The Steel Guitar Forum

ONE OF MY SESSSION 400 AMPS BURNED OUT ON ME THE OTHER NITE. WHEN I TURNED IT ON, THE SPEAKER PUSHED ALL THE WAY OUT AND I COULD SMELL HEAT.I TRIED IT A COUPLE TIMES, BUT NO GOOD. ANYONE HAVE THIS HAPPEN TO THEM. I NEVER HAD ANY TROUBLE BEFORE WITH IT. ANY IDEAS ? PLEASE LET ME KNOW. I'M GETTING READY TO TEAR IT APART. I'M NO ELECTRONICS WIZ BUT SOMETIMES IT'S SOMETHING SIMPLE.

Darrell, I had A seesion 500 do that A few years ago.It even went so far as to blow out the speaker backing.The best I remember, it was quite expensive to repair.

If the speaker went all the way in one direction, it is because of d c voltage getting to the speaker. It is probably the result of a defective transistor, but with the heat that resulted, several other components may be damaged as well.

Good Luck,
Don www.armrest.donblood.com

You gotta quit playing that heavey metal.
Sorry about the joke and your amp. You have some serious problems that only a tech can solve.

If you let the smoke out of those things it's very hard to get it back in .Mine had a small screw fall ouy and shorted out across lots of little electronic gizmos , an expensive episode .

dang!

I thought I was going to read about how you totally nailed a studio gig

Ace Ventura style - Summowkin!

maybe next time (good luck with it)

Some years ago, I was experiencing noises like 'an electrical short' might make thro' a speaker.

A little later, I was getting a slight tingling in both of my hands while playing my Emmons.

A short-time later, I observed chunks of my pedal bar where my volume pedal was arching and burning out pieces.

Later, I could hear 'electrical' sensitive sounds through the speaker.

Some time later, I spotted light smoke up above the Session 400 handle then noticed two very bright little lights near the center of my speaker cone which seemed to be waivering or shimmering. This continued until it was obvious the center of the cone was about to burst into flames, which it eventually did within minutes.

The TECH informed me that the Session 400 had shorted out at a point just beyond the FUSE, and DC Current was getting into the metal structure of my EMMONS. Cost me $180.00, to replace my JBL and some other little electronic thingies.

You might have it checked out.

Years ago when I came back living in Canada from England, I brought a Session 500 back with me.

With having 240/250 volts back there, I had a "techi" transfer it to 110/115 volts on my return on the transformer which lasted about 6 years.

One night it just went silent and apparently toasted the mother board and according to the "techi" - it wasn't worth fixing.

I bought a Session 400 from a good buddy steelie of mine which I used for a little while.
Since I carried both my old D10 Z.B. into the gig plus the "balancing" amp, my arms became 1ft longer !!

I've been playing through a little fender Sidekick 35 and patching it through the mainframe of our main stage amp for about 6 years which has been just great.

An old friend of mine has recently quit playing after a lifetime of playing steel and has a 2 year old Peavey 110 for sale, I'm sorely tempted to buy it just for the hell of it. I'm sure it'll be a good sounding amp for many years to come.

All Z.B.est.

Bob.

When you throw that much DC into a speaker, the voice usually "cooks", so you're probably going to need a new speaker. All it takes is an output transistor shorting, and you're in "smoke city" with a solid-state amp. While the tech has it, have him replace all the electrolytic capacitors in the power supply, too, if the amp is over 15 years old.

Darrell, send me the chassis, reverb pan wiring harness and speaker and we will check it out for you and repair. Call me toll free at 1-877-732-8391, ext. 1180.

Thanks,
Mike Brown
Peavey USA

Mike,

I had a Session 400 in the 70's. It developed a crackling/popping sound so I took it to the local Authorized Peavey repair station. They determined that some of the output transistors went bad. They replaced them and within a week, failure again. After this happened 4 or 5 times, they finally told me that RCA had changed the specs (and manufacturing location) of these transistors and they would no longer work and the amp could not be fixed. Do you remember anything like that happening?

It made me switch to a Webb. After a few years of Webb use, I bought a Session 500. I was doing a lot of outdoor gigs in direct heat over 100 degrees and my 500 kept going down. We also had a CS800 that would shut down because of overheating. Well placed bags of ice and a fan took care of that problem. Finally the Peavey repair station told me I would not be able to keep the 500 running in hot environments. I just returned from Nashville where I was able to gig with a Nashville 400. Came home, 500 failed again. As this was under warranty, the store gave me a NV400 in exchange for the failing 500. Never had a problem with the NV400 and that was a 1983 model. Still use it today (although I did have Ken Fox do his mod about a month ago. Made a great amp even better). Just thought I would share this story with you.

When the speaker goes all the way out and the fuse does not blow then the amp went to one of the rails (50 volt DC). That is usually a result of an open component in the bias line, pushing one set of outputs in the push-pull arrangement to full rail. It usually cooks the speaker.

If a transistor shorts out it will blow the fuse. With all hope it saves the speaker.

I have repaired several of the Session 400 amps with new power transistors. The newer output transistors and these amps do not get along. An RF trap must be installed on the output to stop parasitic oscillation. This info I got from Jimmy at the Peavey repair center after I fussed with one for a week! The cap to ground on the speaker output took care of that. The RF trap was very common on the amps after that period. Typically a 22 ohm resistor in series with a .01uf cap to ground from the speaker output.