Servicing my Peavey Renown guitar amp head.

Hey Everyone,


I'm currently doing some servicing work on my Peavey Renown Solo Series guitar amp head, while the amp does work, when you first switch it on, and with either the clean or lead pre and post controls turned up, it makes crackling noises that disappear if you give the amp a few sharp thumps on the top of the cab with your fist, yeah it's a pretty low-tech fix, eh?

So far, I've given all the pots a good spray with contact cleaner, this weekend I'm going to pop into my local Jaycar Electronics store and buy four new TLO72CP ICs, and one new TLO74 IC as replacements for all the stock ICs, and seeing as I've got quite a few spare IC sockets, I'm going to replace all the stock ones with new ones for good measure, might even get two new 1/4 inch sockets to replace the stock input sockets while I'm at it.


I tried my Peavey Renown out with my Ashton quad box and it seems to work fine with it, apart from the crackling noise.

Later on, I'm going to make a new footswitch for it so I can footswitch between the channels.


The Peavey Renown has a built-in genuine spring-reverb effect that sounds pretty good, definitely useful for surf-rock.

Will post some pics of the Peavey Renown soon.


Stay tuned for more updates.

While you have it open on the bench changing those chips you might want to de-goop the input section of the board.

I had a old VOX VT amp that had yellowish goop holding some parts in place. When new the goop is fine but with a little age and if it is in contact with components in the input stages audio path it develops a weird electronic ability which translates to all kinds of static type noises. Get rid of the goop near input stage components and the noise goes away. In the VOX it completely covered the 1M SMD resistor to ground that referenced the 1st OP amp so the noise was permanently present though far less obvious when the gain control was wound down. Unfortunately when I removed the goop the SMD resistor came off with it so that component needed to be replaced for the amp to work as intended...

The goop when old and hard has far less effect in the main audio and the power section, though it can sometimes slightly upset bias currents...

Quote:

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Originally Posted by Marcel

While you have it open on the bench changing those chips you might want to de-goop the input section of the board.

I had a old VOX VT amp that had yellowish goop holding some parts in place. When new the goop is fine but with a little age and if it is in contact with components in the input stages audio path it develops a weird electronic ability which translates to all kinds of static type noises. Get rid of the goop near input stage components and the noise goes away. In the VOX it completely covered the 1M SMD resistor to ground that referenced the 1st OP amp so the noise was permanently present though far less obvious when the gain control was wound down. Unfortunately when I removed the goop the SMD resistor came off with it so that component needed to be replaced for the amp to work as intended...

The goop when old and hard has far less effect in the main audio and the power section, though it can sometimes slightly upset bias currents...

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Cheers Marcel, I'll give that a go this coming Saturday, I just tried the amp out after spraying the pots and then putting the chassis back in the cabinet, seems to have done the trick, but I'll still swap the ICs and sockets out for new ones, and give that de-goop thing a go too.

When I work on it again this coming Saturday, I'll post some pics of the chassis and the insides, I had a quick look at the main power supply smoothing caps, and they looked okay, no bulges in the bungs or any evidence of electrolyte-leakage, but maybe it might be a good idea to do a re-cap job on it later on.

Here's a pic of the Peavey Renown amp sitting on top of my Ashton quad box:

Attachment 27651


The Peavey Renown is a 160 Watt solid-state guitar amp, I think it's probably about 80's vintage, seems to sound pretty good through the quad box and the clean channel appears to take pedals pretty well, I need to make a footswitch for it cause it doesn't have one, although there is a footswitch socket on the back panel, I'm going to see if I can buy a plank of wood from Bunnings this weekend so I can make a front panel for it, going to cover it in Paisley cloth if i can find some in Darwin, should look cool once I'm finished working on it, the red power indicator Led on the front panel will be swapped out for a blue one, my way of customizing it further.

Update:

I'm going to be doing some more servicing work on my Peavey Renown amp today, had to completely replace the cable for the footswitch since one of my cats decided to chew on it, why some cats have a penchant for chewing on cables I'll never know, anyway, I decided to make the cable 10m in length.


Here's a couple of pics of the footswitch after replacing the original cable:

Attachment 30239

Attachment 30240



Here's what the three footswitches do:

Ch Select......Pretty self explanatory, it allows you to select either the Normal (Clean), or Lead (Saturation) channel, when the Normal channel is selected the Green Led lights, when the Lead channel is selected a Blue Led lights.

Reverb.....Again, self explanatory, it switches the spring reverb on or off regardless of which channel is selected, when the Reverb is switched on a Red Led lights.

Combiner.....When the Combiner footswitch is switched on, both the Normal and Lead channels are selected so you can get a blend of both channels, a Green Led lights when the Combiner is switched on.


Next job to tackle is to make a new speaker lead with a right-angle 1/4 inch Tip/Sleeve plug on each end, the original speaker lead I made also got chewed by one of my cats.

I also need to replace all the wiring to the Blue power indicator Led on the front panel, sometimes it doesn't light up when the amp is powered on, I suspect a dirty contact or two in the plug that plugs onto the circuit board.

And then there's two pieces of pine wood in the back of the amp that need spraying with some matt black paint.

Then the last job on the list is to stain and clear coat the wooden front panel of the Renown amp, which I had made out of a piece of 12mm thick pine wood, I'm using some Cabot's Walnut wood stain to stain it, and some White Knight clear gloss to seal it, should look great once it's finished.


I'll post a pic of the amp once all the work on it has been completed.


I still have to replace all the ICs and IC sockets on the circuit board, that's a job for next fortnight.


Once I get all the above jobs, except replacing IC sockets and ICs, done, I'll post a pic of the Renown amp, and maybe a quick demo.

@ Marcel Do you know of any way of reducing hum in solid-state guitar amp Reverb circuits?, I've noticed that the amp tends to hum a bit when the Reverb is switched on, when the Reverb is switched off the hum goes away.

So today, I finally got round to putting some Cabot's Walnut Woodstain on the wooden front panel of the Renown amp's cabinet, the woodstain itself is water based and will be fairly easy to clean up afterwards, it's what I could best describe as a dark chocolate-ish brown colour, but I'm thinking that it should lighten up a bit, should look nice after clear-coating.

Attachment 30289


The wooden front panel is just a piece of 12mm thick pine wood I bought from my local Bunnings store.


Update:

Just finished clear coating it, so far it's looking really good.

Here's a pic of the Renown after I put it all back together after re-installing the wooden front panel, all it needs now is a silver Peavey logo to go on the front and then it'll be complete:

Attachment 30299

Looking good! How much do you have to crank 160w to get high-gain leads? I've got a 210w Peavey Vegas 400 (slide guitar combo) and used it for party once - you could hear the doofs about 15km away with it turned up to 6.

Quote:

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Originally Posted by G-Axe

Looking good! How much do you have to crank 160w to get high-gain leads? I've got a 210w Peavey Vegas 400 (slide guitar combo) and used it for party once - you could hear the doofs about 15km away with it turned up to 6.

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Since the Lead channel of the Renown has a control labelled "Saturation", I find that the amp doesn't have to be cranked much at all, the three controls on the Lead channel are "Pre", "Saturation", and "Post", Pre is basically a pre-gain control, Saturation controls how saturated the distortion gets, and Post is basically the master-volume for the Lead channel, in addition to that, you have the choice of plugging into a low-gain input or a high-gain input, Pre also has a "Pull-Bright" switch on it as well.


Here's a close up pic of the Lead channel controls:

Attachment 30307


And here's a close up pic of the Clean channel controls:

Attachment 30308


On the Peavey Renown, the Clean channel is called the Normal channel, the built-in Spring Reverb effect works on both channels.

That all looks pretty familiar. My Vegas has everything but the saturation, but that's to be expected.

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