It is currently Mon Mar 16, 2020 2:20 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 12 posts ] 
Author Message
Post subject: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 7:37 am
Offline
Roadie
Roadie

Joined: Sat Mar 09, 2013 12:27 pm
Posts: 207
I replaced the caps in my Concert, but forgot the order of the 1K and 4.7K resistors. If you look at the filter caps with resistors facing you, I have the 1K at the right end and the 4.7K to the left. Is that correct or should it be the other way around?


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 7:52 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Yeah, with resistors closest to you, the 1k-ohm resistor goes on left side (between the first 20mfd cap and second) and 4.7k-ohm next to it on the right (between the second and third). The third resistor in my photo is a 27k-ohm resistor, seen under some Bassman doghouses).

BTW... I like wire-wound resistors in the main PSU. Tough resistors.

http://bmamps.com/Schematics/fender/concert_aa763.pdf

Image


Top
Profile
Post subject: Re: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 8:32 am
Offline
Roadie
Roadie

Joined: Sat Mar 09, 2013 12:27 pm
Posts: 207
Thanks Beemer. Thought so. The amp sounds great with the new caps, but the vibrato is noisy-oscillating gets faster with speed knob, stops with intensity on 1 and gets louder as intensity is increased.


Top
Profile
Post subject: Re: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 8:41 am
Offline
Roadie
Roadie

Joined: Sat Mar 09, 2013 12:27 pm
Posts: 207
Here's a pic
Image


Top
Profile
Post subject: Re: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 8:43 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Krankster, check out the lead dressing around the 12AX7 driving the tremolo/vibrato circuit. Try to keep lines separated. Any lines that cross, keep them at 90-degree angles to each other.

Hopefully, that will solve the coupling-noise issue in your amp. There are other fixes. But, most affect the tone, in some degree.

Image


Top
Profile
Post subject: Re: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 8:45 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Krankster wrote:
Here's a pic
Image


Correct. The photo makes the brown band look pink. You didn't get these resistors from a San Francisco outlet? :lol:


Top
Profile
Post subject: Re: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 9:18 am
Offline
Roadie
Roadie

Joined: Sat Mar 09, 2013 12:27 pm
Posts: 207
BMW2002Ti wrote:
Krankster wrote:
Here's a pic
Image


Correct. The photo makes the brown band look pink. You didn't get these resistors from a San Francisco outlet? :lol:


I'm wearing a pink shirt today. Only a real man wears pink, according to my wife. I did stretch some of the wires leading to the 12ax7 when cleaning out the eyelets. I'll open her up and check them out. Thanks


Top
Profile
Post subject: Re: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 9:19 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
BMW2002Ti wrote:
The photo makes the brown band look pink. You didn't get these resistors from a San Francisco outlet? :lol:


Somewhere in the Castro district perhaps......?

:wink:

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: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 1:18 pm
Offline
Professional Musician
Professional Musician

Joined: Tue Sep 11, 2012 2:14 pm
Posts: 2561
Krankster wrote:
...I'm wearing a pink shirt today. Only a real man wears pink, according to my wife....


Your Wife is Wrong !

Real Men DON'T wear PINK !!!

Real Men wear SALMON !!!! :lol: :lol: :lol:

cheers!

_________________
Image

'11 FSR Am. Vtg. Ltd. Ed. CAR '57 Stratocaster (SN# LE02639)
'14 American Deluxe Ash Stratocaster
'12 Telebration Empress Telecaster
'99 Deluxe Nashville Telecaster
'12 FSR Telecaster HH
'10 Heritage H-535
'99 Martin DC-1E
'13 Lanikai Tenor Ukulele


Top
Profile
Post subject: Re: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 1:50 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
REAL MEN don't wear shirts......

Image

:mrgreen:

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: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 2:07 pm
Offline
Professional Musician
Professional Musician

Joined: Tue Sep 11, 2012 2:14 pm
Posts: 2561
Retroverbial wrote:
REAL MEN don't wear shirts......

Image

:mrgreen:

Arjay


Uh... yea... OK !

Image

:lol: :lol: :lol:

cheers!

_________________
Image

'11 FSR Am. Vtg. Ltd. Ed. CAR '57 Stratocaster (SN# LE02639)
'14 American Deluxe Ash Stratocaster
'12 Telebration Empress Telecaster
'99 Deluxe Nashville Telecaster
'12 FSR Telecaster HH
'10 Heritage H-535
'99 Martin DC-1E
'13 Lanikai Tenor Ukulele


Top
Profile
Post subject: Re: Power grid resistors for Blackface Concert Amp
Posted: Mon Jul 21, 2014 7:33 pm
Offline
Roadie
Roadie

Joined: Sat Mar 09, 2013 12:27 pm
Posts: 207
All this talk about pink aside, The wire from pin 3 on the vibrato tube going to the caps was the problem. Moved it and bingo, no oscillation. You guys are the greatest. BTW, you'll all be hearing from my wife soon.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 12 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: