MichaelW
Well-known member
- Build Rating
This is not a complete build but close....
I'm waiting on a set of matched 2N5952's coming in this next week and I'll post an update.
But based on some dumb questions and my education on the nuances of JFET matching in this thread, I decided to go ahead and build out the pedal and try some of the JFET's I had on hand.
The build itself went very smoothly, no issues except I had to make a couple of substitutions. I could not find a 250k Trim pot so I subbed a 200k. It seems to be fine as none of the trimming so far has gone above noon on the 200k.
I also did not have any 15uf Tantalums that the BOM called for, so I subbed a pair of electrolytic in parallel (10uf + 4.7uf) so it looks a little wierd.
Last thing I did not have was a 3M9 resistor so I used a pair in series to get close. (I think I wound up at 3.79m or something like that).
I used the new Tayda Red Sand colored enclosure. Wasn't sure I was going to like it but I really do! Cool color and goes well with a cream knob and blue LED.
I've posted a short sound clip of each set down below. I just recorded a small passage into my looper and swapped the transistors out and tuned the trimmer to the most phasing sound I could get. All the clips were recorded with the rate knob at noon and the Script toggle off (to the left) and the 45/90 toggle set on 45 (also to the left). I also did not touch the gain or input, any differences in volume are strictly from the transistors used.
First clip: Random set of 2N5457 TO-92’s, all out of spec.
(I was getting some distortion with this set that I could not dial out with the trimmer)
VGs Off
-37.0mv
-112.2mv
-57.4mv
-141.4mv
Second clip: Random set of J201 TO-92’s, all out of spec
VGs Off
-43.3mv
-39.6mv
-44.4mv
-129.9mv
Third clip: Random set of MMBFJ201’s mounted on adapters
(These were the loudest)
VGs Off
+145.6mv
+98.9mv
-35.8mv
-180.7mv
Fourth clip: Matched set of MMBF5457’s.
These are matched but not in the ideal range of -1.4v to -3.5v as per @Chuck D. Bones
At the setting with the most phasing I was getting the ticking you can hear.
VGs Off
-1.190 v
-1.294 v
-1.184 v
-1.123 v
Fifth clip: Matched set of MMBF5457 Script Setting
If I dialed the ticking out then I also had less phasing. But I found that that the ticking stopped if I switched to the Script setting on the toggle (to the right). So this last clip is the same set of “matched-but-out-of-range” MMBF5457’s as the last clip but with the Script setting. Everything else is the same.
I'm waiting on a set of matched 2N5952's coming in this next week and I'll post an update.
But based on some dumb questions and my education on the nuances of JFET matching in this thread, I decided to go ahead and build out the pedal and try some of the JFET's I had on hand.
The build itself went very smoothly, no issues except I had to make a couple of substitutions. I could not find a 250k Trim pot so I subbed a 200k. It seems to be fine as none of the trimming so far has gone above noon on the 200k.
I also did not have any 15uf Tantalums that the BOM called for, so I subbed a pair of electrolytic in parallel (10uf + 4.7uf) so it looks a little wierd.
Last thing I did not have was a 3M9 resistor so I used a pair in series to get close. (I think I wound up at 3.79m or something like that).
I used the new Tayda Red Sand colored enclosure. Wasn't sure I was going to like it but I really do! Cool color and goes well with a cream knob and blue LED.
I've posted a short sound clip of each set down below. I just recorded a small passage into my looper and swapped the transistors out and tuned the trimmer to the most phasing sound I could get. All the clips were recorded with the rate knob at noon and the Script toggle off (to the left) and the 45/90 toggle set on 45 (also to the left). I also did not touch the gain or input, any differences in volume are strictly from the transistors used.
First clip: Random set of 2N5457 TO-92’s, all out of spec.
(I was getting some distortion with this set that I could not dial out with the trimmer)
VGs Off
-37.0mv
-112.2mv
-57.4mv
-141.4mv
Second clip: Random set of J201 TO-92’s, all out of spec
VGs Off
-43.3mv
-39.6mv
-44.4mv
-129.9mv
Third clip: Random set of MMBFJ201’s mounted on adapters
(These were the loudest)
VGs Off
+145.6mv
+98.9mv
-35.8mv
-180.7mv
Fourth clip: Matched set of MMBF5457’s.
These are matched but not in the ideal range of -1.4v to -3.5v as per @Chuck D. Bones
At the setting with the most phasing I was getting the ticking you can hear.
VGs Off
-1.190 v
-1.294 v
-1.184 v
-1.123 v
Fifth clip: Matched set of MMBF5457 Script Setting
If I dialed the ticking out then I also had less phasing. But I found that that the ticking stopped if I switched to the Script setting on the toggle (to the right). So this last clip is the same set of “matched-but-out-of-range” MMBF5457’s as the last clip but with the Script setting. Everything else is the same.
