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I've just completed my first vero-based pedal - worked first time - very stoked.
It's an FY2 using this layout and schematic...
I used some 2sc536f trannies, each about 200 Hfe. I own an original FY2 and the character of the fuzz I'm getting with mine seems right but the eq is way off. I think something is wrong because with the midscoop rolled off completely, the volume drops off to 0. Although the midscoop seems to be working in that it introduces more mid and bass, it is always very mid heavy - it won't scoop! Basically I can't get the eq as per the stock Companion. Any ideas what might be up?
I noticed that the volume pot is not only affecting volume - it's also working as a mid control! It seems the volume and scoop pots have become completely interactive but I can't figure out how to fix it. I disconnected the scoop pot to see what happened and the mid hump is still present and the volume pot still works as a volume+mids control. Any help much appreciated
I'm thinking from the schematic that maybe there's a mistake on the layout and Vol-3 ought to be at b18.....
According to the schematic, the volume should be at C-18, the junction of the 15K(R8) and 1000pF(C7) cap. As the vero layout has it, the volume is parallel with the scoop pot. So the junction is where the 0.1uF(C8) cap and the scoop pot meet.
There seem to be a couple of mistakes in that layout. This should be correct per the schematic. I've taken the liberty to relabel C5 and C6 to work in a top to bottom left to right numbering scheme.
No problem, I hope it works out for you. If it seems I have made any mistakes please let me know and I will correct them. I've never built a vero layout, I usually just make my own PCBs or use perf board. I have used some vero layouts to reverse engineer a schematic to build a pedal from however.
I think I just had to relocate the 2200pf cap to make the layout correct. Done that but it sounds pretty much the same.
Not sure what to try now. Maybe voltages on the transistors? I used those green polyester caps like the original so I thought the tone would be pretty much bang on.
You said you are using 2sc536f transistors, correct? So did you adjust this layout to use with those transistors? Or did you just twist the leads around? The emitter and base are inverse on a 2sc536 in comparison to a BC108. That is, the base on a BC108 is in the middle, whereas on a 2sc536 it is one of the outer pins.
I just figured out my mistake. I put 0.01 caps in for the 1000pf. This is my first build that wasn't a kit and it took me a while to get my head round pf, nf and uf so I made a mistake there and that must be why the eq is so off. At least I now know what being out by a factor of 10 on a couple of caps sounds like!
Thanks for your help. I'll swap the caps out tomorrow and hopefully will be able to report back that I have a nice FY2 clone. I tested the voltages on the trannies and they match the ones on my original to within 1 or 2 hundredths of a volt so I'm hopeful for a good clone.
Ah, yeah that will do it. You moved the peak of the cutoff of the filter network from about 1.2KHz down to around 400Hz. I use the program called Electronics Assistant, it helps make heads and tails of capacitor codes and values along with resistor band values, LED dropping resistor values, and a lot of other stuff. It's free and comes in handy quite a bit. Another program I like is SPICE. It's basically a virtual breadboard. You can render audio through it, but it's very very slow. It does help give you a visual of how a filter will effect the audio, or how much boost an amp will provide. There are several different versions, but I just use the free one. I think it's called LT SPICE.
I will get myself a copy of Electronics Assistant, I need one. I swapped the caps. I only had some little ceramic disc caps at 0.001 but I've put them in and now it sounds like it should. Pretty pleased with it. The mid scoop has far too big a pot on it - 47k, so I'll swap that for a 2k on Mark Hammer's advice which should make it more usable.
Soundwise it's almost bang on. The original has a bit more clarity. Hard to describe but it sounds more pure - it's easier for my ear to pick up all the sonic detail whereas the clone's tone is slightly less direct - the frequency spectrum is a little more cluttered, especially in the top end and the low mids. Might be the trannies, at the moment I've got a BC547 and a 2SC828 in there, just to see what happened so I'll go back to the 2SC536s and see if there's any difference.
My first project from scratch, done! Been a good learning experience this one.
UPDATE: I swapped the trannies for 2sc536f (new ones, not NOS) and it made no discernable difference. I know my voltages on them are near identical so I think the key must be in the caps. I'm so close, I'm determined to make a perfect clone, it's such a great fuzz!
yup, some vintage pedals have some caps in them that are not even made now. some vintage pedals have caps with the dielectric leaked out and dried up. chasing a sound is a dangerous game. do we buy NOS dried up leaky caps now? also, cap values could be %20 in either direction. C8 could be 80nf in the vintage and 120nf in the DIY version. even with two poly films of the same value but different style (box or chicklet), I can hear a difference that is very noticeable in some pedals.
I don't think ceramics degrade, but some types of poly caps can. IIRC ceramics have "harsher" audio qualities. I'm pretty sure there are multiple theories on why, but the general consensus of the sound is pretty much the same. Electrolytics in such low values as are used in this pedal are not common.
