@fsonicsmith1 Cheers :)
Happy when I can provide useful input for others - I way way too into this hobby lol
Question about the headphone amplifier in tubed preamps
. . . specifically the Cary SLP-05, but I think the question would be applicable to any tubed preamp with a headphone amp built in. But my question is: I have all eight 6SN7 tubes installed, although I don't own headphones and probably won't in the foreseeable future. Since I never have the preamp switched to headphones, are those two 6SN7s only in a standby mode when I have the preamp turned on? And if not, should I remove those two tubes and cover their sockets with electrical tape & thus preserve those two tubes for use as "just-in-case-spares"?
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@mulveling you are without doubt one of the most knowledgeable contributors to this Board. Always learn something from you. |
@mulveling and @mlsstl thanks for the info & advice. I will look into those Schitt SS 6SN7s. Currently I have the EHs that it came with in those slots. Thanks again. Stuff like this makes this site great. |
Another interesting option for you -- Schiit has a solid state 6SN7 tube available to replace vacuum tubes. You could get two of those for the headphone section and then you'd never have to worry running down the tube life while they are sitting there doing nothing. And, if you decide to use headphones, that circuit is immediately available. If you go to Schiit's web site, and look in "Accessories" under their product lineup, you'll see them listed as LISST tubes. I bought one for my Lyr 3 headphone/preamp and was quite impressed with how good it sounds. I very slightly prefer the glass 6SN7 but was surprised as to how close the LISST was to the glass tube. Finally, they do have a disclaimer about using these in amps made by other companies, so be forewarned. However, I'd suspect that is mainly CYA wording from their lawyers. But, still something to consider. |
I think the general advice on that was to fill those slots with cheap tubes - like Electro Harmonix, though used Sylvania 6SN7GTB could fit the bill too (and should last a LONG time). I'd hate to leave the slot empty or covered in tape. A pair of 6SN7 in some kind of follower configuration, probably output coupled via electrolytic capacitors, does not make a super headphone amp by today's standards. But it still might sound nice with high impedance headphones like Sennheiser HD600. Tube designs which use transformer coupled outputs can use basically the same circuity for preamp and headphone amp outputs. The problem for OTL (transformerless) amps is providing enough capacity on the output caps to not roll off bass when driving headphones, while also not compromising the cap choice when used as a preamp that doesn't need very much capacity. That's hard (if not impossible) to do well. So Cary made the choice to use a separate output stage just for headphones. The problem is it's probably not up to par with the preamp stage. |