Over the years, we've had tons and tons of folks asking us when we were going to produce an overdrive pedal that emulates the sound of a cranked Fender® amp.
When Brian decided that he was going to see if he could do it, he wanted to ensure that it was perfect. Looking back at it now, we think he must have spent a good 9 months breadboarding and prototyping lots of different ideas, a/b-ing each one with various Fender® amps, tweaking and changing until he found the sound that was accurate.
Once he got a sound that he was 100% happy with, he took it to Nashville studio ace Brent Mason to test it out. To be certain, Brian also took several pedals by other companies that are supposed to do the same thing. Brent knows Fender® amps better than anyone, and Brian knew if Brent thought it was good, we were onto a winner. Long story short, Brent LOVED it!
We've heard guys say they hear The Twin®, some say Vibrolux®, some say Deluxe Reverb® when they play this pedal. Whatever they hear, it still has that "Blackface" type of sound that we were looking for. When you turn it up, it's going to break up more like the amp would if you turn it up.
With the additional of the boost switch, you can increase the gain to make it sound like the amp is being driven harder.
When Brian decided that he was going to see if he could do it, he wanted to ensure that it was perfect. Looking back at it now, we think he must have spent a good 9 months breadboarding and prototyping lots of different ideas, a/b-ing each one with various Fender® amps, tweaking and changing until he found the sound that was accurate.
Once he got a sound that he was 100% happy with, he took it to Nashville studio ace Brent Mason to test it out. To be certain, Brian also took several pedals by other companies that are supposed to do the same thing. Brent knows Fender® amps better than anyone, and Brian knew if Brent thought it was good, we were onto a winner. Long story short, Brent LOVED it!
We've heard guys say they hear The Twin®, some say Vibrolux®, some say Deluxe Reverb® when they play this pedal. Whatever they hear, it still has that "Blackface" type of sound that we were looking for. When you turn it up, it's going to break up more like the amp would if you turn it up.
With the additional of the boost switch, you can increase the gain to make it sound like the amp is being driven harder.
awesome. thanks so much for posting this Mark! i'm going to build it today.
ReplyDeletei got the circuit built and am about to mount in the the enclosure (it just arrived!)
Deletehere's a pic of the vero circuit board:
http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/Black65/Black_65-circuit.jpg
i didn't have any 240K reisitors so i just used two 120K's in series for them. i also used sockets for the tone stack and slope resistor to see if it needed any 'tweaking'.
Excellent work there John as usual, have you tested it yet?
Deletewell it's complete but i haven't been able to even get the slightest peep out of it. something's wrong somewhere. i'll have to trace my assembly but i'm pretty sure that it got it right. the voltages on the drains look way too high (around 7.5V but i don't think that that's my only problem. i lowered the voltage on my lab power supply to 6.54V to get all of them within range and it still doesn't make a sound.
DeleteLet me look it over John
DeleteDoh! Move the Volume 3 wire one row down.
DeleteHi Mark,
Deletei just looked that vero and compared it to the schematic. the blue wire for volume 3 (the input of the output volume pot) isn't connected to anything! i just moved it down one row (like it should be and it works perfect. correct the vero and it's verified! BTW, it doesn't have a TON of gain or volume boost, but it does sound awesome! thanks for posting it!
Hee hee ^^
DeleteThat's excellent, thanks for verifying John, I'll tag it. I must say I didn't think it had a lot of gain in the clips I'd heard, but then again neither did the original amp so that's probably to be expected.
before i read where you said to move the blue wire one row down, i just did it myself. this thing sounds great, but now i'm going to test a bunch of my j201's and if they don't get within its bias spec, i'll socket the bias resistors to see if by getting in the 4V range that i has more gain'overdrive.
DeleteIt's typical that that was the error, because of course with it being at the end of the circuit it was the last thing I had to check. I must have had a brain freeze when I was placing that one. :o)
DeleteI thought 5K6 seemed low for the drain resistors but I suspect with this that it has been done for a reason. If you get the voltage you may not get the desired response, but it'd be interesting to see what you find.
I bought some Alps RH068 trimmers which have really long legs and so would be perfect for some of these JFET effects to simply replace all the drain resistors. You can see them here, 3rd down:
http://www.potentiometers.com/alps_trimmer.cfm
Definitely worth looking out for for the tweakers out there.
for some reason that trimpot link didn't work for me, but i think i'm familiar with those. thanks.
Deletethe guy that measured an original wampler black '65 said that the FET's at the drain measured like this
First FET - 4.08V at the drain.
Second FET 4.00V
Third FET - 3.95V
Fourth FET - 3.93V
VCC set at precisely 9.00V
i can only get one out my batch of 50 J201's to run at 4.53V (which is acceptable to me), but the others are 6.9V and above so i think that socketing all four bias resistors is a good idea for this one, although i would've installed trimpots if i were to build one again.
Cheers for the voltages John, a good point of reference. It does highlight the poor tolerance in characteristics with JFETs which is a bit of a shame for us DIYers when they're being used more and more. They just seem to be all over the place, I hope the manufacturing process and quality control starts to improve with these because there should never be such extremes in a small quantity of components.
Deletei agree. in a circuit like this, IMO,J201's almost alwys need a trimpot for each one. Brain must have some pretty high biasing J201's if he's running 5.6K's in there. i just tried subbing all the 5.6Ks for 10K resistors and the drains are now down in the 6V range. i'm going to try some 22K's next just to go to the other extreme. it seems to have more volume and drive with the 10Ks over the 5.6K's.
Deletejust ried four 20K's and it was too much. they were only pulling 2.5-3V on the drains. it was pretty ugly sounding (mushy/spongy) and couldn't ever really be clean even with the gain set fully CCW. i just tried 12K's and they're all at around 5V and it sounds nice. i have some 13.3K's and 15K's that i'm going to try next, but i think i'm going to go with the 12K's. to me 4.5V-5V is probably the sweet spot on this pedal even though Brian seems to set his a 4V. don't forget, i'm using mine for bass, so want it a little more clean than most peopel will.
Delete"I bought some Alps RH068 trimmers which have really long legs and so would be perfect for some of these JFET effects to simply replace all the drain resistors. You can see them here, 3rd down:
Deletehttp://www.potentiometers.com/alps_trimmer.cfm
Definitely worth looking out for for the tweakers out there."
I fancied getting a few for tweaking, but the 1,200 piece minimum order was just a wee tad off putting :-)
Yes that may be a few too many! :o) I got them from a seller in Germany who was selling 100 mix of any values for around €6. I just checked and he doesn't seem to have them anymore though.
DeleteOoh actually he does have some:
Deletehttp://www.ebay.co.uk/itm/290747298759
So excited to build this. You guys are awesome.
ReplyDeletethe 13.3K's absolutely nailed the bias for me. all four of the J201's are pulling 4.59- 4.63V and for me, that's its sweet spot. the pedal has tons of gain now (including clean boost). with the drive control fully CCW it's clean but FAT. from there on up it it can get pretty gritty, and with the gain boost it goes to a whole new level of grind. it may just be my favorite of all of the pedals that i've built thus far (and i've built 29 of them). this one, and the Wampler Ectasy and this one are at the top of my favorites list.
ReplyDeletehere's a couple of pics of it:
http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/Black65/Black65-01.jpg
http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/Black65/Black65-02.jpg
after dialing this one in, now i'm going to have to go back and tweak the Catalinbread WIIO that i built yesterday. it's just a bit too spongy and dull sounding to me when you start adding some gain.
Fantastic looking build
DeleteThanks Mark. yeah, i love the sound of this one.
DeleteFair fucks John your builds aren't sloppy are they? I'm severely impressed, old Bri himself would be too. How did you do the graphics dude, is it waterslide? I've tried various applique, but with poor results! I've got a powder coating machine so the enclosures look nice, just can't get that text man!
Deletei use a brother p-touch PT-2100 with a computer program for the fonts. that one uses a 'fender font' which you can download for free on the web.
DeleteVery pro looking mate. Thanks!
DeleteAwesome........How do you put the white lettering on top of the black enclosure? silkscreen?
Deletei still have problems with my build: although the drain voltages look fine (3,9 - 4,3V) there is almost no overdrive/distortion at all... its more of a (great sounding) clean preamp. all controls work as they should (except the gain;-)) and the signal coming out of this box is LOUD, so the build should be ok. btw: the gain pot does actually nothing in the first half of its rotation, any ideas are welcome..... tia Heiko
Delete"problem" solved;-). long story short: use trimmers.....! this pedal sounds absolutely great and has a wonderful tone control, from clean to heavy grit, it´s all there! thanks again mark!
DeleteGlad i have a ticket for today's draw on national lottery, because the first four J201s from the bag worked like a charm. Didn't even measure them, because i don't want to know if they are "correct". Sounds so good i can't describe it. This has more subtle preamp-like tone, that it has definitely place on my board. Normal for base sound and boosted for leads that don't require fuzz. I used 3PDT stomp switch for boost and used third pole for 3mm indicator LEDs for normal/boost. Otherwise it's a stock build with engraved labels :)
ReplyDeletehttp://mirosol.kapsi.fi/varasto/boxes/65.JPG
I just couldn't resist building it. I had 4 others finished and i checked my list of finished builds. ROG's English Channel was number 64, so i just had to do this. It's my 65th finished build to date.
Drawer with "to-be-boxed-soonish" label has now only 10 bags waiting :) Yup. BB boxes are cheap :)
Anyway. Not a bad weekend. Thanks for everything again!
+m
congrats. mine worked okay with just about any four J201's with the stock resistor values, but it wasn't until i started tweaking the drain voltages by socketing and trying various resistor values until it got great. IMO, if you're in the 4.25-5V range on the drains it should sound great. above 5V and it'll be pretty clean and below 4.25V it'll get dirtier.
DeleteI don't mind the clean :) Actually it's just what i've been looking for - preamp with an edge.
DeleteMight try to tweak if i get my head around building another. This one is just perfect for me.
+m
Cool, thanks for the pic Miro
DeleteNo problem. Did you catch the other four from this weekend already?
Delete+m
Yes just been catching up mate. Nice work. Did you make another Pastrami and OD850 or have you just got round to boxing them?
DeleteJust boxed them. There is always enough ready boards waiting to be boxed... :)
Delete+m
so awesome you posted this!
ReplyDeleteso is there anyway to test jfets before you install them to see if they're going to get you close the voltages desired?
I guess I'm just wondering how much voltage can you drop off the drain by changing the resistors? and is there a point when using a larger resistor will make it sound bad?
Thanks!
I've seen 100K trimmers used to bias JFETs, it isn't the resistance value that will make the effect sound bad, just too much or too little voltage. The best bet is socketing the 5K6 resistors or using something like 20K trimmers instead.
Deleteso is there no point in matching the jfets? or would it be like if I matched the jfets (not sure what measurement would matter in the "amp in box" circuits versus phaser's and whatnot) would that then allow me to use the same value bias resistor for each jfets drain?
Deleteyour the man!
if I matched the jfets wouldnt I be able to just find one resistor value and then not have to go through and change each bias resistor to get in spec?
ReplyDeleteeh? or does it not work like that?
is it like the reason you need to adjust each bias resistor because we're not using matched jfets- where wampler uses the same bias resistor for each jfet because he is using matched jfets?
If you match the fets for drain voltage then the resistors would stay the same, but it could be a long and arduous process and you may need a lot of J201s. It probably makes more sense to use any JFET and then select the resistor value that gets the drain closest to the required voltage (4V looking at the measured voltages in the original). It will be even easier if you socket the resistor locations and then use a trimmer to establish the best value resistor to use for each.
Deleteso does the original have trimmers in it? if not, he must be using matched jfets right?
ReplyDeleteI hate using sockets- they always seem to wear out on me and make terrible contact for the most part.
so is the point of the jfet matcher just for the phase 45? I was about to do the formula no 5... what should those be biased at? can we get bias recommendations for the jfet pedals? Or really trimpots on the vero would be best... that way it would be really easy to dial it in however you like it- i think that would be awesome
No it didn't have trimmers and so yes he must be matching JFETs and for a commercial builder that makes absolute sense. He'll save himself many hours of extra work fixing pedals under warranty that have had their trimmers messed with by their owners. For DIY builders who know enough to build the things in the first place with an understanding of what the trimmer is there for, it makes more sense touse the trimmer simply because it makes it quicker and easier to do.
DeleteIf you don't like socketing and/or you don't want to breadboard it first to get the right resistor values, then you're going to struggle pre-selecting the JFETs too, because whichever way you choose, you're going to have to swap something, either the JFETs or the resistors.
The point of the matcher is to match Idss and Vp measurements in the JFETs which makes it useful for any pedal where matching these characteristics is important like the phasers where the JFETs are used as variable resistors. I don't know what single or combination of characteristics determine the drain voltage given a set resistor value and so I couldn't say for sure which measurement to match to get common drain voltages in something like this. It could be that the matcher would work very well but until I've had the opportunity to do some testing and experimentation with it I don't know the answers for certain.
Why just do not change 10R with a bigger value? In the beginning I had 6,8V in drains, so I changed 10R with a 1,5K resistor and now I have 4,2V.
ReplyDeleteThat does make a lot of sense! All the connections to 9V rail after 10R are the 5K6 drain resistors. I bet 1K3 would nail it pretty well...
Delete+m
interesting- so if I did match my jfets then I would get similar voltages at the drains at each jfet- then I could adjust them all at the same time with that 10r resistor?
Deletedoes that sound logical?
I'd really just rather use a layout with trim pots... but I always screw stuff up trying to add trimpots on these vero layouts- i find it really difficult to add colums and rows without getting something else wrong. i suppose I could take my time and be prepared and neat about it, but who wants to tkae their time with so many pedals to build!
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ReplyDeleteThis was my 1st "big" vero that worked the 1st time. Sounds the part too! My drain voltage was at 7.50 with the listed values. I just adjusted the 10r (think I ended up at 1k)to get them down to 4.50 with a fresh 9v.
ReplyDeleteIf someone could direct me to the cap/resistor that effects bass..I would be thankful. I could use a pinch more bottom end.
Thanks again for the layout.
This one is a must build if you are looking for the Fender sound.
more low end? mine has more than enough low end and i use mine with a bass.
DeleteYep...Need some more bottom. Don't get me wrong it sounds fantastic. I just need to thicken it up a tad down low.Pushing the bass knob past 3:00 muds it up a bit on my rig. Using a set of 2x12 black widow speakers in a sealed box. They are crisp and punchy but can be a tad on the harsh side.
ReplyDeletehttp://i1115.photobucket.com/albums/k543/jd_roost/65Medium.jpg
ReplyDeleteI can see Vol.2 is the output but i can't see anything coming from the board marked input.Anyone help?
ReplyDeleteIn the notes, "Input to Sw3 & Sw4"
DeleteDoh...Could'nt see it for looking,Thanks
DeleteBy the way. I played around with this a bit today and i swapped the 10R resistor for 2K trimmer. I'm getting all drain voltages at around 4,1V. So Voodoomen's mod idea works.
ReplyDeleteAlthough.
It sounded just a touch cleaner with that 10R - drain voltages at ~6V, but now, with 2K trimmer and the drain voltages at ~4,1V, it sounds exactly like the demo. I really do like the boost switch as stomper :)
+m
This comment has been removed by the author.
DeleteHow do you wire up a trimmer in place of the 10R resistor.
ReplyDeleteTake out the 10R, solder it in where the resistor was with the wiper going to one hole and either of the two outer lugs to the other. If your trimmer has short legs you may have to solder flying leads to the lugs and then just tuck the trimmer in somewhere when you've finished.
DeleteOh Dear,i'm going to sound like a newbi hear but i have been building pedals for 2/3 years,but what do you mean by "the wiper"
DeleteThe middle lug which moves from one outer lug to the other. This diagram should make it clear:
Deletehttp://www.st-andrews.ac.uk/~jcgl/Scots_Guide/info/comp/passive/resistor/pots/var_res/var_res.gif
Now i understand.I'll file that away & hope i remember it the next time someone mentions the "wiper"
DeleteJust built this as per the vero layout.As mentioned in previous comments was'nt a lot of gain or volume so i first replaced the 10r resistor with a 1.5k but there was very little change in gain or volume.Next i put the 10r resistor back in then removed the 5.6k resistors and added trimmers,then adjusted the bias to as near as possible the voltages that John Kallas gave.There's now plenty of gain & volume,infact the pedal now sounds just like the demo.
ReplyDeleteGood stuff Sid. I think replacing the 10R resistor with a bigger resistor or trimmer will work great if you've matched the JFETs first so you can be sure you're getting the right voltage on all the drains.
DeleteThanks for the layout!
ReplyDeleteI dont have a 2k pot. Is it okay if i solder a 5k resistor parallel to a 5k pot? Will the difference be noticable?
Thanks,
Daniel
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DeleteUse 5K pot and solder 3K3 resistor between lugs 1 and 3. That equals 1K988. I bet you won't notice any difference between that and 2K pot.
ReplyDeleteDamn i typoed it. It's lugs 1 and 3.
+m
Thanks, I'll try that.
ReplyDeleteThis might be kinda a stupid question, but...
ReplyDeleteAre the 1uF caps greencaps, hence not polarised? Is it possible to use polarised 1uf elec caps? If so, which direction do i place them in?
They are supposed to represent Panasonic ECQ caps which is what I use, and so yes they are polyester. You can use a polarise cap though no problem, just put the positive lead to drain in both cases.
DeleteCool! Thank you very much!
DeleteHi
ReplyDeleteFinished this one lastnight and played and tweeked it today, got it purring now.Sounds really warm and smooth playing jazzy/blues stuff without gain booster on.
Couldnt get the J201s so used 2N5459 Jfets which sound ok to me.Ended up putting 20k trim pots on all the Jfet drains and setting drain voltages to 4.1v which was the sweet spot between too dirty and too clean.
It was tricky getting the trimpots to fit on the vero but took my time and got 'em on there- worth the trouble.
Power cords with Gain Booster sounds wicked too.
Cool pedal ,thanks
Thanks for the info and glad you're liking it. As has been mentioned, because the only things connected to the supply are the drain resistors, if you match the JFETs first, you should then be able to get away with a single trimmer replacing the 10R.
DeleteGreat effect. Finished building it, sounds sweet. As John Kallas has mentioned this thing really sounds best with a 4.5 -5V drain voltages. I matched the JFETs and with the stock 10R resistor they were giving 6.6V then changed the 10R to 1.2K and got 4. 6V, which really made it sound the best having optimum gain. Thanks again Mark for another wonderful layout.
ReplyDeleteI just built it up tonight, I matched my fets too, and I had to use a 2.2k to get a 5v drain. I might fiddle with the 5.6k's a little bit to see if I can squeeze some more gain.
ReplyDeleteThis one gave me some work.... Had to end-up using 27k on the drain resistors to get a 4.6ish V. Not really sure why I had to go all that way but it does sound awesom once you do. Using all Fairchild J201s... The boost is really a boost in volume and gain. Is it a cool, fat dinamic overdrive pedal!! COOL COOL COOL!
ReplyDeleteIs it possible to swap the 2k pot for either 1k or 5k?
ReplyDeletei wouldn't. just solder a 3.3K or a 3.4K resistor across lugs 1 & 3 on a 5K pot and that'll make it a 2K pot.
DeleteAright, I shall do that. Thanks!
DeleteDoes this change the taper to something like an audio pot?
DeleteI'm thinking midway on a 2k linear pot, lug 2 of the MID pot would see 1k resistance to ground, but with this "mod" you'd have lug 2 of the modded 5k pot at 2.5k in parallel with the other half of the pot's 2.5k plus another 3.3k resistor to ground so lug 2 is seeing 1.74k to ground with the pot at midpoint.
That seems like midway on this modded 5k pot would act as if you had a proper 2k turned up about 7/8s of the way.
And if that math is correct, you'd have to have the modded pot at 1/4 turn to just about match 1/2 turn on a proper 2k linear.
Seems like most of your mid adjustment would be in the 1st 1/4 to 1/2 turn of the modded pot.
NO. it doesn't change the taper at all. it's still a linear pot, only where it was a 5K pot, with a 3k3 resistor on lugs 1 & 3, it's now a 1K988 linear one.
DeleteJust completed this. Sounds Great!
ReplyDeleteI have built three of these, and after using a breadboard to pick drain resistors, used trimmers. This is a great circuit.
DeleteMy problem is oscillation, feedback. I have used shielded cable but still can't get it to go away. This only happens when gain and volume are maxed and boost engaged. When the FETs are in the sweet spot the thing squeals. I can back off and make it behave, but I can hear that I'm missing the best OD. Have also tried a trimmer instead of a voltage divider after staqe 1, and that works, but then there is not enough change from the boost.
I found that taking out the 3pdt fixes this, but I need a bypass! I am using jacks on the North Face of the box, so the cable runs inside are kind of long.
Hi Mark, thanks so much for this!
ReplyDeleteDo you happen to have a schematic for this as well? I'd like to build one with the boost toggle replaced by a footswitch, and -if possible- an additional pot for boost gain control.
I could try to make a schematic from the vero myself, but I figured I'd just check if you have one already.
Cheers
I get most of the schematics from Freestompboxes. Here's the Black 65 scheme:
Deletehttp://freestompboxes.org/viewtopic.php?f=7&t=16177&hilit=black+65&start=20#p199795
Hi there, I cannot get this effect to work. Right off the bat I'm losing almost all voltage. I'm good from the 9v to the 10r but then at the lower leg of the 5k6 i'm down to 1.8v. I'm pretty new to electronics so i'm not sure what could be causing the problem. I'd take a picture if I had a camera, but sadly I do not. Any help/ideas would be appreciated.
ReplyDeleteThose 4 pieces of 5K6 are setting the JFET biases, and you should probably try to tweak their values until you're getting ~4.5V on all drains.
DeleteOn my build, i matched the JFETs so that they all gave approximately the same drain voltage, then i tweaked the 10R up to 2K7 to get them all around 4.5V
The voltage you mentioned is way too low to work correctly.
The JFETs are a real pain in the a to bias...
+m
Thanks for the quick response. I turns out I had a dummy mistake and had the JFETs in backwards, so I got that sorted out and am reading around 6.4 volts now, but still no output at all. I click it on and all sound stops. I double checked the layout and everything is where is supposed to be. Earlier in the comments he said to move the volume 3 down one hole, but I assume he updated the layout picture so I doubt that is the problem. Any ideas?
DeleteHi , so I presume you are measuring the above voltages across the drain resistors (5k6).? I have used 20k trimmers in place of these resistors . Do I now tweak each one to read aprox 4.5v ? Do I need to inject a signal while basing them ? Sorry if this appears to an obvious question but I am only just getting back into electronics , memories is studying theory has long departed !
ReplyDeleteYes measure at the drain and using a 20K trimmer would probably be a good idea. Or if you use matched JFETs you can use a single trimmer to replace the 10R resistor from the supply and that will bias them all at the same time. You don't need to be playing when you bias, but the voltage may change based on the position of the pots so I'd probably keep all the pots in the centre position so you're biasing at a mid level.
DeleteThanks mate . I think I will also swap out the toggle boost for a foot switchable one . I've already built the wampler ecstacy which is absolutely fantastic . Thank you for such a brilliant site and prompt answers to questions :-))
DeleteWait, am I supposed to measure the voltage across the drain resistor(5k6 or trimmer) legs, or from the JFET's drain leg to ground? I'm still confused as to where I need to stick the multimeter probes to measure the right voltage.
ReplyDeleteMy build of this is producing sound, but it's very quiet and thin/trebly sounding. Not at all like the demos. With all controls all the way up it's just below unity gain, and that is with the boost enabled. With boost disabled I don't hear any sound. Could this be a biasing issue, or is something else amiss here?
The measurements should be made between the drain pins and ground.
DeleteThanks mate, very helpful. I'll give it another go this weekend with my head cleared.
DeleteCheers
I just built one of these, sounds GZREAT! I ended up with a 3.3K in place of the 10R and that got all all my fets biased to 3.7-4.3 ish, sounds EXCELLENT! Great work once again Mark!!!
ReplyDeletehttps://sphotos-a.xx.fbcdn.net/hphotos-ash4/734941_359084580872461_25800044_n.jpg
https://sphotos-a.xx.fbcdn.net/hphotos-prn1/553154_359084590872460_107214202_n.jpg
https://sphotos-a.xx.fbcdn.net/hphotos-ash4/399450_359084687539117_1862586900_n.jpg
Finally found out what was wrong with mine (bad solder joint on C5) and got it working. Sounds stellar.
ReplyDeleteI'm also quite pleased with my mod: a 4PDT boost stomp switch wired to independent gain pots for non-boost and boost modes.
Excellent vero Mark, cheers!
Hi, just a stupid question, the on/off foot switch isn't represent on the schematics ?
ReplyDeletethe 2 dptd switch rrpresent is the the boost one ?
Regards
Alex
Correct
DeleteThanks
DeleteThis comment has been removed by the author.
ReplyDeletework fine,
ReplyDeletesomeone know how to have more gain ??
What voltages you have on the JFET drains? Wrong bias voltage may cause lower than normal gains on this circuit, but it's not very gainy by design...
Delete+m
thanks for the answer,
Deletei've got someting around 5V
1 Volt can have an effect ?
1V can be a big difference with JFET bias voltage.
DeleteDo you have them all at 5V? If you do, you could try bigger value for that 10R resistor. If i remember correctly, i used 2K7 in it's place and that's how i got them all to around 4.5V. But it's always down to individual JFETs, so you can only find out the correct value by experimenting.
+m
thanks, i'm going to buy a trimmer,
Deletethe corrects value have to be between 4 and 4.5 ?
for now ihave ,no overdrive from the pedal, only a boost
4.4V - 4.6V would be ideal.
Delete+m
thanks, we keep in touch :)
Deletei've moved to a battery beacause of my power supply (to high)
Deletei now have all my fet between 4.2 et 4.8 but still no overdrive,
an idea, something to test ?
Regards
Alex
That's strange.. Like i said, it's not roaring distortion, but slight overdriving design.
Delete+m
i understand you,
Deletein fact it's really clear 2 things :
i have bypassed the gain control by connecting 2 and 3 in direct (no need beacause it's clear) maybie a mistake ?
is it possible thats a fet let audio signal goes but don't add gain ?
Thanks a lot
Alex
Not sure if i understood.. So you have gain 2 & 3 connected to each other? If so, that could be the cause..
Delete+m
yes it 's that :)
Deletei m really newbie, i just want to bypass the gain potyes it 's that :)
i m really newbie, i just want to bypass the gain pot, when gain 2 and 3 are connected it's like gain at 10 no ?
Almost. Those two are connected together when the gain is maxed - but there is 500K+68K resistance between that point and ground. You don't have that if you link gain 2 and 3 on the board. You still need that point to have access to ground through the 500K and the 68K at the gain 1...
Delete+m
i understand, sorry i m really new in pedal, so i can make a test by putting a high resitor between gain 2 or 3 to ground
DeleteThanks a lot mirosol
; i was time consumming for you sorry
You should try it...
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ReplyDeleteBuilt this one a while ago, here are a few pics. Sorry, no gutshots as it is extremely messy. :)
ReplyDeletehttp://bit.ly/16AXbI0
http://bit.ly/XVxQY2
http://bit.ly/10DRTGA
Built my second one today, upped the voltages to around 4.7-5v to get a cleaner sound. Sounds just like i expected it to. Gonna box this one up with a ROG condor =)
ReplyDeleteHi, could you publish schematics????
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ReplyDeleteBoost switch is a 2 position DPDT, so if I want a footswitch I just swap it for a 3PDT to have a LED indication.
ReplyDeleteI was confused yesterday because I first thought it was an on-off-on toggle.
Great site!
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ReplyDeleteThis is my second build, after the Greatly Improved JFET Matcher. I use a footstomp for the boost. I have signal, boost works, but none of the pots do anything. Except for Volume, at max I have, unity. On/off not added yet, fresh 9V battery. All J201 matched, readings of 4.1V; 2,5K trimmer for 10R resistor; nice clean sound, boost gives a nice dirty edge, but no EQ! Don't know what I did wrong. Any help would be appreciated.
ReplyDeleteHi H.A.M., I have used Fairchild J201 but I got bad results. Could you publish your schematics????
DeleteI tried biasing with the 10r and managed to get the fets all into a reasonable range between 4 and 4.6v, but it sounded crappy. Ultimately I scrapped that scheme, used a 100R resistor there, socketed the other drain resistors, and used a 25k trimmer to determine the resistor values for each. I ended up using between 15 and 16.3k drain resistors for Q1-Q3. Q4 (the buffer) was at around 7v with the stock 5.6k... I left it there. Biasing each JFET around 4.4-4.5v (with a 9.3v supply) the effect sounds far better, has some bite and punch, and a good range of volume. I think leaving the bias on the buffer JFET higher, the volume range is much better. I used plain old J201s from Tayda, and used the first four I picked. Great sounding effect now... I was close to scrapping it the first time around... bias is EVERYTHING on this pedal.
ReplyDeleteHere's a youtube video I made of some settings of this pedal.
ReplyDeletehttp://www.youtube.com/watch?v=jpabzh8yTI0
Finished this today , had to use 13.5k to bias the j201 at 4.6-4.8v . sounds fantastic at borderline breakup as my basic clean tone, and stacks brilliantly with the paisley drive.
ReplyDeletehttp://imageshack.us/a/img40/8643/9oe2.jpg
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ReplyDeleteHowdy folks! Any links to schematics? Thanks!
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ReplyDeleteHi! First of all: Many thanks for the great work! Really appreciate the given opportunity to build so many nice effects. A question concerning the Black 65: Can anyone please tell me which 5k6 resistors of the bunch are the drain resistors that should be replaced for a trimpot for biasing? Any help would be much appreciated!
ReplyDeleteHi!
ReplyDeleteI swapped the 10R for a 1k2 (can't find a 1k5) and the four 5k6 for 10k trimmers. Three forgotten cuts... when fixed and bias at 4.5V, sound great !!
http://www.hostingpics.net/viewer.php?id=663383finie.jpg
63 is my year...
Thank you IvIark ! Keep on rockin' !!
Don't you find your mid knob lack of... mids ?
ReplyDeleteMy wiring seems OK but... I'm wondering...
My impressions are confirmed with the Duncan Tone Stack Calculator.
What do you think about it ?
Hi all.
ReplyDeleteI could not read all the posts. This may have been addressed already.
Will an 18v charge pump hurt or help this build?
dale
Hi, I build the blackbird (black 65) and made the boostfunction footswitchable with a 3PDT switch.Does anyone know how to insert a trimpot to adjust the boostvolume, because it is too loud in comparision with the non-boost. And will changing only the Q1 drainvoltage to a higher value, lower the gain on the boost mode?
ReplyDeleteThanks Cowtipper
Use the trimmer daughterboard shown at the bottom of the Offboard page in the menu above:
DeleteThe Sw6 wire from the board goes to Trimmer "Output from Effect"
Trimmer "Output" goes to Sw6 lug on the switch
Trimmer "Ground" obviously goes to ground.
Then the volume of the boost stage is controlled by the trimmer.
Thanks IvIark I understand the principal. Thanks for the suggestion. I also had some replies from a dutch forum that suggested the idea of replacing R6 and R7 (both 240K) with a 500k trim pot with the tapper to VC. This is also a great idea and it will also give control over the gain of the boost itself. What do you think? Regards Cowtipper
DeleteThose resistors are basically doing exactly the same thing, they're like having a 500K volume pot in the dead centre position and so yes if you have room and are happy to mod the board then adding a trimmer in there will do the trick. What do you mean by "tapper to VC"? I don't see how anything will alter the gain, this just attenuates the signal at the end of the circuit and so is a classic volume control.
DeleteThank you for the comment. Sorry if I was unclear, I said "the tapper to VC" but I meant "the wipper to VC". VC is Sw6 in your diagram. I was referring to the schematics found in this diagram in the link below.
Deletehttp://home.comcast.net/~gprause/BuildDocs/Black_V2.1_Build_Doc%20V2.pdf
Regards Cowtipper
I tried the mod today and it reduces the volume and the gain of the boost function. So this will make the boost function sound different. It does enable me to bring the boost down to match the non boost volume. I like to set it a little higher and then use a compressor to to give me a nashville sound. So it works well but does reduce the gain of the boost.
DeleteMaybe changing only the Q1 bias resistor to a higher value will give me back some dirt in the boost function without changing the volume. What do you think? Will this work.
A drop of volume can be perceived as a drop in gain, but it definitely doesn't change the gain at all, it can't do that. It dumps a portion of the signal to ground based on the trimmer rotation at the end of the circuit, and so is a classic attenuator, a volume control. A reduced output means it isn't driving anything following quite as hard and so you may get less dirt out of following stages which again could be seen as a loss of gain but the gain of the boost stage has stayed the same.
DeleteThe gain is solely determined by the drain and source resistor, 5600/1000 and so approximately 5.6x. If you want to alter gain, the ratio between those two resistors is what you will need to experiment with.
With that in mind it may be worth adding another trimmer and swapping the 1K source resistor for a 1K trimmer and tweaking until you're getting the dirt you want out of the stage.
DeleteHi anybody has a full schematic for tracing a pcb board. Thanks
ReplyDeleteYou'll find it on the thread at freestompboxes
DeleteI need the schematics for simulation in PROTEUS/ISIS. Does somebody has URL?
DeleteI've built this and getting no noise from the circuit - all voltages around 8V except for 2V at Q1. Could this be the cause of no output? I've checked over my wiring several times but may have missed something... :/
ReplyDeleteHello, my build is working great aside from the boost switch. For some reason the boost works in one position, but in the other position it cuts the pedal right out so I get no sound at all. Does anyone have any idea what the problem is?
ReplyDeletebuff! amazing.. In the scheme ,100pf caps are 10pf, any diference? I find it a bit strong bass
ReplyDeleteIf you check out the rest of the FSB thread someone mentions buying an original and the 10p caps were actually 100p.
Deletehttp://freestompboxes.org/viewtopic.php?f=7&t=16177&p=222507#p222507
DeleteOk, i found a mistake on my board (1nf output cap was 100nf ) loudness problem solved. Now it's very similar to tweet 57, maybe more clear... GREAT!!!!
DeleteHi,
ReplyDeleteI have an original Black '65 and I wanted to see if I could mod it to have the boost foot-switchable. However I'm loathed to butcher this beautiful (and expensive) pedal.
Can somebody please explain/describe (with a diagram preferably) how I could tap wires off the existing boost toggle switch to have an external DPDT footswitch to sit next to the Black '65 on my board?
If I know this will work I may consider even drilling a hole and putting a mini jack output on the side of the pedal to connect the footswitch (which I assume would be a stereo jack).
Here's hoping!
Thanks.
Sw1, Sw2, etc... to the numbered switch lugs displayed on the diagram.
ReplyDeleteAs for the "remote switch", Im afraid that would be more complicated since there are more than 2 connections involved.
I finally finished mine yesterday, and this thing is awesome. I can get some flubby bass out of my ultratight hiwatt dr-103, plus some extra sparkling up there. I connected the gain boost to a 4dpt stomp switch, and used the original switch to go between 2 presets of volume boost controlled by a trimmer. Here are some pictures:
ReplyDeletehttps://scontent-mad.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/11174968_10206255870466602_7805578923095893462_n.jpg?oh=9d05564f85b2bfbb45d37a93d54e2013&oe=55C71090
https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-xap1/v/t1.0-9/s720x720/11178258_10206255870346599_2322522439009654047_n.jpg?oh=937a5dc64fb3e06189231b233f50bcaa&oe=55E3F015&__gda__=1439616430_569348e2a8e898ff9a0c14b85bdba45a
I´ve set all drains between 4.25v - 4.50v, but I miss some more volume. I´ve got to set the volume knob at about 3 o´clock in order to get unity gain. Any thoughts?
Charger suggested to set the bias higher at the buffer fet to get better volume range. I assume that the buffer fet is Q4, but I don´t know what he meant with "bias higher": more voltage or less voltage at Q4 drain?.
Cheers, Gilberto.
To those who experienced low gain & vol. even with circa 4.5v, I do advise to keep the 1st resistor at 10R as laid down on Mark's stripboard. Instead of tweaking it up to any larger value, replace the 5K6 resistors untill you reach the required 4.5v at every drain. By doing so, I amazingly found a louder pedal with much gain (too much IMO).
ReplyDeleteMy pedal isn't in a box yet, I've been tweaking it for a few days. I finally got it about right and was playing through it for a while. Then all of a sudden the pedal became muddy and distorted on every setting, the gain knob doesn't make a difference. The voltages on the drains are different than normal and changing. Every know and then by wiggling wires around the normal sound comes back.
ReplyDeleteDoes anyone know where the best place to start is for finding the problem? I've already replaced a bunch of dodgy looking wires to no avail.. I
Sounds like a problem with your offboard wiring. Probably just a dodgy connection somewhere - see if you can get it down to one particular wire and then replace it.
Deletestart by checking you're solder joints for the wires, especially the ones that when you wiggle it fixes the pedal when the problem happens. it sounds like a cold or loose joint to me. if they all look good, gently pull on the wires and see if any come out. also, use your DMM on the continuity setting and check the joints. so put one lead on the solder joint and the other on the track. if you get little or no continuity at a joint desolder and resolder that spot.
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DeleteThanks for your help. Now, I have a constant 4.5 volts on 3 of the jfets, but the top left one is changing. When I turn the power on and measure the drain, it starts somewhere then slowly decreases in voltage. The pedal prodoces a lofi fuzz kind of sound :/ Is that a tell tale sign of anything in particular or still just bad joints or wiring? thanks!
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DeleteAnd I have tried swapping out the transistor.
ReplyDeleteHey guys, any idea on how to lower a little bit the level of the boost switch ?
ReplyDeleteThanks
hi guys what is the mean of volume 2 to output ?
ReplyDeleteis it going to jack output or board output ?
jack output
ReplyDeleteIs the line of volime 3 according to the layout? Or is it one row below?
ReplyDeleteIs the line of volime 3 according to the layout? Or is it one row below?
ReplyDeleteAwesome! Got this one working today. Bit of a nerve-wracking build for a beginner as it's quite a packed board, but it seems I got away with it. It doesn't help that the 1n5s I got on eBay were about 5 times bigger than expected... but that means they have mojo, right?
ReplyDeleteFWIW I picked 4 random J201s out the bag and biased them at 4.5v: 3 out of 4 were perfect at 5k6, the last one needed slightly less. Based on other comments, I guess that just shows how variable these components can be.
I know it's an old post and you might not see this but I do want to thank you for this site. I'm learning so much, and having so much fun. And -- as I keep telling my wife -- saving so much money :-)
OMG - the first project i was able to get it work - Thanks!
ReplyDeleteHi, great forum here! I do have an original Wampler Black 65, my first mod is to replace the 100k bass pot to a linear one. The log type is more like an on/off switch to my ears. I also will try to increase the gain. I measured 3.1 - 3.3V at the JFETs. As I learned here, it can be done by tweaking the 5.6K/1K resistors. But on which of the four gain stages, on all of them? Or is it more easy to tweak the 10R comming from the battery?
ReplyDeleteThanks & greetings from Vienna/Austria - Gery
I see no reason why you should mess with the voltage expecting more gain. More voltage will probably give you less gain. Less voltage would probably make the pedal sound sputtery or even mute. Btw, gain stage 1 is for the gain boost, so it's not relevant here.
DeleteOne of the best OD's I've ever played and it's not even boxed yet. It's less noisy (even unboxed) and, in my opinion, better sounding and less finicky than the ROG Azabache. Also, the 3 band EQ makes it much more useable/easy to adjust to your rig/tone you want to hear. Biased all my transistors to about 4v using all 18k resistors in sockets. Ace circuit.
ReplyDeleteVery fun pedal! To get ~4.4v, my bias resistors were all around 15K. Time to built another with a stomp for the gain switch.
ReplyDeleteHi, What is the resistor in voltage section 10R or 100R ? I think it should be 100R
ReplyDeleteit is a 10R asp er the schematic.
DeleteHi. My pedal is having just a hint of gain with the gain all the way up on the normal, and little bit more on the boost chanel. Also with adjusting drain voltage from 3.0v to 5.5v makes too little difference just litle more volume not gain. All drain voltages are identical. Only thing I didn't do corectly was that I put two 220k resistors instead of 240k on the layout...can that make all the difference?
ReplyDeleteOk...done...resistor on positive lead should not be more than 1.5k if you want it to work properly...so it is needed to increase drain resistors on each j201 to meet 4-something volts...then it roars...😀
DeleteDid somebody uses MPF102 to this pedal? Godd results in clean sound?
ReplyDeleteI might try that, just out of curiosity... Probably, it will result in less gain and in less volume too.
DeleteMy 2N5457 have much more gain than my J201. I fiddle the source resistor and use fetzer calculator and i did everything to make the j201 sounds louder and bigger but my 2N5457 has much more gain. I'm really confused becausw according to every forum i've read, J201 has much more gain but this is not what i observe. I change different j201's but all have the same result. I also get the right voltages but still the same. Do you have any idea what had happened?
ReplyDeletehi everyone, in order to get the voltage at the drains within the recommended range I had to use resistors (combinations of them) of ~ 47K, 33K and 20K. Is that ok or is that too much resistance? I am concerned that this might be the sign of something wrong somewhere else in the circuit? thanks for any input
ReplyDeleteI kinda doubt... J201's and other Jfets are often everywhere in readings meaning: they're not consistent at all (people will often claim they got fakes, but I kinda doubt that too).
DeletePedal works very good. I replaced 10ohm resistor with 560ohm and have got 4,6v , 4,2v and similar all about. Replaced one 5k6 with 4k7 to get closer voltage. I'll rise 560 to 600ohm and that's all. I have bad choice of pots here. No log pots no 25k but 20k for tone. No problem for future but for now black 65 copy is realy pretty sounding. Clean is almost without overdrive and boost is awesome. It's close to spirit of fender. I played one vibrosonic with JBL long time ago. Good luck with soldering
ReplyDeleteSo after my third attempt Ive finally got this nailed and it sounds great, but I'm not really bothered about the gain switch though and wondered what I have to do to remove it, leaving only the standard mode. What is the neatest way to do that?
ReplyDeleteTreble 1 & Bass 2 & 3 from a single wire?
ReplyDeleteYes that’s correct
DeleteTreble 1 & bass 2 & wired on a single wire?
ReplyDeletethank you! sorry for the double post!
ReplyDeleteHas anyone try 18v to see if it gets more head room like the dirty little secret?
ReplyDeleteI hope some sees this and gives me a clue. I made this pedal as a preamp followed by a tpa3118 power amp board straight into a Jensen C12K. It sounds like heaven. Almost like a real blackface. One small problem thou is that I really need more treble. Most people wouldn't need this because they use an amp. Is there any way to achieve this?
ReplyDelete