Solid State Guitar Amp Forum | DIY Guitar Amplifiers
Solid State Amplifiers => Schematics and Layouts => Topic started by: R.G. on August 02, 2026, 11:39:36 AM
Hiya. I'm a techie, born and bred. I take short breaks from my day job by reading techie stuff.
::)
I was intrigued by a post in a different forum from a guy who wanted to build a new clone of the Kay 704, which was one of Kay's Vanguard 700 series. These were the first all solid state amps in the US.
I found a Version 1 (V1) and a Version 2 (V2) on the net and mind-wandered through them. Then a tech friend traced out one that was in the shop, and found that not only did the traced circuit in the amp not match the pasted-on schematic inside the amp, it did not match either the V1 or V2 from the net. What the heck??
I think Kay was trying hard to get them to work reliably coming off the line in the face of field reports of issues, and tinkered them as they went. That makes me think there are possibly more of them, all hiding under the "Kay Vanguard 704" label.
Do you happen to have one? Got the time to open the back and get the best-practical shot of the pasted-in schematic? It's got my curiousity up.
I bet changes are small, more tweaking than "new design" and all must or should be functionally equivalent.
If you wish, post them here and let us see the actual differences.