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Russian tubes.

fdegrove

diyAudio Senior Member
2002-08-21 1:20 am
Belgium
From Russia with love.

Since I left the audio scene around the mid nineties a few "new" tubes have hit the market coming in from mother Russia.
6C19P comes to mind for use in OTL circuits,cathode followers and valve regs as a series pass.
6H30P seemed "the " candidate for preamp,driver and what have you.
Then (and I should probably have put it first chronologically) there is this super 6C33C.
I forget some for simplicity's sake here.
And before there was even more variety which we might only see in smallish quantities.
My question to you all is,are there any that you would consider as exceptional? I mean for a particular purpose related to audio of course..I don't need to hear about the vageries of the tube trade here...

Thks all,
 

fdegrove

diyAudio Senior Member
2002-08-21 1:20 am
Belgium
Colt45,

I wouldnt mind doing a OTL with 6C33C

Go for it ,if you need a powerhouse like that but check around.I hear they're prone to failure and have wide dispersions.
They need a lot of drive to get them swinging too.

Dave,

Thks for the url.It's about time they sorted out the nomenclature though.;)
 

Brett

Member
2002-01-07 6:02 pm
fdegrove said:
6C19P comes to mind for use in OTL circuits,cathode followers and valve regs as a series pass.
6C19 is basically half of a 6080 from what I've been told. I have some, but lack a suitable circuit to try them in. I've also read of people using them in SETs and as linestage amps.
6H30P seemed "the " candidate for preamp,driver and what have you.
Excellent tube in both common cathode and cascode circuits in preamps. Can make a good driver epspecially for DHTs, but personally I prefer the ECC99 so far. Very linear, can take about 7W, even though rated for 5, and according to a comment made by Victor K of BAT, can pulse something like 6A (yes amps) in radar applications. Also made tough enough that it can be used as an anti-tank round. I have about 20 nice matched -EB and -DRs in my stash
super 6C33C.
I <i>beleive</i> this is equivalent to both halves of a 6080 in parallel. Grunty, low voltage, high current tube but the curves don't look that linear to me. Compensates by being able to use a lower ratio OPT or autoformer.
My question to you all is,are there any that you would consider as exceptional? I mean for a particular purpose related to audio of course

<b>6C45/6S45:</b> Awesome little driver, preamp and even phono stage tube, similar to a 437.

<b>GM13/813:</b> 125W plate transmitting tetrode that's very well made. Great triode connected for 25/50W SE/PP amp and much easier to drive than an 845. Amazing linearity as a triode. Cheap too.

<b>GM70:</b> Supposedly similar to the 845, but the curves don't look like it to me. Nevertheless, excellent DHT power tube well liked by many. Has a 20V 3A heater.

<b>GK71:</b> Another big transmitting tetrode like the 813, but even cheaper, and the couple of reports I've heard is it makes a good triode. Also direct heated.

<b>7586:</b> Nuvistor. I have some, intending to use them in a phono stage but never got around to it, so I don't know how they sound.

<b>6C41:</b> A big triode I've rad others have successfully used in poweramps.

<b>6H23-EB:</b> A 6922 sub. I have a lot of NOS military ones I like a lot.

<b>GM100:</b> HUGE triode, about the size of a football. Makes a 100W SE amp if you have the power supply for it.

<b>5S8C:</b> Big IDH diode rectifier for high voltage, high current applications.

I know there are others, and I'll post them as I think of them if someone else doesn't before.

Cheers
 
fdegrove said:
Thks for the url.It's about time they sorted out the nomenclature though.;)

It all makes sense if you know the Cyrillic alphabet -- it is people trying to romanize the numbers that screws w the nomenclature.

ie 6H30 H is pronounced "en" in cyrillic.

6C45Pi C is "es" P is often subbed for the "pi" symbol

dave
 

fdegrove

diyAudio Senior Member
2002-08-21 1:20 am
Belgium
RUSSIAN TUBES

Hi Dave,

You know that,I know that.Still what I meant is that these people should sort out once and for all to opt for one or the other.
There is little point in posting both possible references on the same page,wouldn't you agree ?
Divide et impera?
No big deal really but just imagine our young audiophile ordering ?
Imagine his/her surprise when he/she finds out half of that 10K order involves equivalents?
Nobody THAT stupid? I've seen worse.

**Do you care to comment on Brett's input?
This was the kind of info I was asking for.(I'll comment on it later,need to dash.)


Rgds you all,
 
Re: RUSSIAN TUBES

fdegrove said:
You know that,I know that.Still what I meant is that these people should sort out once and for all to opt for one or the other.
There is little point in posting both possible references on the same page,wouldn't you agree ?

While they are at it, they could straighten out EL84/6BQ5 and the like... i don't think it will happen since we are dealing with a lot of stuff from wharehouses that were made 30-40 years ago.

**Do you care to comment on Brett's input?
This was the kind of info I was asking for.(I'll comment on it later,need to dash.)

No direct experience with any of these, but his comments are consistent with those on the JoeList (and given Brett is on the JoeList, possibly where some of them have come from).

dave
 
Brett,

thank you for posting this list, copied it.

Frank and Dave
i only say: Polish tube Vademecum. This book ignores subsequent number codes and orders the tubes by parameter similarity.

All,
be careful with the 6C33C. This tube has sort of a negative tempco concerning plate resistance and transconductance. The tube is heatin up, r_p is going down, G_m is going up, etc. soon tube is :dead:
This tube needs a quiescent-current-sensitive bias regulation or something equivalent to run stable.

All,
watch the huge µ variations/tolerances of Russian tubes. My buddy's databook even specifies it: e.g. 35 plusminus 16 for the 6C45pi. Some matching for µ and also for transconductance has to take place.
Else Russian tubes are gorgeous, the Russians know better than anyone else how to make tubes nowadays.
 

Brett

Member
2002-01-07 6:02 pm
Re: Re: RUSSIAN TUBES

planet10 said:
No direct experience with any of these, but his comments are consistent with those on the JoeList (and given Brett is on the JoeList, possibly where some of them have come from).
True, true, some commentary is culled from the JoeList, but also from the tube forums at a2, especially DIY. Lots of good info to harvest in them thar archives and discussions.

I have used the 6C45pi and 6H30. The 813/GM13 I haven't used in audio, but have some experience of in RF years ago. The Russian ones look very good in terms of construction, at about the equal of all of mine (20+ examples of various brands), except for a couple of NOS CV26's I got recently, which are <i>superbly</i> made.

Cheers
 

fdegrove

diyAudio Senior Member
2002-08-21 1:20 am
Belgium
Russian Tubes.

Bernhard,

I hold a copy of this "Vademecum" but that still doesn't give you a clue about what these tubes sound like ,their merit,does it?

You're spot on re the 6C33C,BIG caveat emptor here.Sufficient familiarity with the tube will yield workarounds though.

On the last point:I don't have those probs with my dealers.
Sounds like early end of cold war to me.
(I mean I saw this problem at the end of the cold war where we were flooded with cheapo rubbish,same happened in Germany when the Berlin wall was torn down.Remember RFT et all?)
Still you're spot on,the Russian make the better tubes nowadays although the Chinese share some the same the components ?
(They're neighbours you know.)
Anyone with indepth knowledge of econimical history out there ?
All in all I'd say thank God for the availablity of USSR tube.we already pay through the nose for junk left overs...
Telefunken anyone ?(Ouch)

Greetz,
 

Brett

Member
2002-01-07 6:02 pm
dice45 said:
Brett,

thank you for posting this list, copied it.

watch the huge µ variations/tolerances of Russian tubes. My buddy's databook even specifies it: e.g. 35 plusminus 16 for the 6C45pi. Some matching for µ and also for transconductance has to take place.
Else Russian tubes are gorgeous, the Russians know better than anyone else how to make tubes nowadays.
Glad I could help.
Forgot to mention the GM13, GK71 and GM70 are all thoriated tungsten types.

You're correct about the mu (how do you do the symbol?) variations. The 6C45pi's were too far apart to be of any use in making a PP diff driver stage. Swapped the 6 I had all over the place, but was never happy, so I put them back in the box. In some experimental SE stages they were very nice sounding. The 6H30s are all really tight between each other, and between halves in my second batch. I bought them matched, but my supplier told me the 8 were from the first 20 he pulled from the box, and the others were satisfactorily close to make pairs from and maybe just lucky with that lot.

Cheers
 
Where's the 6n6p in this story?

They are near equivalent to the ecc99, and in most apps blow them away. I bought these as cheap substitutes for my ecc99 phase splitter tube and ended up selling the ecc's.

As my avatar explains, i am a big GU50 tube fan. There is LOTS of crap for sale. I have seen batches of used tubes that were retstamped and have had tubes that blew up when plugging them in. Look for the ones with the rectangular stamp. Most stamps on russian tubes are bleu when new and will turn orange/red when used.

The triangular stamp was a factory "ok" stamp, the bigger rectangulars are special military selected.

I think the GU 81 is the most badass tube they ever made.

Bas
 
6C33C has a bad rap, but can be an excellent tube for those who know how to handle the beast.
Here is what I found

1)Weed out the bad ones: Buying a box of 10, I found 2 to be faulty
2) Let the heater warm up first, then apply plate voltage.
3) Allow the tube to "burn-in" for a good ammount of time before using it in an amp or attempting to match the tubes

For fixed bias application
4) Don't allow a lot of voltage range in the bias circuit. Especially for OTL.
5) Once the tube is in the amp, bias it when it first warms up, then give it a good 30min warmup before final bias.

If these steps have been done this tube is stable and pretty much undestructible. I used these in in a Single ended cathode follower amp which I listened to daily for two years and never had to re-bias it. I'm currently building an OTL using it.


6C41C- Is another tube that wasn't mentioned. It is pretty much equivalent to half of a 6C33C.