A Quick note on the Kay Tremolo mod

[JerS]

Hi - sorry to revive an old thread, but I recently have used this to help me recreate my version of the Kay Tremolo. The results I came up with based on much of the information in this thread are as follows:
- used MPSA42 transistors (gains between 110-130, purchased from Tayda)
- implemented the depth mod withour the 68K resistor in series
- used 5KB pot for speed, this worked for almost all of the travel of the pot except for the very fastest setting - will tweak this later
- on my version (not shown in the layout below) I replaced the 4.7uf caps with 2.2uf, and the 10uf Cap with a 4.7uf - this brought the lowest speed down slower than the standard which I found to be desirable for my style
Overall, I am really happy with the sound of this trem - it will be on my board for a while I think.

I should mention, this is my first post here - I often post over at BYOC under the name "Jer". I have found this forum to be a really useful resource, and wanted to start paying back where possible with some layouts, etc. Anyway, here is the layout I used. This is for board mounted pots (16mm PCB pin style like from Tayda). I poke the pins through from the copper side of the vero. It fits in a 125B.


A pic from another pedal with this style of board mounted pots to give an idea for what I am doing:

[JerS]

I have been playing with this circuit for a while now and still wanted to get a slower speed from it. After opening up my pedal to try and tweak further, I can report that I made a major error in my note above. I suggested that I changed the 4.7uf caps to 2.2uf, and the 10uf to 4.7uf to slow the speed down. I don't know what I was thinking when I wrote the post - because making that change has the opposite effect - it will speed up the trem.

....so after much fussing around, I realized that to slow the speed, the easiest way is to increase the value of the 10k resistors to something between 15-24k. This brings the speed range down considerable. I am sure you could put these on a switch to get a "high" and "low" speed range (smarter folks than I have likely already done this).

Anyway - if anyone ever looks at this post - I apologize for the misinformation given previously.

[Whatisnotrue]

Hello!

I am currently building a clone of this pedal for a friend of mine. In fact, I am housing two within the same enclosure, they will be running in parallel with two separate inputs and outputs, and be bypassed simultaneously with the aid of a relay controller. His crazy idea is that if he runs them into separate amps, at different (but very fast) speeds it will create interesting phasing effects. He will be in-fact running them into two Marshall half-stacks at fairly high gains, with his guitar going into a buffered signal splitter before the Tremolo.

Problem is, after doing some initial tests with my setup using the maximum gain offered on my amp, I noticed that the choppiness tends to give way to some bleed-through of the dry sound. I suspect that this might be an inherent problem with the design of the pedal, as it does not fully "clamp down" the signal so to speak. This is not an issue at all on a clean setting, just for the record.

The other issue with running it into an amp at high gains is that I begin to hear the circuit oscillating quite clearly.

Has anyone ran into similar issues, or have any thoughts? It would be greatly appreciated!

[JerS]

I do not get any bleed through on mine with the depth knob all the way up - however I did omit the 68K resister in series with the depth pot. Mine seems to completely clamp the volume to "0".

I do however hear the circuit oscillate at high depth and high gain settings. I suspect this would be the case regardless of tremolo pedal (high gains are inherently noisy and sensitive).

[Whatisnotrue]

See, there is a bit of a double-edged sword here because if I add the 68K resistor it does tame the oscillation a bit, however it doesn't shut the signal totally down. I might just nix the design in favor of using an Opamp circuit in conjunction with one of those Vactrol photo-resistors. I was hoping this circuit would be cheap, easy, fun solution to this project but it's presenting too many obstacles. Oh well!

Thanks for confirming that the oscillation isn't occurring with just me... 

[Whatisnotrue]

just an update from my previous post; if anyone is interested I came up with my own chopper tremolo design.

this circuit has a passive signal path, and thus does not need to be bypassed.



some things to note:
there doesn't have to be a clerostat for the speed pot, i'm just a little crazy 
the momentary switch can of course just be a regular on/off stomp switch.
yes, VTL5C1's are a little pricey as far as components go but they work perfectly.

this thing does FULL chop. meaning you can throw as much gain in/after it as you want and it will still completely chop the signal. it is also very quiet compared to the Kay, plus no distortion or signal loss! yaaay.

sorry to derail the thread...   

[John Lyons]

Interesting. Do you have any aural examples perhaps?

[Whatisnotrue]

I did record a video of myself playing my strat through it into a super reverb.... however I was having trouble uploading it because of my lousy internet connection. I will see what I can do!

EDIT: It appears that I have made a silly mistake with the schematic. The LEDs are wired in reverse. Sorry about that!

[mrsamd23]

Hey all! I found this very helpful to my build! I used 3904's and got some gain but not much. I was wondering how to got a stronger effect, because mine is really faint. Also, If i wanted to put put clipping diodes with an spdt switch where would i put those to create an overdriven tremolo? I'm still kind of new to all of this, I've made an amp and a distortion pedal. Any help would be useful! Thanks, sam