R.G. - A/B/Y spitter's uotput impedance

Started by Phorhas, January 25, 2006, 07:07:32 AM

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Phorhas

Hi all and specificaly R.G,

Since I couldn't find eanough info on the subject, I post this question. is the output impedance of the A/B/Y splitter at the GEOFEX site is set by the buffers, or by the Xformer. how do I a really low output impedance to drive my guitar into a mixer?

P.S. - can I add a buffer and ISO out put which permenantly on with no problems?
Electron Pusher

R.G.

It's really set by the buffer plus the DC resistance of the windings referred to the secondary. The transformer has no impedance of its own - only the series wire resistance and the leakage inductance, which are almost always tiny compared to the things it's matching, when it's used for matching.

In this setup, the transformer is not being used for matching, only for voltage transformation. If you're hooking it up to a 600 ohm load, the buffer sees that same 600 ohm load, plus the DC resistances of the transformer windings, which are not neglegible in this case, being about 1000 ohms. So you'll get out a signal about 1/3 of the input signal at your 600 ohm input because the DC winding resistance is a significant fraction of the total load driven by the transformer.

If you have gain available on the board for the input, that may be OK.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.