How loud is a BeeBaa??

[Bernardduur]

OK, I've build one; one thing is that it is not loud. I have a fuzz and all pots work, but it is as loud as the bypassed signal with all pots full on.

I used the schematic from Uzzfay; right now I didn't have 100k pots, so I used 10k pots for the filter and volume pots, the gain pot is 100k
(schematic and more here).

I've also seen other schematics and there are some differents:
- 15k in treble booster is 18k
- 1k8 in other settings is 1k5

I use 2N3904.

Is this volume normal?

[TELEFUNKON]

castration (sorry)

so I used 10k pots for the filter and volume pots

like David Bowie used to say: "Is It Any Wonder?"

[MetalUpYerEye]

If the volume control needs a 100k pot, and you used a 10k pot (which is 1/10 the size of what it needs) then you're only getting 1/10 of the volume. Increase it to 100k and it should be much louder.

[Connoisseur of Distortion]

wrong, and wrong.

the volume pot is just a voltage divider. Using a smaller pot will only change the path to ground, but not necessarily make the pedal any quieter. maybe lose some treble, but nothing like this. the filter, however, would probably be quite different with a 10k.

those transistors are odd. the 2sc828 has a range of 65-700  pretty poor tolerance. try some 2n5087/8 instead, because it is probably that the gain of these trannies exceeds the 2n3904 in most situations. the 2sc644 has a range of 130-700, and definitely should be a higher gain device than the 2n3904, as the 2sc644's bell curve is likely in the 400-ish range.

the 2n3904 is about 300-ish gain range.

as for your resistors, the 1k5 would increase the amplification slightly, but i cannot tell you what the biasing 18k would do. i'm just going to say that i don't think that would cause a volume drop. the bias voltage wouldn't even change all that much, really.

i'm not an expert, but i say that you should put in higher gain transistors, put in the smaller resistors, and get new pots (because they're currently messing with your tone).


and, of course, go over the circuit with an audio probe and see if you're losing volume somewhere and all that good stuff. 

[Unbeliever]

Yep, change to a 2N5088 for Q1, Q2 and Q3 are fine as 2N3904s.

[Dan N]

The component differences could be normal from unit to unit. I've seen that Roland also had a 100uf cap on the power supply that was not on the uzzfay BeeBaa. If you are building from the Roland layout, don't forget that the 68K and .022 are mounted right on the pots.

The range CofD posted leave out the selection letter. 2SC828's increase in gain from Q to T. 644's from R to T (from what I've seen and tested). Shoot for 300ish in the fuzz part and 400ish for the front end and you should be fine. Low noise modern silicons are lovely.

And yea, get out a probe. It should be LOUD from the first collector onward.

[Bernardduur]

Thanks all! I will try it in the morning!

[Paul Perry (Frostwave)]

Just looked at the circuit. There's a 68k resistor going to the top of the vol pot, so putting a 10K vol instead of the 100K WILL knock the volume down heaps.

[Connoisseur of Distortion]

 

thank you paul, i saw that network and automatically thought 'Tone Section, Leave Be'

i'm so used to ordinary tone controls that when a notch filter is thrown my way i just skip over it 

[Bernardduur]

Just looked at the circuit. There's a 68k resistor going to the top of the vol pot, so putting a 10K vol instead of the 100K WILL knock the volume down heaps.

wow..... even I didn't saw that. Now it works!

[MetalUpYerEye]

Ha-ha! I was inadvertantly correct! I remember when I built my 1st box; Electra distortion. I didn't have any 100k pots laying around so I threw a 500k in there for the volume instead. It sounded norm to me because i'd never heard it before, but when I got a 100k I swapped it in just because i'm a perfectionist and wanted it to be exactly to the schematic (didn't think it would change anything). Well when I put that 100k in there the volume didn't go nearly as high... Thats why I said what I said.

[Bernardduur]

Still some weirdness..... with 5088's in it, the fuzz box is as loud as the bypass signal (not the trannies, I tried multiple); with the sustain down I have no fuzz. This only comes in after 3/4 of the pot rotation.

With 3904's the fuzz is very loud; with the sustain down I have a nice fuzz, with the sustain up even more...... love this sound.

I guess I need to find better trannies that mimic the original better.

[Unbeliever]

RG has the schematic up on his site - check it out, take note of the voltages on the E, C and B of each transistor, then report back. A 5088 + 2 x 3904 WILL match the original bee-baa - it's more likely you have a slight wiring or other error.

[Bernardduur]

I checked the voltages; they are right. I wasn't ready to combine trannies, but now I did I am glad I did;

This sounds like the real deal! Thanks all!

Edit: one small mod: in the GEOFEX scheme there is a 1 µf on the second trannie emitter, wich is 10 µf in the Uzzfay's; the 10 µf sounds much much better (depth to the fuzz)

[Unbeliever]

Cool. 

[newperson]

hi,
i see that you are using this for bass.  how different does it sound when compaired to a big muff on the bass?
thanks,
paul.

[Bernardduur]

It is good on bass, but not that good. I don't like the amount of compression it gives the notes (so no difference in loudness) and the way it handles the bass..... I replaced mine with a superfuzz and sometimes a Bass Brassmaster

The filtered fuzz is like a BMP, but without the low end.

It was a good experiment

Oh, if you want to use it on bass, the filter filters out almost all of the bass. Replace the 0.1 µf cap in the filter with a 0.01 µf..... now it sounds wicked on bass (but not enough for me to use it in band situation)

This is a great mod btw for all filter like pedals