Tube DIY Asylum: TEFLON FT3 CAPACITOR AND OTHER RUSSIAN CAP by glc

i THINK THIS TRANSLATION PRODUCED TO ME BY A RUSSIAN EBAY SELLER IS VERY INTERESTING FOR THOSE USE RUSSIAN CAPACITORS.
I ASKED HIM INFOS ABOUT FT-3 TEFLON CAPS THAT I NEED USE IN MY EC8010-VT52 SET AMPLIFIER.
I HAVENT SOLVED MY PROBLEM OF FINDING THE FT3 CAPACITOR ORIENTATION (EXTERNAL AND INTERNAL FOIL CONNECTIONS) BUT I THINK THIS INFOS CAN BE OF HELP FOR YOU.
--------
You are bidding for four (4) items, very rare Russian NOS FT-3 0.47MF-200V 5% audio coupling capacitors(Фторопластовые фольговые). Inside the caps, fluorine film is used as insulator. These caps has no any analogue in USA or Europe. Highly recommended to use as coupling capacitor. These caps built to use in serious space and missile applications in Soviet Russian army. They have very little loss and distortion. Sound is amazing natural and with all fine transfer of microdynamics and nuances. Better than k40u-9 or k72p-6 types. Best coupling caps for serious tube hi-end applications. All new and tested. Happy biddings!

Estimation of effect of interstage (Coupling) capacitors on sounding of amplifiers

Now in the market of radioelements there are a lot of different types of capacitors, both domestic, and foreign, used as dividing capacitors in vacuum-tube amplifiers (1-3). With the purpose to define, what types of capacitors are preferable to use in amateur constructions, electrical measurings of performances of the capacitors were done, and here are judgments of their effect on sound, The greatest attention was given to domestic products because our industry prodused (sadly, in past...) competitive, and, frequently - unique -, products, second, domestic radioelements are easy of access to amateurs.But this article does not claim to be a survey of all available types of capacitors, the aim only is to help amateurs to gain good sound with application of this or that type. I recommend to familiarize also with article (3). I will not concern theoretical calculations, diagrams and other, for all this in detail see (1, 3).I shall view in detail only capacitance of capacitor Cx and energy loss of variable signal, showed in tangent of dielectric loss angle Dx. I shall note, that factor Dx depends on dielectric material, and in many respects - on structure of the capacitor and production technique. Parameters Cx and Dx depend both on frequency, and on amplitude of the signal applied to capacitor.) These parameters were measured by immittance measurer E7-14, which allow to measure at frequencies 100 Hz, 1 kHz and 10 kHz when variable signal is 2 V rms (for frequency 10 kHz measurings was done with signal 40 mV (4). Results of measurings are shown in Table

Judgments of effect of capacitors on sound were done in two stages.At first we used method of exclusion, when estimated capacitor Cx (fig), powered at the input of amplifier was by-passed by contacts of the relay.

After that the substitution method or paired comparison was used: In self-made push-pull amplifier EL34 capacitors were connected between driver and output cascade;
In 300V single-ended amplifier under pattern of H. Reichert - between three cascade.

The sketch is shown on fig., as calibration capacitor Cэт capacitors MIT Multi Cap RTX were used.Listening was made with equipment costing about 4000 USD as follows:Three of my friends, far from technical details, but liking and appreciating music (thanks for them for the time, they have spent!), separately wrote down the impressions from sounding, and at the moment of listening they did not know, whether is connected - 16 USD cost Multi Cap, or 3 ruble cost K78-2. I give the generalized result of this expertise in table.

Type of capacitor
Judgment of effect on sound
Possible application field

СГМ
As by-passer for separating capacitors it improves transmission of "air", can excessively underline high-frequency components.
RIAA equalizers By-passing of capacitors of other types

К-40у-9,

Audio Note
Beautiful soft musical sound, but general pattern can be veiled (not quite clear)
Separating capacitors

K77
Light restriction of the bass, slightly coloured Ã‚Ã— a gamut Light restriction of bass, slightly coloured high frequency diapason
К71-7, ПОВ - R1AA equalizers

K7I-4 - Separating, filters of acoustic systems

К75. К76
Colouring of sound, loss of microdynamics.
Power modules

К72п-6,

MultiCap
Neutral sound, fine transmission of microdynamics
Separating

By-passing of capacitors

ФТЗ
According to transmission of sound nuances and according to position of tools in space - THE BEST
Separating,

By-passing of capacitors

К77
Light simplification of sound pattern, flattening of sound roughness
By-passing of cathode resistors

Filters of acoustic systems

К7В.

W1MA МКР
Weak bass, loss of echoes of tools, simplification of sound pattern
By-passing of power modules

Solen
Loss of microdynamic of sound of tools
Power modules

Filters of acoustic systems

MultiCap

PPFX-S
Лучший среди иаполипропиленовых, но по передаче Â«воздухаÂ» уступает RTX
Separating

By-passing of capacitors

What can we say for results of measurings and listening? I think, the most of interest as separating capacitors are paper â€“oil - foil and fluoroplastic capacitors (FT-3), which are not worse than theirs outstanding analogs.It is remarkable, that for capacitors K40u-9 and ФT3 the tangent of loss angle is reduced with reducing of signal level and reaches Dx=0,0005 for ФT3, that, apparently, affects sound favorably. Capacitors MIT Multi Cap have justified popularity, as for product of French firm Solen I do not advise to use it in weak signal curcuits whereas their application in high-current curcuits - in separation filters of acoustic systems and in power modules gives fine effects. Polycarbone capacitors K77 are worthy also, thay combine big capacity and small sizes, like with polystyrene K71.Combined K75 and lacquer-film K76, despite of trend to decrease Dx when diminution of amplitude of signal, they are better to be used in power modules, as they are developed for this purpose.At the end of table. are given results of measuring of electrolytic capacitors (South Korea SHOEI), the results you see. Despite of good results of oxide-semiconductor capacitors K53-28, their application for by-passing of cathode resistors results in sharpness, " mechanical " sound.,If possible, apply capacitors KBG-MN, K75-24, etc. in power modules of amplifiers (if you will be able to lift such amplifier...)

What conclusion I want to make?So:

1. Measuring of parameters does not give the complete information, whether the given capacitor "sound"s or not; though stability of performances in a wide diapason and decrease of losses at reducing of signal is an encouraging factor.
2. The weaker the signal, the greater it can be effected by dielectric of the separating capacitor.Effect of capacitors in filters of acoustic systems and in output of driver cascade is less distinct, than in input cascade.In input cascades this effect is especially distinct when resistance of leakage is great, that is application of galvanic coupling, that is without separating capacitor is justified. 3.Truly, capacitors influence sound, but the influence shall not be not be exaggerated, as it is weaker than effect of output and other transformers, and other (in particular, choice of modes of lamps, type of lamps). As experience shows, change of operating mode of lamp at the input cascade fundamentally will change sound of all amplifier whereas replacement of separating capacitors in a middle quality amplifier will not change practically anything, let even cost of such "miracle" will increase twice.
4. The vacuum-tube amplifiers, in spite of its simplicity, is a device where all knots, devices, elements interreact both between themselves, and with exterior devices:), signal source, acoustic systems (and through them with a room where it sounds), a network circuit. And sensitivity to type of used radioelements of the amplifier also can change in view of mentioned factors*.Therefore determining type of capacitors (resistors, conductors) is preferable to be made in for each device separatedly, after the amplifier is tested. Also are important the following: personal passions, equipment for listening, prefered musical genres, planed expenses (or opportunities of your purse).
5. Not without pride I shall note, that domestic capacitors (alongside with radio tubes, resistors) provide fine quality of sound in case of competent application. I want to wish to designers successes in such fine hobby! More experiment, try various radioelements, lamps (not neglecting classical ones), and it will help you to feel music really! I hope, that the above-stated material will be useful to you.

See original further info in following page: ( ФТ-3 ) In Krill alphabetic.

http://www.magictubes.ru/ves/kondens.htm

http://cgi.ebay.it/ws/eBayISAPI.dll?ViewItem&item=9714790544&sspagename=ADME:L:RTQ:IT:1

http://cgi.ebay.it/ws/eBayISAPI.dll?ViewItem&item=9714790544&sspagename=ADME:L:RTQ:IT:1 (Open in New Window)