Session 500 breaking up/losing volume/crapping o

John Neff · Post by **John Neff** » 6 Sep 2005 9:07 am

The amp techs here in Athens generally don't like messing with solid state amps. I'm hoping someone here can either tell me what part of the amp is the likely source of the problem, or who in the Atlanta area could/would fix it. I have a gig coming up in a week and a half that will require an amp that loud, and unfortunately, buying a new one isn't an option I have.
Thanks in advance,
John

Bob Tuttle · Post by **Bob Tuttle** » 6 Sep 2005 9:28 am

Try using some contact cleaner and spraying the "pre-amp out" and "power amp in" jacks in the back panel of the amp. Then run a guitar cord plug in and out a few times to clean the contacts. That has worked for me in the past. Or, you can take a short patch cord and connect these two jacks. If that solves the problem, then the cleaning should be all you need.

Jack Stoner · Post by **Jack Stoner** » 6 Sep 2005 9:59 am

Get the amp down to Ken Fox in the Valdosta area. It may only be dirty pots or jacks but it could also be filter caps or whatever.

Ken posts on the forum regularly, I don't have his phone number.

Dennis Wallis · Post by **Dennis Wallis** » 6 Sep 2005 11:41 am

That is a common problem with Peavey amps. They nearly all develop that problem eventually. It is usually a loose solder joint somewhere and is usually hard to find. It is my experience that the ONLY real way to get it fixed properly is to take the chasis out and send it to the PEAVEY repair center. They will fix it right and it will probably cost no more,maybe even less. You won't be sorry. I've had several amps fixed by them AFTER trying local techs and paying them. They said it was fixed but wasn't. TRUST ME on this one.

Jack Stoner · Post by **Jack Stoner** » 6 Sep 2005 12:09 pm

Dennis, although you had problems with local "tech's", there are competent tech's around other than Peavey.

I agree Peavey does an excellent job and the price is right.

Mike Brown · Post by **Mike Brown** » 6 Sep 2005 1:50 pm

Let me state this..................the Session 500 was manufactured in 1980 through 1985. So, the amp in question has to be at least 20 years old. If this amp was even serviced once since that time, I would consider that a good track record.

Any product made by the hands of man is susceptable to break down. Even though you might hear of dirty contacts or switching jacks often on this Forum, consider the number of times that an amp is transported in a car or truck, cables have been inserted into its jack, etc., etc.. The track record is pretty good for Peavey amps.

Our turnaround time is quite lengthy at this time, but I'll be glad to walk your amp through our service department and return it to you as quickly as possible.

Contact me toll free here at Peavey by phoning 1-877-732-8391, ext. 1180 and provide the UPS or Fedex tracking number for your package.

Mike Brown
Peavey Electronics Corporation

Dennis Wallis · Post by **Dennis Wallis** » 6 Sep 2005 6:44 pm

"Experience is the best teacher,but sometimes the tuition is high ".

Dan Beller-McKenna · Post by **Dan Beller-McKenna** » 7 Sep 2005 3:35 am

Mike Brown's comments bring up something I have been thinking about recently. In the age of excessive bidding for vintage tube amps, I have been ever more aware of how many of these amps seem to have chronic problems. Isn't it entirely reasonable to expect a 25-40 year old amp to start losing some quality? Not only are these made by human hands, they are extremely complex devices with dozens (hundreds) of parts, that could fail with age. Of course, some amps will hum along happily for decades if maintained well; but maybe we shouldn't be surprised when, after 30 years or so, they slip or give out all together.

I now own two 25+ year-old peavey amps. I am impressed that they work (and, more importantly, sound) as well as they do. Perhaps we all have let the unrealistically rising price of vintage amps skew our expectations of how long these items can be expected to work as if they were new.

Just a thought.

Dan

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Dan Beller-McKenna
Durham, NH
Dekley S-10, Telecaster, Guild D-35, Peavey Heritage VTX

Gary Walker · Post by **Gary Walker** » 7 Sep 2005 10:13 pm

My "500" suffers when the connectors aren't cleaned once in a while.

Mike Brown · Post by **Mike Brown** » 8 Sep 2005 5:08 am

Thanks Dan, that is exactly the point that I was trying to make. Our automobiles do not function properly without periodic maintenance. <font size="1" color="#8e236b"><p align="center">[This message was edited by Mike Brown on 12 September 2005 at 09:29 AM.]</p></FONT>

Ernie Renn · Post by **Ernie Renn** » 8 Sep 2005 5:35 am

The only one I haven't had in the shop is the Session 400 Limited. I've had a couple of knobs broken off of it and had to replace the pots, but it's never been down to where I couldn't use it. (KNOCK ON WOOD!) It's a little bit beat up, as I didn't have an Anvil case for it and the roadies did a number on it. BUT it still works great! (Well, other than the reverb not working. I didn't fix it because I quit using the stuff.)

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My best,
Ernie

www.buddyemmons.com

Jack Stoner · Post by **Jack Stoner** » 8 Sep 2005 5:38 am

Fortunately for us tech's, equipment does "break" or doesn't last forever. If it did there would be no need for warranties, customer support staff, etc.

However, the reliability of most modern equipment is outstanding, and we take it for granted that when we power it on it will work. Reality is that it ultimately will "break" or need service, some will last longer than others before service is needed but ultimately it will need service.

I will say Peavey does an excellent job with spare parts for most of their equipment. Some others are not that good, e.g. I tried to get a schematic for a Rocktron Sidewinder preamp, made in the mid 90's and Rocktron cannot (or won't)provide a schematic and except for commonly available components (e.g. parts that can be obtained from electronic parts distributors), they no longer have parts for the unit.

Ad Kersten · Post by **Ad Kersten** » 8 Sep 2005 10:15 am

John,

Dennis could be right. I had that problem once and it appeared to be loose contacts at one of the coils near the input jacks on the back.

Ad

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Zumsteel S12U

Yo, Man! homepage

David Wren · Post by **David Wren** » 9 Sep 2005 9:53 am

Mike, I'm constantly impressed by your commitment to go that extra mile for steelers here on the forum. Thanks...
however so far my '80 500 is still working like a champ.... is does seem a little heavier lately?

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Dave Wren
'95Carter S12-E9/B6,7X7; Session500; Hilton Pedal
www.ameechapman.com

JW Day · Post by **JW Day** » 10 Sep 2005 9:33 am

AFTER READING ALL THE 500 POSTS, I FEEL THAT I MUST SEND IN MY 2 CENTS WORTH. I THINK I BOUGHT MY 500 IN 1981. I'VE HAD TROUBLE WITH FROM DAY ONE. NO, NOT WITH THE SOUND OR THE SERVICE IT HAS GIVEN ME. BUT AS I GET OLDER I THINK THE DARN THING GETS HEAVIER. THE ONLY THING I'VE EVER DONE TO THIS AMP IS TAKE IT OUT OF THE CASE AND VERY CAREFULLY VACCUM IT ONCE IN A WHILE. WOULDN'T RADE IT FOR A BRAND NEW 1000. THANKS MIKE AND ALL THE PEAVEY GUYS JW DAY

Al Carmichael · Post by **Al Carmichael** » 11 Sep 2005 8:47 pm

I'm having the same problem with my LTD 400. I've sprayed everything with contact cleaner, but it hasn't resolved the issue.

When the sensitivity is turned down, the preamp section seems to deliver a crystal clear signal. Its only when I turn up the sensitivity and the amp is loud that I get crapping out, or unmusical distortion.

I am going to do a filter cap replacement to start, as the originals have been in there 30 years, LOL! Oh, the amp works--no DC hum or anything, but it won't stay clean on the transients. I'll let you know how it works out.

Jack Stoner · Post by **Jack Stoner** » 12 Sep 2005 2:05 am

Al, get a kit and replace all the electolytic caps on the preamp board. Along with filter caps that should clean it up.

Al Carmichael · Post by **Al Carmichael** » 12 Sep 2005 6:43 am

Jack--I've been trying to find such a kit. Brad Sarno doesn't have 'em and the Lemay site seems to be off line. Is there any other source that you know of?

Mike Brown · Post by **Mike Brown** » 12 Sep 2005 8:31 am

David, thanks for your understanding and support.

Jack Stoner · Post by **Jack Stoner** » 12 Sep 2005 11:57 am

Mike didn't respond but I though Peavey had a kit for the older 400's?

Al Carmichael · Post by **Al Carmichael** » 12 Sep 2005 7:03 pm

Jack--I may try to call Mike, but I think the kit they have is for the Session 400 Limited--the one with the IC chips in the circuit. If nothing else, I imagine they have the filter caps at Peavey.

Jack--if you know some electronics, I have a question for you. Brad Sarno says replace the 2.2uf electrolytics with film caps. OK, I believe him as he knows what he's talking about. I was just a tad confused because I know electrolytic caps are polarized and can only go in one way. Film caps are not polarized, right? They can go in either way? Just making sure!

Jack Stoner · Post by **Jack Stoner** » 13 Sep 2005 2:16 am

Yes, Electrolytics are polarized and film are not. However, here's one for you on the NV400 mod, Lemay reverses the polarity of one electolytic replacement cap, the Peavey mod kit also replaces the same cap but does not reverse it and they both work.

You may want to see if you can find a phone number for John Lemay in Gettysburg, Pa. He probably still has some kits around.

Al Carmichael · Post by **Al Carmichael** » 13 Sep 2005 10:21 am

Thanks Jack. I appreciate your reply and knowledge!