Hi all.
I built up the very rare Foxx Select-a-Fuzz clone last night using the DeadEndFX board and some 2N3569 transistors I bought from a US seller on ebay. The pedal works but sounds terrible. The circuit is pretty straightforward: signal goes in through a rotary switch selecting various input caps for different tones feeding a BJT transistor-based fuzz. The tone that I'm getting in pretty much any input cap setting is muddy, weak and bland. The circuit does not have a "drive" or "sustain" control. There is a very mild and pretty much ineffective "mellow/bright" control.
My basic issues are first off that it's very dark and muddy in all tone settings. There isn't quite enough drive/sustain to the fuzz and the "mellow/bright" control barely affects anything. I'm wondering if there are better cap values that would tailor the tone more to my tastes and I'm wondering if I'm having transistor bias issues.
Has anyone else built this? Any thoughts?
Build Document: https://drive.google.com/open?id=11I8tdRm2zsEqto9nQSaTEGKwolNtMiq1 (https://drive.google.com/open?id=11I8tdRm2zsEqto9nQSaTEGKwolNtMiq1)
Demo video: https://www.youtube.com/watch?v=ChpAV4QzGBk (https://www.youtube.com/watch?v=ChpAV4QzGBk)
Thank you!
Roger
hello...
there are given proper voltage readings in the build doc, try referencing from there...
Good eye. Good point. Thanks for noticing that!
Roger
.... but tell us what readings you get, obvs. also - rotary switch is a warning flag.
Whatever components I used on the breadboard went straight into the build, so no camera trickery there.
Voltages. Yes. Voltages.
Oh yeah, and I did notice that it's fairly sensitive to the transistors used. I tried the bog standards like 2222, 3904, 5088, et al. and none really blew my skirt up. I think not using transistors with too high a gain (less than 200) is key. YMMV
Thanks! I'm wondering if my transistors are kind of part of the problem to begin with. I ordered 2N3569s off eBay, which is always a crap shoot. I tried 5088s too, and they pretty much sounded the same as the 3569s. I will experiment a bit more this afternoon and check voltages.
BTW, I messaged you the other day via the DeadEndFX site. Is there a better way to get a hold of you?
Thanks!!
Roger
Quote from: Rodgre on September 03, 2020, 10:38:59 AM
Thanks! I'm wondering if my transistors are kind of part of the problem to begin with. I ordered 2N3569s off eBay, which is always a crap shoot. I tried 5088s too, and they pretty much sounded the same as the 3569s. I will experiment a bit more this afternoon and check voltages.
BTW, I messaged you the other day via the DeadEndFX site. Is there a better way to get a hold of you?
Thanks!!
Roger
PM sent.
Email was received, just scrambling for time of late.
Quote from: Rodgre on September 02, 2020, 09:53:26 AM
Demo video: https://www.youtube.com/watch?v=ChpAV4QzGBk (https://www.youtube.com/watch?v=ChpAV4QzGBk)
You look just like Dino. But taller.
Quote from: digi2t on September 03, 2020, 06:34:43 AM
Whatever components I used on the breadboard went straight into the build, so no camera trickery there.
Voltages. Yes. Voltages.
Oh yeah, and I did notice that it's fairly sensitive to the transistors used. I tried the bog standards like 2222, 3904, 5088, et al. and none really blew my skirt up. I think not using transistors with too high a gain (less than 200) is key. YMMV
I looked at the build doc in the link.
Have you tried adjusting R1 the 100k first transistor collector value with the 2n2222 etc transistors at the first FF like stage to adjust the collector voltages?
Looking at the last stage, adjusting R10 the 12k might be the easier way to adjust the collector voltage for different transistors.
I normally don't like changing the output collector resistor in a FF like or an output off a collector out gain stage without feedback
however
the first stage of the FF like section is buffered by the 2nd transistor and higher Beta transistor will load it less
The output stage has collector to base feedback R11 this lowers the output resistance
Quote from: willienillie on September 04, 2020, 07:15:27 AM
Quote from: Rodgre on September 02, 2020, 09:53:26 AM
Demo video: https://www.youtube.com/watch?v=ChpAV4QzGBk (https://www.youtube.com/watch?v=ChpAV4QzGBk)
You look just like Dino. But taller.
It's all about the camera angles. That, and elevator slippers.