Soviet tubes
, 06.10.2011, 11:51

This might not be the right forum for this, but you guys helped me before so here goes; I'm planing to build my own guitar amp using 12AX7's and EL34's, and off course I want to use soviet tubes! So does anybody have some recommendations? I want a smooth sound and was thinking maybe Svetlana tubes?

Re: Soviet tubes
vint, 06.10.2011, 12:24

EL34=6П3С soviet tube

Re: Soviet tubes
Zeddy, 06.10.2011, 13:52

Generally, at EL34 the exact analog in isn't present. 6L6 exact analog 6П3С.
Tubes12AX7 precisely correspond 6Н2П.
Good luck!

Re: Soviet tubes
GeorgeM, 06.10.2011, 14:05

6н2п not a 12ax7 ! other pins, heater 6v only. sound is little bad.
el34=6п27с. ...but 6п27с is mifology.
bad idea.

if you want smooth sound - i recommended oktal 6н9с(6SL7) + 6п6с(6V6), or 6п7с, or г807("807").
Kenotron - 5ц4с(5Z4), 5ц4м(5Y3), 5ц3с(5U4G).

or use modern russian tubes "svetlana", "tung-sol", "electro-harmonics". 12ax7 + 6550(as my "15watt champ").

Re: Soviet tubes
Claydon, 06.10.2011, 17:50

I am sorry, but at me a question: what for to make the lamp amplifier on old Russian element base? After all besides radio tubes, the qualitative target transformer is still necessary to provide a correct operating mode of the terminal cascade. Whether to buy the inexpensive semi-conductor amplifier, for example, Ibanez-TBX15R is better?



Re: Soviet tubes
GeorgeM, 07.10.2011, 04:01

tube is better sound.

transformer - its no problem, tvz-*, tesla, beag, modern - yerasov, audioinstrument, e.t.c, modern no russian - millions....

hobo_nephew what amp you need, se? pp?

Re: Soviet tubes
-Putnik-, 07.10.2011, 10:09

GeorgeM, can you share the pattern combo on 10 watts or less for use at home to the Soviet base and a 100% working. How many schemes - so many opinions. )))

Re: Soviet tubes
GeorgeM, 07.10.2011, 11:35

Their thousand. Since fender champ, аnd finishing higain monsters...

at example my combos: [link] - old schematics, modern element base 90% soviet.
For exclusive soviet element base - schematics will differ it is not enough, literally in pair details.

Re: Soviet tubes
GeorgeM, 10.10.2011, 06:33

This 6П27С [link] - one of 5000

Re: Soviet tubes
, 10.10.2011, 09:33

Thanks for all your replies! Looks like I have some work to do checking out all those tubes! The amp design is my own so it might need some tweaking along the way. I uploaded the schematic here: Schematic
Feel free comment about my design as well.

Re: Soviet tubes
GeorgeM, 10.10.2011, 10:18

Interesting schematics, may be will too much hi frequency?
I would increase С1,2,3, 10,11,12, decrease C14. For more vintage(50s-60s) sound may be applied "self-split" phase inverter. Or for more modern, equal sound - may be add negative feedback from output transformer.

R3 - may be 33k, as classic fenders ?

Re: Soviet tubes
, 10.10.2011, 18:43

I will definitely change those values if it makes the design more leveled.
Do I add the phase inverter between preamp section and power tubes? And what exactly does it do tonewise? I do prefer a more vintage sound before modern

Re: Soviet tubes
GeorgeM, 10.10.2011, 20:18


I didn't carry out calculation, but I think that so it will be better. Check is necessary.


If you interesting self-split, then look phase inverters from schemes "vermona regent30" and "fender princeton65(aa964)" - one triode and good old sound.
And look this: [link] - self-splitter pushpull without separate phase inverter. bad for the hi-gain, fine for "chicago sound"


Re: Soviet tubes
violet, 11.10.2011, 14:49

I've built a couple of 5-watters using 6П14П tube for output section (equal to EL84, can be substituted without modifications). Preamp section can be built with 6Н2П of course, you just have to keep in mind that heaters difference.

Re: Soviet tubes
violet, 11.10.2011, 14:55

You may found the following schematics useful:

[link]

[link]


Re: Soviet tubes
, 12.10.2011, 12:18

Are there any good site with information on how to calculate capacitor values? To be honest I don't know how. First time ever trying to build an amp. The phase inverter I do understand how to implement, altho not sure about resistor values.
You guys just made this build a lot more complex for me! But it will be a lot of fun
Thanks for helping me out!

Re: Soviet tubes
GeorgeM, 12.10.2011, 19:57



It s C-R filter.

[link]


simple method:

Cm= 159/(F x Rc2)

Rc2- резистор утечки следующего каскада в кОм
F-нижняя граничная частота в Гц

for example, you scheme:
F=40hz, gain=500KOhm 100%
C2=159/(40*500)=0.008Mf

gain=250k 100%
C2=159/(40*250)=0.01Mf

gain=100K 100%
C2=159/(40*100)=0.033Mf

Re: Soviet tubes
violet, 14.10.2011, 12:15

hobo_nephew, maybe it's better to start with some prepared project from ax84.com site to focus on pinouts, soldering and overall safety

Re: Soviet tubes
, 15.10.2011, 11:09

It would probably be the smart thing to do, but it's not how I do things
I'd rather redo some things along the way and learn something while doing it!
Can't be that hard can it?!

Re: Soviet tubes
violet, 28.10.2011, 21:41

It's ok while you don't touch bare wires, or charged capacitors
Have you already built smth?

Re: Soviet tubes
, 06.11.2011, 20:28

have been really busy so haven't had the time, but the schematic has been updated and I'm quite pleased with it. I have also received the transformers I ordered for the build. Will let you guys know when there is progress!

Re: Soviet tubes
GeorgeM, 06.11.2011, 21:24

hobo_nephew: mirror topic - [link] %-))