A high end valve guitar preamp with a simple PP power stage.

I found a schematic floating around the net of the overdrive channel of a high end "boutique" three channel guitar amp and got the silly idea that maybe i'd like to build this as a single channel low watt amplifier.

I've added a typical global negative feedback circuit with a "rich mod". Its a post phase inverter master volume using a 500k dual gang pot. This should help push not only the preamp stages but also the PI harder at lower volumes.

Now im unsure on the validity of the preamp schematic that im using. It looks feasible to me but perhaps a more accomplished individual could have a quick look and verify that it will not destroy the local power grid :wink:

Now to design a power supply using a hammond 372FX tranny. I just noticed that the output tranny in the schem is wrong, it should be a hammond 20watt 1640. Taps for 4, 8 & 16 ohms with the NFB connected to the 8ohm tap.

I noticed that the forum can't handle the width of the image so it can be seen here too...

http://groupdiy.twin-x.com/displayimage.php?album=lastup&cat=0&pos=0

well that looks like S_ldano. Always seemed like the perfect thing for a small low power amp, most of the sound in those amps are in the preamp, you just need to be sure to have a master volume, which you do. But it seems like you are reinventing the wheel, Mike S already did this and the schematic is online.

Atomic 16

adam

'tis actually a B_gner according to the original schematic but perhaps I should cross reference it just to make sure its not actually a S_ldano.

But since you mentioned it, I dunno if you guys here have seen http://sloclone.yesterdaysrevolt.com/index.php?sid=8ce49e7ea93fd9c27f2a73f23e31f753

its got some nice pcb and turret layouts for s_ldano gear. I've been tossing up what amp to build... 50watts scares me away. Its serious overkill for me...

Your right, I never noticed how simular they are to each other, I assumed you ment the X88R pre or head that was the X88R with a SL_100 power amp, forgot the name of that one though. The S_ldano and B_gners are really close though, just a tweak of a few resistors and you have the other.

adam