Aiwa VM-15 Ribbon mic with an old Sansui 9 pin transformer wiring question

[Tanigumi]

My mic came with funky wiring and I need to redo it. Do you have any idea how I can install one of these? There are 2 wires from the motor and 3 from the cannon plug. Does anyone know the pinout for this Sansui MC 603 transformer?

 

[Khron]

Got an ohmmeter / multimeter? You could consider trying to use it..?

 

[Tanigumi]

Very kind advice! Thank you!

 

[Khron]

I mean, safe to assume the pins are numbered in order, so only two possibilities left there.

The high-impedance winding should be easy to identify, and the lower-impedance winding, the same (it'll be center-tapped). All the rest of the pins go to ground (the core and the electrostatic shield won't have any continuity to any other terminal).

 

[Tanigumi]

Great! I will have a look in the morning with my ohm meter! I am unsure about how to read the diagram on top of the transformer and practically make sense of the 9 pins.

 

[Tanigumi]

This diagram is the only pinout I could find. I should be able to make some progress from here.

 

[Tanigumi]

Would it be true to get the most gain, I would attach 1~2 to the XLR and 6~7 to the motor?

 

[Tanigumi]

Does the ground from the XLR share pin 7?

 

[gyraf]

600(150):50K is not intended for internal ribbon mic use, but for microphone amplifier duties

Look at the secondary, static shield connects to start of secondary - output signal won't be balanced: This is a balanced mic to unbalanced amplifier transformer.

You will need significantly lower impedances AND fully balanced operation to work (well) in a ribbon mic

/Jakob E.

 

[Tanigumi]

This MC 603 trans was inside the mic when I got it. I thought it was added because of red electrical tape. I ordered a Cinemag CM-9887 1:35. Perhaps this will put the mic right.

 

[Khron]

Plus, in ribbon mics, you want the transformer connected as a step-UP, so the lower-impedance winding connects to the motor, and the higher-impedance winding to the XLR output.

 

[duffharrisnyc]

My mic came with funky wiring and I need to redo it. Do you have any idea how I can install one of these? There are 2 wires from the motor and 3 from the cannon plug. Does anyone know the pinout for this Sansui MC 603 transformer?
View attachment 134399View attachment 134400

Just a stab in the dark but my guess is that 1-2-3 are the primary and 7-8 are the secondary.

 

[k brown]

I know you already ordered a Cinemag, but FWIW, Edcor makes some nice, affordable 1:37 transformers especially for use in ribbbon mics.

https://edcorusa.com/collections/ribbon-microphone

 

[Tanigumi]

Just a stab in the dark but my guess is that 1-2-3 are the primary and 7-8 are the secondary.

I know you already ordered a Cinemag, but FWIW, Edcor makes some nice, affordable 1:37 transformers especially for use in ribbbon mics.

https://edcorusa.com/collections/ribbon-microphone

Thanks for that! Good to know!

I know you already ordered a Cinemag, but FWIW, Edcor makes some nice, affordable 1:37 transformers especially for use in ribbbon mics.

https://edcorusa.com/collections/ribbon-microphone

 

[Marik]

My mic came with funky wiring and I need to redo it. Do you have any idea how I can install one of these? There are 2 wires from the motor and 3 from the cannon plug. Does anyone know the pinout for this Sansui MC 603 transformer?
View attachment 134399View attachment 134400

The Aiwa VM15 is an excellent microphone... much better build and consistency quality than RCA77 it is modeled after. This Sansui transformer looks like not a good fit for that microphone, as it is for 150Ω input, while the microphone is some 0.1-0.3Ω, so while it might somehow work expect the noise to be substantial. You will need to use a transformer specifically made for ribbon microphone--there are plenty on the market with quite a broad quality and price range, the torroidal being on the top.

Best, M

 

[Tanigumi]

I've been using the VM-15 with a Cloudlifter with good results but at the beginning of my journey I ordered a Cinemag CM-9887 1:35. I'll see how that will work. Should I delete the stock 50k transformer within or use both transformers?

 

[Tanigumi]

 

[Tanigumi]

I've had some pretty good luck collecting some vintage Japanese mics lately

 

[Khron]

I've been using the VM-15 with a Cloudlifter with good results but at the beginning of my journey I ordered a Cinemag CM-9887 1:35. I'll see how that will work. Should I delete the stock 50k transformer within or use both transformers?

Pretty sure that's meant to replace, not add on to, the existing transformer.