I just built this with very nice results using a 2n404 (low leak, hFe ~ 40) and 2N5088. I also made it a couple of columns smaller by installing a spdt on-off-on for clipping (asymmetrical clipping options between LED/1n4148 and D9E/1n4148). I wouldn't go as far as calling it distortion, but it is a very interesting fat booster/low gain OD/loose fuzz - maybe messing around with the Ge transistor changes the gain. Overall, it sounds good!
Hey guys, I tried building this and replacing the diodes with some LEDs. But only one led lights up. The one connected to the 4.7k doesn't light up at all. Any suggestions?
It is based on George Giblets schematic A.K.A. "HP Concensus schematic". It appears the be the "common" circuit variation but since the circuit evolved over time during its lifespan there is several variations. I've seen at least five other schematics. Some have minor changes, other differs a lot.
Built it, fired up first try. I used 2n2222a (hfe around 180) for q2 and an unmeasured ac128 (tested several of them by ear) for q1. Also replaced diodes with the usual 1n4148 for a tad more headroom. This thing sounds really nice, great range of tones. It really does a lot more than fuzz
Hey! Just built this with a 2n2404a and 2n2222 and it sounds great! Only issue I’m having it it’s got a lot of hiss. Wondering if this is normal? Thought about trying to add a LPF at the end but can’t wrap my brain around where or how to add it. Any thoughts?
I don't know of course, (as per usual) but it could be the diodes you chose. I think the stock type are germanium diodes. So if you have any germs maybe try those. 1n60's might work. I think you made a speaker cranker so you may have some kicking around.
Oh, I found that the Parasit Studio site has TONS of layouts on it btw. Including all of their own original circuits. Most have strip board layouts. They're under DIY Guitar Effects and then Original Effects. Pretty cool.
Try the Black Current Vibrato and Stutter, its amazing. Its at the bottom of the page of original effects. He does a drone synth also which is really cool.
That last one was for Tom. Have you tried the usual suspects Ian, solder bridges, etc... I made a DBA Robot the other day that screamed when plugged in. Took me two days to realise I wired the jacks the wrong way round. Stupid errors that stare you in the face but dont see!!!!
I was all set to build the BC but then heard the Green Current. Maybe I'll build em both. It sounded kinda like a choppy f'd up harmonic trem to me. I also plan to build the Sonic Reducer. I saw that you built that one yourself.
Does anyone know how to get the low octave happening? Or what part of the circuit determines it? Most references suggest it’s determined by the 22k resistor, but I’ve tried varying it via using a trimmer and it’s not getting there. I’ve tried multiple transistor pairings and diodes and although it sounds fabulous it’s just missing that bit of low octave some perks have.
I added a diode lifting switch by adding a cut to D-11 and a connection from D-1 to the center lug of a SPDT daisy chained to Balance 3. B-15 becomes lug 1 or 3 of your switch. I opted to combine a 1N60 and a 4148 rather than using a three way switch with germs and silicons. It sounds best to me. I stuck a small resistor value and another cut to prevent the Harmonics control from cutting out entirely. Looking at multiple HP layouts I realized that I just got halfway to reinventing the Karma Suture. Haha. Anyway, thanks
I swapped in a couple suggested resistor values to emulate the land devices hp-2 according to GBE. Just for fun. The 91k changes to a 47k and the 22k becomes a 91k. It's nice. Albeit somewhat noisier. The subtle octave is slightly more pronounced. It tightens things up similarly to reducing the input cap value. And I changed my mind and added a three position switch for silicon, germs and no diodes. All sound great. Thanks again
I just built this with very nice results using a 2n404 (low leak, hFe ~ 40) and 2N5088. I also made it a couple of columns smaller by installing a spdt on-off-on for clipping (asymmetrical clipping options between LED/1n4148 and D9E/1n4148).
ReplyDeleteI wouldn't go as far as calling it distortion, but it is a very interesting fat booster/low gain OD/loose fuzz - maybe messing around with the Ge transistor changes the gain. Overall, it sounds good!
Hey guys, I tried building this and replacing the diodes with some LEDs. But only one led lights up. The one connected to the 4.7k doesn't light up at all. Any suggestions?
ReplyDeleteI might be losing my mind, but it looks like there are 6 cuts, not 5. Is that a cut in between the legs of the 100pf cap?
ReplyDeleteIt has to be right?
ReplyDeleteYes, there is a cut under the 100pF cap. Horizontal components always have a cut underneath it otherwise the component itself would be redundant...
DeleteWhich schematic was this layout drawn from?
ReplyDeleteIt is based on George Giblets schematic A.K.A. "HP Concensus schematic". It appears the be the "common" circuit variation but since the circuit evolved over time during its lifespan there is several variations. I've seen at least five other schematics. Some have minor changes, other differs a lot.
DeleteBuilt it, fired up first try. I used 2n2222a (hfe around 180) for q2 and an unmeasured ac128 (tested several of them by ear) for q1. Also replaced diodes with the usual 1n4148 for a tad more headroom. This thing sounds really nice, great range of tones. It really does a lot more than fuzz
ReplyDeleteHey! Just built this with a 2n2404a and 2n2222 and it sounds great! Only issue I’m having it it’s got a lot of hiss. Wondering if this is normal? Thought about trying to add a LPF at the end but can’t wrap my brain around where or how to add it. Any thoughts?
ReplyDeleteI built this using an asy70 pnp, and a bc337. I used generic big muff style diodes (1n1914) and the correct tantalum capacitor.
ReplyDeleteI'm not getting any sound at all. Have I gone too far off piste with the parts? All I've got is lound switch pop😨
Hi Ian, have you checked your transistor pinouts and tantalum orientation
DeleteI have sir. 😔
DeleteI don't know of course, (as per usual) but it could be the diodes you chose. I think the stock type are germanium diodes. So if you have any germs maybe try those. 1n60's might work. I think you made a speaker cranker so you may have some kicking around.
ReplyDeleteOh, I found that the Parasit Studio site has TONS of layouts on it btw. Including all of their own original circuits. Most have strip board layouts. They're under DIY Guitar Effects and then Original Effects. Pretty cool.
Thank you! I scored a batch of low hfe leaky germanium transistors with this in mind, so it's a bit of a blow 🤦🤣
DeleteTry the Black Current Vibrato and Stutter, its amazing. Its at the bottom of the page of original effects. He does a drone synth also which is really cool.
DeleteThat last one was for Tom. Have you tried the usual suspects Ian, solder bridges, etc... I made a DBA Robot the other day that screamed when plugged in. Took me two days to realise I wired the jacks the wrong way round. Stupid errors that stare you in the face but dont see!!!!
DeleteI'll do some staring tonight...
DeleteI may just build another board and you sockets just in case my cheap meter is struggling with the orientation of the germanium transistor
Get one of these Ian, I couldnt live without mine. You can test all components on them and transistor pinouts.
Deletehttps://www.ebay.co.uk/itm/353665620430?hash=item52581d19ce:g:3OwAAOSwdsxhOYLV
That looks awesome I have saved it to my watch list!
DeleteThank you!
I was all set to build the BC but then heard the Green Current. Maybe I'll build em both. It sounded kinda like a choppy f'd up harmonic trem to me. I also plan to build the Sonic Reducer. I saw that you built that one yourself.
ReplyDeleteTo be honest Tom, everything from Parasit is amazing. I am planning on the Theremin Fuzz - its sounds great.
DeleteSo here's mine. I first tried some low hfe Germaniums, but it was very muddy. I added a pn2907a and it was a bit better.
ReplyDeletehttps://youtu.be/tOHZLVGnle8
Does anyone know how to get the low octave happening? Or what part of the circuit determines it? Most references suggest it’s determined by the 22k resistor, but I’ve tried varying it via using a trimmer and it’s not getting there. I’ve tried multiple transistor pairings and diodes and although it sounds fabulous it’s just missing that bit of low octave some perks have.
ReplyDeleteI added a diode lifting switch by adding a cut to D-11 and a connection from D-1 to the center lug of a SPDT daisy chained to Balance 3. B-15 becomes lug 1 or 3 of your switch. I opted to combine a 1N60 and a 4148 rather than using a three way switch with germs and silicons. It sounds best to me. I stuck a small resistor value and another cut to prevent the Harmonics control from cutting out entirely. Looking at multiple HP layouts I realized that I just got halfway to reinventing the Karma Suture. Haha. Anyway, thanks
ReplyDeleteI swapped in a couple suggested resistor values to emulate the land devices hp-2 according to GBE. Just for fun. The 91k changes to a 47k and the 22k becomes a 91k. It's nice. Albeit somewhat noisier. The subtle octave is slightly more pronounced. It tightens things up similarly to reducing the input cap value. And I changed my mind and added a three position switch for silicon, germs and no diodes. All sound great. Thanks again
ReplyDelete