[Carl]

Quote:

Originally Posted by AudioCats /img/forum/go_quote.gif Since everybody is talking about tube amps..... What kind of signal level is needed to drive the ECC99/5687? (signal voltage and current) I am thinking about using two ECC99 per channle, (one push one pull), and wire each tube to SRPP config, will it work well?

The 5687 and ECC99 are different tubes with different pin outs, although they are electrically similar (they don't really sound that alike, though). 6N30Ps, 6CG7/6FQ7s and 6DJ8s are also fairly similar.

I'm not sure on their exact op points, you'd best ask on diyaudio.com or something, unless you know how to make a loadline up from the tube curves (something I really need to upskill myself on).

If you want to take the easy route you could always slap a simple differential stage onto the back of Peter Millet's ECC99 headphone amp.

 

[spritzer]

Quote:

Originally Posted by AudioCats /img/forum/go_quote.gif Since everybody is talking about tube amps..... What kind of signal level is needed to drive the ECC99/5687? (signal voltage and current) I am thinking about using two ECC99 per channle, (one push one pull), and wire each tube to SRPP config, will it work well?

You could also try something like this. It's nothing special but it shouldn't be expensive to build. You should definitely design your own if you want to but there are dozens of designs out there, though most are in Japanese.

 

[AudioCats]

Quote:

Originally Posted by Carl /img/forum/go_quote.gif The 5687 and ECC99 are different tubes with different pin outs... If you want to take the easy route you could always slap a simple differential stage onto the back of Peter Millet's ECC99 headphone amp.

Thanks Carl, how differently do the Ecc99 and 5687 sound?

 

[AudioCats]

Quote:

Originally Posted by spritzer /img/forum/go_quote.gif You could also try something like this. It's nothing special but it shouldn't be expensive to build.

Thanks birgir.... wait, that circuit is asking for 20V signal input

 

[Carl]

Quote:

Originally Posted by AudioCats /img/forum/go_quote.gif Thanks Carl, how differently do the Ecc99 and 5687 sound?

I'm not sure if I can accurately quantify it. To me the 5687 rocks more. I don't have a lot of experience with the 99, though.

Quote:

Originally Posted by AudioCats /img/forum/go_quote.gif Thanks birgir.... wait, that circuit is asking for 20V signal input

That's only a voltage gain of 10 from a CD player. Shove a bog standard common cathode stage in front of it and you can fix that easily enough.

 

[spritzer]

Quote:

Originally Posted by Carl /img/forum/go_quote.gif I'm not sure if I can accurately quantify it. To me the 5687 rocks more. I don't have a lot of experience with the 99, though.

The 99 is very musical and linear in the right circuit and the same goes for the 5687 but it is also a bit more dynamic with more kick to it. Both are excelent tubes.

Quote:

Originally Posted by Carl /img/forum/go_quote.gif That's only a voltage gain of 10 from a CD player. Shove a bog standard common cathode stage in front of it and you can fix that easily enough.

I didn't even see that.

This design has never interested me all that much so that might be the reason...

 

[Carl]

Quote:

Originally Posted by spritzer /img/forum/go_quote.gif I didn't even see that. This design has never interested me all that much so that might be the reason...

For some reason I never did like that design, but stare as I might at it I can't for the life of me figure out why.

 

[spritzer]

Quote:

Originally Posted by Carl /img/forum/go_quote.gif For some reason I never did like that design, but stare as I might at it I can't for the life of me figure out why.

I don't know why I never liked it. Could be the name...

 

[ferrstein]

Okay, so I think I finally have too much Stax stuff. I say this because I lost one of my SRM1/MkII amps. I can't find it anywhere.

I guess that's why I have a backup!

 

[justin w.]

http://gilmore.chem.northwestern.edu/head3.htm

Here is an interesting project for those here looking to DIY a Stax amp. I built this one a few years ago, but was losing all the gain across the string of gas tubes. Kevin said this didnt happen with his, so it could have been my tubes. I never bothered to try different ones. It's a neat project, the gas tubes dance to the bass.

 

[spritzer]

Quote:

Originally Posted by ferrstein /img/forum/go_quote.gif Okay, so I think I finally have too much Stax stuff. I say this because I lost one of my SRM1/MkII amps. I can't find it anywhere. I guess that's why I have a backup!

Yeah I have the same problem. It got so bad that I was buying models that I already had so I put up a list on the wall with all the models I'm going to buy and have marked of the ones I already have bought. I should really do the same with my amps and adapters as I'm always finding some stuff I didn't know I'd bought.

Still they are a good source of 6 pin sockets as I can't stand the Allied stuff.

Quote:

Originally Posted by justin w. /img/forum/go_quote.gif http://gilmore.chem.northwestern.edu/head3.htm Here is an interesting project for those here looking to DIY a Stax amp. I built this one a few years ago, but was losing all the gain across the string of gas tubes. Kevin said this didnt happen with his, so it could have been my tubes. I never bothered to try different ones. It's a neat project, the gas tubes dance to the bass.

Your tubes must have been faulty. It would be a cool amp but it needs bigger output tubes.

The KGSS power supply would be an easy choice and make it an easy build for those of us with a stack of PCBs at our disposal. I need to buy some more IRFBC30s...

 

[Andre Jute]

Quote:

Originally Posted by AudioCats /img/forum/go_quote.gif Since everybody is talking about tube amps..... What kind of signal level is needed to drive the ECC99/5687? (signal voltage and current) I am thinking about using two ECC99 per channle, (one push one pull), and wire each tube to SRPP config, will it work well?

You need to learn to use the spec sheets and transfer curves, both available off the net. Here is a sample of what you can learn by drawing lines on the tube's characteristic curves:

http://members.lycos.co.uk/fiultra/112KISScurves.jpg

More from the illustrations page of my KISS amp:

http://members.lycos.co.uk/fiultra/KISS%20190.htm

and description of how to use the information at Jute on Amps:

http://members.lycos.co.uk/fiultra/JUTE%20ON%20AMPS.htm

HTH.

Andre Jute
Impedance is futile, you will be simulated into the triode of the Borg. -- Robert Casey

 

[ironbut]

Any suggestions on EF86s and 5687s to try?

Funny you should ask this question. I'm in the middle of tube rolling some of these. I'm sure my application is pretty different than what your thinking about. Mine is a custom tape head preamp. Low, low noise is important so some of the tubes I've tried and rejected might work just fine for you.
New production
Electro Harmonics EF86 =pretty nice top to bottom FR. medium noise floor, pretty smooth but not super detailed. Pleasant, but nothing really great
Tung-sol EF806sg= identical to EH cosmetically but significantly lower noise floor, I only have about 10 hours on this pair but so far the upper mids and highs get hard when the level is pushed. Further break-in could improve this, not real impressive bass, aside from the noise floor, nothing to write home about
Svetlana EF86= almost as quiet as the Tung-sol labeled "reissue". Much more lively presentation and nice bass, highs can get hard when pushed so far-16 hours on this pair, for the price, not too shabby
JJ EF806s a pretty nice tube I think? I'm not positive because for some reason, this pair of tubes has way lower gain ( I have an email to the seller about this). This raises the noise floor of the tape preamp to attain a normal listening level to the point that it obscures the music. In other applications it might sound very good from what I can tell.
NOS and used
Telefunken silver plate =these were an ebay purchase and one is very noisy, nice smooth presentation but not much in the bottom octave, real evaluation should wait till a proper pair is found
Valvo e80f pinch waist, d getter, red print, Herleen factory= drop in replacement that was developed for low noise medical/magnetics applications. Great bass! super smooth presentation, excellent details, slam,almost as good as it gets, unfortunately, the very tip top lacks sparkle, otherwise The ef86 as far as I'm concerned. Also branded Phillips but the factory code tells the tale. You can find these for around $50 a pair.
Telefunken EF806s= legendary! When recording engineers talk about this tube for powering their mikes, they use hushed tones! Very rare, very expensive! I just had to bite. I've got about 7 hours on these so far and the stories are true. This is almost like a different tube type. Quieter than any of the above, more gain, I've never heard better detailing, dynamics, slam, the list just goes on and on. These still have a bit of harshness on top but are improving quickly. Entry to this club is $300 a pair but man, is it worth it!
The other usual suspect that I have yet to try are the GEC Z729 ( I think?) super fine mesh silver plate that are fav's with Quad owners.

 

[Carl]

Quote:

Originally Posted by ironbut /img/forum/go_quote.gif The other usual suspect that I have yet to try are the GEC Z729 ( I think?) super fine mesh silver plate that are fav's with Quad owners.

Yes, I was looking at those with interest. Silver mesh is enough to get me moist.

 

[derekbmn]

Quote:

Originally Posted by Carl /img/forum/go_quote.gif Yes, I was looking at those with interest. Silver mesh is enough to get me moist.