Treble pot on RF #102

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M Fowler
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Treble pot on RF #102

Post by M Fowler »

Is the treble pot on the RF #102 250kA or 250KL?
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dreric
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Re: Treble pot on RF #102

Post by dreric »

Hey Mark

It's one of the Fender 2-35 which is a custom taper. I forget the taper.

Eric
Eric
1949 Zenith, Zenith Toggle Recoil, Zenith 55 & 440
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M Fowler
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Re: Treble pot on RF #102

Post by M Fowler »

Perhaps J-taper? It is shown as 250KL on schematic but shown as 250KA on layout Tony and Martin did.

Ceriatone has it as 250KL. I was thinking of using a custom CTS pot for guitar which is 30% taper 250KL.

Mark
Mark
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Re: Treble pot on RF #102

Post by Mark »

#0102 uses a custom taper pot which has been used by Fender in Brown Face and Black Face amps. A 30% taper pot will do. I believe Ted Weber sells 30% taper pots, some of the pots for guitars have a 30% taper too.
Yours Sincerely

Mark Abbott
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M Fowler
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Re: Treble pot on RF #102

Post by M Fowler »

http://www.mojotone.com/guitar-parts/Po ... plit-Shaft

This is the pot I bought for Dumble amp use CTS 250KJ 30% taper.

Mark
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M Fowler
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Re: Treble pot on RF #102

Post by M Fowler »

RF 102 board.JPG
I started loading my RF #102 board but ran out of 6PS 0.1uf caps, placed an order. My drawer had 418 caps in it which may be the same thing as 6PS?

I also had to order Dale 110k, thought I had those but no?

May change some of the CF to Dale as well like the 220K/220K.

Mark
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ToneMerc
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Re: Treble pot on RF #102

Post by ToneMerc »

dreric wrote: Mon Jul 31, 2017 4:39 am Hey Mark

It's one of the Fender 2-35 which is a custom taper. I forget the taper.

Eric
I checked a few dozen of these, it's kind of funky the first 45 degrees of rotation . I found many to be close to 40% at midpoint.

TM
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M Fowler
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Re: Treble pot on RF #102

Post by M Fowler »

I think I might try two different CTS pots this one first the 250KL 10% and other 250KJ 30%. Looks like many guys just used regular 250kL Alpha pots.
dcribbs1412
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Re: Treble pot on RF #102

Post by dcribbs1412 »

Looking good Mark
AFAIK the 418 are polyester same as 6ps.
250k A J L pots can all sound fairly similar, just set to different levels.

D
Aaron
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Re: Treble pot on RF #102

Post by Aaron »

According to Brandon, who has been in Robben's amp, the Treble pot is a Linear Taper.

Aaron
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M Fowler
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Re: Treble pot on RF #102

Post by M Fowler »

Thanks guys appreciate the information.
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M Fowler
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Re: Treble pot on RF #102

Post by M Fowler »

Dumble builds have the most part count of any amp I build including resistor and cap values only found in the Dumble.

I will continue until I run out of parts and then make an order list, no problem. :roll:

Got some more done on the chassis and boards.

Mark
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dcribbs1412
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Re: Treble pot on RF #102

Post by dcribbs1412 »

Looking good Mark!

D
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didit
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Re: Treble pot on RF #102

Post by didit »

Looks great, but that's no surprise Mark. Slight disappointment seeing that fourth hole simply plugged.

Watching carefully to learn. At least few months to go before starting mine. Slowly bookmarking advice and preparing lists for the key orders.

Best .. Ian
talbany
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Re: Treble pot on RF #102

Post by talbany »

I got the pot specs from a reliable tech (overseas) who was actually in 102 and did some repair work for Robben in the late 90's (hell I even documented the pot (Date)codes on the layout I did :lol: )

250K A 2-35 (the 35 indicates the taper) 35%..The 2-35 Fender (CTS) T-pot was the standard for most if not all of Dumble's amps from that (non HRM era)...IMO the pot tapers that are most critical are in order of..Vol,Mstr,Drive,Ratio or Level,Trigger then Treble then Bass..Mid and presence being the least important..IMO..The 102 layout is pretty accurate..BTW if you even want the same Plate caps as what's in 102 use 2X220uF Illinois..
I used to use the brown (Dale's) plate resistors for a few years?..Then switched to KOA's and have not looked back..The Dales for me on several amps were too strident on the top end and in a bright amp setting (bright cap) were a bit harsh..This is just me use a grain of salt etc..etc..

Good Luck..Tony
" The psychics on my bench is the same as Dumble'"
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