In Reply to: Help me pick a preamp for my SETs! posted by Jim in Blacksburg on October 18, 2006 at 19:22:55:
What's the sensitivity of your 811 SET? Is it DIY, or a commercial offering. My guess is that it's sensitivity is close to 2Vpp. If it
weren't for the poor drive capabilities of passive preamps, you'd be in business.I'm really really liking balanced, transformer coupled movement of signal. The input transformer does alot of good things ; like provide complete galvanic isolation of preamp and amp, as well as excellent common mode noise rejection. The balanced cable is bulletproof for avoiding noise induction. You could get a nice set of input transformers for $140 and mount them externally to the SET amp... Next, you'd need a preamp with 600 ohm XLR outs and probably no more than +6dB gain.
I had a really fantastic experience with this a few months ago... With an 811A DIY SET :) and some Sowter 3575 input transformers... What was doing the driving was a lovely $99 Gemini PA-7000 DJ Mixer. Has balance, volume, selector and even a MM RIAA stage.... About $30 in new op-amps and replacement capacitors and it was really pushing wonderful music. Op-amps driving balanced lines and transformers can be surprisingly good. Alittle bit of old and new... 1947 Class B transmitter tube. 2004 vintage Op-amps from Analog Devices. Some nice nickle cored, mu-metal shielded transformers from Jolly Old England. :)
-- Jim
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Follow Ups
- Probably need more cable line drive than gain.... - Jim Doyle 22:55:15 10/18/06 (0)