BSIAB2 with no bass and way too much treble

[FDWguitar]

  Title says it all, just finished the build today and plugged it in and the lack of bass is extreme.
the two problems I'm having:
1. No bass
2. Too much treble, both tone and contour just act like treble controls and I cant get them past 20% without painful amounts of treble.
I've fiddled with the trimpot but I feel like it'd be better for me to try and sort out this bass-loss and contour knob ear-piercer problem dealt with. Plus I can't hear any discernable change other than the volume of the pedal decreasing dramatically when turned clockwise for the last 30-40% of its sweep.
  I had to change one capacitor from 250pf to 240pf cause that the only one I could find without going out of my way to buy one single capacitor.
  The FETs I used Q1 to Q5, Q1 & Q2: 2N5457, Q3 & Q4: J201, Q5: 2N5457. No idea if that information would mean anything in this context. Not sure which one this is based on as I just bought this off a guy that does PCB clones of pedals, should probably inquire him about this problem too. Do tell me if I should post a picture of anything related to this, I'm going in blind as far as I know. (this is only my 3rd pedal build)

[GibsonGM]

Hi, welcome!  Yeah, we'd like a picture please. 

Have a gander at this, see if you can provide any info and copy/paste it here if you can:

https://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Closely check each connection, be sure the parts are where they should be, the wires to pots are going to the right legs of each pot (!) and so on.  It's usually a build error, we all make them!    But a couple pix of both sides of the board would be very helpful, plus any 'build info' you may have got with it (schematic...).    Your cap substitution isn't a problem as long as it's in the right place.

[antonis]

Although I think the issue is located around Tonestuck configuration (maybe a LPF falsely high value cap or even shorted to GND), we DO need the following:

1. Schematic and/or build docs..
2. Photos of your build..
3. Voltages (on ALL Drains/Gates/Sources, at least)..

[FDWguitar]

Found the schematic on the store. Parts list and pcb image included, though a photo of my build will have to wait for daylight tomorrow morning as its dark out where I am in the world and I've got no good lighting for clear pictures. I'll try figure out how to measure the necessary voltages. I'll also be checking the connections and solder points. I noticed battery power being mentioned in the link but I didn't build my pedal to take battery power, power from the wall seems okay as it powers my other builds with no issue. I'll get to all this tomorrow hopefully.
  Also these pictures have the name of the guys doing these PCBs and I do not want any of this to reflect badly on them. I've had 2 successful PCB builds from their stuff so all this fuss is likely user error. Dunno if such a disclaimer is even necessary lol.

[antonis]

Check C11 for proper value/connection..

[GGBB]

Found the schematic on the store. Parts list and pcb image included, though a photo of my build will have to wait for daylight tomorrow morning as its dark out where I am in the world and I've got no good lighting for clear pictures. I'll try figure out how to measure the necessary voltages. I'll also be checking the connections and solder points. I noticed battery power being mentioned in the link but I didn't build my pedal to take battery power, power from the wall seems okay as it powers my other builds with no issue. I'll get to all this tomorrow hopefully.
  Also these pictures have the name of the guys doing these PCBs and I do not want any of this to reflect badly on them. I've had 2 successful PCB builds from their stuff so all this fuss is likely user error. Dunno if such a disclaimer is even necessary lol.

In comparison with the original BSIAB2, this one is missing an important treble filtering cap on the output - 2.2nF after R14 in parallel with the volume pot (see C14 here: https://generalguitargadgets.com/pdf/ggg_bsiab2_sc.pdf).

I suppose there could therefore be other differences as well which might account for your experience, but FWIW, IME I found the BSIAB2 to be generally very bright.

[FDWguitar]

  I'm realizing I've placed Q5 and Q4 in wrong... (J201 and 2N5457) Never should've assumed it's in numerical order. Time for the pain of desoldering.
   Ignoring the mess, a visual inspection shows that everything seems to be in order joint wise. I have yet to check all the resistors cause I'd have to read the stripes which I have not learned to do. But all the caps except that one substitution of a 250pf for 240pf are in order. I have yet to measure any voltages so I'll give it a try. One probe to ground and measure each leg of the transistor? That's what I caught from looking at tidbits of info.
  Perhaps I'll ask the shop about this. Also might replace the 4-wire fandango with individual wires if I find the will to desolder it... again.
  All this makes me wonder if I would've been better off building some BE-OD clone. I really seemed to have jumped off the deep end with this thing.
End of long wordy post with not much info :/ I'll be back hopefully 

[GibsonGM]

Keep at it, it's great experience, believe it or not     

Careful unsoldering/resoldering the Q's, they can die from heat pretty easily.  A clip-on heat sink gadget works wonders!

Pro Tip: take the time to learn to read resistors. It's not that hard once you've worked at it for a little bit, and saves time/big effort.  Just reading R"s in-circuit can give really odd results - some may be in parallel and so on, giving very misleading readings (Can't trust meter in-circuit unless you lift on resistor leg).

Make a chart for your bench wall with transistor/opamp pinouts, formulas, and color codes! 

[antonis]

3PDT switch lugs on respective PCB (FX-008) DO need a good solder reflow..

Also, there might be a short between OUT & LSW pads on main PCB..

Last, but no least, there might be a short between the upper legs of two 82k resistors (lower legs must be shorted to GND)..
(this may be the cause of your issue 'cause one of them is part of Treble HPF..)

[duck_arse]

as said by Gibbo, take the time to learn the colours. then take the time to turn all your resistors so the tolerance bands are facing the same way before you insert them to solder. this is what the pro board assemblers do did, otherwise they'd cop it from the bench techs. a long time ago, but we still do do it proper, hereabouts. you might laugh and say why waste the time, but, observe.

you have two resistors side by side that are, from this distance and without a meter to check [and also noting that the tolerance bands aren't all aligned] identical, 10k. one should be 120R. as it turns out, we sometimes use 120R as an "in" joke among the hard nuts the joke's on me: 12k is the gag value.

the more stupid little time wastes you do - leg bends w/ pliers, meter test, band aligns - the more chances you have of it being right when you first gass it up. trust me.

[GGBB]

you have two resistors side by side that are, from this distance and without a meter to check [and also noting that the tolerance bands aren't all aligned] identical, 10k. one should be 120R.

Definitely worth double checking, but if I were to hazard a guess based on the pic, they look correct based on the distances between brown and red versus brown and black bands of each.