I’m sure there are a few people around here who could put it together competently for you.
The designs are pretty well documented and most of the parts are available if you want to get one built. I know the 26 preamp I had for a bit was really quite something once I had ripped out the Sales shunt reg.
If I would be after a DHT preamp on a reasonable budget, I would definitely play with Bartola 4P1L variations. I’ve heard a few and sonically like them all. A tube microphonic issue is whole lotta different bag, though none version had it properly addressed with springs, dampers etc.
The 4P1L is a bit if a nightmare especially as it is often used with direct output, the 26 was ok used with a step down output transformer, Thomas typically uses the 801A etc with a step down output transformer driving an autotransformer volume control, this way you can avoid most issues with microphonics
I have a couple if Ale’s boards to try out, but suspect I will prefer the nice double C core OTX I had made which sound v nice.
Yes capacitor output. I.e. no form of attenuation between tube and power amp, so there is no attenuation of noise and microphonics.
Using an output transformer helps in this respect and an otx into avc helps a lot in reducing the noise.
Having a low gain power amp will also help in this respect.
thanks, that’s helpful. it is interesting story with stepdown otx, i’ve recently heard an outstanding phono with it. totally silent beyond anything i’ve heard before. i’m also awaiting for a local AVC wound with a decent silver wire, i think that would address the problem in the same way as TM does, think he uses now unobtainum combination of AVC and step down made by pete tribute.