It is currently Tue Mar 17, 2020 4:10 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 10 posts ] 
Author Message
Post subject: Buzz from my Fender Pro Reverb
Posted: Wed Sep 08, 2010 4:36 pm
Offline
Hobbyist
Hobbyist

Joined: Wed Sep 08, 2010 4:24 pm
Posts: 4
Hi,
I have a Fender Pro Reverb. When I power up the tubes, let them warm up for 4-8 minutes and flip the power switch I get a buzz sound. It doesn't matter if my guitar cable is plugged in or not, but does get worst if I do plug it in. I've tried several power outlets, but no difference. I tried to replace the tubes but made no difference. I used it for about 7 months, just one day it would start the buzz. (bought it used) Any suggestions/comments will be appreciated. Thanks,


Top
Profile
Fender Play Winter Sale 2020
Post subject:
Posted: Thu Sep 09, 2010 12:31 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Sat May 08, 2010 4:31 am
Posts: 411
Location: France
It could be a supply capacitor; Tell us if you hear a 60Hz hum ? How old is this amp ?

_________________
Tissan '52 Tele RI & Washburn Hawk 1980, Epiphone Casino MIK, Blues Deluxe RI & VOX ...


Top
Profile
Post subject:
Posted: Thu Sep 09, 2010 3:58 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14050
Location: Province de Québec, Canada
Test with no guitar:

Do you have more buzz with volume pot turn right ( more volume) ?
If it supply capacitors you will heard no effect with volume.

If you have more buzz with high volume : turn amp off remove the first tube, the one at right when you look at back of the amp.
Amp power on ; no buzz problem is this tube or circuit before this tube
Always buzz; amp off, remove the second tube.

Do that with all your 12AX7 tubes or 12AT7 until no buzz.
Do you have buzz or hum ? Buzz is high pitch and hum is lower, this will help us.

Witch tubes you tried to replace ? All ?

Good luck and come back


Top
Profile
Post subject:
Posted: Fri Sep 10, 2010 7:38 am
Offline
Hobbyist
Hobbyist

Joined: Wed Sep 08, 2010 4:24 pm
Posts: 4
The amp is a "Fender Pro Tube Reverb" was manufactured 2002-03. I will do those tests and let you know what I find.


Top
Profile
Post subject:
Posted: Fri Sep 10, 2010 10:09 am
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Sat May 08, 2010 4:31 am
Posts: 411
Location: France
On top of what Stratele62 propose, put a mark (1, 2, 3 for instance) on 12ax7s in order to not mix phase inverter and other amplifier triodes.

_________________
Tissan '52 Tele RI & Washburn Hawk 1980, Epiphone Casino MIK, Blues Deluxe RI & VOX ...


Top
Profile
Post subject:
Posted: Fri Sep 10, 2010 1:41 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14050
Location: Province de Québec, Canada
+1 Tissan


Top
Profile
Post subject:
Posted: Thu Oct 07, 2010 9:01 am
Offline
Hobbyist
Hobbyist

Joined: Wed Sep 08, 2010 4:24 pm
Posts: 4
when removing the 4th 12AX7 tube (from right), all buzz and sound stops.

also, when i turn the volume knobs from either channel past 2, i start getting a high-pitched feedback. increasing the reverb also increases the buzz, although there is still some buzz when reverb is set to 0.


Top
Profile
Post subject:
Posted: Thu Oct 07, 2010 12:57 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Sat May 08, 2010 4:31 am
Posts: 411
Location: France
Please download:
http://support.fender.com/manuals/manua ... Reverb.pdf
Page 7 --> tell me if it is V4.

_________________
Tissan '52 Tele RI & Washburn Hawk 1980, Epiphone Casino MIK, Blues Deluxe RI & VOX ...


Top
Profile
Post subject:
Posted: Thu Oct 07, 2010 3:17 pm
Offline
Hobbyist
Hobbyist

Joined: Wed Sep 08, 2010 4:24 pm
Posts: 4
Yes, it is V4..

Tissan wrote:
Please download:
http://support.fender.com/manuals/manua ... Reverb.pdf
Page 7 --> tell me if it is V4.


Top
Profile
Post subject:
Posted: Fri Oct 08, 2010 3:39 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Sat May 08, 2010 4:31 am
Posts: 411
Location: France
V4 is the long tailled stage, also called dephaser. Removing that valve cuts the signal to the amplifier consequently no sound and no hum.

First make sure your earth connection is good --> test with another amp

Does both channels make noise ?

Did you make the tests proposed by Stratele52, valve by valve?

If you don't feel confident, ask to tech is a good idea.

_________________
Tissan '52 Tele RI & Washburn Hawk 1980, Epiphone Casino MIK, Blues Deluxe RI & VOX ...


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 10 posts ] 

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: