acoustic systems: 35AC-212 or “S-90” and 35AC-012 in the modifications “S-90B”, “S-90D”, “S-100B”. The time has come to modify the older model 35AC-212, as well as its predecessor 35AC-1, which have a similar set of speakers.
These models have switches for the level of attenuation of the energy supplied to the midrange and tweeters, allowing you to adjust them to the level of the woofer and adjust the system to specific listening conditions. All this is good, of course, but it “thumps and clicks” no matter how you turn the switches. I want it to be musical. Somehow I was talking about alternative thoughts about finalizing the S-90. These thoughts happily dissipated without being realized. They were replaced by others, more interesting ones. It seemed the most promising to use the “Nivaga 9” filter from the previous article and convert it to another set of speakers, and leave the midrange and high-frequency switches in their original factory form. The resulting filter diagram for the S-90 is shown in the figure. I propose to call it “Nivaga 10”.

A distinctive feature of the filter is the presence of resistors R1, R2, R3, R4, which provide direct potential contact of all speakers with the PA output and do not allow the phase response to deviate far from a linear frequency dependence. If you look closely at the diagram, you will notice that the resistance of these resistors is close to the active resistance of the corresponding speakers. Meticulous comrades can of course add the inductive equivalent of these speakers. I was lazy, because even in this form the sound quality completely satisfied me, but I didn’t have the opportunity to experiment in a sound chamber. Well, if you look even more closely at the circuit of the bandpass filter leading to the midrange speaker, you can see that it was created from a previously developed filter like “Nivaga 6 or 8” by replacing the speakers with equivalent resistors. Similarly in the lowpass and highpass filters resistors R1 and R3 are equivalent to the corresponding speakers. Therefore, this circuit with parallel connection of speakers is a logical development of the previous one with series connection of speakers, which means it retains all its advantages, which were described in earlier articles, and at the same time it creates new possibilities for movement. the cutoff frequency of all four filters included in the circuit independently of each other, controlling the peaks and dips in the frequency response of the speaker, which was not the case in the previous circuit. In the specific case of this circuit, I sought to expand the cutoff frequencies of the low and midrange speakers, as well as the cutoff frequencies of the midrange and high frequencies. speakers by half an octave. The results are brilliant. Elastic bass, stereo panorama, volume, clear mids - everything that a music lover's ear craves is present in the modified S-90 speakers.
The fear that the introduced resistors would heat up was not justified. Their power is theoretically based. In practice, it can be reduced by 2 - 3 times, but the resistors must be wirewound.
Practice shows that not everything that I like suits others. Well, the proposed scheme is open to reasonable modifications, and I am ready for serious discussions.
This treatise was compiled on February 20, 2012.

Manufacturer: PA "Radio Engineering", Riga.

Purpose and scope : for high-quality reproduction of music and speech programs in stationary living conditions. The S-90 acoustic system, developed in 1975, is the first domestic system that meets the requirements of international documents for Hi-Fi equipment. Later models of this speaker “S-90B” and “S-90D” are distinguished by an expanded range of reproduced frequencies. Introducing an indication of electrical overload of loudspeakers and a new appearance. The recommended power of a high-quality household amplifier is 20 - 90 W. 35 AS-212 “S-90” and 35 AS-012 “S-90”, similar to AS, the difference lies in GOST.

Characteristics

3-way floorstanding speaker with bass reflex

Frequency range: 25 (-15 dB) – 25000 Hz

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

Sensitivity: 85 dB (0.338 Pa/√W)

Directivity at angles of 25±5° in the horizontal plane and 7±2.5° in the vertical plane, from the frequency response measured along the acoustic axis of the speaker:

in the vertical plane: ±8°

horizontal: ±6°

Harmonic distortion of speakers at a sound pressure level of 90 dB at frequencies:

250 – 1000 Hz: 2%

1000 – 2000 Hz: 1.5%

2000 – 6300 Hz: 1%

Resistance: 4 ohms

Minimum impedance value: 3.2 ohms

Rated power: 35W

Maximum (nameplate) power: 90 W

Short-term power: 600 W

Weight: 23 kg

Dimensions (HxWxD): 710x360x285 mm

Installed speakers:

LF:

MF:

HF:

Design

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, made by stamping from aluminum sheet, 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 and right. On the front panel there are also knobs for adjusting the midrange and treble levels, and in the lower part there is a plastic overlay panel with a nameplate and a rectangular hole 100X80 mm, which is the bass reflex output. The nameplate shows frequency response curves corresponding to various positions of the level controls, as well as the name of the speaker and the manufacturer's logo. In addition, the front panel has bushings for attaching a decorative frame with fabric. On the back wall, in the lower part, a block with terminals is attached. Each head on the front panel side is protected by a blackened metal mesh.

The internal volume of the speaker is 45 liters. To reduce the influence 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 crossover frequencies between LF/MF are 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.

The package included: four plastic feet that can be attached to the base of the case; removable decorative frame, covered with knitted fabric with high acoustic transparency.