Another preamp kit - Solid State this time

Tom_S

I took a gamble on an $16 Chinese kit that's been around in various forms on eBay for quite a while. They (whoever they are) claim it's a copy of the Accuphase C-3850 circuit, but many people have their doubts. I don't know if anyone has published the Accuphase schematic, but I haven't looked too hard. I will say this thing passes a good looking square wave at 100kHz. I cobbled it into my 6J1 preamp case and I'm running it from the +/- 12v supply. I bypassed the bridge and regs on the preamp board - those feed it 15v, but it seems to running just fine. I was A/Bing it last night compared to an old Parasound HT preamp. I would be hard pressed to name which one was playing if I didn't have control of the switching. Some of you with better ears might hear some differences, but who knows? I'll throw it in the car and bring it to Ankeny next month.

https://ebay.com/itm/126011222570?var=426973158295

4thtry

Cool. Be interesting to compare the sound of this solid state preamp to one of the 6J1 preamps that we recently built. The 6J1's roll off much faster above 20kHz or so. How about if I bring one of my 6j1 preamps along, together with my custom preamp A/B switchbox. If time permits, maybe we can do a quick A/B comparison to see if this is audible.

Tom_S

Yeah, that would be great to compare the two. I had been having issues with my 6J1 rolling off the treble no matter what cables I use. I will revisit that another time, but I need to solve some measurement issues with my bench rig first. I can't even seem to get a clean loop-back measurement from my Motu interface right now.

PWRRYD

Cool project Tom! It'll be fun to hear it back to back with Bill's 6J1 tube project.