Questions about original Cal Alpha DAC

Hi
When i upgraded to Alpha from Sigma II about 10 years ago i also noticed the brightness.Actually,comparing them back to back i always preferred Sigma.I always used Svetlana 12ax7s with CAL.Overall,i still miss CAL sound and never found a good substitute for it.

Hi, I also notice a seemingly hotter output of the Alpha versus the Sigma II, and I understand through a bit of Alpha research, that there was the ability to swap out a resistor inside, thus adjusting the output.
(Some have stated that the Alpha did come with a resistor, or resistors supplied from the factory?)

Unfortunately, this DAC came without Owner's Manual, so that will be one item I would like to acquire, whether it be an original manual, or a copy, probably doesn't matter much. Mark

I have and use both the Alpha and the Sigma II. With identical tubes in each they are sonically very close with the Alpha being slightly more 'detailed' and the Sigma being more rounded. The Delta is less sensitive to tube choices the Alpha much more so.

Neither of these are treated critically in my systems so I have stayed with new production tubes. If you don't like bright/cold/etched sound, don't buy Sovteks. I've used EI's for a very smooth sound and, for a fuller bass at the loss of the EI's smoothness in the mids and highs and with a bit of roll off in the highs as well, some EH's. If you've willing to spend the money on NOS tubes and you want a warmer sound, think Mullards (possibly some of the new 're-issues' which are purported to sound like Mullards ?).

The Cal Alpha/Delta IMHO can be one of most easy combo's to listen to over the long haul. You lose a bit of resolution, bass impact, and treble extension, but for the mid-range, especially with small groups, vocals and instrumentals, etc, it remains my favorite digital source.

Don't give up on it, just spend some time finding the tubes that will please your ear.

PS I forgot to mention mine is not the one with up-sampling, this could make a difference.

I've had very good luck with Sylvania 3-mica blackplate 5751s in the Alpha. They've become pricey, but the results have been worth it. Email me with your address and I'll send you a photocopy of the manual.