The Latest Amp Project

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Chrome Dinette
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The Latest Amp Project

Post by Chrome Dinette » Wed Jun 11, 2008 7:58 pm

So, one of the amps I built recently has this noise problem that has been hard to track down. The problem is that I don't have enough time between practices to work on it with enough confidence that I will have it back together quickly.

So, I resurrected this old heap:

Image

It started life as a Sovtek Mig 100. One of my earliest learning experiences was to convert it to using EL34's. To that end, I added a filament transformer amd also the output transformer from an old Traynor bass amp that got something like 160 watts from 4 EL34's.

I eventually got tired of it and wired it up like an Orange, but didn't like that, either.

Since I was in need of an amp, I recently gutted it again and built something new. It uses three 12ax7's and 4 6550's. I think I am done with EL34's. Current production seems too delicate and old ones are dissappearing and priced accordingly.

I wanted a decent amount of gain, but not too many stages, so I used the entire first tube for a cascode gain stage and the second and third tube for the typical Marshall cathode follower-tone stack-phase inverter.

Preamp tubes are using dc on the filaments. I used some hi-fi tweak-tricks also. The rectifier diodes are IXYS freds. I bypassed all electrolytic caps with orange drop film caps. I used Solen fast caps for all signal caps.

So far, it sounds great at home(through a THD Hotplate), but I'll find out how it really does at practice tomorrow.

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Moog$FooL$
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Post by Moog$FooL$ » Thu Jun 12, 2008 2:59 am

I love it!!
I really wanna build a combo amp with a single 12" someday, I'm just not sure what style to go for???

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Chrome Dinette
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Joined: Sun Feb 03, 2008 9:14 am

Post by Chrome Dinette » Thu Jun 12, 2008 5:00 am

If it's your first build, pick a design you know you like the sound of, but that isn't too complex. It also helps if you can find pictures of the inside of an existing amp that shows a parts layout similar to what you want to build In some of my earlier attempts, I made some weird layout choices when easier solutions already existed.

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