6A3/6B4G/6S4S(2A3/2S4S) project

[feralmeida]

By all means!!
My respect to the other members, with its valuable contribution!
THANKS

 

[vtrifun]

The project was "slightly" modified
Here is the last version:
http://www.geocities.com/dreamsdestroyer/6C4C_cap.gif

Hi,
I am planning to build SE tube amp with 6S4S russian tubes.
Unfortunately the link you sent, modified scheme I can't access.
Can you send me the modified scheme for SE Tube amp with 6S4S tubes?
Thanks in advance.
Regards Vojin

 

[jazbo8]

You should start a new thread, he posted in 2006!

 

[vtrifun]

6S4S Tube Amp scheme

Sorry, mea culpa!
I didn't know the the rules for old/new threads.

Regards,

Vojin

 

[jazbo8]

It's not a rule, just a suggestion, or you can try to contact widowmaker via PM.

 

[vtrifun]

Well, my idea was to address the question directly
to the person. Obviously I made it wrong way.
Thank you, anyway.
I'll try again.
Regards

 

[Bigun]

This is a good thread, perfectly OK to dig up old threads, I do it all the time

so, 6C4C. It's pretty much the same as 2A3. I think you can choose one of the many different designs for 2A3. What will need to be different is the filament heating supply. The heater voltage is 6.3V and likely at this voltage you will experience hum in the speaker unless you use DC instead of AC heating. I know some people were happy with AC heating but mostly I see people use DC with this tube.

I have a few of these triodes and am considering using them in SE too.

 

[widowmaker]

Here is the updated schematic of that amp.
Please, adjust cathode resistor of the output
stage in such a way that you have about 66-68mA
anode current. And don't worry about higher power
dissipation of output triode, I have several amplifiers
with more than 20W dissipation and they still work.
(about 7-8 years without any changing of bulbs)

 

[mcandmar]

I am currently building a SET using 6C4C tubes and Rod coleman filament regulators. It is so quiet i also use it as a headphone amp with HD800's

 

[VladimirK]

I agree, that these interstage tantalum lytics are good, they do not increase impedance at high frequencies as ordinary lytics. But, is it really good idea to connect them in chain, soundwise and reliabilitywise?

 

[widowmaker]

Simply you can try to compare the sound with high quality paper in oil
(or other type of) interstage cap and that chain of tantalum caps
As you're from Tashkent, there is no problem for you to find some K52-2, right?

P.S. you can use also ЭTO 10uF/300V or 10uF/600V, but they are quite expensive
and the result will be the same, I already tried them.
some info in russian:
http://www.155la3.ru/datafiles/eto.pdf
http://www.oksid.com/index.php/produktsiya/item/190-конденсатор-к52-2

 

[soulmerchant]

I find this very interesting Daniel.

Do you find K52-2 as good as K73-16? Which of course can also run them in a chain..

 

[VladimirK]

Simply you can try to compare the sound with high quality paper in oil
(or other type of) interstage cap and that chain of tantalum caps
As you're from Tashkent, there is no problem for you to find some K52-2, right?

P.S. you can use also ЭTO 10uF/300V or 10uF/600V, but they are quite expensive
and the result will be the same, I already tried them.
some info in russian:
http://www.155la3.ru/datafiles/eto.pdf
??? «????????????? ????? ???????????? «?????» - ??????????? ?52-2

Daniel, I never seen or even heared about 300V K52-2 or ETO caps. I believe 90V is their maximum voltage. They are good compared to ORDINARY cheap paper in oil. But, from my experience, one can not invent something new for interstage caps. Best solution is based on teflon, polystyrene and silver-mica. Shunting by silver-mica adds ultimate "shining" and "detales" to sound, provided that recording and other system are of very good quality. But, with regular CD and DACs, shunting with silver-mica can bring a risk of revealing the residuals of digital artefacts and other imperfections. I think this is the main reason, why many people prefer dark and "musical" sound with paper-in-oil caps.

 

[VladimirK]

I find this very interesting Daniel.

Do you find K52-2 as good as K73-16? Which of course can also run them in a chain..

K73-16 give detailed, but a bit "dirty", "contaminated" sound, that is well listened on good vocal recordings, compared to other better solutions.
K52-2 are with more "vintage" sound, that, as for me, can be improved by shunting.

 

[widowmaker]

I'm talking about ЭТО-4, there are several values - 50uF/150V, 30uF/250V, 25uF/300V, 15uF/450V and 10uF/600V.
Actually this is a tantalum capacitor with identical construction like ЭТО-1. Then they became K52-5, they are similar,
but not identical with ЭТО-4 (like K52-2 and ЭTO-1), the manufacturer simplified its inner construction to avoid use of
expensive elements (like palladium for example). Nowadays all of ЭТО-4 caps are very hard to find, as they are no
longer in production. I still have some stock at home, but not for selling.
There are also ЭТО-2 and ЭТО-3 types, but I'm not familiar with their construction. tried to find something in russian
on the web, but without any success. Vladimir, if you can find some ЭТО-4 (some stock left in a military warehouse,
from that time, when your country was part of Soviet Union), just try with them, they are much better than K52-2
and K52-5 types.

An externally hosted image should be here but it was not working when we last tested it.

 

[walangalam]

Hi widowmaker, I'd like to try the K52-2 cap. Which is the positive terminal?

Thanks

Here is the updated schematic of that amp.
Please, adjust cathode resistor of the output
stage in such a way that you have about 66-68mA
anode current. And don't worry about higher power
dissipation of output triode, I have several amplifiers
with more than 20W dissipation and they still work.
(about 7-8 years without any changing of bulbs)