Noisey Champ Help!!

ccuwan · April 27th, 2004, 09:59 PM

I have a sf vibrochamp. After it warms up it gets very noisey. I have changed both the rectifier and output tubes without improvement. Anyone seen this before and can provide some advice?

AtomicMassUnit · April 28th, 2004, 01:55 AM

If you're not into working on it yourself, take it to your nearest reputable tech. Nothing in a Champ is hard to fix, or very expensive except the transformers, and it's very very doubtful that's what's wrong. It's most likely the can cap or plate load resistors. If your amp's never been serviced, the cap definitely needs changing. I'm in Louisiana, if you want to ship it I'd be glad to work on it for you.

Atomic

ccuwan · April 28th, 2004, 05:45 PM

Thanks Atomic but I'm in Toronto...so a pretty serious shipping hassel. I have no idea if the cap has been replaced as I recently bought the amp from ebay. I would prefer to perform the surgery myself.....is there an easy way to recognize the faulty cap and do I need to purchase an original fender part or are they pretty much standard.
Thanks Again

11 Gauge · April 28th, 2004, 05:53 PM

...the values of the resistors, caps, and such with a good Fluke meter or similar.

but it's hard to determine the actual physical state of the 3 caps in the can, since they are inside of it, and it's sealed up. You can get a new cap can built for you - there are people out there who do it. i had one built for mine but can't recall the guy's name who did it.

the amp is easy to work on, and you can get schematics from the Fender Amp Field Guide (amongst other places).

a higher wattage soldering iron is a plus for unsoldering the can from the chassis - it's held in place pretty well by the solder joints themselves (along with bent over prongs).

make sure you get the highest quality electrolytic capacitors you can find, and make sure their working voltage is high enough. if you don't, you may be sorry...

AtomicMassUnit · April 30th, 2004, 02:39 AM

The part is available from antique electronics supply for sure at www.tubesandmore.com Be sure to have a big enough iron to solder to the chassis. It should be really easy!

Atomic

peteb · April 30th, 2004, 03:29 AM

it could be the preamp tube

Rob DiStefano · May 2nd, 2004, 07:36 AM

When the filter caps go South on my '66 Champ - as it appears it's starting to do now - I'll replace the cap can with a PTP eyelet board and Atoms. Just easier and cheaper to do, and the caps will be way better than any currently available new stock cap can, and easier to service years down the road. YMMV.

peteb · May 2nd, 2004, 04:00 PM

Rob,

You said your champs filter caps are starting to go south. How do you know? I have a 65 and a 66 and I want to replace the filter caps when they start to go. I do not think mine are going yet because the plate voltages are high and they do not hum. How do you know?

Rob DiStefano · May 3rd, 2004, 07:57 AM

I dunno for sure - I'm far from being an amp tech - but my Champ is acting weird: there's a fizzy aftertaste noise that's readily heard on bass notes, and sometimes the overall volume of the amp just drops. My amp guru will fix it up good as new - probably *better* than new - in short order.

peteb · May 3rd, 2004, 10:44 AM

Thanks Rob

April 27th, 2004, 09:59 PM	#1 (permalink)
ccuwan TDPRI Member Join Date: Feb 2004 Location: Toronto Posts: 14	Noisey Champ Help!! I have a sf vibrochamp. After it warms up it gets very noisey. I have changed both the rectifier and output tubes without improvement. Anyone seen this before and can provide some advice?

April 28th, 2004, 05:53 PM	#4 (permalink)
11 Gauge Friend of Leo's Join Date: Mar 2003 Location: The East Coast Posts: 3,085 10 Photos	easy to measure... ...the values of the resistors, caps, and such with a good Fluke meter or similar. but it's hard to determine the actual physical state of the 3 caps in the can, since they are inside of it, and it's sealed up. You can get a new cap can built for you - there are people out there who do it. i had one built for mine but can't recall the guy's name who did it. the amp is easy to work on, and you can get schematics from the Fender Amp Field Guide (amongst other places). a higher wattage soldering iron is a plus for unsoldering the can from the chassis - it's held in place pretty well by the solder joints themselves (along with bent over prongs). make sure you get the highest quality electrolytic capacitors you can find, and make sure their working voltage is high enough. if you don't, you may be sorry... __________________

April 30th, 2004, 03:29 AM	#6 (permalink)
peteb Tele-Meister Join Date: Apr 2003 Posts: 248	it could be the preamp tube it could be the preamp tube

May 2nd, 2004, 04:00 PM	#8 (permalink)
peteb Tele-Meister Join Date: Apr 2003 Posts: 248	How do you know your champs filter caps are going? Rob, You said your champs filter caps are starting to go south. How do you know? I have a 65 and a 66 and I want to replace the filter caps when they start to go. I do not think mine are going yet because the plate voltages are high and they do not hum. How do you know?

May 3rd, 2004, 07:57 AM	#9 (permalink)
Rob DiStefano Friend of Leo's Join Date: Mar 2003 Location: Park Ridge, NJ Age: 63 Posts: 4,915	Re: How do you know your champs filter caps are going? I dunno for sure - I'm far from being an amp tech - but my Champ is acting weird: there's a fizzy aftertaste noise that's readily heard on bass notes, and sometimes the overall volume of the amp just drops. My amp guru will fix it up good as new - probably better than new - in short order.

April 28th, 2004, 01:55 AM	#2 (permalink)
AtomicMassUnit Tele-Meister Join Date: Apr 2003 Posts: 153	If you're not into working on it yourself, take it to your nearest reputable tech. Nothing in a Champ is hard to fix, or very expensive except the transformers, and it's very very doubtful that's what's wrong. It's most likely the can cap or plate load resistors. If your amp's never been serviced, the cap definitely needs changing. I'm in Louisiana, if you want to ship it I'd be glad to work on it for you. Atomic

April 28th, 2004, 05:45 PM	#3 (permalink)
ccuwan TDPRI Member Join Date: Feb 2004 Location: Toronto Posts: 14	Thanks Atomic but I'm in Toronto...so a pretty serious shipping hassel. I have no idea if the cap has been replaced as I recently bought the amp from ebay. I would prefer to perform the surgery myself.....is there an easy way to recognize the faulty cap and do I need to purchase an original fender part or are they pretty much standard. Thanks Again

April 30th, 2004, 02:39 AM	#5 (permalink)
AtomicMassUnit Tele-Meister Join Date: Apr 2003 Posts: 153	The part is available from antique electronics supply for sure at www.tubesandmore.com Be sure to have a big enough iron to solder to the chassis. It should be really easy! Atomic

May 2nd, 2004, 07:36 AM	#7 (permalink)
Rob DiStefano Friend of Leo's Join Date: Mar 2003 Location: Park Ridge, NJ Age: 63 Posts: 4,915	When the filter caps go South on my '66 Champ - as it appears it's starting to do now - I'll replace the cap can with a PTP eyelet board and Atoms. Just easier and cheaper to do, and the caps will be way better than any currently available new stock cap can, and easier to service years down the road. YMMV.

May 3rd, 2004, 10:44 AM	#10 (permalink)
peteb Tele-Meister Join Date: Apr 2003 Posts: 248	Thanks Rob