Anyone have the Bosstone CA version schematic?

[John Lyons]

Anyone have the Bosstone CA version schematic?

Thanks

John

[tcobretti]

I think Andy posted these originally.  I've heard it is great, but I am not a fan of diode clippers in general.  Have you built the Bosstone TN?  How do you like it?

[brett]

Hi
the version of the Bosstone with the pair of 18k (sometimes 22k ?) collector resistors sounds excellent.

Here is that schematic by RG Keen at geofex.com :
http://www.geofex.com/FX_images/bosstone.gif

In that form, the first transistor gives high-gain and the second is a low gain (2) buffer. 

IMO this sounds best when Q1 has a low hFE (100 to 250), as would have been in the original.  TIP or BD139/140 devices spring to mind.  And 3 (rather than 2) x 1N4148s add tubish harmonics.
cheers

[John Lyons]

Travis
Yes, the SHO/TN version is a ripper! I put in a little variable filtering (Supidly Wonderful Tone Control ...thanks mark H !)  to add versatility. Very cool circuit. Bypassing the diodes has a good lound as well. loud and heavy.
Thanks for the schematic. I did see that one before but for some reason I wasn't sure it was correct (or final).

Brett
I used 2n2222 for Q1 and 2N3906 for Q2. I have some other old transistors that I'll have to try in there (thanks for the recommendations)
I used an asymetrical 1N4001 clipper set and it does sound nice.

John

[tcobretti]

Brett, thanks for the tips!

John, that is the only schem I have seen for the Bosstone CA.  I seem to remember that Andy loved the CA, and posted a PCB layout for the CA followed by a BMP tone stack.

I'll have to build these.  I just watched the 'Fuzz' movie, and a guy who runs a vintage gear shop in LA and rents gear to the stars recommends it very highly.  It got me wondering why I never put one of these together.

[foxfire]

i breadboarded one a few days ago using the schematic over at fuzz central. i like it a lot. mine had a really nice growl. now i'll have to try this schematic.

[John Lyons]

I think you'll like it Travis. It's not so much of a straight diode clipper as the diodes mainly clamp the level and add a little more fuzz to the signal. Without the diodes is sounds pretty good and has monster growl.

I always though that Andy's JBT was the Nashville one, I'll have to look at it closer...

EDIT: Yes, both Andy's are of the nashville version.

John

[Sir H C]

If you search I think there is a thread on the CA and Nashville versions that I have schematic'ed.

[tcobretti]

In addition to your recommendation, I read some comments in the archive that make it sound like something I'd like, so I'll definitely give it a try in the near future.

[mac]

I replaced both 560K (Geo's schem) with a 1M-B pot, the 0.022uf cap to the center lug.
Also used a 50K pot instead of the 18K to Vcc to set bias.

mac

[John Lyons]

Mac
I came across your post with those modifications.
The 1M replacing the 560Ks to.02 sounds interesting, I'll have to try them since I have it on the breadboard now.


John

[mac]

John,
IIRC I put the pot because I was not happy with the 0.022uf. Instead of the pot you could try different cap values or no cap.

I began tweaking a cap here, a resistor there, and suddenly the bosstone was similar to a bazz fuss... 

mac

[John Lyons]

Mac
There is much more gain and "growl" with the cap connected to ground.
The octave overtone isn't there without the cap either. This tends to come through more with a larger input cap, .1uf or so.

John

[mac]

Yeap, the cap and resistor are a filter that alters the feedback signal. Without the cap this effect is gone. Maybe I was looking something different at the time. I´m going to breadboard it again.

mac

[foxfire]

how about this one, http://www.diystompboxes.com/smfforum/index.php?topic=57936.msg454042#msg454042? scroll down for Dan N's schematic.