Death By Audio - Robot

Glass_Hero · Post by **Glass_Hero** » 02 Feb 2011, 14:03

I work at a guitar shop, doing repairs etc... I was able to come across a DBA Robot (new production model) for a pretty good price (under 300)..

its a simple circuit from what i can tell, Its a HT8950 set up to do the octave up/down thing and some vib with tons of gain and fuzz.. Kinda fun..More fun on a keyboard than guitar..

Glass_Hero · Post by **Glass_Hero** » 02 Feb 2011, 14:05

The zener diodes on the side of the board are there to hold the voltage to the 5-6 volts the HT8950 wants to see..

culturejam · Post by **culturejam** » 02 Feb 2011, 18:21

Thanks!

Any way we can get a pic or two of the bottom of the board?

culturejam · Post by **culturejam** » 02 Feb 2011, 18:26

It's probably got to be somewhat close to the attached schematic I stole out of the HT8950 datasheet:
http://www.classiccmp.org/rtellason/chipdata/ht8950.pdf

But instead of a transistor output stage, it looks like the TL072 is maybe an input buffer and output amplifier.

jb351 · Post by **jb351** » 02 Feb 2011, 19:26

culturejam wrote:Thanks!

Any way we can get a pic or two of the bottom of the board?

I went to check out the demo of it on Youtube and PGS had a gutshot in the demo.
Here's a screencap of it. I see it has DBA's trademark sloppy layout and soldering.

culturejam · Post by **culturejam** » 02 Feb 2011, 19:42

Maybe this is close:

http://www.generalguitargadgets.com/dia ... ter_sc.gif

the3secondrule · Post by **the3secondrule** » 03 Feb 2011, 08:47

culturejam wrote:Maybe this is close:

http://www.generalguitargadgets.com/dia ... ter_sc.gif

there are a tonne of threads on DIYSB debating how difficult it is to get the DH pitchshifter circuit working. If the soldermonkeys at DBA can get this working, then I hope we can get this badboy traced

~arph · Post by **~arph** » 03 Feb 2011, 10:04

The most interesting part here is the wiring of the function select switch and according (six pins I believe) on the holtec. I have a couple of these chips in my drawer for this pedal for over a year. I've experimented quite a bit with the GGG schematic, but couldn't get it to do what the robot does.
I look forward in tracing this thing!

culturejam · Post by **culturejam** » 03 Feb 2011, 17:25

I love how the silkscreen next to one of the resistor spots says "maybe exclude".

These guys kill me.

Jack Deville · Post by **Jack Deville** » 03 Feb 2011, 18:16

culturejam wrote:I love how the silkscreen next to one of the resistor spots says "maybe exclude".

These guys kill me.

teej212 · Post by **teej212** » 03 Feb 2011, 21:57

i bet they werent happy that PGS showed the guts in their video.

i think theyre running out of solder.

Glass_Hero · Post by **Glass_Hero** » 03 Feb 2011, 23:13

i have more pics front and back... let me know if you want me to post them..

ftelettronica · Post by **ftelettronica** » 05 Feb 2011, 16:09

Hi Glass Hero, could you please post the values of other caps, trimmer and pots?? I'm tryin to design a schematic of this pedal using your pics, thank you...

(This is my first post)

Glass_Hero · Post by **Glass_Hero** » 05 Feb 2011, 19:05

ok no program i have will let me type on the pic unless its white on white.. i dont have time to mess around wiht graphics programs so i'll just tell you..

all the (4) brown/red caps are 0.33uF (334), the little blue one is a 470pf (471), the (2)green ones are 0.1uf (104), the (2) green electrolytes are 33uf 50v, the blue electrolyte is a 2.2uf 50v..

opamp tl072..vol A100k, control B500k, trim 1 meg, ht8950, zeners 1n5227B

devastator · Post by **devastator** » 05 Feb 2011, 21:00

i think theyre running out of solder.

.

I just looked at the datasheet by culturejam , this HT8950 looks really cool . we could me something really nicer , like a ring mod , than this ugly 8bit fuzz

ftelettronica · Post by **ftelettronica** » 05 Feb 2011, 21:16

Glass_Hero wrote:ok no program i have will let me type on the pic unless its white on white.. i dont have time to mess around wiht graphics programs so i'll just tell you..

all the (4) brown/red caps are 0.33uF (334), the little blue one is a 470pf (471), the (2)green ones are 0.1uf (104), the (2) green electrolytes are 33uf 50v, the blue electrolyte is a 2.2uf 50v..

opamp tl072..vol A100k, control B500k, trim 1 meg, ht8950, zeners 1n5227B

very useful, I'll post soon my results..

Bellyheart · Post by **Bellyheart** » 06 Feb 2011, 19:58

With so few components, why is the thing a) so expensive b) huge...

Rare chips?

roseblood11 · Post by **roseblood11** » 06 Feb 2011, 20:15

c) capitalism

Hides-His-Eyes · Post by **Hides-His-Eyes** » 06 Feb 2011, 20:27

It's huge because that gives them more space for the cool artwork, and it's expensive because the difference in cost of producing a tap tempo analogue delay and an electra distortion is less than you'd think

ftelettronica · Post by **ftelettronica** » 07 Feb 2011, 11:04

NOT VERIFIED ! ! CAN SOMEONE DO IT ?!
(switching section still missing but it's not a problem)

Death By Audio - Robot [traced]