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CAL ICON MKII tweaks / mods shortlist

For those who want to improve the sound quality of their California Audio Labs CD players, here's a list of mods that I performed on a CAL ICON MKII HDCD Power Boss:

- Replace output RCA sockets with Vampire OFC parts (suppliers: Welborne Labs; PCX);
- Re-wire outputs with OFC AWG 22 solid core wire (Handmade electronics, Audiocom.UK.com); do not twist those wires; the slight inductance increase will help filter out-of-band noise.
- Replace +15 V and –15V diodes with 11DQ10 schottky diodes (Digi-Key);
- Replace diode bridge for the analog supplies with a bridge made of 11DQ10;
- Replace ALL electrolytic caps on the digital and analog boards with Sanyo Oscon or equivalent low-ESR caps, same value;
- Remove the Power Boss capacitors (1,000,000uF or 1 F each) and replace with very low ESR, audio quality 100 uF caps. The Power Boss upgrade was a step backward, large electrolytics do improve the bass, at the expense of a distorted midrange and dirty treble. 100 uF after the regulator sounds much cleaner and is enough capacitance to provide powerful bass down to 25 Hz, in my system;
- Damp the top plate (internally) with a piece of 3M's aluminum damping sheet.
- Damp the transport's integrated circuits with 3M's aluminum damping sheet or equivalent damping sheets;
- Damp the chassis bottom plate with two to four Parts Express automotive sound-deadening sheets (originally used for car audio installations);
- Cover every free surface around the transport with 2 layers of Parts express sound-deadening sheets; take care not to interfere with the transport's operation. DO NOT operate the drawer manually, it will be a PITA to make it work afterwards.
- Short the Power On switch (this leaves the CDP on 24/7);
- Wrap 4-5 turns of 3M's high voltage fusion insulating tape around the crystal. Hold with tiny nylon strap; OR replace clock with Guido Tent's clock: 16.9344 MHZ. The raw 15V power supply is a good tap point for the clock PS. I added a series 2 mH 0.1 ohm DCR choke and a 100 uF 25V cap to ground, in order to make an additional LC filter for the clock PS (which has its own regulator).
- Caution: the original crystal is soldered to the transport board. You must have SMD dessoldering tools and an ESD-free environment to remove the SMD caps that connect to the crystal.
- Last but not least, carefully dessolder the BB PCM-1702 chips and replace with select grade PCM-1702K from Digi-Key. This will improve noise and linearity.
- You may want to try running two PCM 1702-K in parallel per channel a la BOW ZZ Eight. I did not try it and recommend that you do this mod only if you are sure that the I/V conversion will not be upset.
I did not have access to a CAL service manual. If a good soul out there has a copy, please contact me via Asylum email.

ENJOY! Your CDP should sound much cleaner and more musical. You will hear a substantial improvement in soundstaging, midrange timbre and treble purity. Bass will lose some excess weight and will sound much faster.

P.S. I have no connection to the above suppliers, besides being a frequent customer.
I do not perform mods for a fee (thanks God).
Anyway feel free to ask questions, I will help as much as possible.

Good Luck!
Carlos



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Topic - CAL ICON MKII tweaks / mods shortlist - Carlos 15:26:07 06/26/03 (1)


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