The Reference 6SN7 Thread

[Isaacc7]

I have ECC31, ECC33, ECC34 n ECC35, n they all have the same basic Mullard house sound. Only if you listen very closely, you can still hear the very slight differences in the final sound production here and there due to the differences in the electrical specs. I have heard the ECC32 on multiple times but same as others, I wouldnt pay for the current asking price.

I believe many like the ECC32 a lot is becos of its additive wide soundstage sound, overall it has a well-rounded tone from high to low.
ECC31 is very close behind ECC32 in wide soundstage sound but has a more "neutral" sound compared to ECC32, which has more coloration, IMO. Fact is many love coloration...LOL. Out of these, ECC33 has the best clarity from high to low, this is why some prefer ECC33 over ECC32. ECC34 has the darkest tone in the family but not dark like the famous RCA 6SN7 grey glass, it is still a Mullard after all and retain the Mullard house sound. TBH, I dont think one can go wrong with any of these tubes as they all sound amazing regardless of your personal preference.

Oh yeah, dont ask me which one to get becos I will say get a pair of each...

Right now, the Mullard “house sound” seems kind of thin and compressed lol. Not sure why the ecc31 refuses to behave while most other twin triodes are fine. Although I’ve noticed a similar issue with the bl63. Hmm… Will try those with the 6aq5 when I get back home.

 

[TLO]

Right now, the Mullard “house sound” seems kind of thin and compressed lol. Not sure why the ecc31 refuses to behave while most other twin triodes are fine. Although I’ve noticed a similar issue with the bl63. Hmm… Will try those with the 6aq5 when I get back home.

Really sorry to hear you are having so much trouble with ECC31 for quite some time now...lol
Do you have any troubles with other British made tubes beside BL63 n ECC31?
Btw, pls advise what is the tube configuration on your amp?

Edit: oic, you have a Ultrasonic Studios Odyssey push pull?
2X 6SN7 / 6SL7
4X KT88

are those 6SN7 / 6SL7 series or parallel connected between the triodes?
AFAIK, ECC31 with a shared cathode can only work in either...
1. 1 triode for each channel setup
or
2. parallel connected between triodes (1 big triode - 1 stage amplification) for each channel setup

It will not work if the setup is series connected between the triodes (2 individual triodes - 2 stages amplification) for each channel.

 

[LobalWarming]

Not too long ago they were in the range of $20-$30 but now they are easy to ignore because of the price. And yeah, those are ugly adapters lol. Not sure I could ever trust those side contact tubes, they just bother me for some reason.

I bought a dozen back when they were $10 each. Side contacts are fine and easier to clean than pins. Ugly adapter is overcome when eyes are closed and beautiful sounds enchant the ears. No peeking!

They bother me too - very difficult to insert and even worse to pull out. However, the FDD20 I have was adapted to an octal socket.

The trick with pulling out a FDD20 from the adapter is to never do that. Instead by an extra dozen adapters.

 

[mordy]

I bought a dozen back when they were $10 each. Side contacts are fine and easier to clean than pins. Ugly adapter is overcome when eyes are closed and beautiful sounds enchant the ears. No peeking!

The trick with pulling out a FDD20 from the adapter is to never do that. Instead by an extra dozen adapters.

Problem is that I don't have room for 12 bath tubs,

 

[David A Silva]

??? 12 bath tubs ???

 

[Isaacc7]

Really sorry to hear you are having so much trouble with ECC31 for quite some time now...lol
Do you have any troubles with other British made tubes beside BL63 n ECC31?
Btw, pls advise what is the tube configuration on your amp?

Edit: oic, you have a Ultrasonic Studios Odyssey push pull?
2X 6SN7 / 6SL7
4X KT88

are those 6SN7 / 6SL7 series or parallel connected between the triodes?
AFAIK, ECC31 with a shared cathode can only work in either...
1. 1 triode for each channel setup
or
2. parallel connected between triodes (1 big triode - 1 stage amplification) for each channel setup

It will not work if the setup is series connected between the triodes (2 individual triodes - 2 stages amplification) for each channel.

Right, push pull, balanced input only. Each output tube has a triode section driver not each channel. Each triode of each 6sn7 drives an output tube directly. The adapters I got for the ecc31 split out each triode so they should now act like a 6sn7. Well, a 6sn7 with different specs lol. My amp was designed specifically to be flexible as far as tube usage goes. I can use most pentode tubes as outputs. The amp has a regulated variable b+ ranging from 250v-400v. The input tubes can be just about any triode as long as I have 4 of them. The input is set for automatic bias and a fixed b+.

I have been mostly using 6l6 family output tubes (807, 6bg6, 6ar6) and have not had any issues using Brimar 13d1, GEC b36, GEC l63, and Cossor 6c5g. The only tubes that haven’t worked well are the ecc31 with adapters and a quad of GEC ktz41 in triode mode. The former sounded just ugly while the latter just sounded “off” both sounding weirdly large and phasey. Switching to 6aq5 output tubes and the ktz41 sound absolutely lovely. The ecc31 have improved quite a bit but are still clearly not up to driving the outputs properly. The bl63 was just thin and compressed sounding with the 807. Now that I think about it, the current sound of the ecc31 and 6aq5 is very similar to the sound I was getting with 807 outputs matched up with the bl63. Hmm…

I am visiting family and so will be away from my system for a week (sob) but will try the bl63 with the 6aq5 when I get back. My current hypothesis is that the triode sections of the ecc31 just are not up to the task of directly driving the output tubes I have been using. The 6aq5 are known to be easy to drive so maybe that’s why there is an improvement using them?

Tomas made some of his amps be able to use either 6j5 or 6n7 tubes as inputs. He had a clever design so that if you plugged in a 6n7 it would parallel the triodes and turn it into a single triode. The thought occurred to me that I could have some adapters made that would do the same thing. That would be crazy. Surely no sane person would do such a thing. On the other hand, any normal person looking at my setup would question my sanity so…

 

[TLO]

Right, push pull, balanced input only. Each output tube has a triode section driver not each channel. Each triode of each 6sn7 drives an output tube directly. The adapters I got for the ecc31 split out each triode so they should now act like a 6sn7. Well, a 6sn7 with different specs lol. My amp was designed specifically to be flexible as far as tube usage goes. I can use most pentode tubes as outputs. The amp has a regulated variable b+ ranging from 250v-400v. The input tubes can be just about any triode as long as I have 4 of them. The input is set for automatic bias and a fixed b+.

I have been mostly using 6l6 family output tubes (807, 6bg6, 6ar6) and have not had any issues using Brimar 13d1, GEC b36, GEC l63, and Cossor 6c5g. The only tubes that haven’t worked well are the ecc31 with adapters and a quad of GEC ktz41 in triode mode. The former sounded just ugly while the latter just sounded “off” both sounding weirdly large and phasey. Switching to 6aq5 output tubes and the ktz41 sound absolutely lovely. The ecc31 have improved quite a bit but are still clearly not up to driving the outputs properly. The bl63 was just thin and compressed sounding with the 807. Now that I think about it, the current sound of the ecc31 and 6aq5 is very similar to the sound I was getting with 807 outputs matched up with the bl63. Hmm…

I am visiting family and so will be away from my system for a week (sob) but will try the bl63 with the 6aq5 when I get back. My current hypothesis is that the triode sections of the ecc31 just are not up to the task of directly driving the output tubes I have been using. The 6aq5 are known to be easy to drive so maybe that’s why there is an improvement using them?

Tomas made some of his amps be able to use either 6j5 or 6n7 tubes as inputs. He had a clever design so that if you plugged in a 6n7 it would parallel the triodes and turn it into a single triode. The thought occurred to me that I could have some adapters made that would do the same thing. That would be crazy. Surely no sane person would do such a thing. On the other hand, any normal person looking at my setup would question my sanity so…

hmm...in that case, it should work for you...
each triode driving each output tube independently...dont know why...lol
have you checked on the adapter to make sure the shared cathode of ECC31 is connected to both cathode of the 6SN7?

 

[mordy]

hmm...in that case, it should work for you...
each triode driving each output tube independently...dont know why...lol
have you checked on the adapter to make sure the shared cathode of ECC31 is connected to both cathode of the 6SN7?

My Euforia amp uses two 6SN7 tubes which are wired in parallel. Using EEC31 to 6SN7 adapters I can run 6N7 and 6J5 tubes in this amp.

 

[Isaacc7]

hmm...in that case, it should work for you...
each triode driving each output tube independently...dont know why...lol
have you checked on the adapter to make sure the shared cathode of ECC31 is connected to both cathode of the 6SN7?

It’s more of a purist design. Balanced signal in, each phase of each channel is amplified directly. It eliminates the phase splitter stage. Differential amp maybe? Anyway, the tube is “working” in the sense that sound is coming out, I have a soundstage, full frequency range etc. Since it sounds so much worse with the 6l6 family makes me think it just isn’t driving the outputs well.

 

[TLO]

My Euforia amp uses two 6SN7 tubes which are wired in parallel. Using EEC31 to 6SN7 adapters I can run 6N7 and 6J5 tubes in this amp.

My amp, Line Magnetic LM508, has 3 input tubes...
1x 6sl7 - one triode for each channel
2x 6sn7 - parallel connected between the two triodes
Hence, I can use ECC31 on all three inputs.
Here is one on the 6sl7...

n this with ECC31s on both 6sn7

 

[LobalWarming]

??? 12 bath tubs ???

He meant a dozen bidets

 

[Isaacc7]

Using triode strapped pentodes is very common with Feliks-Audio's amps, Elise / Euforia. Those forums are replete with examples. I just upgraded Elise to Euforia AE and here's my current (pun intended) roll, sounds excellent:

Marconi KT63 & GEC KT88. Adapters made by fellow head-fi'er @Deyan.

Old post I know but aI just want @TLO and @LoryWiv I have been using triode strapped pentodes successfully for a little while now. The Fivre 12j7, c3m, and MOV ktz41 have made excellent drivers for some output tubes. The post I’m replying to has blown mind though. Both 6f6 and 6v6 are used in triode mode as preamp/driver tubes but I never considered using them for my amp before. With a 2x 6v6 to 6sn7 adapter aI could use 6v6, 6f6, 6k6, and in combination with adapters I already have the 6aq5 and el81. If the el81 sounds good I might even try out the n34 with a different adapter. I had given up hope using those tubes without buying a new amp! Glad I got over my fear about this!

On the other hand, I need more tube combos like I need poison ivy. Still, I won’t be getting bored any time soon lol!

 

[OctavianH]

The trick with pulling out a FDD20 from the adapter is to never do that. Instead by an extra dozen adapters.

These are truly words of wisdom.

You were saying "low cost alternative" Mr. Lobal?

 

[mordy]

These are truly words of wisdom.

You were saying "low cost alternative" Mr. Lobal?

Crazy prices - a few years back I could have bought them for $9 each including shipping…

 

[Isaacc7]

Crazy prices - a few years back I could have bought them for $9 each including shipping…

It’s especially crazy considering the hoops most people would have to jump through to Use them at all. My gut feeling is that there weren’t that many of the tube to begin with, people got excited about them here on Head-fi and whoever actually had some decided to jack up the price since there isn’t seemingly any completion selling them. I’d be willing to try them and get the adapters for less than $30-$40 but not more.