Correction to the LAL 86 Oscillo Fuzz layout Hi! I’ve recently built the 86 Oscillo Fuzz and found that the original layout and schematic available online have a small but important wiring error. The correct version has the 470Ω resistor connected to +9V together with the 47k, and its other side joins a 10k resistor going to the collector of Q2 — this node is also where the 100nF output cap and Osc switch connect. I’ve redrawn and tested the corrected schematic — it now works perfectly, producing the expected fuzz and siren-like oscillation. Hope this helps anyone trying to get this great pedal working properly!– how can I upload the sechematics here? Thanks Sérgio
I can see no failure / error from the turretboard and schematics from FSB web to this board and the changes you tell are already here: 47k and 470r from 9v.47k one to Q1 colector and Q2 base and 470r to a joint with a 10k, and the other end to Q2 collector. This joint row used for the output cap (100nf) and switch 1 lug. Am I missing something?
The only differences I can see are the added polarity protección diode and the 47uf filtering cap. Being this one a fuzz designe to oscillate, filtering is not desired. With this in mind, i'd remove both diode and 47uf cap, and save two columns, two cuts and a link.
The 470r & 47k do connect to 9v through the protection diode, but the error is that the other side of the 47k goes to the base instead of the collector of Q1?
Well, I had a few Pn100, so as this is a half an hour build, I can tell this fuzz works. Being basically a silicon Fuzz Face, and removing the filtering cap and the diode (not present in the schematics, and would affect the oscillation), you'll get the distinctive "frying bacon" noise with fuzz and volume dimed.
Oscillation runs ok and you get the "siren" noise if you want. Highly recommended to include the cv pedal to control oscillation with your feet.
How to wire: Tip to E1, tip switch to fuzz / fq 3., Ring to A1, Ring switch to fuzz/fq 2. Sleeve to ground.
B/10 which is labeled Level 2, should be Level 1 instead?
ReplyDeleteWhere's the CV input from the original?
ReplyDeleteRead the Freestompboxes thread in the schematic link?
ReplyDeleteHi Anders, hope you're doing fine! Keep up the amazing work. I wanted to build this but it seems that the schematic shows lvl2/output is grounded :
ReplyDeleteYea, Level 1 should be grounded & Level 2 goes to Output as usual?
ReplyDeleteWhat other NPN general purpose transistors work well as replacement for the PN100?
ReplyDelete2n2222, 2n3904, 2n4401, etc. anything in the lower medium gain range?
ReplyDeleteCorrection to the LAL 86 Oscillo Fuzz layout
ReplyDeleteHi! I’ve recently built the 86 Oscillo Fuzz and found that the original layout and schematic available online have a small but important wiring error. The correct version has the 470Ω resistor connected to +9V together with the 47k, and its other side joins a 10k resistor going to the collector of Q2 — this node is also where the 100nF output cap and Osc switch connect. I’ve redrawn and tested the corrected schematic — it now works perfectly, producing the expected fuzz and siren-like oscillation. Hope this helps anyone trying to get this great pedal working properly!– how can I upload the sechematics here? Thanks Sérgio
Open an account on freestomboxes.org and post the corrected schematic there.
DeleteYour schematic in the link is correct, however the layout has errors?
DeleteI can see no failure / error from the turretboard and schematics from FSB web to this board and the changes you tell are already here: 47k and 470r from 9v.47k one to Q1 colector and Q2 base and 470r to a joint with a 10k, and the other end to Q2 collector. This joint row used for the output cap (100nf) and switch 1 lug. Am I missing something?
DeleteThe only differences I can see are the added polarity protección diode and the 47uf filtering cap. Being this one a fuzz designe to oscillate, filtering is not desired. With this in mind, i'd remove both diode and 47uf cap, and save two columns, two cuts and a link.
Have a nice day!
The 470r & 47k do connect to 9v through the protection diode, but the error is that the other side of the 47k goes to the base instead of the collector of Q1?
ReplyDeleteNo, the 47K goes to collector of Q1 and base of Q2.
DeleteThe other side of the 47k should only connect to Q1 collector & not Q2 base
ReplyDeleteWell, I had a few Pn100, so as this is a half an hour build, I can tell this fuzz works. Being basically a silicon Fuzz Face, and removing the filtering cap and the diode (not present in the schematics, and would affect the oscillation), you'll get the distinctive "frying bacon" noise with fuzz and volume dimed.
ReplyDeleteOscillation runs ok and you get the "siren" noise if you want. Highly recommended to include the cv pedal to control oscillation with your feet.
How to wire: Tip to E1, tip switch to fuzz / fq 3., Ring to A1, Ring switch to fuzz/fq 2. Sleeve to ground.