Noisy Peavey EVH 150

[Ted]

I've got a Peavey EVH 150 here. It sounds unusually noisy, but I was wondering if anyone had any experience with them - just to find out if they're all like that.

With the Lead channel selected and everything at 10 I'm seeing about 4V of noise into an 8 ohm load. (Measured with an audio millivoltmeter). This only amounts to a couple of watts but it sounds very noticeable.

I appreciate that high gain channels tend to be noisy. Any opinions?

[Enzo]

Everything on 10? In a 5150????? Good Lord, that's like sitting on a bonfire and complaining about the heat.


I can;t tell you if you get excessive noise, but there is plenty of hiss in the lead channel. Gain and noise go hand in hand. Some amps are noisier than others, sure, but as a rule of thumb that is usually the case.


But tell me this, with the knobs all on 10, can you actually plug a guitar into it and get anything useful out?

[Ted]

But tell me this, with the knobs all on 10, can you actually plug a guitar into it and get anything useful out?

Plug a guitar into it? I think not. No sensible person would do that. Would they?

Just turned up to 10 as a reference on the off chance that someone out there has one on their bench to compare.

The owner has complained about excessive noise. But I wasn't convinced. Some hard measurements would convince me.

[Dave Curtis, dB AudioTech]

Every 5150 I had on the bench was, IMHO, very noisy. That, coupled with the non-tech-friendly build, are two main reasons I don't like them.

[bluesfreak]

Maybe I am considered not normal but I like the 5150, at least after doing some modifications to it
The "problem" of this amp is IMHO that even the clean channel runs thru all six gain stages and each stage is designed with very high gain where a lot of it is thrown away again after each stage thus a lot of hiss is added to the signal. I did replace a lot of the caps in the preamp with WIMAs (much more silence after that!), got rid of the 2 100pf caps on the output stage and adjusted bias properly. Those peaveys do run ice cold so if you get the poweramp into a more normal region it sounds even better, having it all on 10 will then kill any small animal within a 20ft diameter...
Also have a look on the FX Send/Return and Preamp Out sockets, dirty contacts there can cause a drop in signal quality and add noise as well.

just my 2c

bluesfreak

[JerryP]

The 5150 lead channel with the gain above 3-4 is noisy.
-Different preamp tubes can be noisier than others, you might try swapping them around.
-Try using the low input jack.
-If the noise really bothers you a noise gate in the effects loop will take care of it.

I find the 5150 one of the easiest amps to work on. I can have one completely gutted and on the bench in less than 15 minutes.
Jerry

[Dave Curtis, dB AudioTech]

The 5150 lead channel with the gain above 3-4 is noisy.

Boy, howdy!

-Different preamp tubes can be noisier than others, you might try swapping them around.

Or getting some from a dealer who screens them for noise. Good advice for any hi-gain amp.

-Try using the low input jack.
-If the noise really bothers you a noise gate in the effects loop will take care of it.

Both of these suggestions "fix" an issue that, IMO, should have been addressed in the prototype stage.

I find the 5150 one of the easiest amps to work on.

You have an odd sense of humor. In my book, they're not quite as difficult as the average Mesa amp, bit they're certainly not the easiest amp I've worked on. So far, that would be the old Earth B2000 I had in a few weeks back; flip it over and remove the bottom panel. No tunnel-shaped circuit boards or ribbon cables or 1/4 watt resistors. I can see why you'd defend the build quality, since you stand to benefit from "fixing" these hiss generators. I work on them, but because of the modern "production line/spit 'em out" build, it takes longer. That, however, is not exclusive to this amp. Many newer amps use construction methods intended to get the maximum number of amps out the door per day using the least amount of money. Construction methods that are best left in computers, IMO. Accountants have more control of the build than EEs do.

I can have one completely gutted and on the bench in less than 15 minutes.
Jerry

Well yeah, but please tell me how replacing one of these pots could be considered "tech-friendly":

[Enzo]

Well, Dave, that photo is not of a 5150. That is maybe a 5150 COMBO or a Classic 30. Those two models from PV are indeed inconvenient. But even on those, once you have done it once, it takes longer to gripe about it than to take it apart.

Jerry may have a vested interest in 5150s for his mod business, but I don't. and I have to agree with him that the 5150 - NOT the 5150 Combo - is not hard to work in at all, nothing remotely as inconvenient as some recent Mesa. The boards are simple enough to get out, with the exception of the power tube socket board, and frankly that almost never has to come out. If it does, then 8 rivets and it is done. Change a pot? 15 minutes.

Both of these suggestions "fix" an issue that, IMO, should have been addressed in the prototype stage.

That may be right, but the point is moot. The customer already owns the gear. It is too late to have it redesigned for him.

[Ted]

Well thanks for your responses - enough to convince me that "they're all like that". As someone pointed out, passing the signal through 10 stages of tube amplification would tend to make it pretty noisy.

A new set of tubes, tighten up the sockets, clean the pots and my customer was very happy indeed.

[Dave Curtis, dB AudioTech]

Yes, it's the (rather heavy) combo. I've had a few heads in here but I didn't have to open them up. Sorry for going a bit off-topic; I didn't mean to pop anyone's bubble. They are decent amps and what they do, they do well.

[bluesfreak]

Good to hear that it is running again Ted.
Btw: Has anyone tried one of the so called Integrated Tube Kits which means that you run a Mix of KT66 and 6L6 in this Amp? I would expect some more boldness in the sound and more bottom. SO far I haven't tried that yet but I am considering to test it on my own windsor as according to the schematic it also can run 6L6...

cu
bluesfreak

[PFC_Camp]

Your picture the white little box on the left what is that it fried today in my peavey 5150 combo

[PFC_Camp]

Today my 5150 combo died i turned it on letting it warm up like usual then it made a faint pop sound and started smoking a stinking i unplugged it took it apart and found this white box thing top right of picture fried and the board where the post that holds it is a little burnt also what is the part and is this thing fixable sorry could not use my own picture said it was to large for forum

[g1]

Do you mean top left in that picture?