Schaller Tremolo schematics!

Carlos · May 16, 2006, 11:40:43 AM

From our German DIY fellows and their forum:
http://forum.musikding.de/yabbse/index.php?topic=5806.0:

Carlos

Carlos · May 16, 2006, 12:00:35 PM

BTW the pots are wired as variable resistors.
Maybe somebody can clean up the schematics a little bit.
It's a good sounding tremolo
(compare http://www.harmony-central.com/Effects/Data/Schaller/Tremolo_TR-1.html)
and easy to build, almost like the EA tremolo.

Carlos

Arn C. · May 16, 2006, 04:22:07 PM

Thank you Carlos! and WELCOME!!!

Peace!
Arn C.

Dan N · May 17, 2006, 04:29:52 PM

Thanks Carlos! I always wondered about this one.

TELEFUNKON · May 17, 2006, 04:39:49 PM

gotta sound warm with <100k input impedance !

Zero the hero · May 18, 2006, 08:08:43 AM

I'm drawing a layout for this tremolo. hopefully, I'll post it tonight or tomorrow morning.

MartyMart · May 18, 2006, 09:26:42 AM

I have an original and it's a very very nice tremolo

, quite vintage amp style..
Non TB switching is a bit "tone sucking" ( FET ) but not too bad, this version
should sound fantastic, nice one

MM.

Paul Perry (Frostwave) · May 18, 2006, 10:22:16 AM

Thanks for that! Pretty unusual phase shift LFO there, guess that is to get a sine.

gez · May 18, 2006, 10:44:09 AM

Quote from: Paul Perry (Frostwave) on May 18, 2006, 10:22:16 AM
Thanks for that! Pretty unusual phase shift LFO there, guess that is to get a sine.

I'm sure it's a sine, but it is a little on the exotic side isn't it!

I wonder if that pot arrangement results in a more linear feel (everything doesn't bunch up at one end)? Also of interest is the emitter resistor for the first trannie of the Darlington. I should think, as RG pointed out the other day, this would raise the gain.

Anyway, thanks from this hemisphere too!

gez · May 18, 2006, 10:46:33 AM

Quote from: gez on May 18, 2006, 10:44:09 AMI wonder if that pot arrangement results in a more linear feel (everything doesn't bunch up at one end)?

Hmm, probably not if they have a fast/slow switch...

Zero the hero · May 21, 2006, 02:06:23 AM

DONE!
I uploaded the layout for this tremolo on my site this morning.
It's semi-verified since I triple checked everything but I haven't built it yet.

JHS · May 21, 2006, 06:46:12 AM

Some additions to the schem:

The 5uF I/O caps are tantal, in the early '70 version are 3 BC237C and 1 BC239C, all 10uF are 22uF and
the 50k Pot is 100k log but over 50k the tremeffect stops, so 50k is the better value.

All Rs are 1/2W Carbon Comp 20%.

The original units are not true bypass and produce a middier clean sound in bypass mode and when on with slight distortion.

Box is plastic, inside coated with graphit lacquer, overall build quality is plain horror but after a rewiring the unit sounded quite pleasing (very similar to the Fender trem on the early tweed tube amps).

Due to the 47k input impedance there's nearly no noise or hiss.

Trannies can be substituted with BC547/49 types to reduce the noise furthermore.

JHS

Zero the hero · May 21, 2006, 06:59:45 AM

Thanks JHS, these infos are so valuable!
May I add them to my project page, with credit to you?

TELEFUNKON · May 21, 2006, 07:09:57 AM

obviously it`s NON-bypass
as opposed to non-true-bypass.

Bernardduur · May 21, 2006, 07:44:02 AM

Great schem.... love to build it soon!

markm · May 21, 2006, 11:45:54 AM

I think I'm going to give this won a whirl.
Anyone know if the switch make it "choppy" like the Pulsar?

TELEFUNKON · May 21, 2006, 01:00:37 PM

make square out of sine from LFO.

Carlos · May 21, 2006, 01:09:39 PM

That's
http://topopiccione.atspace.com/PJ20SchallerTremolo.html
Zero's layout, isn't it?
Glad you like
I think I'll use a footswitch for the speed switch. Does it double the speed like the switch on Fulltone trem?

Regards
Carlos

Zero the hero · May 21, 2006, 04:45:13 PM

that'sgoodthat"sgoodthat'sgood!!!
The layout works, the whole tremolo works! I think that the layout is a bit messy and some components are too close to each other. Anyway...
It's very nice sounding, but I haven't tested it alot (it's 11PM and I cannot turn up the amplifier so much...).
LFO speed varies from 2-3Hz to the realm of slight ring modulation and the switch simply doubles the speed.
Thanks Carlos for sharing!
Tomorrow I'll do more tests on it.

Carlos · May 22, 2006, 11:35:21 AM

Hi everybody, hi Zero the Hero,

the Schaller tremolo I ordered some time ago has just arrived. The build quality, however, is dismal, so that I will send it back and get a refund. It's a plastic box covered with graphite lacquer from the inside.
In the meantime I took a few pictures. Zero the Hero, if your layout is okay and you make a PCB, would you mind making a PCB for me, too? I'll verify the schematics.

and

Have fun
Carlos

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Schaller Tremolo schematics!