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5670 W396a 2C51 6N3P tube thread

post #1 of 12
Thread Starter 

This little marvel is starting to show up in many configurations. It's a capable, compact double triode that apparently was designed for tanks half a century ago.


I have it in a preamp amplifying low voltage sources to an OTL headphone amp. NOS seem to be scarce, and if anyone is manufacturing it today it will probably come from China or Russia (6N3P).


I recently bought som Penta tubes. Anyone know if these are old or new?




Have also seen some vintage GE, RCA and 1950s LM Ericsson (expensive) around. Would be interesting to know your experiences of these.


And in what amp/DAC do you have them?

Edited by MDR30 - 9/9/13 at 12:05pm
post #2 of 12

This is a great tube, and is one that hasn't been given the credit it deserves, especially in headphones amps. The Russians also made this tube and in a DR rating (Russia best). It is known as 6N3P-DR and 6N3P are often made by Reflector (but also Foton and October). The Western Electric is relatively common and still decently priced. The 5670 are excellent (I especially like the GE 5* and RCA Command). You will also  see these as CV4013 and even CV8247s. Raytheon, Sylvania, RCA, GE all made very good examples however my favourites are Sylvania GB - 5670 Gold pins and LM Ericsson 5670s also gold pins. You will also find WA variants and CK5670s (Raytheons) but to be honest many will just love the 'basic' 2C51s. Old NOS examples are readily found of all of these. The only ones I have not warmed to was the generic Chinese one, even the 'J' JunDui (Military class) one I did not warm too. If I had to pick one it would be the LM Ericssons from Sweden however this tube is one of the most consistent of all tubes.


I mostly use it in pre amps and as a driver tube for SETs.

Edited by Nic Rhodes - 9/10/13 at 11:08am
post #3 of 12

I agree with Nic.


I would add the Tesla ECC42 pinched waist and normal.

I like the Foton variant.

I have some 5670's which were specially made for Lufthansa and marked as such.


I use them in my Stockholm DAC and as drivers in my SP's with a 2C51/6SN7 adapter. 

post #4 of 12
Thread Starter 

Well, it seems the Penta above is not recognized, but chime in if you see a resemblance to any other manufacturer.


I've acquired a few GEs as well, and it looks like the size changed during production.



The left one is from 1967, the right one from 1987. Now where would that get us in 2007?


Seems these compact double triodes (including the 5687) have some good features that might put them above the standard triodes in the right circuit.

post #5 of 12
Thread Starter 
Found some triple micas Raytheon 5670 which I have yet to try. Anyone know if these were originally made by Raytheon or contracted? Will send pics tomorrow.
post #6 of 12

As far as these variants, I have tried a bunch and this is the one instance were the Chinese 6n3t (taller version) is better than the NOS stuff out there. All of the NOS sound dull and boomy

post #7 of 12
Thread Starter 
Originally Posted by scottosan View Post

As far as these variants, I have tried a bunch and this is the one instance were the Chinese 6n3t (taller version) is better than the NOS stuff out there. All of the NOS sound dull and boomy


I guess it depends on application. I use the cheap Chinese Matisse amp as a prestage in my OTL headphone set-up, and I was surprised this sounded so good and supplied the meat of the sound. I have Chinese and Russian tubes that I didn't reall compare, but the GE5670 and Penta5670 both sound fine to me, not dull and boomy.


When I have time I will set up a straighter player/amp combination (no multiple sources or amps) with an Oppo Bluray that can play my SACDs. Then we'll see which tubes cut the mustard.


Here's a pic of the Raytheons in the meantime, probably used in aircraft or warfare equipment, but look little used.



Missed a couple of Ericssons some time ago, but not sure if the the qualities justified the price.

post #8 of 12

Hello! I have an amplifier and some 6n3pe tubes with me. Stock, it has ecc88 in it. Do you think I can pop in the 6n3pe and try? My amp is an MF x-can v8p by the way. Really need help on this one.

post #9 of 12
No it will cause damage
post #10 of 12
I feared that, since it seems the legs are connected differently. Thank you
post #11 of 12

If you want a russian tube you need to look for 6N23 or possiblely 6N1 BUT with the latter you will need to check on heater current. I have certainly tried then in the X10D from musical Fidelity with no issue.

post #12 of 12

Hey guys! Instead of making a new thread, I might as well continue this current one.

I'm looking for a pair of tubes that are at most $25 USD each. I'm using the Q701's so I require punchy bass, sweet mids and treble extension. Basically just "musicality". I'm not worried about detail and soundstage, my odac/o2 covers that area.

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