Sano 500r schematic?

[glebert]

Anyone have one? I can't find any on the web for this preamp, although there are some that seem fine for the power amp. Musicparts.com supposedly has the right schem, but their website says "We will be back soon" and won't even let you search for a schematic. And paying them $20 for a scan of a schematic they didn't create to me is kinda BS, but that is my hangup.


TIA,
Greg

[Jazz P Bass]

The 160R may help with the preamp.

[glebert]

Thanks, I will check it out!

edit: taking a quick look, I think the tremolo will be different for sure, since the 160r is a power tube bias wiggle type, but on the 500r the trem can be selected to either or both of the two inputs, so it can't be modulating the power tube bias. The trem is super sweet on the 500r, so no complaints, just different.

[glebert]

Found some info that Sano amps were also sold as Supernovas, and found a not-very-clear-but-better-than-nothing schematic from one of those from someone on a steel guitar forum.

https://bb.steelguitarforum.com/view...39f6927491c612

[glebert]

Update, got a better copy of the preamp schematic.

[NX0R]

Did anyone ever find the schematic? I need one particularly the power amp/power supply. Also, is there a tube list? We suspect one has been subbed.

[glebert]

Did anyone ever find the schematic? I need one particularly the power amp/power supply. Also, is there a tube list? We suspect one has been subbed.

If you look at the second schematic in post #4 you can almost make out that the power tubes should be 8417s and the driver/PI tubes for the power amp should be 12AU7. I'm (going to be) using EL34s in mine but need to add screen resistors, just haven't gotten around to it. I think the 8417s had very high gain for a power tube. If it needed a bit more gain I was thinking about subbing in a higher gain variant for the driver tube.

[NX0R]

Would anyone have the tube layout for the 500r? I am suspecting some of the tubes in the amp I'm working on have been switched with others that have the same basing diagram.

Thanks Jim

[glebert]

Would anyone have the tube layout for the 500r? I am suspecting some of the tubes in the amp I'm working on have been switched with others that have the same basing diagram.

Thanks Jim

Preamp tube layout is shown in post #5, power amp should be 12AU7 and 8417 as far as I have found.

[glebert]

Since there has been some recent interest in these amps, thought I would share that I changed my plans on mine and went with 6550 tubes instead of EL34. This is mostly because I found myself without EL34s but a gaggle of old 6550s. The power tube sockets are mounted fairly close, and coke bottle type 6550/KT88s don't really fit, but straight cylinder 6550s seem fine. I have a 10 watt 470 ohm cathode resistor installed. The plate voltage is 480, and with both tubes in I'm getting 41V at the cathode, so about 20 watts per tube at idle. Maybe a bit cold, but I'm not hearing any crossover distortion and I would rather err on the side of cooler than hotter when doing some sort of conversion, especially since the power tubes are closely mounted. Amp sounds really good, not super loud though. The transconductance of the 6550 (same as EL34) is maybe half of what the 8417s would have so at some point I will probably swap in something with higher gain in for the driver 12AU7.

[glebert]

Put a 12AX7 into the driver spot on the power amp and it really brings this amp to life with the 6550 power tubes. Can get a nice little bit of breakup with a telecaster, could probably get into full on overdrive with hotter pickups or more aggressive playing.