Amps "frying" noise

[Vidar Lund]

Mike said "
"I would do nothing until I was forced to."
YAH, Tell that to the Fire Marshal ! ! !" - and your insurence company!

[Mike Nye]

Greg,
Call Bill at Musicmenders. His number is 770-313-3698. He is a good tube amp repairman. He has worked on all three of my tube amps and has always done a good job. After you call Bill, drop your amp off at Gwinnet Music in Lawrenceville and it will be repaired in a matter of days.
Good Luck.
Jim Prater

FINALLY . . . some SOLID advice . . .

[Mike Nye]

Mike said "
"I would do nothing until I was forced to."
YAH, Tell that to the Fire Marshal ! ! !" - and your insurence company!

Mike might be an IDIOT, but would NEVER blurt out something like that . . .

If you look at my post, you'll see that statement was in QUOTATIONS, as I was commenting on another poster's comment.

[Brian Ingram]

I have a great old Fender Princeton Reverb amp that I bought new in the early 70s. Recently, it has developed a "frying" or crackling noise, not loud, but noticeable. Anyone have any experience at solving this type problem?

The amp sounds really good with my NC and I'd like to keep it in use. By the way, today when I noticed the "frying" noise, it also seemed that my reverb faded out. Thanks in advance for your input.

One thing to note:
You've pointed out a couple of symptoms that make me suspect something specific, but the "frying noise" can be caused by a variety of issues. If you haven't had the amp serviced in years (decades?), you might ask the repairman to do a preventive maintenance on it.

That would involve cleaning pots/tube sockets, retensioning loose sockets, verifying grounds, checking for loose/cold solder joints, and replacing electrolytic caps, as needed.

Frying bacon noise is often old carbon comp resistors becoming noisy, but can be due to dirty/intermittent contacts or a broken/intermittent lead going into a component. It can also be caused (in slightly different form) by all the other "preventive items" I noted above. And the typical scenario with a 40+ yr-old amp is that as soon as you fix one cause, another pops up. That's why it's often best to knock them all out at once.

Additionally, the reverb circuit in a lot of 60's-70's Fender amps can introduce quite a bit of hiss (the Princeton generally isn't too bad in this regard). There is a specific troubleshooting technique the repairman can do to pin down exactly where the noise originates, and fix it.

If you have the time, interest, and know which end of a soldering iron to hold, these are things you could learn to do yourself and save $$$, however, if you don't already have some electronic gear it might be a wash buying that stuff vs. paying the repair guy.

[Mike Nye]

The 'sizzling hiss' in MOST cases is surface-charge noise from DRIED-OUT FILTER CAPS ! ! !

Case in point . . . They're IMMEDIATELY BEHIND the rectifier IN FRONT OF EVERY CIRCUIT in the amp, so you're also gonna hear 'em in the reverb & trem circuits as well . . .

[Vidar Lund]

Sorry I misinterpreted your post, Mike.

[HeyMerle]

http://www.300guitars.com/articles/tube ... o-look-for

"On a vintage amp intermittent crackling can be caused by a few different things. The first and most obvious is the tubes. You should always have a good set of tubes in your amp. This reduces the chance for noise and crackling as well as provides the best sound and reliability. In a vintage Fender amp “tweed disease” can cause this unwanted noise to spoil your tone. "

[Mike Nye]

Sorry I misinterpreted your post, Mike.

Oh, don't worry bout it Vidar . . .

I just DON'T want ANYONE to ever get the idea that I'd say something so foolish & irresponsible ! ! !

[Mike Nye]

Tweed Disease was common with 50s era PRE-CBS (Pre-March '64) Fender amps.

Greg's amp was from the early 70s, that should have a fiberglass or fiberglass-impregnated resin mounting board.

The original material mentioned in the video was produced by American Phenolic (Amphenol) that was used in just about every electronic product manufactured in the US from the 20s through the 60s . . .

PS: There were also other similar products produced by Armstrong & Monsanto that had a high content of pulverized mica, (Quartz) that over time oxidized, becoming highly CAPACITIVE to a point to where it would actually feedback on itself almost as if it were a condenser mic within inches of the speaker. This was a problem with aging school public address systems that were made by Rauland in the 30's.

I've owned many a Fender amp that re-capping restored them to a dead noise floor level. If you listened carefully to the video the KEY word relating to the noise was CAPACITANCE ! ! !

Here's another tip . . . If you're going to record DIRECT into the board through a DI box from the amp's reverb send port, get yourself an ISOLATED Veriac. This will isolate any un-parallel ground potentials from creating 60-cycle hum and/or knocking you on yer ass ! ! !

[Greg Butler]

Thanks, guys!