Here another classic fuzz, the Mosrite Fuzzrite. This is the silicon version. The original transistors were marked "TZ82" so be sure to use sockets and try a few different ones out. The original pots were 350k and 33k, which are going to be difficult values to track down. You can either use 500k and 50k, or use 500k and 50k and add fixed resistors in parallel (between lugs 1 and 3) to try and recreate the original values.
Hello, mister. Is the 22k resistor from Depth lug 1 the 'one' that gives the original character sound of the pedal? I have built one based one General Guitar Gadgets schematic, wich has no 22k resistor at all. Sounds good, but different from that cool 60's fuzz and the Depht pot also doesn´t affect much the sound. I've searched on the web about that resistor, but didn't clarifyed my mind. In tagboardeffects for example, one guy commented that should be sticked from Depth lug 3 to ground. Sooooo... What's the deal?
ReplyDelete(I'm sure breadboarding is the way to go, but it's fullfilled with another project right now, while I make the boards for this one.) Thank you very much again!
It's been a while since I researched this circuit and laid it out, so breadboarding is definitely the way to go. I believe this is the schematic I drew this from:
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I may have gotten confused on the pot orientation of the depth control. Other schems seem to have the 22k going off of lug 3 like you said. So I may just have it backwards...
So I got this one breadboarded now. The 22k goes from Depth lug 3, indeed.
DeleteIt acts like a passfilter (together with the 0.0022 out cap form Q2) and the Depht pot balances the signal from Q1 and Q2. Changing the value of the resistor can bring some different response frequency. I'm on 100k.
Change the out caps also looks like a good idea (bigger ones for more bass sound), I'm on 10nF.
I fixed the copper trace on the picture, really simple, if you are interested.
Thanks for the info! By all means, show your fix and I'll update the layout.
DeleteI'll try this something like this:
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one 2n cap goes a litte up, swap Depth 1 and 3.
One word of advice - early silicon transistors (like the original ones in the Fuzzrite) had LOW Hfe. It's a good idea to try lower gain devices - I used the old 2N2369 which is supposed to be a VHF transistor and usually has an Hfe of 70 - 120. I found that these sounded much better than higher gain, modern parts (but hissed a little more).
DeleteIt's also worth experimenting with the DC blocking capacitors to vary the frequency response. It's also worth adding a small capacitor (47 - 150pF) between base and collector of each transistor to smooth off the harsh edges a bit, eliminate any AM radio pickup, and reduce the hiss a bit!
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