WEM, Watkins, Rush - Pepbox, Rush Pep Box  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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boblob
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Post by boblob »

Hi all. Kind of interested in doing a Studio 2, saying as the nice repros are £270 (they are nicely done, but still...). There's some good gutshots here:

http://www.flickr.com/photos/49994685@N ... 6544/show/

Seems to tally well with the schematic posted earlier in the thread, but I've never seen anything like that silver "M" cap between the two collectors (which is very likely the 47pF cap that supresses oscillation). Anyone know what that is - the "M" looks a bit like the Motorola M.

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Post by Electric Warrior »

That schematic is based on these pictures.
No idea if they got the circuit right, I'm not sure if they had access to a vintage unit to base it on...

The M on the styroflex cap looks nothing like the motorola logo. Might indicate a tolerance of 20%.

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Post by boblob »

I'd be mighty surprised if they didn't have an original. Don't think those CDIL BC107s or carbon films will be period correct though. Styroflex is a new one on me, I guess a silver mica will do if you still want to keep it expensive :D...

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boblob
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Post by boblob »

boblob wrote:I'd be mighty surprised if they didn't have an original. Don't think those CDIL BC107s or carbon films will be period correct though. Styroflex is a new one on me, I guess a silver mica will do if you still want to keep it expensive :D...
Just as an aside - anyone know the benefit (if any) of a silver mica over ceramic for this cap. I remember some ad copy for the Mahoney Buzztone mentioning he uses a silver mica in the same way, as recommended to him by Robert Keeley (must be something in it then)...

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Post by phibes »

boblob wrote:Just as an aside - anyone know the benefit (if any) of a silver mica over ceramic for this cap. I remember some ad copy for the Mahoney Buzztone mentioning he uses a silver mica in the same way, as recommended to him by Robert Keeley (must be something in it then)...
There's no advantage. Both will work just as good. It looks great for marketing though!
GuitarlCarl - "TGP = The Gear Polishers"

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Post by Electric Warrior »

boblob wrote:I'd be mighty surprised if they didn't have an original. Don't think those CDIL BC107s or carbon films will be period correct though. Styroflex is a new one on me, I guess a silver mica will do if you still want to keep it expensive :D...
They're quite rare. They're currently selling the germanium one and the auction text says it's "one of only 2 original pepe rush series one fuzz boxes in existence". I know who's got the other one and from what I know he never sent them any pedals. Just pictures.

Styroflex isn't expensive. They're in the same price range as polyester film capacitors.

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Post by boblob »

Electric Warrior wrote:
boblob wrote:I'd be mighty surprised if they didn't have an original. Don't think those CDIL BC107s or carbon films will be period correct though. Styroflex is a new one on me, I guess a silver mica will do if you still want to keep it expensive :D...
They're quite rare. They're currently selling the germanium one and the auction text says it's "one of only 2 original pepe rush series one fuzz boxes in existence". I know who's got the other one and from what I know he never sent them any pedals. Just pictures.
Wow, cool. I was going to do some work for a friend of David Toop (UK music/art journalist, musician and huge Pep Box fan - he wrote a paper on its use in his mostly digital work) and was thinking about asking for a lend of his to photograph and trace, but the project fell through and I never got the opportunity. I guess he has the regular production version.

So, there's only one original silicon Rush Studio 2?

That auction's been going on for some time now. It's from a collection belonging to a guy from Angel Music down Denmark Street (London), isn't it? They pulled the original auction at the last minute, probably after finding out John Lennon may have breathed on it. Maybe. Reminds me of The Young Ones - Neil's "Martial" amp: "Don't touch that! Jimi Hendrix once pissed on it!"

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Post by Electric Warrior »

No, there's more. But there's only two they know about. Very misleading item description...

The auction got pulled because Music Ground bought the pedal.

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Post by bootle »

boblob wrote:
Wow, cool. I was going to do some work for a friend of David Toop (UK music/art journalist, musician and huge Pep Box fan - he wrote a paper on its use in his mostly digital work) and was thinking about asking for a lend of his to photograph and trace, but the project fell through and I never got the opportunity. I guess he has the regular production version.
don't suppose anyone has that Toop article?
would love to read it, his books are great.

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Post by boblob »

bootle wrote:
boblob wrote:
Wow, cool. I was going to do some work for a friend of David Toop (UK music/art journalist, musician and huge Pep Box fan - he wrote a paper on its use in his mostly digital work) and was thinking about asking for a lend of his to photograph and trace, but the project fell through and I never got the opportunity. I guess he has the regular production version.
don't suppose anyone has that Toop article?
would love to read it, his books are great.
Sorry, I don't. It's available here: http://www.mitpressjournals.org/doi/abs ... alCode=lmj, but it's subscriber content. I'll ask around and see if I can get a copy.

I have Toop's new book "Sinister Resonance" - not read it yet, but it looks really good.

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Post by bootle »

boblob wrote:
bootle wrote:
boblob wrote:
Wow, cool. I was going to do some work for a friend of David Toop (UK music/art journalist, musician and huge Pep Box fan - he wrote a paper on its use in his mostly digital work) and was thinking about asking for a lend of his to photograph and trace, but the project fell through and I never got the opportunity. I guess he has the regular production version.
don't suppose anyone has that Toop article?
would love to read it, his books are great.
Sorry, I don't. It's available here: http://www.mitpressjournals.org/doi/abs ... alCode=lmj, but it's subscriber content. I'll ask around and see if I can get a copy.

I have Toop's new book "Sinister Resonance" - not read it yet, but it looks really good.
cool, thanks, didn't know it was out, I'll be picking that up.
haunted weather was a great read.

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Post by drewl »

So I found a prototype of the silicon version I had made a while ago.

What's the final consensus?
There's the germanium version, and the silicon version
which you like better?

I'll have to try the Ge. version and see how it sounds.

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Post by royaltoots »

bootle wrote: don't suppose anyone has that Toop article?
would love to read it, his books are great.
pdf attached - Enjoy!
Mark Hammer sent it to me a couple of yrs ago
Attachments
Rush Pep Box.pdf
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Post by drewl »

Thanks, fun little article.
The author didn't seem to know much about his pedal though.

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Post by royaltoots »

drewl wrote: The author didn't seem to know much about his pedal though.

true, true

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Post by Electric Warrior »

Jerms bought it: http://stompboxes.co.uk/forum/viewtopic.php?f=11&t=9881

Here's the complete schematic:
germaniumpepbox.png
germaniumpepbox.png (17.85 KiB) Viewed 5134 times

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Post by skumberg »

Thanks for the update EW. Interesting that it turned out to be a 10klog fuzz pot. I recently changed from 47k to 20klin because of the summer warmth. But had probably increased the 100r with a 10klog. Of course this all depends on leakage hfe and season.
I think this might be the fuzz used on beatles It's all too much. At least It sounds close to that sound. I had to use earplugs to get the feedback with my strat. The middle and neck pickup together seems to get the best feedback.

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Post by dwstanford »

Should i bias this circuit like a fuzz face? What voltages should i look for on each transistor?

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Post by skumberg »

dwstanford wrote:Should i bias this circuit like a fuzz face? What voltages should i look for on each transistor?
Heloo, I think my clone had around -6.5 to -7.3 on Q1 with hfe 90-70. Since fuzz pot controls bias on Q2 you'll see almost -battery voltage when fully off. When fuzz pot(I used 20k which is wrong) is fully clockwise I had mine set up so it would not go below -2 volts. I have no Idea what the original might have. I was aiming to get a slightly misbiased sound at full gain since that is how I interpret some bits on "it's all too much". I don't know if this type of fuzz was used at that song but to me it sounds similar.

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Post by Electric Warrior »

Whoops, here it is with correct transistor symbols (PNP):

Image

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