CAL Alpha DAC: Stock vs. 24/96 upgrade

I currently run an Alpha (non 24/96), and have a Sigma II as well, both run with CAL Delta Transports.

I'll second what I've found with using Mullard CV-4004, as I tried a good pair of Platinum graded Upscale Audio Tubes, that were donated to me to try, by a very kind agoner here, "zinfan", and it was just too lackluster, dull, and killed detail.

Jan/Phillps 5751 Tubes that came in this DAC ( I bought it used) were the exact opposite, like fingernails on a Chaulkboard.

I contacted Kevin Deal, decided to try 3 pairs, NOS '50's RCA Triple Mica Blackplates, the GT Mullard 12AX7M re-issue, and a pair of JAN/GE 5751. All sounded very good, with the RCA's coming out the clear winner. All were platinum graded. The GT Mullard was close second behind the RCA. Lastly, the JAN/GE 5751, but not at all bad either, being a wee bit more forward in the mids.

I did not long ago, buy 3 pair of New Sensor/Sovtek Mullard Long Plate re-issues from The Tube Store, and while these Tubes initially seemed to sound a little darker than both the RCA, and GT Mullard, these New Sensor Mullard re-issues seemed to really come around with a little run time, and I've found provide very nice sound indeed!

I am currently running these now for the last few months, and they give good sound top to bottom, good even detail without being over-analytical very nice bass weight, and tone to the sound, and so far, appear to be holding up, no problems. This I feel is a great Tube to try, without breaking the Bank.

Another great "cheap" Tube that also might be worth considering, that will have a different sound than the New Sensor Re-Issue "Mullard", but may work very well in a particular system, would be the Sovtek 12AX7LPS.

I've tried to read every available post out there about the Alpha, and there's two camps in which some like the 24/96 upgrade, and others that didn't. You may get more favorable results by Tube Rolling.

Re-Capping, and changeout of other parts to superior components, would/can be another option, but again, won't be exactly a cheap option.

As for the vintage NOS 5751 Tubes in the Alpha. Although I've never tried them, I'd probably concur, that the Sylvania Triple Mica Blackplate (with D-Getter I believe) would probably be the ultimate "holy grail" choice, and if one can find a good pair cheap, then god bless you, but I had to shy away when I seen the asking prices. Just can't see shelling out $140+ ea for a tube, that not many years ago you probably could've gotten for $12-$20 each.

I've also heard from one strong personal proponent of the Sylvania TM Blackplate 5751, that although a fantastic sounding Tube, they are not a long lasting Tube.

Hope this helps, Mark

Hello Kevin, Goto The Tube Store, The heading "Tube Type" on the main page, click "12AX7". Scroll down in alphabetical order till you get to
"M" There you will see this Tube under "Mullard 12AX7", it of course is not a "real" vintage Mullard, but the New Sensor Clone made in Russia.

Great Tube, I really like them in my Alpha, and as I said previously, won't break the bank, and will hopefully stop your search, and desire for futher money being spent on your Alpha. Mark

Approved Audio Service may be the only act left in town, as far as acquiring specific CAL Audio Parts, but may not be the last act for doing Mods-Upgrades.

Great Nothern Sound was one who regularly did substantial upgrades on Cal stuff. I've got a CAL Delta Transport fully modded by them, Blackgate Caps throughout, high speed Rectifiers, and Bybee Filtration.

I did business once with Approved Audio, for a pair of Drawer Belts for one of my Delta's, thinking it was bad, and needed replacing (It wasn't) $5 ea, and $10 to ship them in a little brown envelope. Postage was actually like .72 cents. God forbid what they'd charge to ship back an Alpha to sombody? I got an excuse from them, that it cost thier guy a lot of time to ship that envelope out to me. Mark