1960 Fender amps and Allen Bradleys

[Voxbox]

Hi ,

Did Fender use Allen Bradley resistors in 1960?

I have a Vibrasonic that looks like its had ALL the resistors replaced with ABs. The joints look reworked and one of the Rs has the wrong value, 4k7 instead of 470k, which resulted in excessive chuffing on the output from the vibrato mix circuit.

Cheers, VB

[HotBluePlates]

Allen Bradley was only one brand who made carbon comp resistors when that amp was made.


I'm not familiar enough with carbon comp resistors to be able to distinguish between various brands made in the old days (new Xicon carbon comps are visibly different). Fender likely used whatever was cheapest in big quantity.


I know there used to be an electronics wholesaler near me when I lived in Nashville. They had open bins full of a given value of resistor, and all varieties of carbon comps might end up in the "100kΩ carbon comp bin".


Using "Allen Bradley" probably confers no special advantage, except that the leads might be longer than new carbon comps, and the background brown color on the resistor body is darker. A-B also had these in production until 1997, so they might have been easier to source.

[Voxbox]

Hello again HBP,

Take your point about whatever was cheap.... 
NOS ABs that I bought recently are identical in every way to the ones in this amp. size, body colour, paint colours. One other reason to think that all the resistors had been replaced.

Cheers, VB

[eleventeen]

In my multi-decade electronics "career", I've never seen an audio-taper A-B pot. Not one. I've seen zillions of them, but they have all been in instrumentation or test gear, so if you are talking about their 2-watt "Type J" units, I've never seen anything other than a linear taper A-B pot. But that's just me.


Thus they wouldn't be right (though they would certainly work) in amps.

[PRR]

> Did Fender use Allen Bradley resistors in 1960?

What else would they use?

Yes, there were other brands. But A-B was very dominant in development, marketing, advertising, distribution, and military qualification. Their volume meant low costs. So other brands had to be significantly cheaper (in price and quality). You find these in $9.98 radios. Maybe in some Fenders? But it would not take much trouble with "the other brand" to make Leo go to all A-B. (CBS days may be different.)

[eleventeen]

I will call you on that one, PRR. No amp manufacturer used A-B pots, they were Centralab or CTS, Stackpole or Clarostat. 90+% were CTS


You can look around all you want for images of 195X late Fender amps.....and they are all over the place. But you very rarely see a photo that shows the pots very clearly! Still, they have the characteristic opening that all 3 lugs go through.

[HotBluePlates]

I will call you on that one, PRR. No amp manufacturer used A-B pots ...

The question was about fixed carbon comp resistors, not pots.


But you are right about the pots: I've only seen the brands you mentioned in old Fender amps.

[sluckey]

I will call you on that one, PRR. No amp manufacturer used A-B pots, they were Centralab or CTS, Stackpole or Clarostat. 90+% were CTS

You're the only one who has used the word 'pot' in this thread.

[eleventeen]

Sorry, I misread.

[Voxbox]

"Pot"?? Freudian slip.....

Vintage amp saver? Is that a thread?

This amp has gone well beyond saving, its been total rebuild. Replacement original type speaker, new transformers, new G10 turret boards, new grillcloth, new valve bases. The only things original now are three pots, the knobs, chassis and the tolex and cab hardware, and some black Sprague caps on one channel and a few other insignificant caps in the oscillator.

It DOES look like a Jan. 1960 Vibrasonic on the outside though!! Sounds really good too now - rich, lush, solid, tight, voluptuous, sinuous, muscular, articulate, and above all, Fenderlicious. 

I'm going to post pics and info when I'm done in a few weeks hopefully.

Thanks for all you help and comments folks,

Cheers, VB

[Voxbox]

Actually its 240V.