Peavey 5150, the OG, the GOAT

I tore down the EVH tonight. The problem turned out to be the transistor that mutes the pop that happens when you switch channels. It identifies as two diodes rather than a JFET.
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J174s are obsolete so i put in a J175. I know it’s working because it’s friggen LOUD again.

The main board is kinda flimsy and judging from all the jumpers it must be cheaper to hire prison labor than to pay for a double sided PCB. 😂
 
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Well, putting the amp back in the head shell, I mucked up two of the cage nuts. I need some fresh ones. I believe they are plain old 10-32s.

Oh, I swapped some preamp tubes and it’s much less noisy now.
 
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I had the pre amp valve schematic for that amp and it made all the difference when knowing the gain staging in replacing preamps.

I even had an old thermostat westinghouse AX12 in mine at one point. (That was colorful)

Here's an off question, does anybody know where to find the baffle screws for those cabs? I seem to be missing a bunch and have gotten dead links for replacements so far.
 
I had the pre amp valve schematic for that amp and it made all the difference when knowing the gain staging in replacing preamps.

I even had an old thermostat westinghouse AX12 in mine at one point. (That was colorful)

Here's an off question, does anybody know where to find the baffle screws for those cabs? I seem to be missing a bunch and have gotten dead links for replacements so far.
Are you talking about the 21st thing on this list?

 
Are you talking about the 21st thing on this list?

Nah, those are for mounting speakers to the front baffle.

What I'm looking for is what holds the back baffle on the cab to keep the low end tight. (My baffle warped without me knowing when it was in storage and the screws fell out, lost forever)

They kinda have a round washer head with a self drilling tip.

I'm very lost on this one, and that's usually not my Motus operandi
 
I should have tried rolling tubes long ago. It made a significant difference.

Long plate in V1 and a low noise 7025 in the phase inverter gave it a little more girth and really quieted it down.
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Last Sunday was quiet and relaxed. It was hot outside — around 87°F.
My AC was battling the heat off my MW Dual Recto while I was having an absolute blast.

Then, it happened. I opened Reverb, and there it was in my feed: a 5150 Block Letter. The one I had been eyeing for the past week. Located in Arizona. Local pickup only — 365 miles away, just over five hours of driving.

I’d been leaning toward local options anyway, mostly out of concern for what could happen to a such heavy and old amp. This one looked OK, and may by? thanks to the desert climate, there was no visible rust. Aside from some small tolex chips here and there and a small scratch on the faceplate, it looked good.

Listing picture:

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My GAS spiked. I messaged the seller with a few questions and completed the transaction.

The next morning, Monday, I woke up at 6 a.m., jumped in the car, and hit the road.

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Sometimes it really is a blessing to work remotely.

Twelve hours and over 720+ miles later… it’s finally home.

I cleaned every inch of it and took a look inside. The PCB is pristine. No mods, no visible repairs. No scratchy pots, no popping. It's in amazing shape for a 33-year-old amp. The serial number puts it at 1992, and some PCB markings show 1991.

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Power tubes are a mix: two inner Sovtek 5881/6L6WGC and two outer Sovtek 6L6WXT. I don't have a strong opinion on those yet — they sound good so far. I might grab a matched quad with a low rating just to see if it makes a difference. From what I understand, this is a fixed cold-biased amp, so maybe it won’t matter too much for my needs.

As for the preamp, most of the 12AX7s are unbranded with just a vertical red "12AX7" marking, along with a couple JJs.

It sounds glorious!

I still need time to explore all the classic settings and see what sticks. First thing I did was dial in the "666" settings — and I was surprised. It actually sounded a lot like my Dual Rectifier, but with a very noticeable midrange honk. That was interesting.

Compared to the EVH 5150III I used to have — which I quickly A/B’d by re-recording some of the same riffs — this OG 5150 has less gain, more body, and a different kind of sizzle. It doesn't sound the same — and that’s what I was expecting.

So far, I’m loving it. This amp is a keeper for sure.

Now I need to replace my shelving to fit 3 amps.

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So is OP gone because people told him to eat fish prepared correctly and using global cuts is not always the way to go when using modelers?
 
IDK but OG 5150s are :chef

I sometimes wish I still had mine but it's big and heavy and I can definitely scratch that itch with a good modeler through the power section of a tube head.
 
Get a schematic of the the order for the Pre Amp Valves - if you want to adjust beyond all matching 12AX's.

I tried the 5881's solo, and a combo with 6L6's, but that amp was MADE for 6L6's and nothing sounds better on a stock version than matching 6L6's.
 
Well, my old 1992 amp is having the fading volume issue. Looks like I’m going to have to open it up.

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Old thread I know, but I assume when you say fading volume that you mean it started loud but dropped off?

I ran into an issue with the volume on mine in late 2024, opened it up a couple months ago and found I was dropping a lot of voltage between the power tube heater supply from the transformer and the filament rail. The heater filament wire connector on the ribbon cable between the main PCB and power tube PCB was scorched, so I soldered a wire jumper across the posts and saw an improvement but still a noticeable drop, so I added another wire jumper direct from the heater supply pads directly onto the heater supply trace. I think it made another improvement, but now I'm paranoid that it's still not quite as loud as it should be. Were you able to test the transistor in-circuit, or did you have to desolder it? I'd be interested to check mine just to be sure.
 
Found this comment and rushed to my QC to try this preset… Holy fucking hell is it good!!! 🤘🤘

Father and Inositol?


Inorite? Haha. Glad you dig! I dont normally like the factory ones but I still go back this one from time to time, it's sweet.
 
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My very first tube amp was a block letter 5150 I got off eBay when I was 15 or 16. It was glorious to me at the time for a bit then quickly died and ultimately got stolen by a coke head “tech” that fleeced me for “parts” for a bit


Years later I had a 6505+ that after a lot more experience, I ultimately could never bond with. Got kind of soured on the the OG line. One of those “sounds good in everyone else’s hands but I hate this in mine” type scenarios


The III I have now (but also hardly ever plug into these days) is everything I ever wanted a 5150 to be but I know lots of folks disagree with that take
 
The III I have now (but also hardly ever plug into these days) is everything I ever wanted a 5150 to be but I know lots of folks disagree with that take
I love the 50w III’s. I was an OG 5150/6505 guy for a long time, then I got a 1st gen 5153 50w and loved everything about it except the volume jump between the green and blue channels. That single flaw sent me on a decade+ long journey through many different amps. Years after they released the 2nd gen 5153s I found my way back and realized it was pretty much perfect.

And then I recently reinvigorated my love for the OG again. I suppose if I was smart I’d just have a 5150 and a 5153 50w 6L6 and call it done. But I’m very happy with my QCs ability to hit those tones and I’m happy with not using space on multiple amp heads.

But damn, I do love me some 5150s and 5153s ❤️
 
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