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CAL Alpha DAC - Cool Tubes?

This is a two part question. First, I recently purchased a CAL Alpha DAC with the 24/96 upgrade. I have found that I prefer the sound of a tube DAC and I am enjoying it very much. However, I've noticed that it is completely enclosed with no holes for ventilation and cooling. This is obviously by design, but I wonder if this is good for the tubes and internal components in general. I know that there are quite a few current and former owners out there and would welcome your comments. Second, I would appreciate any recommendations on tubes, tweaks, and such. I am currently running Mullards.

Thanks!

John
stereomaniac
jdlepera's avatar
jdlepera
234 posts
 
Do a search[Audio asylum and here] on the Alpha.I remember a lot of people thought they sounded better with top off.I have a Sigma II 24/96 and have always had top off.Easy for tube rolling too.
dlshifi
41 posts
 
I left an Alpha running night and day for several years, with the cover on, and had no problems. The tubes might have deteriorated somewhat, but if they did I couldn't hear it.
fpeel
455 posts
 
Some owners believe the Alpha sounds better with the cover off. One unit listed on AudioGon in the past even had louvers stamped into it! The cover stays on mine so as to protect the internal components from dust. As for NOS tubes, Mullards (best bang for the buck) and Amperex Bugle Boys (best all around) have been my favorites thus far, especially the latter. '60's vintage Sylvanias were OK, too. If cost is a concern the Sovtek 12AX7LPS is a surprisingly good tube, especially given the cost. Very good extension on the top, but without the sterile sound of the rest of the Sovtek family. BTW, my Alpha does not have the 24/96 upgrade.
newbee
4,794 posts
 
i keep the top on - have newver had a problem with tube life. here's a thought on tubes on the cheap - try some yugo el12ax7s. they are cheap and have a very transparent high end. very clean. i prefer them. i don't have the converted model (24/96). my unit has a standby switch. did they change this with the 24/96 upgrade?
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