The El Diablo... A Dave Main creation, part Sola Sound MK1.5 Tone Bender / part Vox Tone Bender - hence the MK1.75 moniker. And why El Diablo? apart from the colour, this thing sounds mean as hell.
They appeared to use a couple of different transistors for Q2, but the OC75 remains up front - the OC75 definitely provides a sonic signature in a circuit like this. The version I saw with the OC84 transistor has a small silva-mica cap between the collector and base of Q1 (I couldn't see the value).
From the Vox:
- smaller input cap
- smaller Level pot
- a resistor placed between the Attack pot and ground
- resistor values
- OC76 for Q2
From the MK1.5:
- 10n output cap (although some Vox carried this)
- and of course, the OC75 for Q1 is pretty important
SOLA SOUND MK1.75 'EL DIABLO' TONE BENDER - 0.15" VERO LAYOUT
So to get something sounding like the video below from pinstripedclips, I needed to use a relatively low gain transistor ~50hfe for Q1 and in some cases the D*A*M dirty hippie mod, often employed to help bias an OC75.
I added the video below, as this is much closer to what I was getting on the breadboard with most of my transistors. Also worth noting as mentioned by Phil in the comments, pinstripedclips has a fairly specific set-up, and who knows how that contributes.
OC84 VERSION
OC76 VERSION
Yeeeeeah! For the videos this is a mean sounding Vox Tone Bender! I will have to make one!
ReplyDeletethis sounds amazing, definitely going to have a run at it
ReplyDeleteHi Andy regarding the 1st video I know that pinstripedclips uses a ZT Lunchbox (solid state) amp for most of his videos / clips and the fuzzes always have this super-crispy upper midrange tone. Similar to this tone which i love as well :
ReplyDeletehttps://www.youtube.com/watch?v=ZzeqjbA4iGY
I've never managed to replicate his tones for builds i've made for the pedals he displays. As you say it's a combination of many factors. You can never rule out some extra processing in the DAW either. Anyway thanks for posting the layout, all the best
Phil.
Thanks Phil - no doubt fairly different, but I might try hitting my little Vox Escort solid state with it to see comes out of that.
DeleteThanks for pointing this one out to me too.
thanks for putting this one up Andy! I put an NPN version together on the breadboard with GT404s, sounds legit to me. Thanks again! https://youtube.com/shorts/51ceaxbOe3g?feature=share
DeleteSounds the business G.G. Nice, and NPN to boot
DeleteVery nice G.G.! what gains for the transistors did you use?
ReplyDeleteNIce. What is the dirty hippie mod? :)
ReplyDeleteI added some information on the mod in this post. https://vero-p2p.blogspot.com/2023/03/sola-sound-goldie-mk15-tone-bender-vero.html
DeleteExtra resistor to ground on the base of Q1 to help with OC75 biasing, sometimes a 10n to ground on the input.
Phil, I really should put together a test circuit to measure transistor gains. I only have a handful of germaniums though so I've just been going with what I have. FWIW the GT404Bs I have all seem very consistent, I auditioned a few in this circuit and they all sounded the same. Tone-wise they're very compatible as well. This may sound like heresy, but I started with the PNP version on my breadboard using an OC75 I borrowed from a MKI build and ended up preferring the GT404Bs.
ReplyDeleteRespect to Dave Main and Ant Macari for what they do - part of which is excellent marketing.
DeleteThere’s nothing wrong with using different transistors, as they quite often sound the same or 95% similar to the ‘right’ transistors.
Soviet transistors are often more predictable and better behaved than your average OC75.
Thanks G.G. As they say whatever sounds good is good! Just nice to get a bit of background info re. all that stuff. Ive got one of those Atlas transistor testers and the trouble is I probably get too hung up on HFE / leakage. Your's sounded great so i'm hoping I won't have too much trouble finding a good working set.
DeleteI agree with you Andy. The hyperbole that D Main uses to describe his (admittedly incredibly built / sounding) pedals borderline on ridiculous but I suppose it's all part of the fun and there are only so many ways to describe a fuzz pedal before it gets dull. Everyone admits that the original builders were fairly casual with their transistor selection so given what we know about hfe / leakage and voltages taken from good working pedals it shouldn't be impossible for us to build great sounding replicas.
DeleteI used to get hung up on a lot of details too, then after a lot of time on the breadboard testing transistors, I found that it mostly wasn't worth worrying about.
DeleteIt's good to know that transistors in a certain range tend to work well in a particular circuit, but that's about where I leave it. For me, the MKI remains the hardest to get right.
I used have a hard time time with the MK1/Zonk trying in vain to remove the dreaded sizzle / chirping. Swapping transistors for days cursing my lack of the 'right' ones until I read about using an input pulldown capacitor. Usually a 1nf cap will remove the high-end (sizzle) and not kill the highs. Now transistor swapping and circuit tweaking is far more forgiving and enjoyable.
DeleteI nearly always cheat on Zonks and use a 2n2 instead of a 1n input cap as well.
DeleteOK now the secrets are being revealed, getting my popcorn. :-D :-D :-D
DeleteYeah Andy 1nf is punishingly bright and quite tinny sounding. I've gone all the way up to 10nf sometimes ha.
DeleteI've heard of the 10nf mod - I think it's called the MKI ;-) 1n is just too small for me. Even a 3n3 still keeps the Zonk sound, but just removes some of that nastiness
DeleteAh cool will try that next time. Didn't even occur that it was the mk 1 cap! i've seen a few builders add switches to change the caps, may do that as well.
ReplyDeleteI’ve made one with a switch and they sound pretty good.
Delete