Mic amps...Transformer or not?

Mic amps...Transformer or not?

Postby Ted Fletcher » Mon Jun 29, 2009 11:05 am

There is a serious underlying problem to any discussion about mic amps….. Do we want a microphone/amplifier combination that reproduces exactly what it hears, or do we prefer a combination that flatters the sound, making it ‘nicer’ to listen to?
There is no question that a small diameter capacitor mic with a fully solid-state signal path is the most accurate way to record a sound, yet by far the most preferred choice for a vocal is a large diameter capacitor mic with transformers and even tubes in the path.
A voice recording should produce the sound that the producer wants the listener to hear; it should be the sound that the listener believes he wants to hear!
My view is that this is very rarely a ‘true’ recording, and there are a number of standard ‘enhancements’ that are essential: There’s the proximity effect, placing the singer close to the microphone. This usually leads to a lift in low frequencies that needs a compensating lift in the highs to make it sound right. The result is a dip in the middle, that’s actually useful as it sits the voice in the mix with less chance of ‘muddiness’.
After that, there’s the natural glassiness of capacitor mics, the harmonics from transformers augmenting that glassy sound, and the way the microphone ‘matches’ to the mic amp….. in short, there’s a whole mass of ‘distortions’ that go to make a good sound!

Yes, the mic amp can contribute to this process and it’s true that each mic amp brings its own subtleties to the sound.
The early JoeMeek mic amps used transformers, and proved to be quite ‘coloured’ in sound. My design change to the ‘CS’ amplifier eliminated the high cost of the transformer, while the design retained good matching and a clean and less ‘coloured’ sound; in fact, for most uses in the studio it was superior.
More recently I have returned to using a transformer for all inputs, later circuit designs eliminate the ‘heaviness’ of the sound where it’s not wanted, and the sound is clean yet still sparkling.

Recently, there has been a great deal of forum ‘chatter’ about the relative merits of the old JoeMeek VC1 and the slightly later VC1CS.
And that's what it is.... just chatter. For 90%+ of studio tasks there is no difference between the two. For recording a lead vocal with a very good singer on a ballad type recording, I would prefer the old transformer version; but even more, I would prefer a new P110 which is even better!
But seriously, the differences are very slight.
Don't forget that the 'sound' of a modern capacitor mic is determined mainly by the construction of the mic itself, the amplifier and the coupling transformer (on the good ones) to the pre-amp.
Ted Fletcher
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Joined: Tue Feb 12, 2008 2:06 pm

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