Friedman - Dirty Shirley

bugg · Post by **bugg** » 28 Oct 2017, 12:39

Just finished tracing the Dirty Shirley. This is basically a modified BE-OD with a few component value differences, an extra Vref buffer, and an active midrange control.

Cleaning up the schematic now and will post shortly.

PCBs will be available here: http://www.pedalpcb.com/product/dirtysanchez/

bugg · Post by **bugg** » 28 Oct 2017, 21:50

: DirtySanchez.png (109.5 KiB) Viewed 7960 times

PCBs are on the way.

andlord · Post by **andlord** » 28 Oct 2017, 21:51

Hope you have them in stock. Gonna need a few of those.

Any chance you also gonna do the Buxom Boost?

bugg · Post by **bugg** » 28 Oct 2017, 23:30

andlord wrote:Hope you have them in stock. Gonna need a few of those.

Any chance you also gonna do the Buxom Boost?

Hopefully I won't run out of them like I did with the Thermionic Distortion...

I'll gladly do the Buxom Boost if i can get my hands on one. I have the Motor City Drive traced but haven't gotten a PCB layout worked up yet.

sprentiss · Post by **sprentiss** » 31 Oct 2017, 19:25

Could someone explain how the bass control works? I know it's the same layout as in the BE-OD but I'm having trouble understanding it conceptually. From simulating it it seems to be a variable bandpass filter, I just can't find anything to back up that idea and explain it on an obnoxiously detailed level.

bucksears · Post by **bucksears** » 31 Oct 2017, 22:34

Anybody know if the DS-OD mid control can be applied to the BE-OD?

bugg · Post by **bugg** » 01 Nov 2017, 01:14

bucksears wrote:Anybody know if the DS-OD mid control can be applied to the BE-OD?

Yep, should be no problem.

J0K3RX · Post by **J0K3RX** » 01 Nov 2017, 01:35

Said it in the BE post before I knew the was a DS topic started... You could do both on one board and there's your mid pot mod for the brown eye, if ya want it or leave it off if don't ...

HamishR · Post by **HamishR** » 02 Nov 2017, 10:54

I've already ordered a few boards - Can't wait to get them now! I even bought some BAV99s and will try to use them on one. I'm no expert on this stuff, but I assume that one BAV99 replaces a pair of 1N4148s? I was planning on wiring the single pin on one side to where the pair of 1N4148s are connected and the two pins on the other side to where the other ends of the 4148s would go. It could all go horribly wrong but I figure it's worth a try...

bugg · Post by **bugg** » 02 Nov 2017, 23:56

HamishR wrote:I'm no expert on this stuff, but I assume that one BAV99 replaces a pair of 1N4148s?

That's correct. In the original pedal the pair of BAV99's are connected to the circuit at the junctions of pins 1 & 2, pin 3 of each device is not connected to anything.

There is no difference electrically if you choose to use pin 3 of each device as your connections. In either case, pins 1 and 2 should be connected together as shown.

: BAV99.png (3.95 KiB) Viewed 7330 times

HamishR · Post by **HamishR** » 04 Nov 2017, 03:14

Oh wow - my BAV99s arrived. They're TINY! I knew they would be I guess but was shocked at just how tiny they are. Luckily I ordered a few boards - I think I'll use 1N4148s on the first build. I wonder how different 1N4148s will sound? I have used various diodes in builds before just to hear the difference and yes, they can make quite a difference to the sound/feel of an overdrive. I guess the BAV99 is still silicon? So it should sound close to a 4148?

BIGSMITTY · Post by **BIGSMITTY** » 04 Nov 2017, 03:54

: IMG_4038.JPG (42.35 KiB) Viewed 7193 times

Branimir · Post by **Branimir** » 04 Nov 2017, 09:17

HamishR wrote:Oh wow - my BAV99s arrived. They're TINY! I knew they would be I guess but was shocked at just how tiny they are. Luckily I ordered a few boards - I think I'll use 1N4148s on the first build. I wonder how different 1N4148s will sound? I have used various diodes in builds before just to hear the difference and yes, they can make quite a difference to the sound/feel of an overdrive. I guess the BAV99 is still silicon? So it should sound close to a 4148?

Try to solder them on a perfobard and have them switchable via small dpdt and you can have a direct comparison, I'm also interested in sound difference!

And then comes BIGSMITTY with the 1N5819... Now I have to try that one also! heh

J0K3RX · Post by **J0K3RX** » 05 Nov 2017, 16:50

Branimir wrote:
HamishR wrote:Oh wow - my BAV99s arrived. They're TINY! I knew they would be I guess but was shocked at just how tiny they are. Luckily I ordered a few boards - I think I'll use 1N4148s on the first build. I wonder how different 1N4148s will sound? I have used various diodes in builds before just to hear the difference and yes, they can make quite a difference to the sound/feel of an overdrive. I guess the BAV99 is still silicon? So it should sound close to a 4148?
Try to solder them on a perfobard and have them switchable via small dpdt and you can have a direct comparison, I'm also interested in sound difference!

And then comes BIGSMITTY with the 1N5819... Now I have to try that one also! heh

Look here.. don't know if anybody tried them?
https://www.freestompboxes.org/viewtopic ... 19#p264989

You could try BAV99S.. 1 package with 4 diodes vs. 2 but they are SOT363 so, if you don't like nano sized shit you really won't like this package size...

I find it sort of ironic that allot of people want to make these tiny ass pedals but they cower in fear at the idea of using surface mount components

bugg · Post by **bugg** » 05 Nov 2017, 17:46

HamishR wrote:I really don't understand why there are so many different kinds of diodes - and I don't even know what a Schottky diode is, and I suspect a 1N5819 is a Schottky. But I have been to Zagreb a few times. I really like Zagreb.

Schottky diodes are designed for faster switching and have a lower forward voltage drop. In this case that means slightly brighter and earlier signal clipping.

Manfred · Post by **Manfred** » 10 Nov 2017, 17:27

The awaited BAV99 arrived today, so I could made a PN-junction trace.

Manfred · Post by **Manfred** » 11 Nov 2017, 12:49

Here, the comparison between the BAV99 and 1N4148 Curves, the shape of the curves are quite similar.

Branimir · Post by **Branimir** » 11 Nov 2017, 13:35

That shows the voltage dependant cut off or?
Can you please explain the plots.

Thanks!

Manfred · Post by **Manfred** » 11 Nov 2017, 19:28

Branimir wrote:That shows the voltage dependant cut off or?
Can you please explain the plots.

Thanks!

The traces show the current as a function of the anode-cathode voltage in forward operation,
but if you want, if Vak < 0,48 Volts, the diode is off.

Branimir · Post by **Branimir** » 11 Nov 2017, 22:01

I understand, but that's with DC current, what about RF signal ? Can you sweep it with pink noise and voltage dependant 0,5 to 1V?

There must be some measurable difference between the 1N4148 and the Schottky

Exucuse my poor technical English!

Friedman - Dirty Shirley [traced]