Boss FZ2 has a very powerfull boost setting which is great for driving tube amps. It also has a powerful eq. Some people requested this, not wanting to build the whole FZ2 circuit which is quite big!
So here is two layouts, one stock with a FET input buffer and a discrete FET/PNP BJT op amp. The other one is Hyped Boost, the "cheat" version with a dual op amp for the input buffer and boost.
Props for whoever requested this, it's a fantastic Booster. You can tag the PedalPCB version, works perfectly and passes the comparison test with the boost mode of my SF300.
ReplyDeleteThanks for the layout!
Thanks Pedro!
DeleteI'll tag as soon as I can!
I got the pedalpcb -version to work but it is not very loud. The eq works well but it is not boosting at all...any suggestions? I couldn´t find any mistakes.
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DeleteBuilt both of them this week, killed a bunch of jfets with static in the process, hence the removed comments....
ReplyDeleteAfter grounding my iron and a bag of cheap JAN2N4861's, she roars with the grace and beauty of my OG FZ-2. Accept no substitute, the original version sounds a bit better, and breaths fresh air into my "My Own Summer" cover.
Played around with it some, definitely inspired the Catalinbread SFT, the array of jfet gyrators in that pedal are quieter than the opamp driven gyrator. Should probably check that one out sometime.
I cleaned up the noise floor a bit over the original, KSA992 worked the best in the PNP spot, and its partner KSC1845 on the output buffer.
Biggest cleanup in noise came via the opamp used. OP270 worked best here, would also recommend C0G ceramics in the eq section, as well as shielding the input and both jacks.
Any jfet works, would of went with 113's if it wasn't for the fact I zapped a bunch of them in my stash. Metal cans for me from now on.
... also, the 56k's in both layouts should be 10k according to most recent schematics and my FZ2. Q1-Q3 are all 2SK184-GR in my pedal along with a 5218 in original, which is noisy as hell.
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Delete.... also, on the actual FZ2, the level control isn't in the boost eq circuit. That 50k level pot is neutering the legendary FZ2 boost mode, and won't allow for it's signature party trick.
ReplyDeleteBoss also matched their differential pairs, otherwise the mirroring PNP is useless, and would just be replaced with a resistor. Most clones sound like ass for these reasons. Same goes for the BD-2.
to avoid making a testing rig and buying a bunch of conversion Tosh's from Aion, just spend the dough on a LSK389A which is basically a matched pair of 2SK170's, works like butter in my build. PN4393 would probably be the best choice for your input buffer.
ReplyDeleteBypass that damn level pot, and your boring preamp pedal becomes rawkus as fuck, and don't buy into the SF300 blasphemy, even my bandmates that know dick about circuits told me to shove my build up my ass and bring my FZ-2 back to practice before I got it right.
Listen to Nick's testimony here, dude makes killer records...
https://youtu.be/VQ6dUnUuiwI?si=OEz92ldpCWu_cebT
and for the only "right" FZ2 schematic online...
ReplyDeletehttps://www.tfrelectronics.com/FZ-2-Hyper-Fuzz/#&gid=1&pid=1
this Jon Wain guy is a straight G, even got the orientation right on the electrolytics in the signal path, confirmed with both of my FZ-2's.
didn't get schooled by Borbely on differential pairs though, that has to be right to coax the "hyper" out of this thing.
after reading these comments, I shotgunned a Lacroix, smashed the can on my head and yelled "who wants some??!!!" at my dog. Seriously tho - thanks for the insight on the FZ-2 - I've built a couple variations that I've been happy with, but just may have to revisit them with these changes in mind.
DeleteI've been fucking with mine for a month now trying to get it right, finally just cracked it yesterday, FZ-2 boost mode is my lifesblood since '96. Stef Carpenter has been wrecking one since Adrenaline and turned me on to it originally.
DeleteNothing quite compares, and some hifi bros helped me out in how to get it to tick right.
I hate how this thing gets pegged to Dopethrone, this pedal is on so much shit, and maybe if Boss caught wind on how bad ass this pedal really is, they may Waza it for the masses, the right pieces are out there in SMD format.
Just discovered this blog and feel like a kid in a candy store, fuzzheads Evil Filter layout helped me reverse engineer the big box. Been pulling my hair out over that one too, got it right last week TRS expression and all.
All these recommendations also carry over to the full version, that's how you really bring out the nasty ring mod effect that renders chords useless in mode 2.
all the other clones just gave me Bee Baa vibes, typical boosted superfuzz tones that you can actually riff on. That's not an FZ-2, I can barely play chords on my originals. JHS makes a low info video and the gear world just parrots each other, and no one has an actual FZ2 to compare it to.
DeleteOne of the primary reasons I continue to visit and contribute to this blog is that the community here is super helpful and encouraging. I've shied away from FSB and a lot of other small signal audio forums because they are packed full of angry little boy-men who like to posture with negativity, bullying and hypermasculinity. Not only is there a wealth of information contained here, but I've never been called a "noob" (or worse) for asking questions or getting things wrong.
DeleteI agree. I find the constant bickering and competitive, mean spirited behavior very frustrating. If people thought in more of a cooperative/collaborative way we would have a better community overall. A better world frankly.
Deletedefinitely have a cool community here.... My RV-2 shit the bed on me and figured it's time to start cloning some of my Boss oldies and wound up here.
DeleteWill share any insight I have, still shaking off some rust, as I just dusted off the ole soldering iron, haha
...and forgive me if my long drawn out findings become annoying, I tend to share things as I'm working them out, hoping it may be helpful to another builder that stumbles across my dribble.
DeleteMost of the time when builders figure things out, they never report back, leaving their fellow solder junkies to assume.
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ReplyDeleteboxed my FZ2 Boost/Eq up today as it's finally worthy....
ReplyDeleteto bypass the level pot in that schematic, I removed the pot all together, the 1uf tied to the base of the output buffer. and ran a jumper from R3 to L19 for authentic FZ2 boost mode tones.
My build is pretty damn close to my original FZ2 boost mode now, but with lower noise floor. Stoked for sure!
My build utilizes...
Q1 PN4393
Q2 - Q3 a single LSK389A for the differential pair, which is a dual monolithic pair of 2SK170, "A" specs the same as -GR on the Tosh chips...
Q4 2N5807... Dynacord used these to reduce thermal noise in their differential pairs, Boss yanked the design from them. High HFE recommended here, mine measures 500 hfe
Q5 2SC1815-y... buffer of choice for most of the old MIJ stuff, have a bunch, low noise, work well
Built the hyped boost as well, that one is a bit more plug and play. Got the most volume out of TL072's after bypassing level, but was still lacking a few db compared to the other layout and the IC rail clipping was a bit less present.
.... OP270 gave me the lowest noise floor for the EQ driver, a bit more gain than the 4558 as well, so rolling with that one.
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Delete.... considering the nature of gain here, and without the Boss switching circuit present. It's most likely going to sound like a shotgun blast when you engage the footswitch. It's going to be your LED more than likely.
ReplyDeleteJack Orman has your back with a work around...
https://www.muzique.com/lab/led.htm
works well for me usually.