Digital Processor That Are Great Matches 4 Tubes?

Fullrun,

Sorry I haven't followed up, and glad to see my comments helped.

I don't necessarily claim one "strategy" is better that the other, though.
One "strategy" is to optimize the server and use a DAC that is very good and server-sensitive. I believe most DACs fall into this category, and it allows the use of JPlay or Audionirvana+ in Apple with which users are very happy.
Another strategy is to spend most of your budget on a DAC that is in-sensitive to the feeding computer - the catch with those is that over the years a number of companies have claimed such independence but few, if any, have yet achieved it.

About 9 months ago AudioPhil, the maker of the Audio Optimizer, told me a laptop with WS2012 and Optimizer would get me to 60-70% of where a fully optimized server would. Not bad for a rather simple solution! In my view, buying a very good DAC and feeding it with a laptop with WS2012+Optimizer would be a very valid solution. And you could later decide if you want to upgrade the server.

Sure, the other strategy is also valid - as long as the DAC is indeed insensitive to the source! The only DAC I know of that might fit this bill and is below $4k is exaSound, but I have not come to a conclusion yet with mine (have not had the time). exaSound president told me the previous owner of my DAC sold it out of frustration he couldn't leverage what he had spent on his optimized server into sound improvements. Encouraging from my point of view, but clearly disappointing to the previous owner.

Here's another curved ball :-) We all know the room has the highest impact on sound of all "components". Many have lately spoken highly about some digital room correction units and software packages. See the thread "Is DEQX a game changer?" here. It seems that after room correction and time alignment different hardware sound more alike than different and they all sound VERY good (within certain logical quality ranges, of course).
What if we used a powerful computer running DRC/DSP and feeding an insentive-to-the-source DAC (now the heavy processing at the server wouldn't translate into jitter fed into the DAC)? Maybe the shortcomings of a not as good volume section in the DAC would be more than compensated by DRC/DSP vs. our beloved preamps?

Indeed, that is part of my hidden agenda. ;-)
In reality I am most interested in the exaSound e28, that has 8 channels. My idea is to drive a pair of 3-way speakers plus 2 subs using digital crossovers at the server and using an amp to directly drive each speaker driver (no passive XO). Hence a 2 channel preamp won't work for me. So all of this is fascinating IF the exaSound is INDEED insensitive to the fed stream.

This opens a fascinating door. I have a hard time letting go of my preamp, though. So I bought the e22 to experiment and I'm also in the process of trying Acourate DSP/DRC software package.

Sorry for the extra long post to ramble over something you didn't ask. Bottom line is both strategies can lead to easier solutions to implement or to quite sophisticated ones. A dual-PC setup using JPlay would be the extreme sophistication along the lines of the first strategy. See JPlay/Computer Audio forum for this.

Finally, do read the long thread about DEQX. I have exchanged with a user who claimed to have replaced a $30k DAC with DEQX HDP-4 and was very happy. Bifiwyne in the mentioned thread tried one at home, was thrilled, and is coping with the idea it might sound the same as without his Audio Research Ref 5 preamp in the chain - a paradigm shift for him. The DEQX might even be a good solution for you!

I know this post is coming back without a clear suggestion of what I'm proposing. I just propose you think about the options, I try to provide food for thought, and let you decide what sounds more appealing to you. Personally, I currently don't have a point of view...I might be transitioning a paradigm shift myself!

Hello Fullrun.

I have a McIntosh MC275 tube amp and a Lamm LL2 preamp to drive it and love the combination. My digital front end is a highly optimized PC feeding (thru PPA USB card) to Audiophilleo with PurePower and into a Metrum Octave DAC. I have just received an exaSound e22 that I'm in the process of breaking-in and expect to compare it to the AP+Metrum combo later this week, and eventually compare it driving the amp directly vs thruu the preamp.

Bottom line: I cannot provide input on the e22 yet, but will be able to soon. The e22 retails for $3.5k. One feature is it is supposed to make the computer source quality irrelevant by buffering data in the DAC (not relevant for my situation, but might be for you).

Fullrun,,

Another factor to keep in mind is the server computer. My PC is highly optimized and I did notice a significant sound improvement with certain upgrades with the Audiophilleo+Metrum, like using Windows Server 2012 with AudioPhil's Optimizer (that's a software upgrade). My point is certain DACs are more sensitive than others to what they are being fed even if all of them have asynch USB. My Audiophilleo has asynch USB and has the PurePower option and you would think it would be insensitive to the computer feeding it, but it's not - and it's a very good converter!

Your MacBook Pro, just like any other laptop, won't be a top notch server. Sorry to be brutally honest here - I do not mean this in a mean way. But a laptop cannot take hardware upgrades like desktops can. I suggest you take this factor into consideration when selecting your next DAC. Are you willing to spend on a top notch server? If not really, then place extra value on those DACs that really are designed to isolate their performance from the quality of the server feeding them.

I say this because isolation from the server quality is a design goal for exaSound. So much so that exaSound president was giving me a hard time because I was driving the e22 with an optimized server running WS2012.

BTW, look also into Lampizator. They are VERY well liked and you can order one tailor-made to your needs, including a very good volume control. If my end goal wasn't multichannel I would be looking VERY seriously into Lampi.

Auralic Vega is very well liked by many computer audiophiles too, and I believe it has a good volume control too. At that price range there are many very good units with great volume controls. Have you checked computeraudiophile.com?

Hello Fullrun.

I thought I should give you feedback now I have had some time with the e22. Unfortunately the answer is not a clear cut one.

I found the e22 fed with DSD @ 5.6MHz sounds very good, and I'm not yet decided if it sounds better through my Lamm preamp or driving my McIntosh MC275 directly, which in and of itself is telling already. It sounds very good. BUT there are some considerations too:

1) the above is when upconverting 16/44 files to DSD using HQPlayer. I tried doing this with JRiver and didn't like the outcome. Such upconversion is resource intensive at the PC, so you need to have a suitable machine. And I find HQPlayer's interface cumbersome at best, and requiring a laptop to remotely control my headless server vs. jRemote on my iPad when running JRiver.

2) When using JRiver and playing 16/44, 24/96 and 24/192 files natively, I found my Audiophilleo with PurePower feeding my Metrum Octave feeding the Lamm LL2 sounded better than the e22 feeding the Lamm. I can hear some glare on voices, especailly female, and find the sound in general a little more harsh.

So I haven't decided yet. Another comparison I need to make is with Audiophilleo and Metrum driven by JRiver and with Windows server in core mode and with the Audiophile Optimizer on. The last two make a significant impact in that setup. And try that vs HQPlayer feeding e22. Unfortunately HQPlayer doesn't work with the AO, so the cycle time to do A/B is rather significant.

I hope this helps and I hope I'm not flooding you with info. Feel free to ask back.

Cheers,
Horacio