Hi guys,

I am starting the mod of my microphone after researching a lot around i got some parts from AAmicrophones.
Dave has been very helpful providing the parts and now i am facing some issues.

I am starting with the circuit, i removed C6, C7, C9 and C10 and i have swapped C8 for a 2.2ufd

I have taken the Transformer out and i will be putting the new one in... it's quite difficult to get the cables around since the leads from the BV8 are very short... i have to clean up a bit.

Now i am looking at the power supply.

Dave sent me a Zener diode which is 1N4754a which should be 39volts.

THough the one on my PSU, D5 and D6 are respectively 1N4782A (82volts) and 1N4780A(68volts).

I don't know which value i should be ending with and which Zener diode to change... Maybe both? or should i swap D6 with the 1N4754A and get a total of 121 Volts?
This voltage should be bringing down a bit the harshness from the capsule i heard.

Finally i will be trying the mic with the stock capsule before installing the K47 one...

I would greatly appreciate if you guys could help with that Zener diode and any other tip...

Here are some pics :
« Last Edit: October 22, 2012, 11:33:44 AM by manulaudic »




Parts out




120V is a good spot for your B+ to be. I used one 62V and a 56V when I last modded an alctron PSU.

That body, capsule and transformer is probably a good candidate for a G7. However, you will have to modify your own PCB by removing the space for a PCB mount transformer as Jakob's layout is too long and won't fit. It's fairly simple to do though.
« Last Edit: October 22, 2012, 07:08:25 PM by Enchilada »


Thanks Enchilada,

I will stick with 121 volts then replacing that Zener.
The circuit is exactly the same at the Apex 460... though the body is more of a U47 like.

I am not gonna go for a G7 though, i've heard lots of things about it and i'd like to build that separately. Maybe something in between Royer mod and G7.

now i will be upgrading the circuit exactly the way Dave Thomas adviced me and we'll see.
I'll keep on posting pictures and by the end of the week some sounds samples...



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