I am building 2 of these and figure its worth messing around with tho see if it really makes a difference. Are you saying that connecting the ge diode from leg 1 to 3 of the 2n7000 will accomplish this?
Germanium OCD
- Thread starter Aquaticwombat
- Start date
SillyOctpuss
Well-known member
There's a thread and some schematics on the germanium OCD at freestompboxes. I'm out at the minute but will have a look for the thread when I get home later
Chuck D. Bones
Circuit Wizard
Some of the OCD schematics I've seen have a Ge diode in series with one of the MOSFETs, other schematics have no series diode. When there is a series diode, it's pointing the same direction as the body diode, therefore it's not blocking anything. I posted some MOSFET diode curves here.
PapaBear
Well-known member
Ok, I'll dig it outDefinitely would be interested.
Feral Feline
Well-known member
You may be already aware of the following, but for the aid of those unfamiliar...
Some background info:
Mosfet Body Diodes - AMZ-FX Guitar Effects Blog
Mosfets are 4-terminal devices with a gate that controls the conduction of the drain to source channel. The body (or substrate) of the typical n-channel enhancement mosfet is a P-type material with the drain and source formed from N-type materials. The oxide layer insulates the metal gate...
www.muzique.com
Applying the knowledge:
AMZ - Guitar Effects & diode clipping
How to use mosfet transistors and zener diodes for clipping in guitar fx pedals.
Chuck D. Bones
Circuit Wizard
Those Ge diodes have a single green band, yes? That would make them Д9Ж (D9J). They're hard-wired to the MOSFETs (Q2 & Q3). The diodes, MOSFETs and wires are glued down as a strain relief. 'Cuz clear goop would just be silly.
Sure are a lotta extra parts on that board compared to an OCD or Alpha Drive.
Sure are a lotta extra parts on that board compared to an OCD or Alpha Drive.
Robert
Reverse Engineer
That's the newest version of the OCD with "Enhanced Bypass".
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Robert
Reverse Engineer
Do you see a cut trace anywhere around where those germanium diodes connect to the SMD transistors?
EDIT: Nevermind, I think I see it in your second pic, right above C4.
Looks like he just added a germanium diode in series with each MOSFET clipper.
I believe you are correct. Although I didn't realize this was built on the V2, I thought the Ge version was older than that.
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Chuck D. Bones
Circuit Wizard
I wonder if there is a market for carbon comp resistors in SMD packages?
benny_profane
Well-known member
This board looks so hacky.
Robert
Reverse Engineer
They haven't always been so bad...
Oh wait... yes, yes they have. But to be fair.... this one doesn't oscillate.
K Pedals
Well-known member
There are some German and Japanese 1N314’s that have a sing green band as well… these look more like one of those to me.?.?
SillyOctpuss
Well-known member
They look a lot like the green band unizen 1n34a. I have some I can take a picture of later if it would help?
@Barry is this the limited edition candy Red germanium OCD from around 2 or 3 years ago?
I thought the germanium ocds only used one germanium diode with one of the mosfets but your pedal has one for each. Maybe that's the difference between the customer shop red one and the older units? The newer one is a V2 with a germanium diode on each mosfet
@Barry is this the limited edition candy Red germanium OCD from around 2 or 3 years ago?
I thought the germanium ocds only used one germanium diode with one of the mosfets but your pedal has one for each. Maybe that's the difference between the customer shop red one and the older units? The newer one is a V2 with a germanium diode on each mosfet
PapaBear
Well-known member
Mine is green
fig
Village Idiot
Do you have a DMM and / or audio probe ? Try soaking it in Palmolive.They haven't always been so bad...
Oh wait... yes, yes they have. But to be fair.... this one doesn't oscillate.
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