Grid Battery Bias Comparison

Recently there was a thread discussing the merits when positioning a battery in the grid circuit for bias. See link below for the detail.

I thought it inconclusive with respect to how the variations would sound although the sims tended to favour the parallel connection. Sims can't tell how something will sound.

I have the ideal existing circuit to try the variations out in; my phono stage as the first stage is battery biased.

I converted one channel but in the process of doing so in the shed and getting the phono amp back into its box, I forgot which channel was which. I played all kinds of music though each channel in turn and ultimately couldn't identify reliably any differences. This I thought very strange. At some points, I thought I had a favourite but then after a few more goes I didn't.

I've altered the layout keeping the circuit exactly the same and have been able to identify differences. This lack of difference is a first for me. Normally with a difference this small, I would have given up in the first 5 minutes as differences this small are not worth pursuing but for this I thought I had better put in more effort.

I would conclude that the position of the battery should be chosen based on the best config for the supporting circuitry. I can now see why the Artemis phono stage goes for a series battery. It allows direct connection of a cartridge using battery bias where as the parallel connection would not. If this was a line stage, a series battery would not need an input coupling cap.

I went into this with no preconceived ideas thinking only that this is something that should be tried. I was genuinely surprised by the result.

cheers,

Stephen

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