mac

Valve buffer amps $25 Ebay items - how do they work??
« on: January 15, 2010, 05:52:41 PM »
http://cgi.ebay.com.au/Special-for-Tripath-12AU7-Buffer-Amp-for-smooth-sound_W0QQitemZ250562718881QQcmdZViewItemQQptZVintage_Electronics_R2?hash=item3a56b3aca1

How does this work? I thought the tube would need something up near 300v for the anode??

says it runs on 43 volts...
(so my tube education continues......)
 :)
Mac

Barclaycon: The client said 'That sounds great, what are you using on it?'
The engineer's reply was: '30 years of experience'.


PRR

Re: Valve buffer amps $25 Ebay items - how do they work??
« Reply #1 on: January 15, 2010, 06:10:31 PM »
> I thought the tube would need something up near 300v for the anode??

Why?

If you want good performance from a HIGH impedance device like hollow-state, yes, you should run high voltage. But all the tube data shows operation from 90V supply, and often quite good for sub-Volt signals. I would expect a 43V stage to clip badly near 10V peak signal, so it needn't be horrible at the 1V level it is sold for. (However their notes suggest it may be deliberately non-"optimum", and not go past 5V cleanly.)

My experience with 90V hifi preamps is that they sound "soft" at hifi level, that hotrodding to 250V seems more accurate. But that was then, this is now. Much stuff is very accurate (or has annoying artifacts), they sell stuff to soften-up the sound.

shabtek

Re: Valve buffer amps $25 Ebay items - how do they work??
« Reply #2 on: January 15, 2010, 07:33:17 PM »
dc-dc converter:12 to 43 vdc...
too good to be true? yous gets what you pays for?
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

Svart

Re: Valve buffer amps $25 Ebay items - how do they work??
« Reply #3 on: January 16, 2010, 12:17:37 AM »
What's wrong with that?  ;D
Welcome to the GroupDIY leper colony! when something falls off, we just replace it with a tube!
occupation: General Electron Mayhem

Alesis X2 information repository:
http://www.theopiumdenproductions.


 

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