BSIAB 2 from GGG sounds ok, but not so strong as i heard in soundclips

[gigimarga]

hello,

i've just finished a BSIAB2 (http://www.generalguitargadgets.com/pdf/ggg_bsiab2_lo.pdf) and sounds ok, but no so "strong" as in the soundclips that i listened

the output volume is low, too.

my voltages using a 9.2V battery are (in the paranthesis i wrote the GGG test voltages):

Q1: G=0.00 (0.00)     S=0.86 (0.95)     D=4.95 (4.50)
Q2: G=2.85 (3.80)     S=4.95 (4.50)     D=8.54 (8.00)
Q3: G=0.00 (0.30)     S=0.08 (0.75)     D=4.27 (4.30)
Q4: G=2.85 (3.80)     S=4.30 (4.30)     D=8.57 (8.00)
Q5: G=1.25 (0.50)     S=0.80 (0.90)     D=3.60 (3.40)

it's obviously that there are some important differences...so it's misbiased??

how can i bias it right?

thx a lot all!

[John Lyons]

Have you adjusted the trim pot yet?

[gigimarga]

Yes...it sounds almost good...but it don't have a full sound...like Van Halen...

[gigimarga]

HEEEEEEEELP!

[gigimarga]

 

[jonathansuhr]

what's your guitar/amp rig?

[rikkards]

Looking at your voltages it appears that Q5 is low, I think that it should be around 4.5v.

Anyways take an audio probe (you have made one right?) and work your way through the circuit (the Drains Q1, Q3 Q5 and the middle lug of your Tone, gain and volume) you should be able to find where it is misbehaving.

[jpm83]

What FETs do you use? Get a bunch and socket em up. There is great variances between FETs even with same type.

Janne

[gigimarga]

Thx all  for your answers!

My guitar is a Squier Affinity (3 singlecoils) and a 20W tube amp which has only one clean, Fender-type channel.

The Q5 is biased as in the building notes. I've biased it at 4.5V and it didn't sound better. I didn't use the audio probe yet

I used the FETs as in the schematic: J201 and 2N5457.

[Solidhex]

Yo

  I doubt anyone could get much of a "Van Halen" tone from some single coil pickups. We often concentrate so much on our stompboxes ( naturally ) on this site that we neglect the fact that guitars/pickups/string gauge/ampiflier/tube type/speaker wattage/configuration/...infinity has a part in the tone equation. Anyways...
  Install a humbucker in that guitar or get a humbucker equipped guitar then let us know what's shaking.

--Brad

[rikkards]

+1
I can't believe I didn't correlate this with my previous experience. I had the same thing with my Epi LP with the MayQueen I built. It sounded week. But the difference between what the OP is going through and mine was that I also have a Peavey Tracer which pickups were hotter (aka higher output voltage) and it sound good with it. I hadn't played with the humbuckers on the LP since getting it as it sounded fine. I ended up moving them closer and that helped a lot. This might help you but be aware that moving them closer will change the sustain of the guitar a bit as the magnets are closer to the strings thus having an affect. Also if you crank it up as close as you can it could distort. Google for adjusting pickups on the interweeb and you will find a plethora of info. But what Solidhex said is true. The other option is put in a booster in front and see if that makes a difference.

Yo

  I doubt anyone could get much of a "Van Halen" tone from some single coil pickups. We often concentrate so much on our stompboxes ( naturally ) on this site that we neglect the fact that guitars/pickups/string gauge/ampiflier/tube type/speaker wattage/configuration/...infinity has a part in the tone equation. Anyways...
  Install a humbucker in that guitar or get a humbucker equipped guitar then let us know what's shaking.

--Brad

[jpm83]

String gauge is one thing that matters a lot. You get much more "beef" using 11 set in standart E tuning in place of 10 or 09 set. This is my personal experience.

Janne

[gigimarga]

i agree that the pickups/strings/amps have a big influence...but my problem is: why with the Big Muff Pi, in the same setup, my sound have "big balls", and with the BSIAB no?

[Grizz]

I think it's your guitar...I don't get the EVH tone with my strat and single coin p/u, but I do with my SG copy.

Grizz

[rikkards]

Probably the same reason why my Mayqueen sounds weak while my BSIAB sounds good, not enough signal for that pedal. Try building a quick booster and see if that makes a difference. If it does then that probably is the problem. Two choices:
1. use a booster in front
2. Get hotter pickups.

i agree that the pickups/strings/amps have a big influence...but my problem is: why with the Big Muff Pi, in the same setup, my sound have "big balls", and with the BSIAB no?