mshilarious
Banned
Earlier this month I got my inheritance early, my mom had an early-90s Peavey Rage 8" practice amp, which oddly enough she used as a PA for puppet shows 
Since I am due to get a new guitar for Christmas (yes, the So-Cal), I thought if I was gonna use this thing, I was gonna need to hot-rod it.
So I popped that bad boy open, called Peavey and got the schematic. Here's what I found: the two channels run off 1/2 each of the usual 4558 opamp, the guitar pedal maker's favorite. On top of that, there is the standard diode arrangement on the lead channel. I started to wonder why the Peavey's infamous Saturation control sounds like such poo, given its not very unique selection of components. Certainly, the complete crap speaker the RAGE suffers with is part of the problem, but looking at the lead channel opamp gain, it seems that it ain't real long before the opamp is driven into disgusting clipping. I ain't no wizard of opamp gain calculations, but I think the gain maxed at something like 3000
Needless to say, the lead channel had to go. I've designed a replacement with a 12AX7 stage, the design largely stolen from a Fender Champ. Of course that necessitated a revised power supply. . .
The clean channel I'm leaving largely intact, except for a few component changes: OPA2134 for the 4558, and few capacitor upgrades. The goal of the hybrid design is to get a clean channel as squeaky clean as it can get, and a tube that can be moderately overdriven.
The other thing the amp needed was reverb. I scored a spring reverb unit from the manufacturer, which sells custom reverbs on eBay. Cool, as I could spec exactly what I wanted--a short delay reverb, perfect for my surf-style guitar
The circuit board has a bunch of empty holes and lonely traces, a brief review indicates that it was designed for a reverb. That makes my life a lot easier in modding, as I will use the space for the reverb drive & recovery as well as some of the tube interface. Most of the tube and high voltage PSU components are going on a DIY circuit board.
That's the plan, along with a new Eminence 8" speaker. I had some of the parts, including the tube and transformer, so my parts cost is around $100 so far.
Here's my schematic:
Since I am due to get a new guitar for Christmas (yes, the So-Cal), I thought if I was gonna use this thing, I was gonna need to hot-rod it.
So I popped that bad boy open, called Peavey and got the schematic. Here's what I found: the two channels run off 1/2 each of the usual 4558 opamp, the guitar pedal maker's favorite. On top of that, there is the standard diode arrangement on the lead channel. I started to wonder why the Peavey's infamous Saturation control sounds like such poo, given its not very unique selection of components. Certainly, the complete crap speaker the RAGE suffers with is part of the problem, but looking at the lead channel opamp gain, it seems that it ain't real long before the opamp is driven into disgusting clipping. I ain't no wizard of opamp gain calculations, but I think the gain maxed at something like 3000
Needless to say, the lead channel had to go. I've designed a replacement with a 12AX7 stage, the design largely stolen from a Fender Champ. Of course that necessitated a revised power supply. . .
The clean channel I'm leaving largely intact, except for a few component changes: OPA2134 for the 4558, and few capacitor upgrades. The goal of the hybrid design is to get a clean channel as squeaky clean as it can get, and a tube that can be moderately overdriven.
The other thing the amp needed was reverb. I scored a spring reverb unit from the manufacturer, which sells custom reverbs on eBay. Cool, as I could spec exactly what I wanted--a short delay reverb, perfect for my surf-style guitar
The circuit board has a bunch of empty holes and lonely traces, a brief review indicates that it was designed for a reverb. That makes my life a lot easier in modding, as I will use the space for the reverb drive & recovery as well as some of the tube interface. Most of the tube and high voltage PSU components are going on a DIY circuit board.
That's the plan, along with a new Eminence 8" speaker. I had some of the parts, including the tube and transformer, so my parts cost is around $100 so far.
Here's my schematic:
I've been dying to build one of thoose ax84 amps forever. The whole kit is like 200 bucks. But the total cost would probally be well over 300 or so. That seems like a lot of money to invest in something that I *hope* I can put together. Your project is looking good though. You'll have to post mp3's when you finish.
