It is currently Mon Mar 16, 2020 9:08 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 16 posts ]  Go to page 1, 2  Next
Go to page 1, 2  Next
Author Message
Post subject: fender champ early 70s buzzy sound when hot?
Posted: Mon Apr 16, 2012 3:50 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 16, 2012 3:21 pm
Posts: 5
Image[/img][/img]hi, ive recently purchased a fender champ 6w amp, which seems to have an intermitant problem and wondered if anyone could advise me please, basically firstly i dont think its been serviced in a while, now the problem is it ll play perfect for say 20 mins, superb tone, then it starts to get a low buzzing type sound which stays even if you take the lead out of the guitar,and goes up and down with the volume control,[img][img][/img][/img] and i noticed while plugged into guitar if you roll back the tone it goes completely, ive tried several different leads and a telecaster and a strat which both play fine through my blues deluxe, i think the valves may be originals as they are rca, ive added acouple of pics, any help would be gratefully received cheers.....][/img]Image[/img]


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Mon Apr 16, 2012 4:06 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
You're using incorrect HTML tags for displaying an image on this forum. For Photobucket, select the fourth option on the pull-down menu for each photograph that begins with "img src" and use a carriage return between each pic's location code when you insert them within a post.

It sounds like one or more sections of your amp's filter-cap can is heading south. If it reaches that destination it's possible that the resultant runaway voltages will take the rectifier tube and the power tranny with it. It needs immediate servicing.

HTH

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Mon Apr 16, 2012 4:30 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 16, 2012 3:21 pm
Posts: 5
ok cheers for reply, i think ive altered pics so you should be able to view, so basically i need to take to a fender dealer and get serviced asap,,,thanks for info...


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Mon Apr 16, 2012 4:34 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
Better to find a competent amp tech who's familiar with these older Fender models (not necessarily an authorized service center). Many dealers and their support staff are unfamiliar with this older technology. Judging from the date stamp on your existing cap-can, the amp is a '72 and the can is original to the chassis.

Ask plenty of questions before entrusting your amp to any shop.

HTH

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Mon Apr 16, 2012 4:49 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 16, 2012 3:21 pm
Posts: 5
hi, yes thanks for info, you are just confirming what im thinking which is take it to a dealer, theyll prob replace all the valves and give me a hefty bill, valve changing i could do myself anyway,and presumably this isnt the issue, i do know an electrical engineer whos pretty knowlageable is there any schematics drawings available with relevant fault finding etc available anywhere, so to test the various caps etc and determine the prob, cheers again ...


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Mon Apr 16, 2012 6:06 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
This should be the appropriate schematic for your amp......

http://web.archive.org/web/200805160858 ... mp_cbs.pdf

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Mon Apr 16, 2012 6:42 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Mar 01, 2011 3:10 pm
Posts: 5646
Location: Gateway to the West
Fender Agenda...you are also missing a nut on the lower left (from the pic) on the speaker, which could cause some buzzing too. Not the buzzing you discribe, but if you are taking it in or getting it serviced, tighten that speaker down while it is in.

HTH

T2

_________________
-----------------------------------------------------------
What time is it? It's Fender Time.


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Mon Apr 16, 2012 9:32 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
T2Stratman wrote:
Fender Agenda...you are also missing a nut on the lower left (from the pic) on the speaker, which could cause some buzzing too. Not the buzzing you discribe, but if you are taking it in or getting it serviced, tighten that speaker down while it is in.


Indeed.

A speaker must be adequately anchored to the baffle board to ensure optimum performance and prevent deformation of the frame. You can pay robber baron prices for a set of 8-32 kep nuts from Angela Instruments or The Parts Guru OR stop by your local Ace Hardware and pick them up for around 15¢ apiece.

Here's what they look like......

Image

They're the same type of retaining nut used on the strap screws that hold your chassis securely within the cabinet.

HTH

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Tue Apr 17, 2012 4:08 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 16, 2012 3:21 pm
Posts: 5
hi yes i will get a nut, thanks for pointing out, many thanks ...


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Thu Apr 19, 2012 2:29 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Arjay, is that the stock PT? It's the biggest PT I've ever seen in a Champ or VC for that matter.

Thanks!


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Thu Apr 19, 2012 7:27 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
BMW2002Ti wrote:
Arjay, is that the stock PT? It's the biggest PT I've ever seen in a Champ or VC for that matter.


It does seem a tad "overscale" for the size of the chassis......

And I'm curious about that coin-base power tube -- 6L6GC?

:shock:

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Thu Apr 19, 2012 4:34 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Arjay,

I beleive it is a 6V6GTA. Some of the very last sets to be made in the US (by RCA, Sylvania & GE, primarily), had coin-bases.



http://www.blujay.com/item/6V6GTA-RCA-V ... 00-1775339


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Tue Apr 24, 2012 11:44 am
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 16, 2012 3:21 pm
Posts: 5
hi, its now gone to a competant service man who ive had recommended, thanks for all your advice and im curios whats pt? cheers...


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Tue Apr 24, 2012 2:52 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
PT = power transformer. Yours appears to have more lamination plates in it (taller body), than any Champ or Vibro-Champ I've seen.


Top
Profile
Post subject: Re: fender champ early 70s buzzy sound when hot?
Posted: Sat May 05, 2012 10:35 pm
Offline
Amateur
Amateur

Joined: Sat Apr 21, 2012 6:39 pm
Posts: 154
BMW2002Ti wrote:
PT = power transformer. Yours appears to have more lamination plates in it (taller body), than any Champ or Vibro-Champ I've seen.


My guess is that the OP is in England. The export power xformers were larger, since foreign countries use 50Hz AC. I suspect that filter caps used larger values as well.

_________________
1963 Princeton
1965 Twin Reverb
1968 Bandmaster
1970 Champ
1983 (?) Musicmaster
2012 Mustang III
West Grande (x2)
Acoustic G60-T
Marshall JTM 60


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 16 posts ]  Go to page 1, 2  Next
Go to page 1, 2  Next

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: