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About a year ago, I finished a pair of eiclone monoblocks. Because I already had a pair of OTs with 6600 ohm primaries, I decided to go with the less popular cathode biased version (which specified 6600 ohm primaries). A year on, I'm wondering if I would like to move towards the better overall performance and efficiency of the fixed bias version.

My question: will I get good performance from fixed bias with the higher impedance primaries? I do not want to go to the expense of swapping OTs. I just want to build the bias supply into the chassis and remove the existing cathode resistors/bypass capacitors from the EL34s.

Greg

I wouldn't hesitate to switch to fixed bias with the 6600 ohm outputs if you need the extra juice. What speakers and output transformers are you using?

Shannon

My output transformers are the Hammond 1650H (6600 ohms, 40 watts) and 1650 P (6600 ohms, 60 watts). Not so great having mismatched transformers for a stereo pair of monoblocks, but I got them on the cheap so that's what I went with. The 1650H is a little on the small side for a 50 watt amplifier, but the Hammonds are generally considered to be under-rated so I'm not too worried.

At some point, I'll make the change. I'm just tired of losing 10 watts of output power in the cathode resistors. These amps run hot enough as it is, and I'd like to have a better handle on output biasing.

Greg

See my Advantages of Fixed Bias article which is the fourth listing on the eiclones index.

Mike