I'm not a professional blogger, doing some organizing posts here. I think maybe somebody might find this helpful.
MXL V89MBP donor body for RoyerMod/BigUgly/G7'sh mic update 21-July
Picked up one of these that was not working on battery. Had the hole
already cut and a switch so thought to make cardioid/omni version of the
Schoeps circuit. (I am not interested in doing any metal work) Upon a
brief inspection, some of the circuitry is on the main board on a smd
circuit board, and some on the board containing the switch. Seemed too
complicated now.
But there is about the same amount of space as found in the MXL
9000/76t; so I thought I could just gut the thing and do a point to
point SELA/Royer'sh with a 6AK5 instead of a 5840 and a dual sided
capsule. I have some generic K47 clones so will use that. Will post some
pics of the internals soon. One more project on the table. This should
be relatively simple though.
Have taken apart mic partially, removed XLR plug (which was in pretty
tight) remembered this time that the screw is threaded counter-clockwise
and tight is up not down. The switchcraft I have will go in much
easier. Need to solder the wires to it next. I've sketched out a
schematic and a parts placement guide. Plan to leave the switch board in
place as it already is lined up, and just remove all the other parts on
it. Here is my schematic, the circuit is pretty much the Royer/SELA
with an added grid resistor (I have a 2G to try out, with longer leads
than the 1G's from the original mic) also an omni/card pattern switch. I
want to keep my PSU's consistent (for no good reason, I'm not going to
have that many....) so will use the 100/60 voltage divider as in the
Royer rather than the 120/60.
Here is my proposed layout, basically following the schematic:
The transformers are noname appr 11.5:1 or so. I used one in my other
RoyerMod 2001, and in the "U87 Front End" mod I did to another 2001. I
got several of these off Ebay and in a trade.