Schaller Treble-Bass Boost  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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bluesbreaker62
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Post by bluesbreaker62 »

Hi guys, haven’t posted here in forever. Couldn’t find a threat in this one so here goes.

Really nice booster pedal from Western Germany. 5 position rotary switch goes from spanky treble tones to fat/muddy bass.

I didn’t take any voltage reading, but I can do that if requested

If you need any more pics or info, please ask. Enjoy…


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Schematic…

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The 47nF cap on pole 7 to ground is a little redundant as it just switches parallel to the 100nf in position 1 (Bass1 in schematic), so you could just use 150nF there

vintagecharlie
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Post by vintagecharlie »

Thanks for sharing and the work involved! Do you have an idea what this might be based on? The Schaller fuzz seems to be a fuzz face copy. This might be inspired by other design to or is this a fairly original circuit?

Manfred
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Post by Manfred »

I made a PCB layout derived from the shots and the schematic.
SchallerTrebleBassBoostLayout.JPG
Print the PDF-file using the original size setting.
schallerTrebleBassBoostPCB.pdf
(14.47 KiB) Downloaded 56 times

Pj_Rocks_wales
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Post by Pj_Rocks_wales »

Hey guys. Trying to recreate one of these for a friend who had one back in the day. The schematic appears to have expired from the hosting site can anyone repost it please? Apologies for disturbing an older thread. Cheers in advance! Pj

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Cub
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Post by Cub »

Hey Pj,

The files are still on the server, but photobukkit doesn't allow the images to be seen on any other site but their own any more.
Click on the links in the bit quoted below to see bluesbreaker62's original uploads.

You could use Manfred's splendid layout but if making PCBs isn't your thing, the blokes over at TagboardEffects made a stripboard layout.
Guitar FX Layouts: Schaller Treble-Bass Boost

Good luck with the build, please let us know how it turned out. :thumbsup
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Pj_Rocks_wales
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Post by Pj_Rocks_wales »

Wow awesome thank you for replying so swiftly and with bang on info.

I certainly will keep you posted. We're trying to get a local legend going again with gear based on what he used to have to try and reinspire him after ill health. Ive got allsorts of boosters but he gets really dewy eyed over the memory of the rotary switch tuning in his tone so thought it would be cool to try and recreate the exact thing.

Thanks again! Hoping to get more involved here after years of stalking the shadows.

Pj_Rocks_wales
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Post by Pj_Rocks_wales »

Unfortunately the schematic doesnt seem to be hosted there anymore when i went to the link.... wondering if its because im using firefox. Bizarre..

Anyway thanks again I'll keep fiddling and see if I can get it to work!

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Cub
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Post by Cub »

Happy to help ! :mrgreen: Looking forward to your build stories and pics and other contributions.
I had to install Firefox, but I think I see what's happening. Try clicking a link, letting everything load and then hitting refresh.
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karul
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Post by karul »

Pj_Rocks_wales wrote:Unfortunately the schematic doesnt seem to be hosted there anymore when i went to the link...
You're right. Only the thumbnail from photobucket is still present on google.
But you have PCB layout, and you can draw a schematic from it.
Attachments
shaller bass treble boost.jpg

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Cub
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Post by Cub »

karul wrote:You're right. Only the thumbnail from photobucket is still present on google.
This is getting more peculiar by the minute. :scratch: Am I immune to photobukkit's new policy ?
Either way, here's the schemo at the original resolution, downloaded freshly from the bukkit.
Attachments
Schaller TB Boost001_zpstsgsgzjz.png
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Pj_Rocks_wales
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Post by Pj_Rocks_wales »

Thank you Ive downloaded it from your post. Regards the hosting it does seem very odd doesn't it.

I went to a different machine and a different browser and can get some of the photos but not the schematic. I'll try the refreshing trick.

Considering what they want to charge for third party hosting they should be looking to have their servers behaving more consistently at least lol.

Thanks for persevering with me really appreciate it. Just have to get down to the mucky business of sourcing decent transistors. I was building a zonk machine/hs treble boost a couple of years back (prior to being stopped in my tracks by a cardiac arrest and subsequent coma) and went through the process of buying stuff only to find I must have been going through someone elses cast offs of low gain and/or massive leakage. Futile. Think i'll try and aim for some period correct equivalents in the hope of avoiding that this time. Id have thought having somewhere near the correct hfe range would be necessary to maintain the correct high and low pass filter responses?

Cheers again

marshmellow
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Post by marshmellow »

Any transistor with reasonably high gain (>300) will work fine.

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