Octava MK/MC 319 Mods

  • Thread starter Thread starter omtayslick
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Changing the FET

I want to change the existing FET on my MK319 to the 2SK170BL.

The existing fet has 4 pin connections and the 2SK170BL has 3.

The 4th connector on the existing FETgoes to the - [ground?] rail of
the PCB.

Do I just connect in the G S D of the new fet and thats it or is there more to it
than that. Is there any additional wiring needed to get the new Fet to work.

If anyone can help I would be gratefull.
 
Changing the Fet

Its OK, I have figured out what to do.

Demto
 
Question about modding 319 Bad Capsule?

I am a little confused about this revision 4 board. In the the article it says avoid this one. Unfortunately this is what I got. Is there any updated info on this one? It says that the schematic is for the revision 3 board. Just wanted some advice before proceeding.TIA, Mark.
 
Octava 319 rev 4. Can anyone tell me if this is hooked up right?

I hooked it up and it sounds like it works but haven't tested it fully yet because I'm not finished. I have the center capsule wire to ground and the other to the left nylon stand off. Seems odd to me that I shouldn't attach anything to the other standoff but this is what I understood from one of Michael Joly's posts. TIA
 
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Mark Tokach said:
I hooked it up and it sounds like it works but haven't tested it fully yet because I'm not finished. I have the center capsule wire to ground and the other to the left nylon stand off. Seems odd to me that I shouldn't attach anything to the other standoff but this is what I understood from one of Michael Joly's posts. TIA
Click to expand...

Not sure if you were still working on this but it sounds like you did it right. I just did mine last night and it sounds great. Good luck.
 
I tried to do the switch mod on my 319 and was having a heck of a time wiring up the capsule leads correctly, but I stumbled across this thread and it got me straightened out, so thanks for the indirect assistance :)
 
demto said:
I want to change the existing FET on my MK319 to the 2SK170BL.

The existing fet has 4 pin connections and the 2SK170BL has 3.

The 4th connector on the existing FETgoes to the - [ground?] rail of
the PCB.

Do I just connect in the G S D of the new fet and thats it or is there more to it
than that. Is there any additional wiring needed to get the new Fet to work.

If anyone can help I would be gratefull.
Click to expand...

Although an old message, just to avoid confusions, indeed, 2SK170BL will work in the 219/319 beautifully. It is however, not a direct replacement for the stock or 2N3819 FETs, and needs to be re-biased to get the optimal results.

Best, M
 
This thread makes me happy. What a fabulous example of how people can freely share information and support in search of sound!

Hooray for nice people!!:)
 
MK-319 Basket Mods

Although this thread is very old, the MK-319 is new to me and I am preparing to do the mods. I am wondering what basket mods are advisable. I have removed the inner basket screen. Short of replacing the entire basket with a custom made one as has been done by others in this thread, are there other mods that are worthwhile? If it is the vertical support posts that cause reflections, how about cutting the vertical support posts leaving the top and bottom support rings and just the single screen for the entire circumference? How about lining the rear portion of the basket with felt? Strategic placemernt of a bead of silicone? If anyone has tried any of these and/or can steer me in the right direction, it would be appreciated. Thanks.
 
hrsnapper said:
... If it is the vertical support posts that cause reflections, how about cutting the vertical support posts leaving the top and bottom support rings and just the single screen for the entire circumference? How about lining the rear portion of the basket with felt? Strategic placemernt of a bead of silicone? If anyone has tried any of these and/or can steer me in the right direction, it would be appreciated. Thanks.
Click to expand...

The first part of your suggestion outlines my Floating Dome mod - I remove the inner mesh, cut off the side bars, completely disassemble the headbasket into it constituent parts, grind all surfaces clean to be electrically conductive, then reassemble with conductive silver epoxy and regular 5 minute epoxy. This reduces internal reflections, removes HF coloration and provides improved detail and transient response.

Forget the silicone beads or felt lining. The former is not effective and the later will obstruct the operation of the rear diaphragm. Enjoy the process!
 
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Hi. I know this is an old thread but hopefully someone who's in the know can help me out. I am trying to figure out the layout for the components on the PCB for the MK319. I've attached a jpeg with the parts labelled that I think I know based on a schematic I found here diy_schematic2.webp (please correct me if any are labeled wrong) and then I have labeled 5 components numbered 1-5 in white that I am not sure which components they are. This board is a 4th revision board so it has C1, C4 and R5 on the daughter board.
Any help would be appreciated!
Thanks.
mk319 layout.webp
 
update to my last post

It turns out I figured out what the remaining components are. A couple of the resistors looked like capacitors to me so it threw me off. In my picture, 1 = R4, 2 = R3, 3 = R2, 4 = C2, and 5 = R1. Hopefully this will help someone out.
 
I think you're missing a couple of connections to the transformer. DC won't pass through a transformer, so the mic schematic as shown here won't result in any voltage reaching the capsule or the FET.
 
dgatwood said:
I think you're missing a couple of connections to the transformer. DC won't pass through a transformer, so the mic schematic as shown here won't result in any voltage reaching the capsule or the FET.
Click to expand...

This is a standard layout, where the phantom power voltage is collected between the center pin of the transformer and the shield, where C9 stands.
 
Ah. Now that I look at it again, yeah, that makes sense. The first time I looked at it, I incorrectly assumed that the center pin on the transformer was grounded. :)
 
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