Extreme Peavey RAGE mod!

[mshilarious]

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:

[mshilarious]

Now the fun stuff: it has to look the part too, matched up with the So-Cal The Peavey cheap black vinyl had to go, along with the cheesy pointy logo and aluminum strips.

I chose burgundy carpet and a turquoise-silver grill cloth. Tomorrow the speaker and grille cloth go on, but here's where I am right now:

[mshilarious]

Stay tuned for more updates! This weekend I'm starting work on the circuit boards, I'll post pictures as I go, and hopefully I'll finish by Christmas, then I'll post a clip with the new axe

[Jamal Bucket]

you realize you are doomed to hell for buying that guitar right?

DOOMED.
TO.
HELL.

hey but that looks like a cool little amp project ..funny i have that same 158 staring at my from the corner of this room .



DDDOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOMED

[mshilarious]

Originally Posted by Jamal Bucket

you realize you are doomed to hell for buying that guitar right?

DOOMED.
TO.
HELL.

It'll be a gift

hey but that looks like a cool little amp project ..funny i have that same 158 staring at my from the corner of this room .

Yeah? I could design a lot simpler mod if you are interested. And I will have leftover grille cloth

[JazzMasterWil]

What's a so-cal? I must be really out of the loop.

That amp project is looking fun 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.

Where are you in N.C.? I'm right outside of Charlotte.

[mshilarious]

Originally Posted by JazzMasterWil

What's a so-cal? I must be really out of the loop.

That amp project is looking fun 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.

Where are you in N.C.? I'm right outside of Charlotte.

I'm in Kill Devil Hills. Hey, join the HRBBS Frappr!

http://www.frappr.com/hrbbs

Warning: timid guitarists should divert their eyes!
















This is a So-Cal:

[Jamal Bucket]

Originally Posted by mshilarious

It'll be a gift



Yeah? I could design a lot simpler mod if you are interested. And I will have leftover grille cloth

hell yeah !...actually i have often thought about covering the entire outside in aluminum plate ...back when i worked at a metal fab shop ..

[gbondo9]

I like the guitar (As I stated in the flame socal thread before)...but have you tried it yet? Anybody know what it sounds like?

T

[gbondo9]

Nice project btw!! Ive dinked around with making a few easy distortion pedals, but I still have alot of trouble reading schmatics. Seems I have to re-read my books every time I want to do something new.
You got any good suggestions for remembering and reading scematics?

[apl]

Holy Smokes, ms!

You've jumped a few notches in my tech repect book!

And it takes a special kinda guy to play that So-Cal!

[punkin]

You already know that you're a freak...right!

Love whatcha doin' child...love it!

[mshilarious]

Originally Posted by punkin

You already know that you're a freak...right!

Hmmm, let's see, I'm a guy that uses his wife's SN . . . yeah, I figured that out already

And it takes a special kinda guy to play that So-Cal!

In the summer, I'm all Hawaiian shirts, all the time

I like the guitar (As I stated in the flame socal thread before)...but have you tried it yet? Anybody know what it sounds like?

Nah, like I said, it's a Christmas present. If it sucks, I'll send it back. If I like it, then I'll mod it

You got any good suggestions for remembering and reading scematics?

I'm still working on basic concepts. First you gotta understand Ohm's Law, and how to calculate series and parallel resistance. Next, try to understand how these components work:

- Voltage dividers, AKA a couple (or more) resistors.

- Opamps. Probably the most complicated component, but fairly easy to understand their function.

- Transistors. These are commonly used in a couple of different ways.

- Tubes.

- Diodes.

Here's a good website:

http://hyperphysics.phy-astr.gsu.edu...roncon.html#c1

for tubes:

http://www.rru.com/~meo/Guitar/Tubes/t2.pl

I had a look at the AX84. That seems like a fairly straightforward project. Personally, I've never felt a great need for power tubes, since I'm not gonna drive 'em hard enough to matter. A solid-state output stage is a lot cheaper, since you don't need the power tube (obviously) or the output transformer. But then again, that's a big part of the tube amp sound.

hell yeah !...actually i have often thought about covering the entire outside in aluminum plate ...back when i worked at a metal fab shop ..

PM me and I'll mail you some leftover grille cloth

I'll send you the Peavey schematic . . . the simplest thing I think would be to change R15 (not R15 above! Referring to the Peavey original here), that is responsible for clipping the lead stage so bad. The stock value is 100; I'd start with 3.3K and adjust up or down as necessary. Hopefully that should make the SuperSat knob useful past 2

I haven't decided what I'm doing about caps. The electros are being replaced with better-quality units, but there are many ceramics in the signal path. The EQ works entirely off of ceramic caps. That isn't necessarily a bad thing; they can add lots of 'color'. The other option would be to replace all the ceramics with poly film caps, which should be cleaner. I will change all the large-value ceramics (>100pF) outside the EQ circuit, inside the EQ I dunno yet.

The next obvious change is the speaker, the Eminence is a $50 part though. You might want to wait until I have a listen

A change to the schematic--R2 to 470K. That first opamp stage thus far is Peavey stock, other than cap swaps and the opamp swap. I want a higher input impedance. C8 also changes to 10pF; the stock design filters above 7kHz It's supposed to just filter ultrasonic frequencies to prevent RF from hitting the opamp.

Next I would look at the diodes in the lead channel. They are 1N4148, silicon diodes placed for hard clipping. If you wanted to change the quality of the distortion, try changing them to germanium or LEDs (route one of the LEDs through the front panel for a drive meter ).

A good page for that:

http://users.chariot.net.au/~gmarts/ampovdrv.htm

The stock Peavey is most similar to the ProCo Rat schematic, but at potentially higher levels of opamp gain (and thus clipping).

[mshilarious]

Here's a picture of the unmodded board--I have mounted the new transformer though. Just to the left of the tranny I have mounted a grounding screw--the stock Rage uses a two-prong plug and is grounded via the input jack

[Toki987]

That`s slick. You should send Hartley some white paper and pics of the results. He might give you a job out there. But you`d need to learn how to eat peas and cornbread.

By the way, did you get the matching spandex pants for that guitar?







It`s nice and has clean lines.

[mshilarious]

Originally Posted by Toki987

By the way, did you get the matching spandex pants for that guitar?

Yeah, I bought some of Kevin Dubrow's old ones off eBay. Man, I tell you, he needs to learn to wipe

[TheRockDoc]

Originally Posted by mshilarious

Yeah, I bought some of Kevin Dubrow's old ones off eBay.

I hear they came with a free hairpiece if you do a "buy it now"...
"C'mon, feel my noize...
no hair- on my toyz"

LEMME HEAR YA SAY YEAHH

[Jamal Bucket]

OR ...
you could save all the effort of modding that peavey and just get one of these!!!

http://www.hottieamps.com/

[mshilarious]

Originally Posted by Jamal Bucket

OR ...
you could save all the effort of modding that peavey and just get one of these!!!

http://www.hottieamps.com/

That's awesome In my younger days I built a mini-ITX radio controlled Hummer, inspired by this site:

http://www.mini-itx.com/

I never submitted it to that site; I probably should have

[bigwillz24]

Well I know who to ask my questions about audio electronics next semester...

[mshilarious]

OK, here's today's progress. Unlike the ugly rear-mounted stock speaker, I wanted the Eminence flush with the front, hi-fi style It will be more of a pain to swap in the future, but I'm not the type to blow a speaker (I'll be testing the circuit with the stock unit!)

So I had to route the front to fit it in--first time with a router, not too bad for me, I think (woodworking and me do not get along )

It's an Eminence Front

[mshilarious]

Here's the rear view:

[mshilarious]

Next came the grille cloth. That was harder to work with than I thought. I wanted it to run diagonally for the extreme look, but those of you experienced with the fabric arts know that it's a pain in the ass stretching on the bias

So I retreated to the conventional look:

[JazzMasterWil]

Looking good

[Jamal Bucket]

Originally Posted by mshilarious

Next came the grille cloth. That was harder to work with than I thought. I wanted it to run diagonally for the extreme look, but those of you experienced with the fabric arts know that it's a pain in the ass stretching on the bias

So I retreated to the conventional look:

man that looks AWESOME!..nice work ...have you plugged it in yet??