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Driver stage for the ultimate sv83 SE  amp (Read 2113 times)
crazy bill the eel killer
Ex Member



Driver stage for the ultimate sv83 SE  amp
12/09/05 at 01:54:47
 
Hey guys,

I bought a couple of books to start my studying(Rozenbilt and Morgon Jones-Rozenbilt first), and I THINK that someday in the future I'll have enough knowledge to do an amp from start to finish w/o stealing someone else's circuits. I've gotten through half of Rozenbilt's book, and now that  :D I'M AN EXPERT  :D ( the smiley's mean that's a joke), I've gotten to thinking. ( Always a dangerous thing).

My output stage will be a SE SV83(actually that nice cyroed Russian version I got from Gnat Leader in that group buy(incredible tubes)). However, I'm not tied to any particular tube for the driver stage. So my question is this:

If you(either based upon experience or thoughts), were to build an amp as described, what would be YOUR CHOICE of tube for the driver stage and WHY. Would you keep a 6922 or a variant thereof, or is there a better tube for this purpose?

As always I thank you for your kind assistance,

Bill

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Obi-Vaughn Kentubi
Ex Member



Re: Driver stage for the ultimate sv83 SE  amp
Reply #1 - 12/09/05 at 06:32:34
 
For driving a single SV83? A strapped-triode Mullard EF86. It sounds mindnumbing, SCARY good. In strapped triode, it only produces about .1% distortion when the SV83 hits zero grid voltage (18V p-p), and has a very low noise floor and extremely low heater hum induction. It was never meant to drive power tubes, but the SV83 is so easy to drive that it can pull it off quite easily.  

But if you've already got plate load chokes (was that you?), they'll not have enough inductance to load an EF86 down to the lowest frequencies, with it's higher Rp. Off the top of my head, about 120 Henrys would do it.

Second choice is a 6922/6DJ8, unless you have a rather hot source (3 volts or more), in which case I'd definitely use a 5687. If I was using a preamp, I may even try a 5687 SRPP stage (has very low gain).

Eddie Smiley
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Eli Duttman
Ex Member



Re: Driver stage for the ultimate sv83 SE  amp
Reply #2 - 12/09/05 at 07:14:55
 
Aussie DIYers have done work with choke loaded SRPP stages.  Gain comes up and the sound is GOOD.

The converse to a "hot" source is a HOMC cart. combined with a phono stage whose gain is approx. 40 dB.  Mu 33 tubes (6922/6n1p) don't have enough gain to obtain full power O/P.  The 5965 is a GOOD sounding high gm/low Rp type with a mu of 44.  There's the extra gain needed to deal with a "cold" source.
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