Verify it! Cool sounding fuzz with lots of control. I ended up substituting a BAT46 for the 1n5817 diode and a MPSA13 in place of the 2n3904 at Q3. I think it sounds a weeeeee bit bigger with the darlington at the end.
Just put this together, and all the pots seem to work backwards. It's not quite sounding as it should. Is this diagram labelling the pots from bottom, 321?
Hey Ian! Yeah, lug numbering shown is the normal "321". However, theere is no lug numbers shown in the linked schematic above so it is possible that the Bias and Starve pots is backwards. But it seems very odd that you having the Volume and Fuzz controls backwards?:-/
I'd love to have another go at this..I don't quite understand the modification to reduce oscillation bleed through in bypass. Would you be kind enough to spell it out for an idiot like me?
Hey Ian. I'm sorry that I can't help you on this one. I have never seen this simple noise bypass arrangement before. Usually it is enough to have the input of the board grounded when in bypass mode which is one of the more common ways to wire up the bypass switch.
Just built this.. It's all up and running but it's very odd.... the starve pot just seems to want to be effective in the final 1/4 turn...all below that is super low motorboating...it's got few good spots and they're tricky to find.
I think it's a great fuzz, but it did require a little tweaking. In addition to the pot changes, I also found this circuit responds much better to BC547 transistors for whatever reason. Maybe the lower collector current and higher frequency bandwidth? I don't know, but after making those changes there's much less "dead space" in the pot sweeps.
I built one some time back and liked it but didn't box it. But it hasn't left my mind. It has something and I don't know what it is. I found that auditioning 2n3904's was needed. They all gave me different results. I have it in my hand now and don't see any deviation from stock. I sourced some more trans that I plan to try. I think I'll box it up basically as is though. For some reason it reminds me of Yankee Hotel Foxtrot.
I messed with this circuit a little tonight. I found that using lower HFE 2N3904 trans made the circuit gate less. Q3 seeming to be most important in this respect. Q1 and Q2 should be around 200 or so and Q3 is closer to 100-150 actually. I stupidly stuck Q1 in the wrong way and lost my sweep entirely. Cuz Im dum. So is this circuit...in a great way. Thanks for the layout.
I just made up another one of these for a buddy, but this time I consulted the schematic to make my own layout for practice. Every other schematic for this lists different values than what is listed by Mellowtone. Using the values from the other schematics yields much, much better results. Try - Fuzz 25k, Volume 100kA, Bias. 100kb, Starve 10kc.
Verify it! Cool sounding fuzz with lots of control. I ended up substituting a BAT46 for the 1n5817 diode and a MPSA13 in place of the 2n3904 at Q3. I think it sounds a weeeeee bit bigger with the darlington at the end.
ReplyDeleteCool! I'll tag it.
Deletehttps://www.instagram.com/p/CPB_6BMsu87/?utm_medium=copy_link
ReplyDeleteFew more minor changes from the source!
Thanks Ross for the "factory" schematic! Layout updated.
DeleteJust put this together, and all the pots seem to work backwards. It's not quite sounding as it should. Is this diagram labelling the pots from bottom, 321?
ReplyDeleteThank you 🙏
Hey Ian!
DeleteYeah, lug numbering shown is the normal "321". However, theere is no lug numbers shown in the linked schematic above so it is possible that the Bias and Starve pots is backwards. But it seems very odd that you having the Volume and Fuzz controls backwards?:-/
I'll try again some time...
DeleteCheers
This comment has been removed by the author.
DeleteI'd love to have another go at this..I don't quite understand the modification to reduce oscillation bleed through in bypass.
ReplyDeleteWould you be kind enough to spell it out for an idiot like me?
🙏Ian
Hey Ian. I'm sorry that I can't help you on this one. I have never seen this simple noise bypass arrangement before. Usually it is enough to have the input of the board grounded when in bypass mode which is one of the more common ways to wire up the bypass switch.
DeleteHi. That makes sense because the skreddy switch wiring should fully bypass the circuit anyway???
DeleteThank you for you reply. Its really amazing that you answer all these queries.
Thanks as always
Ian
Just built this..
ReplyDeleteIt's all up and running but it's very odd.... the starve pot just seems to want to be effective in the final 1/4 turn...all below that is super low motorboating...it's got few good spots and they're tricky to find.
Thank you
Forget that 10kc for starve - way too much - use a b 5k, and an A50k for bias and you'll get much better results.
ReplyDeleteCheers. I'd forgotten about this I wonder if I should revisit it one day...🤔
ReplyDeleteI think it's a great fuzz, but it did require a little tweaking. In addition to the pot changes, I also found this circuit responds much better to BC547 transistors for whatever reason. Maybe the lower collector current and higher frequency bandwidth? I don't know, but after making those changes there's much less "dead space" in the pot sweeps.
ReplyDeleteI built one some time back and liked it but didn't box it. But it hasn't left my mind. It has something and I don't know what it is. I found that auditioning 2n3904's was needed. They all gave me different results. I have it in my hand now and don't see any deviation from stock. I sourced some more trans that I plan to try. I think I'll box it up basically as is though. For some reason it reminds me of Yankee Hotel Foxtrot.
ReplyDeleteI messed with this circuit a little tonight. I found that using lower HFE 2N3904 trans made the circuit gate less. Q3 seeming to be most important in this respect. Q1 and Q2 should be around 200 or so and Q3 is closer to 100-150 actually. I stupidly stuck Q1 in the wrong way and lost my sweep entirely. Cuz Im dum. So is this circuit...in a great way. Thanks for the layout.
DeleteI just made up another one of these for a buddy, but this time I consulted the schematic to make my own layout for practice. Every other schematic for this lists different values than what is listed by Mellowtone. Using the values from the other schematics yields much, much better results. Try - Fuzz 25k, Volume 100kA, Bias. 100kb, Starve 10kc.
ReplyDeleteJust tried it out and it is very funny to play with. I don’t have a 10KC so a regular 10KA works. I’ll try some BC547s. Great layout
ReplyDelete