Tuesday, 20 March 2012

Schaller Tremolo

Request.  I've already done the Hearthrob but someone asked for this, and you can never have too many tremolo options I suppose.  Some of those transistors look like they may be difficult to get hold of, so I'd probably just use 2N5088's which work fine in the Hearthrob.

If you do use other transistors make sure the pinouts of your build match the pins shown in the layout.


  1. Hahaha, that video :p
    Germans are always so well-humored. She actually says "have fun" in the beginning of the video, with a tone as if somebody has died.

  2. Battling this one and few others at the moment. Seems to be working right, or at least the controls work and i get perfect Schaller sound from Q1 base by probing. Get nothing to the output though. I'll continue probing and checking..

    1. Did you end up using 2N5088's? Although this isn't verified, it 'should' be ok because the layout is adapted from the Hearthrob Tremolo layout which is verified. Again if you can post some pics I'll see if anything stands out

  3. http://mirosol.kapsi.fi/varasto/boxproblems/SCHTRE_top.JPG

    You know it's hard to show people how you solder. I feel shame :(

    Yes, i'm using 2N5088's and unlike i said, the closest to the truth is probably Q2's base, but here's same test results - voltages and probes:

    9V battery at 7,4V
    Q1C - 0V - Silent
    Q1B - Flux, -0,07/-0.08V - Throbbing and clean guitar
    Q1E - Flux, 0.0/0,2V - Throbbing

    Q2C - 0V - Throbbing and almost tremolo*
    Q2B - 0V - Silent
    Q2E - 0V - Silent

    Q3C - 7,4V - Throbbing
    Q3B - 1,2V - Throbbing
    Q3E - 0,6V - Throbbing

    Q4C - Flux, 1,7/3,4V - Throbbing
    Q4B - 0,6V - Throbbing
    Q4E - 0V - Silent

    Might not be the greatest descriptions.. By throbbing i mean throbbing sound and it changes it's density and speed with the pots. So some of this is definitely working..

    *by almost tremolo i mean that throbbing sounds like it's getting mixed to the guitar signal but not well enough.

    Hope you can make something out of this. Like always, i've triple checked all the components, holes and wiring.

    Thanks again for your help and for your great blog.

    1. There's nothing wrong with your soldering, as long as it's nice and shiny with no cold joints then the solder side doesn't have to looks like a work of art.

      The voltages show there is obviously some problem with it, have you tried any other 2N5088's in there just in case one has failed? Also have you run a knife between each track just in case there is an unwanted bridge somewhere?

      I'll have a look over it in the meantime and see if I can spot anything, but on first glance your cuts look fine and from what I can see the component positioning looks fine.

    2. Hmm. Call this one verified with four 2N5088 transistors (couldn't find BC170's). And you call me stupid while you're at it...

      There is one slight quirck to the layout though. Depth pot is in reverse if compared to the frequency pot. Reversed that and everything is working perfectly!

      I can grab the correct voltages if someone needs them, but as this is verified, i don't think anyone does.

      Thanks again!

    3. Ha ha, it happens to all of us sometimes! :o)
      Thanks for verifying, I'll update the depth pot. And I'd be interested in the voltages, it may be helpful if anyone else has problems. Cheers!

    4. I'll grab them later tonight, if you remove that typo comment from below :)

  4. Don't know about accuracy, but these readings will probably land you in the right ball park. Here we go!

    9V battery at 10.0V

    Q1C - 0V
    Q1B - Flux, 0.04-0.18V
    Q1E - 0V

    Q2C - flux, 3.28V/2.25V
    Q2B - 2.05V
    Q2E - 1.59V

    Q3C - 9.82V/9.88V
    Q3B - Flux, 1.09V/1.23
    Q3E - Flux, 0.55V/0.66V

    Q4C - Flux, 3.10V/6.40V
    Q4B - Flux, 0.55V/0,65V
    Q4E - 0V

    Personally i like this more than Hearthrob. May it be, that the momeries of owning one about 13 years ago still haunted me :)

  5. http://mirosol.kapsi.fi/varasto/boxes/blacktrem.JPG

  6. hi mark, i've built this with success but i'm experiencing a loud popping sound when engaging and disengaging the pedal. how can i solve this? thanks.

    1. Try putting a 1M resistor between the input connection on the board and ground. If that doesn't work, try increasing the 47K input resistor to something like 150K or 180K.

    2. thanks for the quick reply, mark. by "between the input connection on the board and ground" you mean solder one end of the resistor at (from the top)row 7 and the other end at row 11, the area near Q1?

    3. Either solder it on your switch between the wire going to the input of the board and the permanent ground connection for the LED, or you're going to have to fudge it on the board, maybe from the top of the 47K resistor and the hole below where the output wire attaches to the board (which is grounded)

    4. i soldered the 1M resistor across the input and ground connection for LED but the pop is still present. i haven't tried increasing the 47k input resistor though! i'll try it as soon as my parts order arrives. but even as it is now, i'm very happy with this build. thank you, mark, for your help, and i look forward to more layouts from you.

    5. The LED can also be causing the popping, have a read of this:

    6. i have tried removing the LED altogether from the switch and tested it, but still there's a pop. weird. could the switch itself be the problem? i could be having a dud?

    7. Could it be the way the switch is wired? Mark should have a pick of the Skreddy method of wiring a switch.

    8. Here is it is, try wiring the switch to this method.


    9. I have been using GGG's basic 3PDT method for all builds without a problem.. http://www.generalguitargadgets.com/pdf/ggg_sw_3pdt_tb_gi_dcj.pdf

      Just thought i'd share, since my schaller trem clone works fine with this.

    10. One of those pain in the arse things eh Mirisol.. I had it with the DAM Rooster, nothing would get rid of the pop... I just gave up and took the LED out as it was for me anyway.

    11. thanks for the link, mark. it was a good read that page.

      yes guys, i had my switch wired according to GGG's diagram initially when i discovered the popping. i have since rewired it using the diagram found at the offboard wiring section but the popping, til now, still persist. yes, this issue is indeed a PITA! ha ha. i'm going to leave it be for now and move on to another layout. thanks for the inputs, you two!

    12. Before you move on try increasing that 47K though. A guy on FSB couldn't cure his popping with usual methods either, but doing that sorted it out for him.

    13. hi mark, finally able to socket the 47k today. i tried putting across a 200k first and then 2M resistors, but none could sort the popping. with the 2M across, i noticed some drop in volume..is that supposed to happen?

    14. Yes there comes a point where the resistance will cause a noticible volume drop so that's expected. The only other thing I could suggest is leaving the anti popping resistor on the switch and put something like a 47nf cap in series with the input wire and see if that helps.

    15. i've put a 47nf cap in but it still pops.. :(
      he he nevermind, mark. i'm moving on.

      btw, i just finished building the ecstasy today. love it! thanks for the layout.

  7. I built this with 2N5088's and the Heart Throb at the same time to compare both. I MUCH prefer the sound of this one to the Heart Throb, but like the way that the Heart Throb can go slower. Can I modify this to run slower, and if so which components need changing?
    Thanks guys!

  8. Built this and it sounds really good. Weird thing is i used an on-off on SPDT as i had run out of on-ons and i get three different speeds slowish, med & fast which is really cool. Think I'm going to keep it that way.

  9. I have just built this with 2N5088s and it is working, but the output volume is very, very low and there is an audible "beat" on the pulse for some rates. The rate pot, the depth pot and the speed switch all seem to work as advertised. It is my first build and I am unsure how to go about troubleshooting. here are some measurements from the transistors:

    power: 9V power at +9.08V

    Q1E: 7.6mV - 7.9mV flux
    Q1B: 320mV - 180mV flux
    Q1C: 0V

    Q2E: 3.1V
    Q2B: 2.06V
    Q2C: 1.45V

    Q3E: 9.08V
    Q3B: 1.1V - 1.3V flux
    Q3C: 0.53V - 0.69V flux

    Q4E: 0.4V - 3V flux
    Q4B: 0.54V - 0.69V flux
    Q4C: 0V

    any help greatly, greatly appreciated. my readings vary quite a bit from mirosol's so i know there's an issue there but don't know where to start. thanks heaps guys for the great site and the plethora of amazing circuits. you guys rock. cheers, Gavin.

    1. OK, so I found one issue with a cap placement. Now she is makign sound at the correct output level. Seems to "lag" the strummed note a little though. More degugging necessary I guess. I might try replacing the transistors and see if that helps..

  10. Dear people, hello
    I'm experiencing the same pop-ing issue. Can some one send a pic from his wiring so that I can see what is going on?
    I have tried all mention methods and also I have made it with millennium bypass 2 and still pops...


    1. Have you tried a 1M on the Input to a static ground on the switch, and 100K on the Output to a static ground? Someone in the forum had success with this.

    2. Oh, man thank for your reply...I think I have tried everything...noting happens- I think is some of the parts in between cose the pop is unusually loud. Maybe is returning signal from some of the transistors I don't know maybe I'm talking nonsense...It's not very important build for me so I'll live it that way. THANKS!!!!

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