New FET Valve Hybrid DAC

dminches · « **on:** 18 Nov 2011, 01:17 pm »

I have been listening to my new Van Alstine FET Valve Hybrid DAC for about 1 week now and I am loving it. It is very detailed yet not colored, fatiguing or unbalanced at all. It produces a very warm sound - very undigital like.

I am using 2 RCA clear top 6CG7s currently but will also be trying some 6SN7s (with an adapter).

Right now I am using it in my office setup, being fed, via coax, a digital signal from my Logitech Touch, with a Leben CS300sx integrated amp and either Audez'e LCD-3 headphones or Totem Mite speakers. It sound great with both.

This is a wonderful sounding DAC. Highly recommended.

dminches · « **Reply #1 on:** 22 Dec 2011, 10:17 pm »

The sound of this DAC just keeps getting better.

I bought a pair of 6SN7 > 6CG7 adapters and tried a pair of RCA 6SN7 VT231s in the DAC and the tubes brought out a new level of detail and tightness in the bass. I am going to try other 6SN7s since there are so many varieties. The adapters open up a whole new world of possibilities with the DAC.

I do need to find a permanent solution with the cover since the tubes plus adapters are too tall for the case. I need to find someone who can knock out a couple holes for me.

srb · « **Reply #2 on:** 22 Dec 2011, 10:39 pm »

They could be cut with a metal hole saw or a chassis punch if the steel cover is not too hard (or is it aluminum?). Are the tubes ~ 42mm (1.65") in diameter? A 2" hole would give you ~ 1/8" clearance and a 2-1/8" hole ~ 3/16" clearance.

I assume you wouldn't want to ship the cover back and forth, where are you located?

Steve

dminches · « **Reply #3 on:** 22 Dec 2011, 10:57 pm »

PM sent.

rcag_ils · « **Reply #4 on:** 23 Dec 2011, 12:01 am »

Has the 6SN7 tube been approved by Frank? If it has been approved, I'll give it a try too.

dminches · « **Reply #5 on:** 23 Dec 2011, 01:01 am »

Quote from: rcag_ils on 23 Dec 2011, 12:01 am

Has the 6SN7 tube been approved by Frank? If it has been approved, I'll give it a try too.

6SN7s and 6CG7s have the same electrical properties. The 6CG7 is effectively a mini version of the 6SN7. I spoke to Frank and he said it was find to use it.

rcag_ils · « **Reply #6 on:** 23 Dec 2011, 02:55 am »

My Ultra DAC was designed to use 6N1P, then later changed to 6CG7 with no change in passive component. I wonder if the newer DAC has different passive components designed for the 6CG7, and make it more interchangeable with the 6SN7.

dminches · « **Reply #7 on:** 23 Dec 2011, 03:10 pm »

Thanks to Steve (srb) I was able to successful cut 2 holes in the cover of the DAC to allow for the use of 6SN7s with adapters.

http://www.davidminches.com/images/Modified%20Van%20Alstine%20FET%20Valve%20DAC.jpg

mca · « **Reply #8 on:** 23 Dec 2011, 06:18 pm »

Looks good! What other DACs have you heard or had that you can compare this to? This DAC is high on my list now that I sold my MWT.

dminches · « **Reply #9 on:** 23 Dec 2011, 07:14 pm »

I have heard the Channel Islands Audio VDA2 which is a solid state DAC for a third of the cost. While it sounds very nice it can't really compare to the AVA DAC which is 3x the cost. I also have a Modwright Transporter which is similar sounding to the AVA but more expensive since it also streams music.

The AVA dac is really analog-sounding, not to over use that phrase. You should check it out.

Stercom · « **Reply #10 on:** 24 Dec 2011, 09:34 am »

I thought the new FET Valve equipment only came in a silver case? I must of been mixed-up about what Frank said about that. Anyway, very nice!

dminches · « **Reply #11 on:** 24 Dec 2011, 12:48 pm »

Actually, it does come standard in a silver case but I wanted a black case and i didn't have to wait as long for the black case.

setamp · « **Reply #12 on:** 24 Dec 2011, 03:40 pm »

Hi Dminches,

How would you characterize the bass of this dac? Is it rolled off at all? I am not a bass head but have a LF hearing loss. Because of this, I prefer my equipment to have neutral if not heavier bass. Thanks.

dminches · « **Reply #13 on:** 24 Dec 2011, 05:56 pm »

I would characterize the DAC as being very neutral sounding. It is certainly not bright.

One of the advantages of using 6SN7s is that there are more tube choices than with 6CG7s so you can tailor the sound more by selecting a particular tube.

setamp · « **Reply #14 on:** 24 Dec 2011, 06:40 pm »

Great. Thank you.

avahifi · « **Reply #15 on:** 24 Dec 2011, 08:27 pm »

I can add that the Fet Valve DAC does indeed have a powerful, controlled, and very deep and clean bass response. The analog output stage has a Broskie dual triode combined with a big high current power mos-fet follower. It is not the dinky little linear op-amps or pea sized transistors used in most DACs

Frank Van Alstine

I.Greyhound Fan · « **Reply #16 on:** 24 Dec 2011, 09:19 pm »

Frank, how does the new FET Valve DAC compare in sound to my modded Ultra DAC? Does it have more air and transparency as well as warmth? Also, is it better at taming sibilance as I cannot use the stock Electroharmonix tubes in my system with my Parasound Halo amp and Magnepan speakers because of sibilance on certain CD's.

Larry

setamp · « **Reply #17 on:** 24 Dec 2011, 09:56 pm »

Thank you, Frank. I'll give you a call after Christmas.

avahifi · « **Reply #18 on:** 26 Dec 2011, 03:34 pm »

Hi Larry,

You can borrow a Fet Valve DAC (and Fet Valve preamp) for a weekend soon if you would like. Perhaps you should take a Fet Valve amp too to get the full musical effect.

Frank

I.Greyhound Fan · « **Reply #19 on:** 26 Dec 2011, 05:34 pm »

Frank, my back is better now and I will give you a call this week.

By the way, my wife almost contacted you to buy a 400R for a Christmas present for me. Lucky or unlucky for me depending how you look at it, she did not do it because we just dropped $1000.00 each into my son's and daughter's cars. There is always next year.

Larry