ribbons & transformers

P

paresh

Member
Hi - I have old Beyer Dynamic ribbon mics & they used to work fine plugged into a guitar amp through a (low to high Z?) transformer. But I don't get any boost in level using the transformer plugged into my interface or analog mixer. Why doesn't that work? thanks.
 
Hi Paresh

Your microphone is low impedance (Z) and your amp has a high Z input. So your low to high transformer will increase the voltage and the impedance, giving you an increase in gain.

But your mixer is also low impedance. You can plug your microphone straight in and it should work.
But with the transformer in line, the mic-transformer pair behave as a high impedance source and there is insufficient current to drive the low impedance input on your mixer. Usually you will lose the bass frequencies first.

I wrote a little blog post about ribbon mic transformers and impedance matching, which might help….

Xaudia Microphone Blog: A few thoughts about ribbon mic transformers... part 1

Cheers
Stewart
 
What impedance is the Beyer Paresh?

If it is very low, 30 Ohms like my Reslo RB you could try a 1:4 transformer such as the one I bought from Sowter?
This gives about a 12dB voltage boost and a source Z of 430 Ohms, still low enough for a 1k5 mic input to have little effect.

This brings my RB in line with an SM 57 in terms of output but because the Reslos are not "buck wired" hum is a bit of a bother.

BTW a feature of the RBs is a replaceable ribbon "module" but I have not been able to source any and I have a second mic in dire need!

Dave.
 
thank you both. I don't know the Beyer impedance but I think I am going to buy a Fethead pre which uses the phantom power (safely protecting the ribbon) to boost the level.
 
Hi Dave

>BTW a feature of the RBs is a replaceable ribbon "module" but I have not been able to source any and I have a second mic in dire need!

Feel free to drop me a line either through the messages here or, better, via xaudia.com - we have all spares for the RB models, and I just had 100 new ribbon frames made.

Cheers!
Stewart
 
xaudia said:
Hi Dave

>BTW a feature of the RBs is a replaceable ribbon "module" but I have not been able to source any and I have a second mic in dire need!

Feel free to drop me a line either through the messages here or, better, via xaudia.com - we have all spares for the RB models, and I just had 100 new ribbon frames made.

Thanks Stewart. I think the eyes and hands are passed fixing ribbon mics now! Soldering XLRs are even a bit of a trial now but at least them's not fragile and almost irreplaceable! So,

Once the C card, taxman, car tax and insurance is sorted I shall ship the mic to you for refurbishment. THEN! I shall have to find another nifty for a Sowter traff!

What is this "body" thing???

Dave.
Click to expand...
 
You must log in or register to reply here.
Back
Top