BSIAB2 squealing.

[Hupla]

Well bad news. Brought it to practice and it started squealing again. Had to roll the volume on my guitar off a tiny bit to get rid of it. Any ideas?

That means that reducing gain/increasing resistance 'fixed' it....

I just cant understand how it changed from at my room to practice =/

New room, new acoustics, new resonant frequencies, new volume, guitar is a new distance from amp, and plenty of other variables.


 
Keep in mind that BSIAB squeal has been posted about here...hopefully you have (or will) search the forum for similar inquiries that might be enlightening...

In some manner, you might want to add a high input impedance inverting buffer stage at the beginning or end of the circuit, that you can switch that in or out. and compare to what you have right now.   Switch it on and see if that is the issue, as sometimes phase has a factor in squealing, etc.

Honestly, J201s are, IMO, overrated.  Unnecessary gain, low dynamics, lacking in tone.  Possibly far more prone to oscillation due to their being so unique in their 'gain levels' to put it technically.  

 2N5457s aren't that much 'lower gain' typically, to me, in this circuit, however they seem to make a difference for those with these kind of issues.    Are you using it with the gain full up? And If not, put in 2N5457s back - better tone, less prone to squealing, less headaches for you until you can get better understanding of the cause of the squealing.   And If so, maybe it's the wrong design for you, as most people find it mush city when built stock and the gain is cranked up.     Even Ed G. says similar--mostly to avoid the J201s, these days, on some posts and PMs of his I've read if I'm not mistaken...

I'm a big fan of lower gain MPF102s / 2N5459s and higher value emitter resistors around for Q1-Q4, but I've documented a lot about my preferred mods elsewhere, so search my posts if you're interested, but they're not for everyone...back to my main point, stock, that thing has plenty of usable gain, and quite a bit of unusable gain if you ask me.

Beyond reducing gain, I'm a fan of making C10 more like 4.7n, so there is less mid scoop.  However, if you like the tone, that may not be the mod for you.  But try it on the breadboard and see....you might be surprised.  That tone stack as is passive, but exaggerates bass most of all, which may somehow induce feedback, depending on your other equipment and settings, though the rest of the circuit is rather' tight' in the bass.  That one mod makes it more even and midrangey, and helps take the tone pot 'off' the mids and focus on the highs more.  

Still, It's hard to know what kind of 'squeal' you mean, which makes it hard to advise too much outside of the generic...Got any soundclips?    Kidding mostly...

Also, it comes down to 'What PS?' and 'How did you wire the stomp switch?' etc. It could be that you are using a cheap guitar with unpotted and or cheap pickups, for all we know, which would easily squeal with the amounts of gain the BSIAB puts out. There are just too many variables, so it may be better left to your careful inspection and experimentation...isolate / eliminate some of these variables that it may be, one by one, after these rounds of attempted quick fixes...that may be better than everyone continuing to detail every hypothetical possibility and thing to double check.  Change guitars, change rooms, change underwear...isolate the variables.   It's fun.  

Ive read alot of your posts on this subject and i have searched alot before opening this

I was considering putting a boss pedal in front and see what happens alright. Do you know if they are generally phase inverting?

I don't have j201's in it. I found that it actually sounded more marshally without them. WAY too much gain and like you said mushy. The 2n5457's also clip the bass better and make it less "mushy".

I did breadboard it and messed around alot and it only "Squealed" (now that i think of it squeal isnt really the right way of discribing it. Its not a very high pitched noise but Im sure you know what I mean by it") when i put the tone up mostly trebly. But like I said, it worked perfectly at home ha

I wouldnt call it "tight" in bass. It seems to me that the tone stack reduces the volume on the bass alot compared to the treble, or is that not what you meant?

Thanks for the replies though. Very apreciated.

[Hupla]

Oh, I was about to ask for a gut shot, too. 
You didn't wire the ground lugs on both jacks to the ground, right?  I'm just making sure because I can't tell from the picture, all the wiring is covering up the lugs haha.  And is that the input side or the output side of the circuit board that's hovering over the potentiometers?

Yes i did. But I grounded the output jack from the far side of the circuit and not a continued wire from the input jack. Not sure if that would induce a ground loop.

The output side is to the top of the box over the pots yes.

[DUY1337GUITAR]

wait wait wait hold on,
so you have BOTH jacks each having it's own wire connecting to some ground source?  that would be a ground loop; you only need one jack to be wired to a ground because -- since the enclosure is metal -- the two grounds on the jacks are already connected, thus both are already connected to ground.

[Hupla]

wait wait wait hold on,
so you have BOTH jacks each having it's own wire connecting to some ground source?  that would be a ground loop; you only need one jack to be wired to a ground because -- since the enclosure is metal -- the two grounds on the jacks are already connected, thus both are already connected to ground.

Yeah ever since you mentioned ground loops that played on my mind. ha. im goin to change it and see what happens.

[DUY1337GUITAR]

I hope that'll work
winter break is over and now I'm heading for school

[Hupla]

I hope that'll work
winter break is over and now I'm heading for school

I did it but it didnt make any difference in my room. When i turn everythin up on the pedal it only squeals then. Ill have to wait for practice to see if it makes a difference.
Ive got college exams this week. I just wanna stay home and build things. Ha dr. Boogey is next. Fun fun fun

[liquids]

When i turn everythin up on the pedal it only squeals then.

Doctor: "Does it hurt when I do this?"
Patient: "Yes!"
Doctor: "Well than don't do that!"

If you get have everything turned up, I suggest you prioritize--first, address your 'hearing' problem.  Maybe then you can adress the 'squealing problem.'  



Better yet, I'd call that kind of squealing a feature....and hey, maybe you should advertise the practice room for rent.  Advertise that one of the rooms features is that it helps make things squeal when the controls are is turned all the way up!



More seriously....

I was considering putting a boss pedal in front and see what happens alright. Do you know if they are generally phase inverting?

No, most have two non-phase inverting buffers when bypassed.    

Switching an inverting op amp buffer in/out, placed at or before the input, as previously mentioned is the quickest / 'most transparent' option, in regard to determine if phase is part of the issue or fix...sounds like it probably isn't the issue, though.

Thanks for the replies though. Very apreciated.

Anytime.  

[Hupla]

When i turn everythin up on the pedal it only squeals then.

Doctor: "Does it hurt when I do this?"
Patient: "Yes!"
Doctor: "Well than don't do that!"

If you get have everything turned up, I suggest you prioritize--first, address your 'hearing' problem.  Maybe then you can adress the 'squealing problem.'  



Better yet, I'd call that kind of squealing a feature....and hey, maybe you should advertise the practice room for rent.  Advertise that one of the rooms features is that it helps make things squeal when the controls are is turned all the way up

I dunno if you have read everything I wrote in here but i said It only squeals when i turn everything up on the pedal in my bed room, where I do all this, but when at band practice it squeals at the normal settings. ( but of course the amp is alot louder there as well I suppose.)
So no i dont have to have everything turned up. I just did it to see when the pedal would squeal because it wasnt doing it at the settings it was at band practice.

I know you are helping aswell but no need for all the sarcasm. Thanks.

Well i was planning on making a buffer anyways so ill see then.

[DUY1337GUITAR]

oh yeah that reminds me.  I installed Tilman's JFET buffer on my guitar and also my friend's (which has an on/off switch).  When I played on my first Dr. Boogey build, I didn't notice a lot of crappy noise/squeal/humming.  But on my friend's guitar, it was humming like crazy and making squealing noises until he switched the JFET buffer on.  I thought it was interesting so we played another guitar through it which had no buffer and it was also humming.  Then we tried another friend's guitar which has active EMG pickups and no noise.

I guess a buffer/preamp is worth the build.

By the way, a Dr. Boogey will be a challenging build but it is so worth it.  I'm sure you'll love it.  When you build one, you gotta let me know

I don't want to go study either, just wanna stay home and build or hang out with friends and play some music with them.  The DIY world is what making me procrastinate on my work.  I mean seriously, my pickups just came in the mail and is now sitting by my side, and I'm ignoring my text book.....

Good luck on exams!!!

[Hupla]

oh yeah that reminds me.  I installed Tilman's JFET buffer on my guitar and also my friend's (which has an on/off switch).  When I played on my first Dr. Boogey build, I didn't notice a lot of crappy noise/squeal/humming.  But on my friend's guitar, it was humming like crazy and making squealing noises until he switched the JFET buffer on.  I thought it was interesting so we played another guitar through it which had no buffer and it was also humming.  Then we tried another friend's guitar which has active EMG pickups and no noise.

I guess a buffer/preamp is worth the build.

By the way, a Dr. Boogey will be a challenging build but it is so worth it.  I'm sure you'll love it.  When you build one, you gotta let me know

I don't want to go study either, just wanna stay home and build or hang out with friends and play some music with them.  The DIY world is what making me procrastinate on my work.  I mean seriously, my pickups just came in the mail and is now sitting by my side, and I'm ignoring my text book.....

Good luck on exams!!!

Yeah ill definitely build the buffer. Thanks.

Ah i don't think the Dr.boogey will be too hard (skip forward to when Im pulling my hair out over it ha)

Can't wait to do it. Then I need a delay or something.

Yeah I saw your guitar. It looks great. How did you get all the info to make one? or do you just have wood working skills?

[DUY1337GUITAR]

Well on my 16th birthday I got really obsessed with looking up information on how to build a guitar and check out various methods, techniques, and custom wiring.  So I used my birthday and Christmas money put together (my bday is New Year's) and bought all this crap and built everything slowly (because school was also going on). 

Projectguitar.com pretty much initiated my interests.

I did not finish until RIGHT NOW (or probably tomorrow).  It was hard to be patient to build, but I think it was worth it because I also learned very important information during those waiting periods which could have had my project ended bad if I didn't know earlier.  I just skipped my Calculus homework (meh I can do it during study hall) and took all evening to wire the pickups according to my custom layout.   I can't believe it worked the first time, but I can't put all my strings on because I can't find my d*mn allen key wrench to tighten the string lock at the tremolo.  Now I'm sad that I have to go through another whole of school tomorrow before I can use my friend's wrench which he'll let me borrow. 

By that way, which Dr. Boogey layout do you plan on using?

[Ed G.]

Crank up your knobs and try moving the input and output wires around a little bit. Does the squeal change in pitch or volume? If so, use a shielded input cable and it will probably help. I've got a bsiab2 that I was a little sloppy with the wiring and it squeals at top gain but I never crank it up that loud. Ask amp designers how important lead dress is. This isn't much different in that respect.

[Hupla]

Well on my 16th birthday I got really obsessed with looking up information on how to build a guitar and check out various methods, techniques, and custom wiring.  So I used my birthday and Christmas money put together (my bday is New Year's) and bought all this crap and built everything slowly (because school was also going on). 

Projectguitar.com pretty much initiated my interests.

I did not finish until RIGHT NOW (or probably tomorrow).  It was hard to be patient to build, but I think it was worth it because I also learned very important information during those waiting periods which could have had my project ended bad if I didn't know earlier.  I just skipped my Calculus homework (meh I can do it during study hall) and took all evening to wire the pickups according to my custom layout.   I can't believe it worked the first time, but I can't put all my strings on because I can't find my d*mn allen key wrench to tighten the string lock at the tremolo.  Now I'm sad that I have to go through another whole of school tomorrow before I can use my friend's wrench which he'll let me borrow. 

By that way, which Dr. Boogey layout do you plan on using?

Ah thats a great website thanks for linkin it.

I wont be happy until I've built a guitar and amp ha Really though well done on it, it looks really great.

I plan on using the guassmarkov one. What did you use?

Crank up your knobs and try moving the input and output wires around a little bit. Does the squeal change in pitch or volume? If so, use a shielded input cable and it will probably help. I've got a bsiab2 that I was a little sloppy with the wiring and it squeals at top gain but I never crank it up that loud. Ask amp designers how important lead dress is. This isn't much different in that respect.

Ill give that ago when I go home. But on the switch i put the two beside each other (idioticly) so would me moving the wires have any effect at all if they are right beside each other anyway?

[DUY1337GUITAR]

I used the original schematic and the perf layout that you see on google images when you search "dr. boogey"
I didn't do the gaussmarkov layout because I didn't want to make a PCB or wait to buy one.  That one should be better though.

[Ed G.]

Ill give that ago when I go home. But on the switch i put the two beside each other (idioticly) so would me moving the wires have any effect at all if they are right beside each other anyway?

Moving the wires could have an effect. If the output is bleeding into the input, you have oscillation. Even before it oscillates, it will affect response, because it's negative feedback.
If you use a 3pdt sometimes it's good to use the outside legs for the signal, middle leg for the LED.

[Hupla]

Ill give that ago when I go home. But on the switch i put the two beside each other (idioticly) so would me moving the wires have any effect at all if they are right beside each other anyway?

Moving the wires could have an effect. If the output is bleeding into the input, you have oscillation. Even before it oscillates, it will affect response, because it's negative feedback.
If you use a 3pdt sometimes it's good to use the outside legs for the signal, middle leg for the LED.

Yeah. Im considering changing them around on the switch. =/ Ill get back to you when I have this all done. Thanks very much.

[Bucksears]

Are the input/output wires referring to the input/output jack wires to the footswitch, or the wires from the footswitch to the board?

[Hupla]

Ill give that ago when I go home. But on the switch i put the two beside each other (idioticly) so would me moving the wires have any effect at all if they are right beside each other anyway?

Moving the wires could have an effect. If the output is bleeding into the input, you have oscillation. Even before it oscillates, it will affect response, because it's negative feedback.
If you use a 3pdt sometimes it's good to use the outside legs for the signal, middle leg for the LED.

I couldnt really move them much without taking everything out, but watever movement i could do, made no difference.

I also put the tilman buffer before it and that got rid of the squeal thank god BUT it introduced alot of background noise (hissing and the like), but i presume this is because its on breadboard and the BSIAB2 is amplifying everything it picks up. So seems like good news

[DUY1337GUITAR]

Huh, it sounds like it was your guitar pickups' fault for the squealing.  Have you tried playing through your BSIAB2 with a different guitar?
My Ibanez RG has a Tilman buffer and no annoying squeal, but my friend's Ibanez RG doesn't have one and it squeals like hell.  But on his BC Rich VG, it squeals until he switches the Tilman buffer on.  You think it might've been your pickups all along?

[Hupla]

Huh, it sounds like it was your guitar pickups' fault for the squealing.  Have you tried playing through your BSIAB2 with a different guitar?
My Ibanez RG has a Tilman buffer and no annoying squeal, but my friend's Ibanez RG doesn't have one and it squeals like hell.  But on his BC Rich VG, it squeals until he switches the Tilman buffer on.  You think it might've been your pickups all along?

No i havent tried another guitar but it is an RG with infinity pickups, so maybe theres something there.
The tillman changes the sound a good bit though dont you think?