Best 12AX7 for CAL Alpha

While the 5751 is not always a good substitute for the 12AX7, it does very well in CAL DACs. An inexpensive and well-regarded 5751 is the Raytheon. These can be had for around $20 each at places like Tube World and I prefer them over GE JAN grey plates. 5751s have less gain than the AX7s.

I have tried the GE Jan 5751, CV4004 and Sovtek. To me 5751 is the best sounding so far. As detailed as CV4004 but more warmth and a little laidback.

I loved JJ Tesla 12AX7s on my Alpha. The stock Chinese tubes were a little faster, the Teslas richer. I also tried GE 5751s and was not impressed -- to slow, too golden sounding. I found myself longing for the fast Chinese tubes.

Has anyone tried a set of 5751's in a CAL Alpha? Results?

I agree the Mullard CV4004's are great! I also liked the Telefunken(ribbed plate) 12ax7's.

I was considering selling my Alpha until I tried a pair of Mullard CV4004s. These are the tubes that Upscale Audio recommended to me. I was surprised how this little DAC came alive after they had time to break in. A substantial upgrade over the stock tubes...

Best bet is to go shopping at www.upscaleaudio.com. Lots of options; your end decision will depend on the desired sound.

There are a handful of us with Alpha's that enjoy the sound of the low cost Yugo tubes and they allow you to afford other recommended tubes at the same time.Happy listening.