Boss T-Bone Distortio/Octave/Trumpeter

[alex frias]

Guess what simple classic 2 trannies I used for this one?

http://www.youtube.com/watch?v=78XVvOXcecY

[any]

Sounds nice!
Do I see two different trannies in the circuit though?
Classic? hmmm as in 2n5088/89 classic, or bc108/09 maybe?

Cheers

[radio]

Impressiv!

Did you use SAG?

Regards Jean-Marie

[alex frias]

Well, it's a modified Bosstone. Not heavily, just a few mods and tunings.

Bigger caps, one Ge + a 1N4001 at the clipping stage and, yes, a SAG pot, 100K as indicated in another FREE forum about stompboxes.

Regarding trannies, I tried a lot of them. As I saw with Harmonic Percolator, it seems to be a very critical balance between the hfe trannies. In this case the NPN or PNP don't need to be veeeeeeeeeery low. Around 150, I think it's OK. On the demo vid I used a 2N3565 and a 2N4125.

I used my trusty and cheap Parker P-30 with Gold Lace Sensors. I prefer to use the pedal with singles as demosnstrated, but with some reseting it shows the same results with humbucker too. For a plain distortion/fuzz I prefer to use some Ge on NPN or a very low hfe transistor, like BSX20 or 2N2369, for the NPN side of it and not to use caps that big. Piggybacking a high hfe tranny as the 2N5089 presented a very good plain distortion/overdriving sound, but compromise the "trumpetism".

I liked the results, but I find the Paul Trombettas's Tromboner and MiniBone pedals more stable, round and clear.

My version is way rougher, but... Well, it's only rock'n roll but I like it!

[alex frias]

My bad english strikes again, the right question is:

"Guess what simple classic 2 trannies CIRCUIT I used for this one?"

[alex frias]

And the winner is:

[FUZZZZzzzz]

is this the schematic as used in the video?

[Gus]

Alex

sounds nice.

[alex frias]

Fuzzzzzzzzzzzzzzzzzz
Yes, it is!

Gus,
Thanx

[joegagan]

alex, great sample. your guitar playing suits the tone of the pedal, i like it.

[alex frias]

Joe
thanx too

[aquataur]

Well, it's a modified Bosstone. Not heavily, just a few mods and tunings.

Alex,

your device sounds very interesting to me, more versatile than stock bosstones.
Is the circuit verified? I have not seen any responses.

I am asking, because I wanted to draw a PCB when I noticed, that there are some substantial differences in the biasing networks of the transistors. This is confusing me, because this is beyond just a few mods.

For instance, according to the schematic you are feeding Q1 via a 560k resistor - opposed to a 18 k resistor in all the other bosstone schematics.
This seems a bit high but if you say it works... (reminds me more of the CA version schematics that are around except for the PNP output stage)
This resistor then goes to the supply rather than to the 18k other schematics have.

If you could shed a little more light on this I would be thankful,

take care,

--helmut

[alex frias]

Helmut,

You are completely right, your observation proceed.
So I corrected the drawing and I think that's it:

[aquataur]

Thanks, Alex.

This looks more like "just a few mods".
You probably did what happened to me several times: you sling a circuit together and then redraw what you think you changed and lo and behold: the circuit works and the schematic is erroneous. And since you "invented" the bug, you are not likely to discover its existence until somebody else points this out.

Still your variety looks a bit like NPN-NPN CA models whose circuits are around.
You took the feed for the first transistor directly from the rail as they do in those CA models rather than from the 18k load resistor of Q2 (albeit with different values...), as all subsequent models do.

Obviously there are people who have made PCB´s from your circuit, I wonder if any of them worked with the bug in it
So if the Q1 feed is the only change in layout you made one would probably be better advised using one of the standard bosstone PCBs that are around.

take care,

-helmut

[doc_drop]

I just wanted to say thanks for this little circuit. I put it up on the breadboard in about an hour, and it is one of the coolest fuzzes I have played. I love the raunchy sound. I used low hfe trannies, 130 and 159 I think, which worked best after trying a few others.

I definately get the trumpet sound too. I have been playing Herb Alpert all morning. Remember him?...

Fun stuff for those of use who like our circuits a little twisted!

[aquataur]

Building report:

I made a litte PCB incorporating the different bias feed Alex uses plus the bias feed stock units have as switchable option.
Alex´ version, as expected, is a little clearer, the stock bias version sounds comparably flabby.

I tried several low gain (90-140) transistors for both positions. Low power transistors (BDxxx) seemed to work best, although the device always keeps its distinct tone no matter how much you swap.

The 47 Ohm resistor in the emitter circuit of Q1 does nothing discernible. I suspect it should be a 470 Ohm at least. One of the original CA versions has something like that.

On full Attack settings the device seemed to be  prone to motorboating (low frequent oscillation), but this may vanish if properly installed with short wires and a shielding case.

The supply starving worked, but the sound gets farty, worse on some transistor combinations. The more you starve the voltage, the more pronounced an octave below is audible. Interestingly, this works better with  the stock bias feed for Q1 than with Alex´ version.

BTW I found that with my fuzz face I can evoke the same octave below effect if I starve the voltage and remove the smoothing resistor in front.

This is not an octave effect á la octavia. The latter seems to produce uneven products that sound dissonant, whereas the octave this thing produces sounds consonant. I decided that this devices octave effect is not well enough developed to keep it for that purpose only, there are better devices for that.

I could, unfortunately, not evoke the trumpeting effect. Alex´ version sounds like a synthesizer trumpet through his box, so the effect should be really pronounced. Doc_drop, you really got this working? Which version of the schematics did you use? The first one contained an error according to Alex.

Yeah, this yoke sounds rough. Astonishing for a two-transistor device it has enough gain in it or sufficient distortion mechanisms to make for a quite saturated tone, but it tends to swamp all guitar characteristics. Pickup selection questions are a matter of the past.

have fun,

-helmut

[m4j0rbumm3r]

Wow, what a great find is this thread! I really love the trumpeting you demonstrated in the video Alex. That alone makes me very interested in this project.
Could you elaborate a little on the settings used to get the trumpeting going, and also how 'easy' it is to keep that effect going while playing on different parts of the fretboard, picking strings harder and softer etc? It would be less useful for me if the trumpeting is difficult to achieve consistently.

Alex, or doc_drop, could you confirm the second schematic is correct and that the "47R" resistor is indeed meant as 47 Ohm?

Thanks a lot!

p.s. I know this thread is old.

[pinkjimiphoton]

indeed...this is another must have that will kill an afternoon nicely as well as produce some quirky sounds...cool ones!!

well done, mate!!

i tried to embed the video...worth watching repeatedly.

[pinkjimiphoton]

worked this up, gonna build it later. love the demo, alex!!





i know it can be smaller, but...sometimes it's nice to have a little room to breathe!!

[pinkjimiphoton]

EDIT: THIS ONE HAS MISTAKES, PLEASE LET ME UPDATE THE VERO BEFORE TRYING TO BUILD THIS. I WILL UPLOAD THE CORRECTED VERO SHORTLY, SORRY FOR THE INCONVENIENCE IF YOU'VE ALREADY STARTED...

smaller version



this would probably fit in damn near anything!! the switch is bigger.