Pilot SA232
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FlaCharlie
Super Member
The file is too large to attach here but if you send me a private message with your regular email address I'll be happy to send you a pdf of the Sams.
Pilot made more than one version of the 232. I have a version and the schematic I found doesn't exactly match the circuit. A couple of different resistors here and there. I think my version can support a third, "mixed" channel.
Sorry I can't be more helpful, I found a Fisher SA100 and didn't get too far with the Pilot.
Sorry I can't be more helpful, I found a Fisher SA100 and didn't get too far with the Pilot.
Hi Heyraz. Mine doesn't have the third "mixed" channel and has one less speaker terminal than others I've seen. It's a very nice sounding amplifier but I understand not getting far when you find a Fisher SA100.
I sketched a schematic as I took my SA232 apart and purchased nearly all of the components. I even found a quad of Amperex 6BQ5 tubes branded for Pilot.
There were things about the Pilot I didn't like and was considering changing. I thought putting the inputs so close to AC wasn't a great idea. I like to replace the auxiliary AC outlets with a DPDT switch (wired for DPST) so the amp has a power switch, but again...too close to the inputs.
The paraphase circuit was a little tricky for me to understand and the SA100 is just so well designed, adjustments for Bias, AC Balance and DC Balance and an easy way to measure. With the SA100 I have a great sounding EL84 amp, did I need another?
I even considered putting the 232's transformers on another chassis for better layout and accessibility, but then it wouldn't quite be a Pilot SA232....so it sits in a box.
My hope is to one day restore my SA232...who knows when that'll be?
Good luck with yours! The tranny's are huge and I read it's considered to be one of the top 3 EL84 amps. I'll be following your progress.
There were things about the Pilot I didn't like and was considering changing. I thought putting the inputs so close to AC wasn't a great idea. I like to replace the auxiliary AC outlets with a DPDT switch (wired for DPST) so the amp has a power switch, but again...too close to the inputs.
The paraphase circuit was a little tricky for me to understand and the SA100 is just so well designed, adjustments for Bias, AC Balance and DC Balance and an easy way to measure. With the SA100 I have a great sounding EL84 amp, did I need another?
I even considered putting the 232's transformers on another chassis for better layout and accessibility, but then it wouldn't quite be a Pilot SA232....so it sits in a box.
My hope is to one day restore my SA232...who knows when that'll be?
Good luck with yours! The tranny's are huge and I read it's considered to be one of the top 3 EL84 amps. I'll be following your progress.
Thank you for posting the schematic.
Plimpington2
Super Member
Is this Pilot not considered an equal to a Fisher SA100?
The phase inverter design of the Pilot isn't as good and the layout isn't wonderful. Side by side they're both very comparable amps but I'm not sure one is going to sound loads better than the other. If you put both in front of me and let me pick either for free I might go for the Fisher but I wouldn't be upset at owning the Pilot either. I own it's bigger brother, the SA-260, and it has the same layout problems and inverter design. There are other things that measure better, but its still a very good sounding amplifier.
Thank you!
I agree on either one. I own, and use a Fisher SA100 almost every night and it's a wonderful sounding amplifier. I haven't tried the pilot on the same speakers but I will when finished. I did try it on my test speakers and it is a very fine sounding amplifier. I'm going to look at the placement of the RCA jacks.
My SA-232 had the top can replaced with a 80uf- 80uf 525Vcan cap. Everything else was completely original and it was working. The first thing I did was restuff the can so the input cap right off the rectifier is a 47uf@500v cap. The cap right off the 5AR4 shouldn't be over 60uf. I also changed the second cap to 100uf @450v. Doing this, which is closer to the schematic caused a very slight hum which is noticeable in very sensitive speakers. I ended up ordering a 1.5hy 300ma 70 ohm choke that just fits under the chassis and will clean up the hum. I recapped the complete amplifier and found 7 out of tolerance carbon comp resistors. I also replaced the two drifting 120 ohm 2w cathode resistors with high quality resistors. The amplifier came with a Mullard 12AU7 and the rest were new production tubes. I put in a Mullard 5AR4, two Telefunken 12AX7's and 4 matched Telefunken EL84's.
I recently found a Pilot preamp in a large lot of items I bought so this amplifier should match very well.
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The Fisher has larger output transformers and I like the bias controls but I'm not sure which is a better sounding amplifier. As far as build the Fisher is better built but listening when finished will tell me which I prefer to listen too. I guess that's all that really matters.
I have a Pilot AA-908 which definitely has the Fisher build quality but I mostly prefer EL84 amplifiers.
