Problem with my Peavey PV1500 Amplifier

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T

The Wizard Of OZ

Well-Known DJ
Dec 13, 2007
3,130
50
68
Tampa Bay Area
My PV1500 that I got second hand off craig's list that I thought I got such good deal on is acting strange. I've had this problem twice. After running for a couple of hours I get distorted sound. It sounds kind of like crackling and the music is kind of muffled. The amp doesn't seem hot, just warm.

I never get the chance to really crank my system because of the places I play at and the audiences I play to, so I'm not pushing the amp hard at all. I always turn the attenuation all the way up. The last time it happened I was running in stereo with one speaker on each channel. These are not big or power hungry speakers. One time it was my EV SX100+ and the other time it was my EV ZX1 speakers which are little itty bitty things.

My 250 watt Radio Shack amp that I got for free works fantastic! It's not as heavy as the Peavey and not as powerful, but it cranks plenty loud enough and the sound is clean and clear. It's amazing, I bet it's at least 20 years old. The only thing I don't like is that it doesn't have 1/4" or speakon output jacks, just the red and black plastic caps that you unscrew and insert raw wire into.

I've come to the conclusion that either I'm going to get a light weight PLX type of amp or I'm going to go to powered speakers. I hate carrying heavy amplifiers around.
 
The Wizard Of OZ said:
My PV1500 that I got second hand off craig's list that I thought I got such good deal on is acting strange. I've had this problem twice. After running for a couple of hours I get distorted sound. It sounds kind of like crackling and the music is kind of muffled. The amp doesn't seem hot, just warm.

I never get the chance to really crank my system because of the places I play at and the audiences I play to, so I'm not pushing the amp hard at all. I always turn the attenuation all the way up. The last time it happened I was running in stereo with one speaker on each channel. These are not big or power hungry speakers. One time it was my EV SX100+ and the other time it was my EV ZX1 speakers which are little itty bitty things.

My 250 watt Radio Shack amp that I got for free works fantastic! It's not as heavy as the Peavey and not as powerful, but it cranks plenty loud enough and the sound is clean and clear. It's amazing, I bet it's at least 20 years old. The only thing I don't like is that it doesn't have 1/4" or speakon output jacks, just the red and black plastic caps that you unscrew and insert raw wire into.

I've come to the conclusion that either I'm going to get a light weight PLX type of amp or I'm going to go to powered speakers. I hate carrying heavy amplifiers around.
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Wiz, is it one of these? http://www.ourdjtalk.com/album.php?albumid=8&pictureid=215
 
Wiz, I would go with the powered speaker option that you mentioned. QSC HPR 122i might be a nice light weight solution or a Yorkville NX55. Both boxes are 12" models that will give you more than what you will need for the sound applications you described.
 
Sounds like you have a component on the circuit board breaking down under load.

If you are handy working on equipment, get a can of freeze spray open the case up and fire up the amp and run it until the symptom occurs.

Start at the main output transistor of the channel thats has the problem and spray a little freeze on it and listen. If that doesn't work and the audio remains the same, move backward and spray each transistor or IC in succession, until the audio snaps back to normal.

If that doesn't reveal the problem then go back thru and spray the capacitors and then if necessary the resistors.

Component level problems can be a bear to track down and this is best way I know of to find it for this case.
 
Wow, some good info!

Yup, Houston that's the one. Heavy MF too. :sqlaugh:

I payed $140 for it so if it goes belly up I'm not going to be bankrupt. I love bargains, but sometimes what looks like a bargain turns out to be not such a good deal. I have a lot of passive speakers so I'm most likely going to need a good quality, light weight power amp even if I do eventually get a pair of powered speakers. I'm always going to have at leat two different rigs.

I'm going to open it up and see if it's clogged up with dust first. Then I'm going to look at the guts to see if there is anything that looks obvious that might be burnt or discolored etc. If I can't find anything I'm probably going to take it to an audio repair shop for reconditioning. I don't think I'm up to the task of desoldering and soldering transistors and capacitors etc. I would most likely destroy the circuit board and the whole thing would wind up in the trash. :sqerr:

I need to try running in bridged mode to see if it happens.

Thanks and keep the ideas and suggestions coming! :sqbiggrin:
 
if you go the freeze spray route...

spray a section of the board at a time, then once you find the area that is causing the issue, you can narrow it down from there.

I would guess it's more likely to be a bad solder joint somewhere, or even just the connections. Some amps have ribbon cables or other types of connectors.

Before you buy a can of spray, and if you are knowledgeable and feel safe opening it up and running it, then maybe you should put it on the bench (kitchen table?) till it warms up and gives you issues. Then try with a plastic rod or maybe a chop stick (Don't use a pencil, the graphite is conductive!), pressing on connectors and wiggling them a little, maybe you'll find a part that causes it more, or clears it up, then you'll just need to power down and reseat that connector. You could try pressing on various areas of the board also and see if some specific area clears it up or makes it worse. If so, then it's possibly solder joint in that region that can be fixed easily somewhere. Look for the larger components to have solder issues, the boards are wave soldered, and sometimes the larger components don't get heated up enough to get a good solid connection.
 
Once I get the amp working 100% I'm putting on craig's list or ebay. It's way too heavy. If I can't figure out how to fix it I might just offer it up as is. I bet I could get $100 for it as is. It works fine, just not for several hours. What's cool is it has basically a crossover built in. I hope it's something as simple as a solder joint on a connection or a loose ribbon cable. Even I can fix something like that.
 
Wiz,

Don't open it up and i will give you the $100 for it right now no questions ask. I will just go by the way you descibed it working or not working as the case may be!

Once you open it up and start fooling around inside of it I will no longer be interested!

I have seen way to many very simple repairs become a basket case when someone who doesn't know what they are looking for start looking for a problem.
 
Thunder said:
I have seen way to many very simple repairs become a basket case when someone who doesn't know what they are looking for start looking for a problem.
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Got that right.

Gun control, bah. Some people should not be allowed to buy soldering irons. :D
 
I've changed out woofers and tweeters, installed many video cards, hard drives and built several computers over the years. I've done basic electrical wiring and can run a new 120 volt circuit into a service panel. I'm not a dunce, I just don't have experience working on power amplifiers. I'm going to open it up and see if it's clogged with dust and it there are any obvious loose connections. After that we'll see.
 
Present company excepted, Wiz. :)

If it's any help, I along with Steve, Sparkie, Balanced Line and several others here have worked as electronics bench techs. I am sure that I'm not the only one who has seen what we used to call in the biz, a "Chinese Abortion."

That is, you open up a television, a receiver, amp etc to find that someone was in there with a soldering iron and butchered the damn thing. I've seen component PCBs that looked like someone on LSD had taken a soldering iron to them. I've seen televisions that weren't a month old come into the shop, butchered all to hell. I've seen missing components, added components, wiring from power transformers cut... you name it.

Of course, you call the customer and they don't know a thing about it. :rolleyes:

I'm not inferring you'd do that. I know you wouldn't. Just sayin'... there are people out there who will... and do.

Steve will give ya a Franklin for that amp if you don't tinker with it. I'd take him up on his offer. :)
 
I guess Steves offer is no longer valid since you decided to post your current status with the amp and opening it. Oh well. Good luck.
 
I haven't gotten around to opening it up yet. I have a hunch it could be something simple and while I appreciate Steve's offer, I have no doubt I can easily sell it for $100 or more locally with no shipping costs to contend with.

It's still quite useful to me as a rehearsal system since I'm still learning lots of new songs and practicing the ones that are in my regular repertoire. I just can't trust it right now for paying gigs.

Thank Jon for your concern for my welfare. :sqlaugh:
 
Wiz,

I would have paid the shipping cost so you wouldn't have had to pay it out of the c-note!

I know how simple the repairs on these amps are (I have done a few over the years) I have also seen what happens when when repairs are butchered.
 
Thunder said:
Wiz,

I would have paid the shipping cost so you wouldn't have had to pay it out of the c-note!

I know how simple the repairs on these amps are (I have done a few over the years) I have also seen what happens when when repairs are butchered.
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What, you're not suppose to use a paper clip to bridge the Op Amp section to the output stage?

Who knew!

:rofl:
 
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