Oktava MK-012 PCB

[Pat Maki]

I recently did the Dorsey mod on my early 2000s MK-012s. First came out sounding fantastic, but I goofed up the copper trace in a couple spots on the second. So searched the web for a replacement PCB and found some older posts where folks were making/selling PCBs, they all links are defunct. Anyone know where to find this PCB? Thanks.

 

[TillM]

Try this
http://russelltechnologies.co.uk/rt-012.html

 

[emrr]

Cool, hadn't seen that. 

 

[Khron]

Replacing the goofed-up traces with wire-jumpers is a no-go?

 

[e.oelberg]

why not ?  it's called peer-to-peer

 

[Khron]

Point-to-point, perhaps

 

[Pat Maki]

Thanks for your replies all. Apologies, somehow I didn't see these. This is ancient history, but TillM, thanks for the tip...somehow independently, I found out about Russell Tech and did get a couple of his MK012 boards and completed the mod of one of them. The challenge was that the semi-clear plastic saddle that the pin in the mic capsule makes contact with when screwed on had earlier broke in half and partially chipped off. So I ended up rebuilding the chipped off part with epoxy and then glued the two halves together. It was touch and go a few times, but it ended up being structurally sound and the mod overall worked well and sounds very nice...I dare say I prefer the Russell Tech mod to the Dorsey mod (although the noise floor is ever so slightly higher).
Khron, point taken regarding going point to point! next time will do.

Pat

 

[Gus]

J201 ?
does not make sense to me

 

[Pat Maki]

Yes, Q1 (top on pic) is a J201. Had to switch gate and source leads.  What's not right to you about it?

 

[Gus]

IDSS
Gate capactance

 

[Pat Maki]

Interesting...I'll use this as a learning opportunity. Thanks for the tip.

 

[Mworthin]

The old Oktava PCBs often required traces to be repaired/bridged because they were so fragile. 

I looked at Russell’s boards at one point...were his the ones that didn’t lift the gate off the PCB?  (No Teflon pin to isolate the high Z portion of the circuit). Seemed like a recipe for extraneous noise...