The Amp Garage

Just keep in mind that the maggie varistor is SiC and nothing like that modern MOV device, except for the name.

Stephen Keller has the reference on his informative website http://thermionic.info/ Stephen is about to try your variant, as we were both quite interested :D I'm not sure how a split load cathodyne PI can drive the plate voltage below the cathode, and hence change the polarity across the string of t...

I don't recall any noticeable additional noise when testing the clones previously, and certainly no clicking. I'll try and get my maggie 213 clone amp out over the weekend and do some measurements, as I've got my soundcard cro working again. My reverse engineering notes for the nominal maggie vibrat...

Martin, I measured your clone circuit - file 1 result below. A bit wonky below 0.1mA. I removed the back-to-back zeners to make the clone easier to make, and added a 33V zener to iron-out the lower voltage response. A few resistor value tweaks and voila, the revised clone is pretty accurate (file 1a...

Yes AC current will flow, but the net current is of one polarity due to the split load PI configuration. The PI forces the voltage to cycle from idle condition of about 55-60V across each varistor, to the signal pk-pk limits of about 20-30V to about 90-100V (ie. up to a 70-80V pp swing). The varisto...

Martin, you seem to have designed it for bipolar function - was that just to make the clone 'fool proof'. The clone I prepared is polarity dependant - but I didn't think that was a major problem if it emulated a maggie varistor correctly

I updated my cloned varistor and measurements a few months ago. The DC measured results using 36x 3V6 zeners with some matching resistors was excellent. I noticed that my original measurements had a subtle inaccuracy, which is shown in the new results in the linked file. http://dalmura.com.au/projec...