Eros Tube Quality

[Paully]

I was thinking about a thread I read on the Eros some time ago someplace.  To sum up on the tubes in the Eros and their impact on the Sound:

EF86: critical
6DJ8: Not so critical but a good tube will still impact the sound enough to matter
12BH7:  If you use an expensive NOS tube you are wasting your money.

Sound right?

[Paul Joppa]

The Eros is designed around the 6922, and the 7308 premium version is usually an audible improvement. I don't recommend the 6DJ8 - it will work, but it has a reputation for issues with excess plate voltage, making it riskier in a direct coupled amp due to start-up and shut-down voltage transients. Also it draws more heater current and the heater supply is running close to my limit for temperature.

[Paully]

Didn't realize that about the 6922/6DJ8.  Good to know, I will look to see what I can do to replace the one I am running.  Had been running it (an Amperex) for a while without incident but better safe than sorry.

[johnsonad]

Every tube makes a difference, especially those in the gain stages.  As you found with the 6BR7, a low noise quality tube has significant audible difference.  The first stage with the 6922 is equally important.  Unfortunately the premium versions of this tube are some of the most sought after and expensive in audio.  You may want to consider the 6922 Gold Lion reissue.  It has received favorable reviews from people who use it in high gain circuits such as the Eros.  The 12BH7 will make a difference too though not to the level of those in the gain stages.  In the end it's all about system synergy and what sounds good to your ears.  If you

[Paully]

Well if people want to chime in with suggestions, such as the Gold Lion reissue (which I will probably try now that you mention it) I am all ears!  What about the Russian 6H23?  I am always a fan of Mullards, the Mullard CV2493 is listed as a 6922 variant and the Siemens 7308 is affordable at Upscale as well as the Tesla E88CC/6922.  I do have a soft spot for Tesla tubes as well.  Those are the ones I am considering.  So anyone who wants to chime in here, love to get opinions from other Bottleheads but I will head over to the Tubes Asylum and see what people have to say there about the various brands.  Thanks!

[johnsonad]

Maybe give a little more info when asking for recommendations?  What is missing that you desire to correct with the 6922?  Tubes sound different even from the same manufacture and the same type for that matter (different runs, tolerances, years, etc...).  You write you have a soft spot for these two brands, what about them makes you happy?  No matter what tube you shop for in that spot I would recommend a well balanced tube with VERY low noise.   

[Paully]

I like soft, rounded tubey unstrident sound.  Why I like Mullards so much.  But not too worried.  Just want to experiment with some tubes that people think are a good value.  I have plenty of experience with 6DJ8, not so much with 6922 and its varients.

[Grainger49]

I will have to second Paully's question about using 6N23Ps in the Bottlehead phono second stage circuit.  I have used them but don't know if I am changing the design parameters.

PJ, any help here?

[Paul Joppa]

6H23P is very close to a 6922, spec is well within normal tube to tube variation. The Russian tube has slightly higher maximum limits (300v vs 220, 2W vs 1.5w). The mil-spec -EV version is generally regarded as superior.

[Grainger49]

Paul,

Thanks.  I recently bought a quartet of the -EV tubes for a reasonable price and two went straight into my Seduction.  I'm pretty sure Paully has some as well.

[johnsonad]

I picked up one of the Gold Lion 6922's today.  It looks to be structurally the same as a 6N23P which is to be expected. 

[levlhed]

oops, are NOS 6DJ8's really not good to use?  

I gots me some nice Telefunken/Amperex/Etc I was planning to try out!

[Grainger49]

The circuit is designed with the 6922 variant in mind, the specs need to be met.  But that is not to say that a good 6DJ8 won't meet the specs.  It doesn't say it will.  That is why PJ has specified 6922. 

Try it!