Description

Acoustic system Amfiton 50AC-022

Amfiton 50AC-022 - 3-way speaker system with a phase inverter.
Release at the Karpaty Production Association, Ivano-Frankivsk.

The speakers are designed for high-quality playback of music and speech programs in stationary domestic conditions. The recommended power of a high-quality household amplifier is 20 - 80 watts. The preferred installation option is outdoor.
The AC case is made in the form of a rectangular non-separable box made of chipboard, veneered with fine wood veneer. The thickness of the walls and the front panel of the case is 18 mm. The cabinet design includes elements that increase its rigidity and reduce the amplitude of wall vibrations, in particular, a wooden spacer is provided connecting the front panel and the rear wall and located between the low-frequency head and the phase inverter hole.

A set of heads manufactured by PO "Karpaty", Ivano-Frankivsk, similar to those used in acoustic system 35AC-012:

The heads differ only in that the baskets, made by precision casting from aluminum alloys, have an appropriate shape that allows them to be used as decorative parts. appearance AS. This made it possible to refuse the use of any additional decorative overlays in the speaker design. The MF and HF heads are mounted on the front panel asymmetrically with respect to the vertical axis of symmetry of the speakers. To prevent the influence on the characteristics of the midrange head of air fluctuations in the speaker case, which occur during the operation of the bass head, from the inside, the midrange head is isolated from the total volume by a special sealed plastic cap.
On the front panel of the speakers, in addition to the heads, there is a rectangular phase inverter hole with dimensions of 238x22 mm (depth 235 mm); decorative nameplate framing this hole and containing the name of the speaker and its main specifications. On the nameplate there is a head overload indicator LED.
On a small panel located above the treble head, there are two level controls for medium and high frequencies; sound pressure level control limits for medium frequencies up to -6 dB, high frequencies ± 3 dB. The geometric dimensions of the phase inverter ensure its tuning to a frequency of 30 Hz.
Internal volume of the EXPERT - 57 l. To reduce the effect on the frequency response of sound pressure and sound quality, speakers of resonances of the internal volume of the case, the latter is filled with a sound absorber, which is technical wool mats covered with gauze, evenly spaced and fixed on the inner walls of the case.
Inside the case on a single steel chassis are mounted electrical filters, providing electrical separation of the speaker bands into low-, medium- and high-frequency. Each of them is:
low-frequency head filter - first-order high-pass filter, provides a frequency response decay of 6 dB per octave;
mid-frequency head filter - a first-order band-pass filter, provides a frequency response decline in the direction of low and high frequencies of 6 dB per octave;
high frequency head filter - filter low frequencies the second order, provides a decline in the frequency response towards the middle frequencies of 12 dB per octave.
The crossover frequencies between LF and MF heads are 550 Hz, between MF and HF - 5000 Hz. In the design of the filters, resistors of the MLT-0.25, S5-35V, SP5-30 types, capacitors of the MBGO-2, K50-16 types, inductors on plastic frames with air cores are used.

On the rear wall of the speaker cabinet there are special clamps with spring-loaded contacts that allow you to connect the lead wires. The AC terminals indicate the polarity of the connection. Four plastic legs are installed on the base of the speakers.

Technical details:

- Frequency range - 25 (-15 dB) - 25000 Hz;
- Sensitivity - 86 dB (0.39 Pa /? W);
- Uneven frequency response in the frequency range 100 - 8000 Hz: ± 4 dB;
- Harmonic distortion at a sound pressure of 90 dB in the frequency range:
250 - 1000 Hz: 2%
1000 - 2000 Hz: 1.5%
2000 - 6300 Hz: 1.2%
- Resistance - 4 Ohm;
- Minimum impedance value -3.2 Ohm;
- Rated power - 80 W;

Size: 360x675x300 mm;
Weight: 24 kg.

Acoustic system "Amfiton 50AS-022"

Acoustic system "Amfiton 50AC-022/100AC-022" (1986)

Three-way speaker system Amphiton ""50AS-022"", she is Amfiton 100AS-022"", designed to play sound programs from high-quality household amplifying equipment.

The manufacturer of acoustic systems Amfiton "50AS-022" is the Carpathian Radio Plant (PO Karpaty), Ivano-Frankivsk (produced since 1986).

Acoustic systems Amfiton "50AC-022" and Amphiton "100AC-022" are completely identical and have the same power. Of the significant differences, only the different color of the woofer cones can be noted. For AS Amfiton "50AC-022" it has a white color, and for AS Amphiton "100AC-022" it is black.

Heads:

With the help of passive crossover filters, the entire frequency range of the Amfiton "50AC-022" speaker system is divided into 3 bands, each of which is reproduced by its own head.

Three heads are installed in the Amfiton "50AS-022" acoustic system:
- low-frequency type 30GD-11 (75GDN-3),
- medium frequency type 15GD-11 (20GDS-3),
- high-frequency type 6GDV-7.

Peculiarities:

A distinctive feature of this speaker is the use of a woofer with a cone in the "50AC-022" version white color, making it easy to recognize among models of similar acoustic systems. In addition, standard dynamic heads were manufactured by the Carpathian Radio Plant specifically for these acoustic systems. The difference between these heads and production models lies in the fact that their baskets are made by precision casting from aluminum alloys and have a special shape that allows them to be used as decorative details of the appearance of the speakers.

The case of the acoustic system Amfiton "50AC-022" (35AC-218) is made in the form of a phase inverter.

AS Amfiton "50AC-022" has two attenuators for changing the sound pressure level of medium and high frequencies. The controls are located on a small panel located above the treble head. The control limits are 6 dB for the mid-range and 3 dB for the high frequencies.

MAIN SPECIFICATIONS:
Rated power, W .............................................. ..... fifty*.
Maximum power, W .............................................. ... 80.
Reproducible frequency range, Hz .............................. 25...25000.
Rated sound pressure (100...4000 Hz), Pa............ 1.2.
Rated electrical resistance, Ohm .................. 4.
Dimensions, mm ............................................... ..........675x360x300.
Weight, kg ............................................... ................................... 24.

(*All official guides for this speaker indicate the value of the rated power equal to 50 watts. In fact, the rated power of this speaker is 25 watts.)

The uneven frequency response at the lower cutoff frequency of the reproducible frequency range relative to the average sound pressure level is -15 dB.

The level of characteristic sensitivity is not less than 86 dB.

The sound pressure unevenness in the frequency range 100..8000 Hz is ±4 dB.

Frame :

The body of AS Amfiton "50AS-022" is made in the form of a rectangular non-separable box made of chipboard, pasted over with veneer imitating wood. The thickness of the case walls is 18 mm, the front panel is also made of a plate with a thickness of only 18 mm. The internal volume of the case is 57 liters. To reduce the influence of resonances, the internal volume of the speaker cabinet is filled with a sound absorber. To increase the rigidity of the case design, a wooden spacer is provided connecting the front panel and the rear wall.

The phase inverter is set to a frequency of 30 Hz.

Dividing filter:

Crossover frequencies: between LF and MF heads - 550 Hz, between MF and HF heads - 5000 Hz. In the design of electric filters, resistors of the MLT-0.25, S5-35V, SP5-30 types were used, capacitors - MBGO-2, inductors - on plastic frames without cores.
- low-frequency head filter - first-order high-pass filter, provides a frequency response decay of 6 dB per octave;
- mid-frequency head filter - a first-order band-pass filter, provides a drop in frequency response towards low and high frequencies of 6 dB per octave;
- high-frequency head filter - second-order low-pass filter, provides a drop in frequency response towards mid frequencies of 12 dB per octave.

Speaker Comparison:

AS Amfiton "50AC-022" in comparison with the speakers "S-90" have more compact dimensions and slightly less weight, but a similar low-frequency head.
AS Amfiton "50AC-022" actually have a lower rated power and occupy a junior position in relation to the AS "S-90".

In a blind test, the sound of AS Amfiton "50AS-022" can be distinguished from the sound of the older model - AS Amfiton "35AC-018", as well as from the sound of AS "S-90". A direct comparison of the speakers Amfiton "50AC-022" and "35AC-018" will show a slightly different character of the sound of these speakers.

Subjectively, the sound of AS Amfiton "35AC-018" is more powerful and assertive. And at the same time, it is much more detailed in the midrange, in the field of the sound of guitars and vocals. For complex genres - rock, metal - they will be preferable.
For light instrumental genres, AC Amfiton "50AC-022" may be preferable. Its bass is softer, the mids have more mush, but they sound richer, the highs are a little more sonorous. Also AS Amfiton "50AC-022" do a good job with electronic music (not swotting, but music).
All of the above is completely subjective. The differences between the two ASs are minimal and in a blind test with a pause of 20-30 minutes it is almost impossible to identify them.

Although the AS Amfiton "50AC-022", according to the author, is inferior in sound to the AS "S-90", it undoubtedly has a more original appearance and significantly the best quality assemblies. In addition, the targeted production of heads specifically for AS Amfiton "50AC-022" led to the spread of the opinion that these heads have a higher quality and a smaller spread of characteristics compared to their large-scale versions.
Also, these speakers are the only serial Soviet speakers with white diffusers. They definitely deserve a place on a collector's shelf.

Currently, AS Amfiton "50AS-022" are sold at an inflated cost compared to similar models of speakers. This is in no way compensated by any advantages in their sound.

LF and MF heads of the "50AC-022" system, as well as similar heads in the AU Amfiton "35AC-018" were made using foam suspensions, the service life of which is 20 ± 5 years. With long-term direct sunlight on the suspensions, their service life is reduced to 7-10 years.

With a cost comparable to AS Amfiton "35AC-018" or higher and similar problems with the restoration of foam suspensions, the purchase of AS Amfiton "35AC-018" seems more preferable. Of course, only if the speaker is planned to be used for listening.

Recovery AS Amfiton "50AS-022"":

Currently, the purchase of suspensions is not difficult. Taking into account postage a set for two woofers and two midrange speakers will cost 1000-1500 rubles, including shipping costs. Repair is quite painstaking and requires utmost care and accuracy, which not everyone can do.

The method recommended for AS Amfiton "35AC-018" with the complete replacement of heads with similar heads with rubber suspensions (see the article about AS Amfiton "35AC-018" ") is not acceptable in this case, because the heads have different designs of baskets. In addition, non-serial heads are the main advantage of these speakers.

Therefore, if you want to use exactly AS Amfiton "50AC-022" the only option may be to buy AS Amfiton "50AC-022" with "killed" suspensions and their subsequent replacement. I repeat, the repair is quite painstaking and requires the utmost care and accuracy, which not everyone can do.

Manufacturer: Production Association "Karpaty", Ivano-Frankivsk.

Purpose and scope: for high-quality playback of music and speech programs in stationary living conditions (performance category UHL 4.2 according to GOST 15150-69). The recommended power of a high-quality household amplifier is 20...80 W. Preferred installation option - floor

Specifications: DMPZ.843.020 TU.

As follows from the measurement results, the deviation of the frequency response measured in the horizontal plane is almost the same when measured "to the right" and "to the left" of the axis in the frequency range up to 2 kHz (1 ... 2 dB) and differ to a greater extent (6.. .8 dB) in the frequency range of 2.5 ... 6.3 kHz, i.e. in the band of joint operation of midrange and high-frequency heads. Deviation of the frequency response measured at angles in vertical plane(“up”, “down”), up to 20 kHz does not exceed 2 ... 4 dB, with the exception of the frequency of 4 kHz, where it is (when measured down from the axis) 8 ... 10 dB, which indicates some asymmetry of the characteristic speaker directivity in the vertical plane in the band, the joint work of midrange-high-frequency heads.

Forms of frequency response of sound pressure:

1. measured along the acoustic axis;
2. second harmonic;
3. third harmonic.

It follows from the figure that the maximum value of the 2nd harmonic (about 1.5%) is in the range of 2...6.3 kHz; the maximum values ​​of the 3rd harmonic (about 1.2%) are in the frequency ranges below 50, 150...500 and 800...2000 Hz. In addition, there is a narrow harmonic distortion peak in the 4 kHz region (up to 3%).

Specifications:

Shapes of frequency response of sound pressure measured in the horizontal plane at angles of 25° to the right and left, in the vertical plane at angles of 7° up and down

Design features:

The AC case is made in the form of a rectangular non-separable box made of chipboard, veneered with fine wood veneer. The thickness of the walls and the front panel of the case is 18 mm. The design of the case includes elements that increase its rigidity and reduce the amplitude of wall vibrations, in particular, a wooden spacer is provided connecting the front panel to the rear wall and located between the low-frequency head and the phase inverter hole.

A set of heads was used, similar to that used in the acoustic system 35AC-012 (PO Radiotekhnika), manufactured by PA Karpaty, Ivano-Frankivsk. The heads differ only in that the cone holders, made by precision casting from aluminum alloys, have an appropriate shape that allows them to be used as decorative details of the speaker's appearance. This made it possible to refuse the use of any additional decorative overlays in the speaker design. The MF and HF heads are installed on the front panel asymmetrically with respect to the vertical axis of symmetry of the speaker. To prevent the influence of air fluctuations in the AU housing that occur during the operation of the LF head, the midrange head is isolated from the total volume by a special sealed plastic cap from the inside.

On the front panel of the speakers, in addition to the heads, there is a rectangular phase inverter hole with dimensions of 238x22 mm (depth 235 mm); a decorative label framing this hole and containing the name of the speaker and its main technical characteristics. On the nameplate there is a head overload indicator LED.

On a small panel located above the treble head, there are two mid and high frequency level controls; sound pressure level control limits for medium frequencies up to -6 dB, high frequencies ± 3 dB. The geometric dimensions of the phase inverter ensure its tuning to a frequency of 30 Hz.

principled circuit diagram

The internal volume of the AC is 57 dm3. To reduce the effect of sound pressure on the frequency response and the sound quality of the speaker resonances of the internal volume of the cabinet, the latter is filled with a sound absorber, which is technical wool mats covered with gauze, evenly spaced and fixed on the inner walls of the cabinet.

Inside the case, on a single steel chassis, electrical filters are mounted that provide electrical separation of the AC bands into low, medium and high frequencies. Each of them is:

• low-frequency head filter - first-order high-pass filter, provides a frequency response decay of 6 dB per octave;
• mid-frequency head filter - a first-order band-pass filter, provides a frequency response decline in the direction of low and high frequencies of 6 dB per octave;
• high-frequency head filter - a second-order low-pass filter, provides a drop in the frequency response towards the middle frequencies of 12 dB per octave.

The crossover frequencies between the low and medium frequency heads are 550 Hz, between the medium and high frequency heads - 5 kHz. In the design of the filters, resistors of the MLT-0.25, S5-35V, SP5-30 types, capacitors of the MB GO-2, K50-16 types, inductors on plastic frames with air cores are used.

On the rear wall of the speaker cabinet there are special clamps with spring-loaded contacts that allow you to connect the lead wires. The AC terminals indicate the polarity of the connection. Four plastic legs are installed on the base of the speakers.

I came across another version of the reincarnation of the well-known set of speakers called Amphiton 50AC-022. The situation is standard, crumbling foam suspensions on bass and midrange. We restore the bass, change the midrange to 30GDS, naturally with the filter recalculated. General photo for memory.

The photo of the midrange is closer, the cracks on the low frequencies were initially weakly manifested, but the sagging of the suspensions was critical (the coil was overwritten).

During the disassembly, one trouble was revealed. The midrange head looks like this.

Frankly, I thought that decorative overlays were screwed on top of the standard heads. Well, I'm not strong in imperial technology. Difficulties only fuel the imagination. A heavy instrument in hand and instead of one speaker we have two halves. First.

Second. It should be noted that the goal is not to restore authentic acoustics, but to obtain a product with decent parameters. Because kilohertz chants under the knife without pity.

The third step is milling the front panel for the new speaker and keeping the look of the acoustics as close as possible to the original.

When removing the woofers, such an o-ring was found. It should be noted that among developers, opinions are divided into two. One opinion is a good rubber ring for the speaker, and another is the maximum pressing of the speaker to the front panel without any seals. On the face, the second mounting option, adjusted for the cleanliness of the processing of the woofer basket.

New hangers in place.

Photo of the old filter.

We assembled the acoustics, measured the speakers, simulated the filter, built and tested a new one. Photo for memory.

The filter scheme will not be freely available. Final photo.

More details about the reasons for replacing 20GDS-3 with 30GDS are described. They are similar in many respects for the entire line of acoustics with a similar set of speakers. In order to find a worthy replacement for the resulting acoustics, it will be necessary to save up quite a tangible amount. Within reason, of course.

Design features

The AC case is made in the form of a rectangular non-separable box made of chipboard, veneered with fine wood veneer. The thickness of the walls and the front panel of the case is 18 mm. The cabinet design includes elements that increase its rigidity and reduce the amplitude of wall vibrations, in particular, a wooden spacer is provided connecting the front panel and the rear wall and located between the low-frequency head and the phase inverter hole.

A set of heads was used, similar to that used in the acoustic system 35AS-012 (PO Radiotekhnika) - 75GDN-3, 20GDS-3, 6GDV-7, manufactured by Karpaty, Ivano-Frankivsk. The heads differ only in that the baskets, made by precision casting from aluminum alloys, have an appropriate shape that allows them to be used as decorative details of the speaker's appearance. This made it possible to refuse the use of any additional decorative overlays in the speaker design. The MF and HF heads are mounted on the front panel asymmetrically with respect to the vertical axis of symmetry of the speakers. To prevent the influence on the characteristics of the midrange head of air fluctuations in the speaker case, which occur during the operation of the bass head, from the inside, the midrange head is isolated from the total volume by a special sealed plastic cap.

On the front panel of the speakers, in addition to the heads, there is a rectangular phase inverter hole with dimensions of 238x22 mm (depth 235 mm); a decorative label framing this hole and containing the name of the speaker and its main technical characteristics. On the nameplate there is a head overload indicator LED.

On a small panel located above the treble head, there are two mid and high frequency level controls; sound pressure level control limits for medium frequencies up to -6 dB, high frequencies ± 3 dB. The geometric dimensions of the phase inverter ensure its tuning to a frequency of 30 Hz.

Internal volume of the EXPERT - 57 l. To reduce the effect on the frequency response of sound pressure and sound quality, speakers of resonances of the internal volume of the case, the latter is filled with a sound absorber, which is technical wool mats covered with gauze, evenly spaced and fixed on the inner walls of the case.

Inside the case, on a single steel chassis, electrical filters are mounted that provide electrical separation of the AC bands into low, medium and high frequencies. Each of them is:
low-frequency head filter - first-order high-pass filter, provides a frequency response decay of 6 dB per octave;
mid-frequency head filter - a first-order band-pass filter, provides a frequency response decline in the direction of low and high frequencies of 6 dB per octave;
high-frequency head filter - a second-order low-pass filter, provides a drop in the frequency response towards the middle frequencies of 12 dB per octave.

The crossover frequencies between LF and MF heads are 550 Hz, between MF and HF - 5000 Hz. In the design of the filters, resistors of the MLT-0.25, S5-35V, SP5-30 types, capacitors of the MBGO-2, K50-16 types, inductors on plastic frames with air cores are used.

On the rear wall of the speaker cabinet there are special clamps with spring-loaded contacts that allow you to connect the lead wires. The AC terminals indicate the polarity of the connection. Four plastic legs are installed on the base of the speakers.