KRA Filmosound 385 conversion discussion and demo.

Here's an in depth demo and discussion of my Filmosound 385 conversion. I replaced the filter capacitors, made the input and output guitar and speaker cab friendly, and removed all of the non-amplifier circuitry but largely I left the circuit stock. I did have to re-work the power supply when I recapped the amp but it left a lot more space to work inside the chassis. The tube lineup on this amp is; 5879, 12AX7, 12AX7, 6V6GT, 6V6GT, and 5y3 rectifier. The tone control on this amp is a dual-gang pot that controls the bass and treble simultaneously! A clockwise turn not only increases highs, but decreases bass. And a counter-clockwise turn not only reduces highs bun increases bass as well! The amp also overdrives very nicely. The tone control interacts with the overdrive in a really big way that can give you a wide array of overdrive tones. As of the posting of this video, this amp is for sale here:
reverb.com/item/79526929-kra-...

[@GIBKEL]

Is that a two stage preamp with the 5879, then 12AX7 and 12AX7 phase inverter? Sounds beautiful-no mods. Brilliant! Got a 302 and it’s going to get tricky but possible-it’s just more of a rats nest. Does it affect the power transformer when you are using just a couple of the taps for amp only, and not the projector power?

[@roncarter2188]

I love the idea for the new filter caps. Did you redo the circuit or pretty much keep it original? Sounds sweet!

[@KyleReidMusic]

Thank you! I left the audio circuit pretty much stock and removed all the non-audio circuitry and replaced the filter caps (re-wiring the power supply to utilize the caps in that tube socket etc.). It’s a super cool circuit for sure