I've drawn 2 layouts:
- with biasing resistors
- with biasing trimmers
I've also added a charge pump for the 18V required.
You can find the schematic on FSB's original thread here.
Original info:
The Menatone None More Black is a homage to all of their favorite high gain amplifiers. Amps with very German sounding names and amps named after Big Rig fuel. While not based on any specific amp, it is an amalgam of the best aspects of many amps rolled up into one. The gain of the None More Black ranges from hot rodded 800, to crazy, in your face, all out insanity. The SUCK knob can take the mid range from all the way gone, to crazy gobs of fat, vocal, goodness, while the PRES gives total control of the high end. This deceptively simple arrangement gives a surprisingly complete control of the tonal palette.
Man your on fire! Great work Alex. Looking forward to giving these a build. Roll on the weekend!
ReplyDeleteI should let people know that this trace Is off of the rare 18v mxr size version, its not the normal 9v version. me and jok3rx traced this one because I have the pedal and in this version theres a extra j202 as well as the obviously stated charge pump and increase in voltage rating on the caps
ReplyDeleteill link gut shots of both side by side in a few
Hi Jesse!
DeleteI didn't mention you or jok3rx because the schematic was't created on this blog.
I've added a link to the original FSB thread where people can find all info.
The "obviously stated" charge pump wasn't in the schematic.
I've added it because I didn't know if it was meant to be there or run on an 18V power supply.
yah pump was part of the original build so you nailed it! I cant believe how good some of those guys are at tracing at the FSB forum
ReplyDeleteOk stupid question but why are there 2 layouts?
ReplyDeleteIt's written in the introduction.
DeleteOne has trimmers and one has fixed resistors to bias JFets.
Sometimes trimmers can create noise.
Yeah I see it now that Im on my computer. Totally missed it on my phone, Sorry about that. Cant wait to build it
DeleteVeerified the version with trimmers but had to use 2N5457s as i have no J202's, but they are on order. It sounds quite bright but that may be the 5457s. Also there is a bit of hiss n crackle in the background, but it is a high gain pedal, possibly from the trimmers.
ReplyDeleteOther than that sounds pretty good. Cheers Alex.
Thanks Gavin!
ReplyDeleteYou are on a roll!
Trimmers can be noisy.
That's why I've posted 2 layouts.
I think the sound could be the 2n5457.
I also built the version with trimmers. I used j201s and it sounds pretty damn good. I also get a lot of background noise, but I might box this one and hope that helps, my test setup has too many free and crossing wires. I may even take readings from the trimmers later and build the other version.
ReplyDeleteThanks for the layout!
No need to build the other version.
DeleteYou can always remove the trimmers and add the resistors instead. You could put them in diagonal or use 1/8W resistors if you don't want them standing.
Oh... duh... totally didnt even think of that. Thanks Alex.
DeleteJ202s arrived today so slotted them in and just like that it became a totally different beast. Had to re bias the trimmers. Sounds really good now and background noise is minimal.
ReplyDeleteCool! Gavin where did you get you j202s from?
DeleteHello Guys, is there's much difference between J201 and J202? Thanks for your help.
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ReplyDeleteReal nice job Alex, I've made with 2SK30 and it works but I think a little high distorted and also have some noise and crackle. I made it in bread-board, may be should put in a box.I think the bias should adjusted, could you tell me how to adjust POT, or give Vgs of Fets. Thank you in advance.
ReplyDeleteMaybe a dull question, but i'm pretty new to this stuff. what's the purpose of the trimmers? or more importantly, what will be the main difference between the finished product of the two layouts? I'd like to build this and i have everything but the trim pots, should i just build the first layout, or is it worth waiting til i source the trimpots?
ReplyDeleteNo offense, the nature of your question suggests that this build may be over your head.
ReplyDeleteHowever, if you decide to give it a shot anyways, the trimmers are for biasing the JFETs
If it was me I would wait tell u get the trimmers. If u build the first layout u may have problems biasing the transistors if you don't know how to do it. 50k trimmers are easy to find. Only thing I can think of between the to finished layouts is the trimmers might add just a little more noise to the cirquit. But I don't think u will here anything.
ReplyDeleteGudday, just built this with the J202s and trimmers. Sounds great, but the noise make it pretty unusable. I'd like to think it might go away in the process of boxing it but does anyone have any ideas?
ReplyDeleteShould I attempt to go with trimming resistors, and can the trimming resistors replace the trimpots in the trimpot layout?
I've never been lucky enough to have boxing get rid of any noise.
ReplyDeleteThe main thing is gonna be biasing, particularly for the early stages where any noise they produce is further amplified by subsequent stages.
You could try different drain resistor values or use trimmers
It's pretty much always a good idea to use shielded wire at least for the input in a high gain circuit
Everything I have built with multiple J201 or J202 was really sensitive to drain resistors. I would do like Travis said and try trimmers on the drains and adjust it by ear.
ReplyDelete-Brett
I've built the version with trimmers - I was asking about changing to the bias resistors as someone mentioned above trimmers can be noisy.
ReplyDeleteWhat are we looking for when biasing by ear? Mine are all biased around 9v, within .05v or so.
I have plenty of j201 currently too. Might try those in it. Also have some 2sk30.
I know it's a few years ago now, but do you remember how the J201s sounded?
DeleteUpdate: I removed the chargepump (linking pins 1-2 on the socket) and put a klon buffer in front. Much better.
ReplyDeleteThere is 32 cut in thé first layout no?
ReplyDeleteIs their a process or order to turning the trimmers or is just twiddle them until it sounds good?
ReplyDeleteI'm going to remove the single turn carbon track trimmers and replace with wire wound.
The ideal will usually be to get the voltage at the drain of the JFET to measure 4.5V. So if you measure between the drains and ground with a multimeter for each JFET while you adjust the trimmers, that's what you need to aim for.
DeleteFrom the Top left hand trimmer downwards, you'll be measuring:
Q4
Q3
Q2
Q1
and the trimmer in the middle is for Q6
Thanks Mark. I'll get onto that. I replaced the single turn carbons with cermet 25 turn tonight. Is 4.5v a magic number for J202 or is there more of a science behind it?
ReplyDeleteHi cringe, what you are aiming for is half the supply voltage. I looked over the schem on FSB thread referenced above. This circuit is running at 18 volts so you actually want to aim for 9 volts measured at the drains like Mark explained.
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ReplyDeleteHas anyone dabbled in other FETs for this circuit. Although this worked with the J202s I have, it sounds below average with the J202s I bought off ebay. I've tried smd items on carrier boards and am getting no output. Is it worth crossing legs over on 2n7000s and trying them? Is there any foreseeable issue?
ReplyDeleteIf you’re using smd make sure you check the pin out after applying it to the adaptor board. I’ve had to twist a leg every time when doing this.
DeleteIf you’re using smd make sure you check the pin out after applying it to the adaptor board. I’ve had to twist a leg every time when doing this.
Delete