Author Topic: Silicon Buzzaround  (Read 3665 times)

mac

Silicon Buzzaround
« on: August 21, 2015, 09:31:02 PM »
This is my silicon version of the Burns Buzzaround.
A bit more complicated to bias than a silicon Tone Bender 3Knob because Sustain and Balance controls change bias.
I used MPSA42 transistors, cheap and low hfe, 130 to 150.
The modifications are,

- Added R11 to feed the base. It should be between 100k to 150k if hfe is as noted above.
- Decreased R7 from 27K (24k) to 4k7.
- Changed Sustain pot to 250kA, but 100kA can be used too. Since silicons have higher Vbe, I had to include R10 to keep the base above gnd. It sounds bad below 33k to 47k. Can be omitted.
* R7, R11 and R10 are critical at low values of Sustain and Balance pots.
- Silicon transistor, silicon diode :)
- Used the TB 3K tone control to have the same volume when you go from high to low,
changed C6 to 4n7, and included an optional cap C7 to tame highs.
- Added a Volume pot since the Balance pot is more like a Texture pot, but can be omitted.

The schematic,


Yes, that thing that looks like a pot is a Spice symbol that works as a pot :)

A sound clip,
Guitar to breaboard to clean Laney LC30II HH
Mic to Dell Mini
4 riffs at different settings,
- Sustain 2, Balance 2
- Sustain 2, Balance 5
- Sustain 6, Balance 2
- Sustain 6, Balance 5
Tone at 5
http://www.aronnelson.com/gallery/main.php/v/mac/sound+demos+of+my+circuits/boozearound.mp3.html

mac
mac@mac-pc:~$ sudo apt-get install ECC83 EL84

digi2t

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Re: Silicon Buzzaround
« Reply #1 on: August 21, 2015, 10:55:25 PM »
Wow! Interesting.

I'll try to breadboard this when I have some time. I would like to a/b this with the Buzzicon. Samples sound cool. 8)
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Gus

Re: Silicon Buzzaround
« Reply #2 on: August 22, 2015, 10:24:57 AM »
Looks interesting

Kipper4

Re: Silicon Buzzaround
« Reply #3 on: August 22, 2015, 12:48:47 PM »
Yerrrrrr nice Mac.
Thanks add to list.
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otherwise, you might end-up with SOIC or gullwings, for surface mounts."


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bifbangpow

Re: Silicon Buzzaround
« Reply #4 on: August 22, 2015, 02:26:42 PM »
I just finished building a buzzaround clone from a kit because i couldn't find a buzzaround circuit board layout. 
I freaking love the way yours sounds though. Wow. Great mods!
Keep on keepn on.

mac

Re: Silicon Buzzaround
« Reply #5 on: August 25, 2015, 12:58:20 PM »
I tried BD237 of similar gain but much higher internal capacitance.
Like TB 3k it can get ear-piercing at max Sustain and Tone after 5-6. BD237 tame highs better than MPSA42, 2N2222/18 or 2N2369.
C2 could be decreased or removed with this transistors.

mac
mac@mac-pc:~$ sudo apt-get install ECC83 EL84