Question(s) For Brad Sarno (or other amp techs)

Al Carmichael · Post by **Al Carmichael** » 19 Aug 2005 9:13 pm

My questions are in regard to a Peavey LTD 400 that I just picked up. Its probably close to 30 years old and its original inside. I just checked out your Session 400 mods page (great, by the way!). The amp is giving me some nasty clipping at high volumes, especially in the high frequencies.

I want to do the filter cap replacement mod as well as the other mods shown on your website. My first question is: do you or does anybody actually sell a kit with all the needed caps? If not, where is a good source for the filter caps? I've never seen filter caps that have both leads on the same end--only the kind I've used in fender amps in the past. I can probably get all the smaller caps from Mojotone.

Any suggestions would be a great help. Thanks!

Dyke Corson · Post by **Dyke Corson** » 19 Aug 2005 10:31 pm

Got my parts kit from Brad for my LTD, it sounds killer!! Quality parts, great guy - he really knows his stuff!!

Jack Stoner · Post by **Jack Stoner** » 20 Aug 2005 2:24 am

If it's the old 400 with the discrete components in the preamp, John Lemay sells a kit that replaces all the electolytic caps with new ones. I installed one in an old 400 for a local guy and it really perked up the amp. I think Peavey may have a similar kit for this amp (they didn't when I installed the Lemay kit).

Filter caps can be purchased directly from Peavey.

Other than the caps, if it aint broke, leave it alone.

Dennis Detweiler · Post by **Dennis Detweiler** » 20 Aug 2005 5:36 am

Parts are included in Brad's kit. I have a Sarno kit in my 1974 Session 400 and a LeMay kit in my 1976 Session 400. Brad's kit goes into a more extensive parts replacement. He also replaces some of the electrolytic caps with film caps. The tone of the amp isn't changed. It's just enhanced, punchier and quieter.
DD

Brad Sarno · Post by **Brad Sarno** » 20 Aug 2005 6:07 am

Hopefully soon I'll be putting together some more LTD/Session kits. I've been too slammed with my latest project (to be announced soon). Like Dennis said, I put together a kit that completely replaces all electrolytics because they simply just go bad over time. I also go a step further in replacing the electrolytics in the signal path with good film types. Not done yet. I also replace the ceramic tone and reverb cap's with good polypropylene film caps. The amp's circuit is not altered in the slightest, but the performance is enhanced quite a bit. The whole midrange becomes more open and 3D and the top end becomes much more sweet and detailed, less grainy. The stock amp sounds great, but the better caps really do seem to make the amp sound closer to its design's potential.

Peavey really did something spectacular with these old amps. The EQ is fantastic for steel. They just sound great and what's really amazing is how very quiet they are. I swear I have to stick my ear right into my old Session 400's speaker to confirm that it's really on. I don't know of any other 200+ watt guitar amp that's as silent as these.

When I finally get a kit together, I'll post it here on the forum. I'd like to get some ready for ISGC, but really I'm so slammed I'm just not finding time to round up all the parts.

Brad
www.steelguitarblackbox.com

John Daugherty · Post by **John Daugherty** » 20 Aug 2005 10:11 am

Al, I suspect that the clipping sounds are not caused by caps,although it is a possibility. If you mean "cuts in and out", it can be caused by dirty controls and jacks,especially in an older amp. The signal travels through the preamp-out, power amp-in jacks and effects loop jacks.
Sometimes they will clean by inserting a plug,sprayed with contact cleaner, into the jack several times. You might learn if the jacks are the culprit, by connecting a cable from the preamp out, to the power amp-in.
Vigorously rotate all the controls a lot of times to try and clean them.
Clipping can be caused by having the input gain set too high for the signal you are putting in.
There are other causes for this, but checking the controls,jacks and cables is a start.[This message was edited by John Daugherty on 20 August 2005 at 01:48 PM.]

Al Carmichael · Post by **Al Carmichael** » 20 Aug 2005 8:31 pm

I'm not sure what's causing the amp to clip. The cords are fresh George L's, so I think I can rule them out, as I use them for other things with no problem. Cleaning the jacks is a good idea. The pots are clean too.

One thing--the amp sat unused for 10 years, and I wonder if that is detrimental to electrolytic caps?

The guy who owned before me played steel in my band. I got to tell you, this amp was incredibly loud and clean. It could blow your head off with no clipping.

I did lower my pickup slightly on my steel, thinking maybe it was just too hot for the preamp. I'm going to try the "padded" input jack #2 as well and see where that gets me. If it still breaks up when pushed, then I'm shopping for caps. I do have all the info on Brads great site.

Brad, if you do get some kits together in the near future, give me a shout. Otherwise, I will probably just search out what I need. I noticed that the Lemay site is not active anymore, but I don't know why.

Anyway, I'll post again when I get things sorted out, or if anyone else has some other ideas. Thank you all for the information, and keep the steel guitar alive!

Gary Walker · Post by **Gary Walker** » 20 Aug 2005 9:09 pm

Brad, I have a two year old Webb 614E two piece and I remember you had a post of the inferior parts in the newer ones. I had hoped someday you would offer a retrofit kit to bring this great amp up to a higher level with the better caps, Gary.

Donny Hinson · Post by **Donny Hinson** » 26 Aug 2005 6:02 am

One thing--the amp sat unused for 10 years, and I wonder if that is detrimental to electrolytic caps?

Unfortunately, it is.

To maintain peak life of electrolytics, they should be used every 6 months or so. Long terms of not being used after being properly "formed" (which happens in the first few hours of operation) causes accelerated failures.