VOLTAGES @ TRANSISTORS BSIAB build.

[Blind Lemon]

I've done something wrong some where. First stomp box build but I've done a couple of amps.  (5E3 and a Deluxe Reverb....and a VJ).

Here are the voltages @ the Transistors....the first voltage is what is spected and the second is what I have.

     Q1                Q2               Q3             Q4            Q5
G   0/0            3.8/4.0          .3/0              3.4/4        .5/0
S  .95/.434      4.5/5.45        .75/.04         4.3/4.35    .9/.87
D  3.4/3.6        8/8.5            4.3/4.35        8/8.4        3.4/3.6

The box makes "noise" but it is very fuzzy and muddy at just about all settings.

I am hoping something will jump out someone. I tested the resisters before I soldered them to the board and have recheck to make sure I got them in the right place on the board. I also checked  the wiring to the switch and jacks and the transistors are in the right place.

There are 2 caps that on the schematic  show to be polarized but the caps just looked like little poly caps. And I just looked at the BOM and they are.

Any way I hate to have to pull this thing all apart,,,,,so suggestions would be very much appreciated

BTW this is a GGG kit. And I've got more voltages if you need them.   Back to seeing were I screwed up.

                                   Bob

[Blind Lemon]

Schematic====    http://www.generalguitargadgets.com/pdf/ggg_bsiab2_sc.pdf

[John Lyons]

The voltages are pretty close with the exception of Q1 and Q3 source. I recomend a printout of the layout and a highlighter or colored pencil.
Go over the layout with a fresh mind and make sure everything is in the right place and that the parts are facing the right way. You measured the resistors so they should all be fine. There is only one Electrolytic cap I think and that's the 100uf one at the power supply so that's right...
Make sure you do not have any solder briges and blobs touching parts that shouldn't touch. The board is pretty small so it's easy to happen.

It should work if it's correct to the layout. The FETs don't like too much heat while soldering so watch that...

John

[Blind Lemon]

Thanks for the reply John. I'm going to pull it all apart and make sure the caps are correct. The 'olytic cop is in correct. I think I know what the problem may be, but I'll have to do some digging to get to it.  I will not get to it tonight . I'll check in when i do.       Thanks agian.

           Bob

[Blind Lemon]

Ok,......so I lied . I couldn't stand it , I yanked it out. I thought maybe I got the pots mixed up......nope......and since I had it out where I could see the caps I checked that they were right. Checked the back for bridges of solder (bigger the glob ....don't cha know) good with the possible acception of one,,,,,maybe!!!!! Cleaned the CB,,,again.

   BTW, the transistors are facing per layout.

I'm starting to think that it is right and it isn't sounding the way I thought it should.I have to turn the drive way down and the volume down to get what I think might be acceptable. If this is it I'm starting to wonder if it is for me.

   Does anybody have any links to sound samples other than GGG?

                                            Bob

[John Lyons]

Here are a few sound clips: www.mrdwab.com/john/soundclipspage.html

Let me know if you think the sound clips sound like you want it to sound ( or if they sound like yours)
There are a couple things to try out if you want a change.
What do you not like about the sound?
Seems like if you are turning down the drive that you want a mellower sound...?

John

[Blind Lemon]

Hey John;
  Thank you for the help, I thought it could have been more a bluey sound. Heres the sound samples from GGG

          http://www.generalguitargadgets.com/sounds/bsiab2.mp3
   
  Mine sounds more like the link you gave me, not my cup. The link above is more of what I was expecting, with the ability to turn down the gain a little more. I play Strats w/single
  coils through a Deluxe reverb or mod'ed Marshall'ish Valve Junior (El84). I haven't tried it through my 5E3.....I don't think they would play nice together. I left it out of the box to go
  over it again tomorrow. If you have suggestions I'm all ears, I'm looking at this as a learning opp.

  This is the only pedel I own. I heard a clip of a BOSS BD and liked it but wanted to build something.


                                Bob

[John Lyons]

More bluesy or mellow?
Try this. Take out the 150pf cap to start. See how you like that for starters. That cap is a treble bleed cap that (as you turn the drive pot down)  brings the treble up. Without that cap the treble won't be as strong...

Still not smooth enough and too distorted?
Try putting in all 2N5457s they are lower gain FETs and should take the gain down a good bit. They are "darker" sounding as well which with give you a less edgey sound.

If it's the right amount of gain with all 2n5457s but still too bright try removing the 470pf cap which is also a treble lift cap.

The clips is pretty bluesy and mellow on the first part of the sound clip. Are you turning the drive on the BSIAB2 down most of the way and it's  too distorted still? or just too bright?

With the fender amp try setting the treble to 5 or 6 mid to 6 or so and the bass at 6 and using the BSIAB2. Turn the gain down and remove that 150pf cap. Should be able to get the mellow sounds on the clip that way.

John

[Blind Lemon]

    At  this point I really don't have a problem with the it's tone, more the high level (for me) of distortion. I think that I will be able to dial the tone in after I bring the distortion down. It gets pretty muddy on the lows but cleans up when you roll them off. So to answer your question more mellow.

    So FET's are like preamp tubes? If so what are the relative equivalents to the 12AX7,5751, AT7 and so on.

   Still have the crct out of the box, I want to double check it one more time after work before I put it back.

                Bob

[John Lyons]

It's not quite a straight across equivelent from tube to fets but there have been some posts about replacing the 201s with 2N5457s and getting a cleaner sound out. 5457s are lower gain devices. Similar to going from a 12ax7 to a 12at7 in a nutshell.

Try it.

John

[Blind Lemon]

Couldn't find any 2N5457s locally on short notice. Got a couple of NTE457s, I didn't know any better the guy at the LES said they crossed. I did a search here and ofund out they wil work in this application. I don't know if they will sound as good(?), but hey what do I know.

          Bob

[phil]

  This is the only pedel I own. I heard a clip of a BOSS BD and liked it but wanted to build something.

If you liked the BD-2 you might be interested in Doug Hammond's Highway 89 pedal - Here's a thread that discusses it:

http://www.diystompboxes.com/smfforum/index.php?topic=54355.0

I had a Keeley modded Boss BD-2 that sounded really great to me... but I built the Highway 89 and I was so amazed by it that I sold my BD-2 a few days later and haven't regretted it since.

[Blind Lemon]

  Well the new FETs didn't do anything for me. John that in know way reflects on you, I appreciate all your help and suggestions. I'm going to take this thing back down to the board and do it again. Good practice and all that crap. I know how to test the caps and resisters, but have never mess with the FETs until now.

  Don't get me wrong, I'm not dissing anybodies product I'm sure either I have something wrong or it not my cup of tea.

                     Bob

[John Lyons]

I don't know about the NTE457s but there are a few fets that would "work" in the pedal but they may not be the same gain and were possibly  the same as gain as the ones you replaced (J201s) . You should look up the data sheet for the 457s.

Does you build sound like the sound clips you have heard (not the GGG one)?
Why do you think it's Built wrong?

John

[Blind Lemon]

   
John
   
    From what I read here and could determine from the specs, read rookie here, the NTE457 and 2N5457 are about the same. Tone may be a little different according to some but wasn't explained in what way. I went ahead and swapped out the J201s hoping to lower the gain.

   So here goes........I didn't tear it apart. Listened to all the sound bites again and determined that mine didn't sound too far removed from the ones on John's site (?). So I decided to turn the box over and play the guitar though it and mess with the controls. Now there's a novel idea. I set the bias pot to about 3.7 and turned it over and hooked in. What I found out is everything works fine when I got it tweaked just so. Volume and Tone both work great, although it can get very bright..........like I said Strat w/single coils. But with Tone controls on the box and on the guitar (pots on neck and bridge) I've got it just about right.

  The Drive knob still has way more available then I will ever use. If  7 o'clock is off, the sweet spot for me is about 9/9:30....being fed to a single channel DR/AB763 turned down fairly low. Anything past 12:00 is not useable for me. It would be nice to get rid of some more of the gain or change the slope(?) of the gain pot. Get rid of the gain past the 2:00 position and allowing a fine adjustment sooner. Or change to another FETs altogether to lower the gain if that is possible?

  Don't get me wrong, I'm not knocking this peddle. It gets glowing reviews and I like it a lot better now that I have played with it. And its a great learning experience.

                                           Bob

[Ed G.]

I'm not familiar with the NTE457. It could be different than 2n5457. I like all 2n5457s for a medium-gain pedal.
As far as changing the 'slope' of the gain pot, you are talking about the taper. Are you using an audio taper pot for drive? For example, it will say 500K-A to designate the audio taper. "B" designates linear taper, and that will get gainy too fast.

[John Lyons]

Well... there you go. Ed has lots of time with this pedal..he designed it of course..
Get some 2N5457s and it will be like you want.

John

[Blind Lemon]

Hey Ed
   Thanks for looking in. What I meant for the slope off the Drive pot was, to actually get rid of the gain past the 1:00. Hopefully making the pot more sensitive to settings below that......Please forgive if these are simple or dumb questions, if it were a tube amp I know were to go and what values to adjust to get the gain I am looking for. This is my first peddle. And I really did just listen to some sound samples and think "I think I'll build one of those".

   In the mean time I'll hunt up some 2N5457s and try them out also.

   John...... thank you for keeping an eye on this thread and leading me in the right direction.

             Bob

[Blind Lemon]

 Checked around town today and couldn't find any 2N5457. What are they 50 cents apiece. The shipping would be more, I only need 2,  I'll have to wait until decide to make out an order.

                              Bob