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previous: MJ Harnish I'm toying with this idea and was w... -- 6/29/2003 6:16 PM View Thread

Re: Anyone built a tube preamp for acoustic?

7/1/2003 4:52 PM
Rob Mercure
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Re: Anyone built a tube preamp for acoustic?
MJ,  
 
I assume that by "acoustic" you mean for a piezo pickup (funny how we've come to associate the piezo sound with an "acoustic" sound - quite different to my ears). Nuff editorial. Several years ago I prototyped a couple of designs with some e-mail help from Doc Horner - one design I used featured a grid leak bias stage 'cuz it has the truly high input impedance that a piezo transducer wants to see. Tried a few tubes but the one I really liked was a 6BR8 with the pentode section used for the input with something like 50v on the plate directly coupled to the triode section that functioned as a cathode follower.  
 
Oh, one of the following posts mentioned using a 6J6 - generally this isn't a signal tube but instead was commonly used as a low power RF output or driver. It's a medium mu dual triode with a common cathode with a few watts of plate dissipation - interesting choice for an input tube.  
 
Rob

 
Replies:
MJ Harnish Actually I have a Fishman Matrix so... -- 7/1/2003 5:33 PM
jeremy-Scinnimim Amplfiers yeah, the 6J6 could possibly be use... -- 7/1/2003 7:11 PM