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California Audio Labs Sigma II mods

post #1 of 7
Thread Starter 

Here is a refreshed California Audio Labs Sigma II which I have modded. The electrolytic were swapped for a mix of Audio Note Kaisei, Elna Cerafine, and last but surely not least Nichicon KZ muse. The power input filter was swapped for a Fururtech IEC filter. The coax input is using Kimber RCA and the output is using WBT RCA. Both are connected using Type E thermocouple wire. The B+ caps are connected using jumper wires due to their size. A sheet of Stillpoints cloth will be placed under the board. Finally Type E thermocouple wire will be used to construct the power cords. A JJ ECC83s will replace the 22 year old Ei tube which still worked perfectly.


Here is a photo:

Edited by rellik - 1/31/17 at 7:43pm
post #2 of 7
Thread Starter 

Here are the completed photos: The Stillpoints sheet cannot be seen as it is underneath the board.


Edited by rellik - 2/1/17 at 7:27pm
post #3 of 7
Thread Starter 

Here is the Type E thermocouple wire being prepped for use as power cords. This stuff is interesting as it converts heat to current and current to heat quite readily. It has an intrinsic resistance of around 100 times that of copper. This will quickly reduce as the metal alloy begins to migrate to disparate metals at the radius of the conductor like pushing a cone into a rubber tube.


Should prove to be interesting as incoming power from the wall hot and neutral leads will be disipated yet the internal transformer noise will not be as readily discarded.



EDIT: ended up using Cardas power cables

Edited by rellik - 2/4/17 at 9:44pm
post #4 of 7
Thread Starter 
Second California Audio Labs Sigma 2 mods. Using a mix of Jensen PIO caps, Mundorf M-Tube. Roderstein Bakelight. Epcos-TDK Caps similar to Sikorel. Some of the caps have been doubled up, the upper dummy cap will have its leads shorted to reduce EM output and to reduce bloom effect by keeping the upper end of the cap foil windings from breathing. These caps are the post v reg caps for transistor based analog stage and relay power and the final stage caps before the low voltage analog stage. The caps for the relay timer circuit will be replaced with the with Solen MKP for improved relay bounce noise reduction. Relay power is stepped down for relay microcontroller and tube filament power using additional voltage regulators. Will be using 3 small sized Bybee devices rather than a Furutech AC filter at the expense of its tone sweep removing capacitor based standing patterns. Will be relying on the internal "calibration reset" circuitry for that function.

Edited by rellik - 4/4/17 at 11:55am
post #5 of 7
Thread Starter 
Photo of a compliant Stillpoints sheet. Notice the evenness of the light radiated from its surface. The localized difussion zones are simply my cell phone camera and its lens attempting to keep up at its limited aperture by filtering lower frequency light and resultant and inherant lower frequency light interferance patterns.

Edited by rellik - 4/2/17 at 4:16pm
post #6 of 7
Thread Starter 
More photos that show off the quality of the PCB traces. They must be those cool quality ones with varying resistances. The ground planes also have a ridge like structure to help minimize standing currents without hampering current flow through absorbtion/radiation too much. Probably is using some kind of strange metal alloys.

Edited by rellik - 4/9/17 at 1:54am
post #7 of 7
Thread Starter 
Finished photograph of the Cal with RFT ECC83 tube installed. Too bad the text was blurred by the cleaner spray. Added a poster from plazmalab.com. I think this amp will bring "Dead Kennedys" back to life and maybe help fix the dead solder joints on the original push to talk aka "always on DSL" IDEN network which surprisingly still works. https://en.wikipedia.org/wiki/Competitive_local_exchange_carrier

Edited by rellik - 4/14/17 at 6:52am
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