In Reply to: Re: I want to build a parallel 845 SET amp posted by MIchael Samra on October 12, 2006 at 13:23:22:
I am running I think about 920v B+ @ approx 75-80ma (off the top of my head). It's not maxed out but it's a nice op point.I'd think about 24-26w is about the most to expect to get out of an 845 and that's caning it at full dissipation in A1. Anyone that claims to get more is I think BS'ing to a fair degree. It would require running into A2. most amps that claim big power like that lack the driving stage to handle A2, and even if they did distortion is going to be somewhat more significant than a pure A1 amp. On top of that, the 845 is not rated for grid current so running them in A2 is not recommended simply by the nature of the specs as I read them. For a full on flogger amp that goes into A2, the 211 may be the better choice, but even that needs major caning to get up to that sort of power level (35w+). Not to mention a high impedance output tranny.
If you can live with under 25w (and i am guessing you can from the sounds of it) the 845 is the sweetest tube out there I think.
For more power, rather than drive the 845 into A2, I'd look at something bigger. 250TL, 212, 304TL, 849, WL-468/460 are all feasible and will make 40-50W in A1. The most available are 250TL and 304TL, both of which could work into the same sort of tranny an 845 might want. (something like a 5K primary impedance... the 250TL might want a little higher possibly).
Good luck, keep us posted.
-Ed
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Follow Ups
- Re: I want to build a parallel 845 SET amp - Ed Sawyer 06:54:13 10/13/06 (3)
- Re: I want to build a parallel 845 SET amp - Naz 05:20:18 10/14/06 (1)
- And JIC anyone wants to look at Electronluv's artful creations... - jeffreybehr 10:48:30 10/14/06 (0)
- I want to build a SET amp - Sector-7G 18:48:15 10/13/06 (0)