DIY ribbon mics

Hi All,

flushed with success from my recent G7 build and lots of other DIY gear, I am now planning the build for 2 ribbon mics ( I track a lot of guitars in my small project studio)

I already have a couple of OEP TX's surplus which I thought I might be able to use.
http://uk.farnell.com/oep-oxford-electrical-products/a262a1e/transformer-6-3-6-3-1-1-150ohm/dp/1172346

but I worry that the ratio -  even if I pair up the 2 1:6.3 windings to get 1:12.6 - will be low.
Then I wondered whether its possible for at least one mic to use both trannies running into one another to get a 6.3 x 6.3 step ratio - which would give me 1:39.7 ratio overall.  Would this even work ?

I have my magnets coming and already have my Ali ribbon material, perspex and other stuff ready to build so just need a little advice on the transformer options.
I'm in the UK so OEP , Sowter and Xaudia are my TX options if the OEPs wont cut it.
Cheers
Pete

The DCR of the pri in parallel is 0.18Ω, which will result in unacceptably high noise if you use two of those. Also, say, your ribbon is 0.15Ω, then 1:12.6 will result in 23.8Ω output impedance. This is too high for putting those transformers in series and you will get considerable low end loss.

The only way is to make it work is to use a single transformer and very low Rbb BJT active circuit. Still the noise might be an issue. I'd use a proper transformer, specifically designed and optimized for use with ribbon microphones.

Best, M

Thanks Marik.
- good guidance.

I'll look into suitable TXs
Cheers
Pete

Hi

I now have all the parts for 2 ribbon mic builds ready to go - but dont have suitable donor bodies yet.

I used 2" copper pipe for my G7 build but I want to try get something quicker for the ribbon mics

Any suggestions or sales in UK ?

cheers
Pete

Just use some 28mm copper pipe and use 2p piece for ends as per my ones (royer 121 style)

Regards

Spence.