potentiometers for PCB FEnder tube amps - Telecaster Guitar Forum
The Number 1 Fender Telecaster Guitar authority in the world.
   

Go Back   Telecaster Guitar Forum > Amplifier Discussion Forums > Amp Central Station
Forgot Username/Password? Join Us!
Notices

Amp Central Station Amps, tubes, speakers & everything AMP related.


Wilde Pickups by Bill & Becky Lawrence WD Music Products Amplified Parts Mod Kits DIY Amps, Mods, Pedals dallenpickups.com Warmoth.com seymourduncan.com


Forum Jump


Reply
 
Thread Tools
Old December 10th, 2010, 12:46 PM   #1 (permalink)
Doctor of Teleocity
 
Join Date: Mar 2003
Location: Lubbock, TX
Posts: 15,362
potentiometers for PCB FEnder tube amps

I am in a bind. I am looking for a mid tone control pot for a Fender Super 60.
Can anyone help with this search. FEnder doesn't stock the part, and it seems that the parts were proprietary---made for FEnder----. That means that these pots are no longer available. Teh pot is a 25K10A pcb mount pot with a D shaft. I could probably work with anything form 15K-50KA.
I got a response from a well-known tube amp parts resource yesterday...

"Wally,

sorry, I do not have any replacement parts for the Super 60. they are proprietary (made for Fender) and no standard parts will fit. having the "D" shaped shaft doesn't make it any easier too.

I have a 25k mini pot, but it is not circuit board mounted and has a round shaft - not a very close fit.

and yes, Fender left us all out in the cold not providing parts for current vintage amps. They made this decision in the mid 90's - now they don't even know what you are talking about.

this is about the 5th request today for Fender parts.

I had bought out a lot of the guys who did have parts some years ago, but 100% of that stuff is gone."

This response is simular to the ones I got from Darren Riley and Angela INstruments.....no such potentiometer to be had. I ran into this problem with a swtiching pot in a The Twin some years ago....I had to rebuild the switch mechanism with new parts from a new pot...tore the new one up to get those switching parts.
If anyone has any cures for this predicament, I would appreciate the help. PErhaps a mini-pot that doesn't mount to the board could be hard-wired in????
Imho, this certainly diminishes any thoughts I might have about buying any of the FEnder PCB amps from that period---mid-80's through the '90's....unless they were in working condition and the price was very low. And.....if Fender holds true to this method of building amps, when will the parts for the current production no longer be available....or are they using commonly available PCB-mount parts these days?

When I took that The TWin in for work about 10 years ago, the owner said..."Now, you'll be able to get this fixed quickly because it is a newer amp, right? I smiled and said: "IF you had brought me a BF TR, I could have it going tomorrow. With this one, I have no idea when I can get the parts. AFter waiting 6 months for fEnder to respond--through a fender dealer---I rebuilt the swtiching mechanism. THat amp is still going. However, if it had been anything except the switch mechanism that was broken, that pot would be an empty hole......unless someone of you knows where to get these unobtainable pots?????

ANy help is appreciated.

Wally is offline   Reply With Quote

Old December 10th, 2010, 01:00 PM   #2 (permalink)
Tele-Meister
 
Jeff B.'s Avatar
 
Join Date: Oct 2008
Location: Nova Scotia, Canada
Posts: 471
Antique Electronic Supply may have something. They have some Fender PCB mounted "D" pots in their catelogue.
Go to page 54 of their online catelogue.

You don't need to use a PCB mounted pot. Just run wires to the corresponding contacts on the pots terminals. You can just file a flat spot on the pot for a "D" as long as the shaft size is correct for the knob. Protect the pot from the filings.

If you can only find a larger pot value it is possible to lower it's value be adding a resistor across it's terminals. It will alter the taper a bit.
Jeff B. is offline   Reply With Quote

Old December 10th, 2010, 01:18 PM   #3 (permalink)
Doctor of Teleocity
 
Join Date: Mar 2003
Location: Lubbock, TX
Posts: 15,362
Thanks, JEff.....all of those options I have considered. AES has no direct replacements. I have the CE Distribution catalog...whoelsale arm of AES....and they have nothing that is remotely applicable unless I can squeeze a larger pot into that small space afforded by the PCB cosntruction....and that is a tight space under that front panel PCB. I dont' have the amp in hand yet to know exactly what will or will not fit. I am looking for a mini-pot. I suppose 25KA pot such as used with active pickup circuits will have to do???
IT is frustrating to have to spend $30 worth of time modifying a $5 pot to fit an amp that is 15 years old....when I routinely repair amps that are 30-60years old with parts I have on hand, right?

Maybe I am simply venting, eh? I do know that for the fellow who just bought this amp...and he buys a lot of vintage/used equipment....the price/value of this type of amp just went WAY down. For me, it simply reinforces what I already knew....I don't want this type of amp regardless of how it might sound.
AS Chuck Berry sang....
"Too much monkey business,
Too much monkey business.
Too much monkey business
for me to be involved in."
Wally is offline   Reply With Quote

Sponsored Links   #
Sponsored posting
 

Old December 10th, 2010, 01:48 PM   #4 (permalink)
Tele-Meister
 
Join Date: Sep 2010
Location: Near St Louis, MO
Posts: 499
You might try Element14, Wally. It occurred to me that they were suppliers for Yamaha parts, and probably have something in a D style pot board mount as they have to support the Yamaha amps. http://us.element-14.com/
Timbertea is offline   Reply With Quote

Old December 10th, 2010, 01:50 PM   #5 (permalink)
Doctor of Teleocity
 
Join Date: Mar 2003
Location: Lubbock, TX
Posts: 15,362
Thanks, Timbertea, I'll try anything at this point.
Wally is offline   Reply With Quote

Old December 10th, 2010, 08:49 PM   #6 (permalink)
Friend of Leo's
 
Join Date: Jun 2006
Location: Maryland
Age: 53
Posts: 2,875
If you find something Wally, can let me know? I have a Princeton DSP here that had something dropped on its face and sheared all the pots off.
celeste is offline   Reply With Quote

Old December 10th, 2010, 08:58 PM   #7 (permalink)
Friend of Leo's
 
Join Date: Mar 2008
Location: New Jersey
Age: 67
Posts: 2,211
Do you have a gut shot of the pot? Some dimensions, especially pin spacing and distance from the pins to the end of the shaft? I have been through a fair number of pots looking for BJr-compatible, non-Fender parts, and maybe one of them will work.

And if you're really desperate, I've also had experience wiring panel-mount pots to the PCB. You typically don't have much room to work, but it's doable.
Billm is offline   Reply With Quote

Old December 10th, 2010, 09:33 PM   #8 (permalink)
Tele-Meister
 
strat56's Avatar
 
Join Date: Feb 2008
Location: Elkton,MD
Posts: 416
Deleted
__________________
Thanks,
Jack

The older I get the less a lifetime warranty means to me.

My Web Page
strat56 is offline   Reply With Quote

Old December 11th, 2010, 10:54 AM   #9 (permalink)
Tele-Holic
 
kec!'s Avatar
 
Join Date: May 2010
Location: SoCal
Posts: 682
Any pics Wally?

Does it look like any of these?...





kec! is offline   Reply With Quote

Old December 11th, 2010, 12:17 PM   #10 (permalink)
Doctor of Teleocity
 
Join Date: Mar 2003
Location: Lubbock, TX
Posts: 15,362
Celeste, I certainly will let everyone know if I find some direct replacement parts for these applications.
BillM, I don't have the amp on my bench, so I don't have measurements of the spacing for the lugs/tabs. I do have pictures. The amp is in New MExico waiting to make the trip over here.
Kec, the pots in these amp do not have the stand off mounting tabs. IT might be that that mounting bracket could be removed??? Where can one find that pot you show there?
Thanks to all for the time and responses. IT is a pity that Fender doesn't see fit to support these products with parts service, isn't it? The owner of this Super 60 likes the amp...but he is greatly perturbed by this parts dilemna. IF say a car maker didn't provide parts support for their product, that would be the end of that car company, right? OH well....on to work....
Wally is offline   Reply With Quote

Old December 11th, 2010, 01:46 PM   #11 (permalink)
Tele-Holic
 
kec!'s Avatar
 
Join Date: May 2010
Location: SoCal
Posts: 682
Wally,

Found them on eBay. They are however 50k.

Not sure if these are log or linear...

http://cgi.ebay.com/NEW-Genuine-Fend...item2eb1ee3915

http://cgi.ebay.com/NEW-Genuine-Fend...item2eb149a3e4

This one is linear. I think you need log.

http://cgi.ebay.com/Fender-Blues-Jr-...item2308ca4018
kec! is offline   Reply With Quote

Old December 11th, 2010, 02:02 PM   #12 (permalink)
Tele-Holic
 
kec!'s Avatar
 
Join Date: May 2010
Location: SoCal
Posts: 682
Also check Mouser - see links. I narrowed it down for you

http://www.mouser.com/Catalog/catalogusd/642/685.Pdf
http://www.mouser.com/Catalog/catalogusd/642/684.Pdf
http://www.mouser.com/Catalog/catalogusd/642/689.Pdf

As Bill suggested, you may have to wire it manually
kec! is offline   Reply With Quote

Old December 11th, 2010, 03:03 PM   #13 (permalink)
Doctor of Teleocity
 
Join Date: Mar 2003
Location: Lubbock, TX
Posts: 15,362
kec!, thanks for your time and diligence. The ebay seller has a 50K15A snapin pot that might do after removing the mounting frame. Mouser might have a 50KA that will be simpler. They don't have any 25KA, though.
I appreciate your digging,kac! AS a side benefit, your last link took me to some slide potentiometers that I need study to see if anything works for an old Silvertone P.A. unit that is sitting here.
Thanks to all for the help, and I will let ya'll know how things transpire and what cures this problem.
Wally is offline   Reply With Quote

Old December 11th, 2010, 03:47 PM   #14 (permalink)
Tele-Holic
 
kec!'s Avatar
 
Join Date: May 2010
Location: SoCal
Posts: 682
Glad I could help Wally.

Mouser also started carrying Bourns pots for guitars...

http://www.mouser.com/Catalog/catalogusd/642/690.Pdf
http://www.mouser.com/Catalog/catalogusd/642/691.Pdf
kec! is offline   Reply With Quote

Old December 11th, 2010, 06:45 PM   #15 (permalink)
Poster Extraordinaire
 
tap4154's Avatar
 
Join Date: Apr 2009
Location: Southern California
Posts: 6,542
According to the service diagram that came with my Super 210 the pots are all different values.

Main volume: 250K 10A (push/pull on the 112 and 210)

Treble: 250K 30A

Mid: 25K 10A

Bass: 250K 10A

Gain (listed as Ra and Rb -- stacked?): 1 Meg 10A

Dist Volume: 1 Meg 10A

Reverb: 5K

Presence: no value listed.
tap4154 is online now   Reply With Quote

Old December 12th, 2010, 12:16 PM   #16 (permalink)
Tele-Holic
 
ojaverde's Avatar
 
Join Date: Feb 2008
Location: san jose ca
Age: 50
Posts: 569
I have a couple of these pots that I don't need, but they are 250k. Right size, wrong value. Isn't a pot just a variable resistor? Is there a way to add a resistor or cap to change the value?
__________________
"I feel more like I do now then like I did when I first got here". Frank Wakefield
ojaverde is online now   Reply With Quote

Old December 12th, 2010, 12:23 PM   #17 (permalink)
Poster Extraordinaire
 
tap4154's Avatar
 
Join Date: Apr 2009
Location: Southern California
Posts: 6,542
Quote:
Originally Posted by ojaverde View Post
I have a couple of these pots that I don't need, but they are 250k. Right size, wrong value. Isn't a pot just a variable resistor? Is there a way to add a resistor or cap to change the value?
Yes, and I'm assuming the OP is probably aware of this:

http://www.projectguitar.com/tut/potm.htm

However, I'm not sure how far down you can tweak a pot, what it does to the taper, or if it has any other adverse effects. I would imagine using the correct value pot would always be better (?)
tap4154 is online now   Reply With Quote

Old December 14th, 2010, 04:55 PM   #18 (permalink)
Doctor of Teleocity
 
Join Date: Mar 2003
Location: Lubbock, TX
Posts: 15,362
Okay, here's an interesting situation. I have found a possible source for NOS Fender-sourced pots for this era, but I need parts numbers. Does anyoone have a parts list for these amps??? Fender not only won't maintain parts availability, but they won't share the parts numbers, either. My googlin' hasn't brought the parts # info to the surface yet.
Wally is offline   Reply With Quote

Old December 14th, 2010, 06:13 PM   #19 (permalink)
Tele-Meister
 
InyoTim's Avatar
 
Join Date: Jan 2010
Location: Eastern Sierra Nevada, California
Age: 67
Posts: 309
I remember contacting Fender for an optocoupler for a Twin II years ago. They told me to take the amp to an authorized Fender repair shop. Fender not sharing the part numbers with you is probably more of this.
InyoTim is offline   Reply With Quote

Old December 14th, 2010, 06:18 PM   #20 (permalink)
Doctor of Teleocity
 
Join Date: Mar 2003
Location: Lubbock, TX
Posts: 15,362
INyoTim, I just talked to a fEnder authorized service center, and he didn't have the parts numbers either. IMHO, there is noreason for FEnder to 'protect' their service centers....because FEnder doesn't have these parts, anyway! Tehy dropped the support long ago on these amps.
Wally is offline   Reply With Quote

Reply

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump


» Random Photo for Guests
My Japanese Hohner Telecaster Deluxe
Untitled Document



 


Powered by vBadvanced CMPS v3.2.2



IMPORTANT:Treat everyone here with respect, no matter how difficult! No sex, drug, political, religion or hate discussion permitted here.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0 RC 2
© TDPRI.COM 1999 - 2014 All rights reserved.