VC1 V3.02 Prototype

[tgpretend]

Hi Ted,

I have a VC-1 Prototype that I bought a few years ago now. It is a plain metal casing with hand drawn controls! It says V3.02 on it, and enhancer V3.03, and says “Prototype – Nov 1998. TF.”

It seems very hard to come by specific information about different versions of the VC1, so I was wondering if you had information about it.

Great job with the forum here – you’ve always been very accessible and I think it would be great if more manufacturers could take a leaf out of your book. I bought a few prototype TF27’s off you a few years back, and you came across very friendly!

[Ted Fletcher]

Thanks for the post….. Wow, that’s an old one! I must admit I don’t remember it at all.
I’m sorry, I don’t have any circuit information on those very early VC1 models, they did vary quite a bit, and only settled down at the VC1Qcs model when I changed from a conventional transformer input to the more rugged ‘cs’ version.
I will have a rummage at the office on Monday, but I don’t hold out much hope.

[tgpretend]

Thanks Ted, even that is useful information – looking inside I can see now that its equipped with an OEP A262A2C transformer…

[tgpretend]

Hi Ted, do know what transformer the original VC-1 “Brick” had in it? I’ve been asked how this would compare to a brick. From what you say however, there is likely to be circuit differences other than just the transformer…?

[Ted Fletcher]

The original ‘brick’ had the same transformer…. and there’s a story behind that! That transformer was originally designed as a ‘line matching’ transformer for line level audio. To most designers it is physically wastefully big to use as a mic transformer, but in a professional studio one often gets large audio signals that could send a smaller transformer into distortion. This ‘line’ transformer has winding tappings on it so that it can be configured to get the right impedances. It has a high permiability core using 90% mu-metal, and it is wound using a ‘bi-filar’ technique that makes for high efficiency, good frequency response and excellent common mode rejection….. in short, it’s a good mic transformer.
But at the same time, the circuitry around the transformer has to be right too. The original ‘brick’ had a circuit that I developed for radio broadcast mixers; it uses integrated circuits, but spreads the gain requirements so that the maximum gain provided by any amplifier is less than 25dB, this eliminates transient distortions within the amplifiers; (an effect ignored by other manufacturers) making a warm and full sounding pre-amp.

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