D*A*M - Grease Box

phibes · Post by **phibes** » 06 Jun 2011, 20:37

I traced this one way back when it first came out and I found some better gut shots to confirm values. I'm surprised I didn't see a topic on it. Really nothing new going, just a fixed MKIII/MKIV Tone Bender variant with the tone control fixed. I know a lot of guys like the DAM stuff. In my opinion it's a more useful two knob version rather than the 2 knob Park Fuzz Sound which has the gain fixed rather than the tone control. Modifying a pre-existing layout should be a breeze for it.

Rock on and enjoy.

beedotman · Post by **beedotman** » 07 Jun 2011, 06:46

I think that schematic is correct. Can post some gutshots one of the latest purple Grease when I'll back home. I think also have layout somewhere...

beedotman · Post by **beedotman** » 07 Jun 2011, 06:51

First units has 10nf input cap instead 15nf in GB-80.

beedotman · Post by **beedotman** » 07 Jun 2011, 07:09

Grease has really nice clean up, its sounds like blend between drive and fuzz - its not so gainy comparing to others MKIII/IV circuits, so I believe last trannie hfe should be around 60-80.

beedotman · Post by **beedotman** » 08 Jun 2011, 21:00

here is board from copper side - this jumper in read is one of Q1 leg

phibes · Post by **phibes** » 08 Jun 2011, 21:04

Nice! I'll compare it to my schematic.

beedotman · Post by **beedotman** » 08 Jun 2011, 21:04

beedotman wrote:- this jumper in read is one of Q1 leg

this is Q1 emiter

phibes · Post by **phibes** » 08 Jun 2011, 21:07

Can you check the pot values? I just went with normal mkiii/iv values.

beedotman · Post by **beedotman** » 08 Jun 2011, 21:08

and this is layout.
sorry for shitty work - I've done this in excell when I was bored at work

i think its pretty much ok

beedotman · Post by **beedotman** » 08 Jun 2011, 21:10

phibes wrote:Can you check the pot values? I just went with normal mkiii/iv values.

Citec 100KA for both

beedotman · Post by **beedotman** » 08 Jun 2011, 21:19

and little more gut shots

phibes · Post by **phibes** » 08 Jun 2011, 21:20

Yeah that layout matches what I drew up. Thanks for the pot values! Consider this one verified.

beedotman · Post by **beedotman** » 08 Jun 2011, 21:22

trannies:
Q1 - Motorolla metal can OC75
Q2 - CV7004
Q3 - OC71

beedotman · Post by **beedotman** » 08 Jun 2011, 21:23

phibes wrote:Yeah that layout matches what I drew up. Thanks for the pot values! Consider this one verified.

cool!

Post by **azrael** » 14 Jun 2011, 05:20

awesome stuff! i love the MKIII design, so it's always cool to see variants.

beedotman · Post by **beedotman** » 01 Jul 2011, 17:43

redrawn layout

beedotman · Post by **beedotman** » 22 Feb 2012, 15:06

I have finished prototype with transistors on sockets and it sounds really nice.

I think Q3 should has little higher hfe - 85-105 to get proper bias on collector which is around 2.5V in orginal units.
For Q1 and Q2 I have used "standard" gains (50-60 and 70-80 respectively with medium leakage) but this circuit is quite elastic so there shouldn't be problems to get good sounding trio.

Very fun and highly recommended circuit!

beedotman · Post by **beedotman** » 22 Feb 2012, 15:10

BTW... In latest batch AC125 trannies were used with 15K instead of 20K on Q3 collector.

G5120fx · Post by **G5120fx** » 26 Feb 2012, 11:57

beedotman wrote:redrawn layout

Nice Layout, thanks!
I just noticed that C1 and C2 have to be turned 180°! Or the shaded side is "+"

beedotman · Post by **beedotman** » 27 Feb 2012, 08:25

G5120fx wrote:
beedotman wrote:redrawn layout
Nice Layout, thanks!
I just noticed that C1 and C2 have to be turned 180°! Or the shaded side is "+"

Yup!

You're right! "+" should go to ground, I haven't noticed shading before.

Will redrawn it again and post soon.

D*A*M - Grease Box [traced]

DAM - Grease Box [traced]