Audiokarma Audio Festival, May 3-4

pardales · « **Reply #20 on:** 8 Apr 2008, 10:40 pm »

Tom Alverson · « **Reply #21 on:** 9 Apr 2008, 01:57 am »

Frank:

Have you tried this with a phono cartridge? You would need to re-wire the turntable for "dual" output wires, but you could just split the 10K Grado termination into two series 5K resistors, and ground the center tap. That should give you a good "differential" signal to work with.

Tom

aln · « **Reply #22 on:** 9 Apr 2008, 07:14 pm »

How much?

gjs_cds · « **Reply #23 on:** 9 Apr 2008, 10:13 pm »

Frank,

I'm trying to wrap my mind around your engineering... and it seems to be (dare I say) a bit of a paradigm shift relative to audio. I'm no EE, but I'm a professor of speech science (i.e., acoustic phonetics)--so I'm trying to reverse engineer your designs based on your description. I think I get the principle, but I'm not getting how this design could selectively cancel out the bad (i.e., distortion) from the good (everything else). There's probably a really big piece of the EE that I'm just ignorant to...

If you ever write a white paper on your design, I'd love to read it.

avahifi · « **Reply #24 on:** 10 Apr 2008, 04:42 pm »

In balanced (differential) mode, the audio signals are out
of phase and add for twice the voltage over unbalanced mode. The
distortion products in theory, are not out of phase, but common mode.
If they are present on both sides equally, the difference between the
two balanced is zero, so there is no distortion.(in theory)

Simple, huh?

Frank

pardales · « **Reply #25 on:** 10 Apr 2008, 05:19 pm »

Can't wait to hear it at AKfest, any preliminary pricing/spec's?

modular747 · « **Reply #26 on:** 10 Apr 2008, 05:39 pm »

Quote from: avahifi on 10 Apr 2008, 04:42 pm

In balanced (differential) mode, the audio signals are out
of phase and add for twice the voltage over unbalanced mode. The
distortion products in theory, are not out of phase, but common mode.
If they are present on both sides equally, the difference between the
two balanced is zero, so there is no distortion.(in theory)

This only applies to even ordered (2nd, 4th, etc.) harmonic distortion. Odd ordered harmonics, which are more noticeable, don't get canceled this way. Also, for this to work, the differential circuits have to be exactly symmetrical in gain, phase, and nonlinearities. Any non-symmetrical nonlinearities are additive rather than subtractive.

avahifi · « **Reply #27 on:** 11 Apr 2008, 01:23 pm »

Of course the necessary circuits are built to match exactly.

Regarding odd order harmonics, I understand these are the worst culprits normally associated with solid state equipment.

However, the OmegaStar solid state differential preamp/DAC ends up sounding like extraordinarily musical and controlled tube equipment. I wonder what is really happening therein.

Regards,

Frank Van Alstine

avahifi · « **Reply #28 on:** 11 Apr 2008, 01:31 pm »

Preliminary pricing:

OmegaStar Differential Preamplifier/DAC $2499. Just add source equipment and two matching amplifiers.

OmegaStar Differential Amplifier $2499. Over 300 watts per channel. Takes the full differential setup down to two pieces.

Ultra hybrid Differential DAC. $2999

Ultra hybrid Differential Preamplifier $2999

Add two matching amplifiers or OmegaStar Differential Amplifier and your sources.

Available this summer. Showing for the first time at the AudioKarma show, but not with final finished faceplates.

Note that the differential preamps accept both differential and normal stereo sources and output differential signals from either.

Regards,

Frank Van Alstine

Toka · « **Reply #29 on:** 11 Apr 2008, 03:05 pm »

I must say, I'm most intrigued! I am hoping to hit the AK Fest and see this all in person...good chance I won't be able to, so I hope someone takes a lot of good pics!

Frank,

From the way you describe the unit it almost sounds like it'll use 4x RCA outputs...is that correct? Any XLR at all? And if I recall correctly the current Ultra DAC uses different chips...were there any changes sonically/design-wise here (beyond the obvious I mean...still a redbook/r-2r design)?

TomW16 · « **Reply #30 on:** 11 Apr 2008, 03:30 pm »

Quote

Showing for the first time at the AudioKarma show, but not with final finished faceplates.

More new faceplates.

Ryan45872 · « **Reply #31 on:** 11 Apr 2008, 11:22 pm »

Quote from: avahifi on 11 Apr 2008, 01:31 pm

Preliminary pricing:

OmegaStar Differential Preamplifier/DAC $2499. Just add source equipment and two matching amplifiers.

OmegaStar Differential Amplifier $2499. Over 300 watts per channel. Takes the full differential setup down to two pieces.

Ultra hybrid Differential DAC. $2999

Ultra hybrid Differential Preamplifier $2999

Add two matching amplifiers or OmegaStar Differential Amplifier and your sources.

Available this summer. Showing for the first time at the AudioKarma show, but not with final finished faceplates.

Note that the differential preamps accept both differential and normal stereo sources and output differential signals from either.

Regards,

Frank Van Alstine

Hi Frank,

Will the OMEGA and the ULTRA differential pre/dacs be offered in the EC chassis?
Thanks
Ryan

avahifi · « **Reply #32 on:** 12 Apr 2008, 12:59 pm »

Sorry, won't be able to do the differential equipment with tone controls. For the concept to work the channels must match exactly, and as soon as you start using tone controls you are unbalancing the channels. The though of coming up with exact matching four channel tone control pots and circuts is a bit boggling.

However, the absolutely pure range extension and dynamics and control and everything else makes the idea of needing tone controls absolutely redundant.

New faceplates? Nothing new in styling, the two piece units we showed at the last RMAF were just too expensive to do and did not make any styling waves. Just need some new control and button locations on the differential preamp faceplates with the same black with gold text and graphics as now.

By the way we can supply a few one-off units using the faceplates we did for the RMAF. Call us, we can do black on gold, gold on black, or gold on gold on a very few pieces.

Regards,

Frank Van Alstine

Ryan45872 · « **Reply #33 on:** 12 Apr 2008, 01:40 pm »

Quote from: avahifi on 12 Apr 2008, 12:59 pm

Sorry, won't be able to do the differential equipment with tone controls. For the concept to work the channels must match exactly, and as soon as you start using tone controls you are unbalancing the channels. The though of coming up with exact matching four channel tone control pots and circuts is a bit boggling.

However, the absolutely pure range extension and dynamics and control and everything else makes the idea of needing tone controls absolutely redundant.

Regards,

Frank Van Alstine
[/quot

Thanks Frank
I kinda thought that would be the issue.
Look foward to hearing the feedback on these units.
Ryan

Wayner · « **Reply #34 on:** 12 Apr 2008, 07:56 pm »

I talked to Frank on Friday about some cabinet mods that he needs done and I have to say the guy was pretty excited about the new differential preamp. I means he was EXCITED to say the least. Unfortunately, I can't get over to the factory to audition it before the AAF show. For those going, you may want to bring your favorite CD with and have a listen. The new preamp is quite a concept piece and even modestly powered amps will kick butt. I believe their rated RMS power will almost tripple. I wonder what 2 OmegaStar 170's would sound like (one of my favorite small amps (85 WRMS in Dynaco Stereo chassis))? For those of you going to AAF, what the hell, don't you have jobs?

Just kidding.

NIM!

Wayner

Toka · « **Reply #35 on:** 12 Apr 2008, 09:17 pm »

So will these units have the same number of inputs as the regular 'SL' preamps? Any room in there for a phono board/buffered tape loop? Remote? Or do you need two of 'em?

Wayner · « **Reply #36 on:** 12 Apr 2008, 09:50 pm »

I don't think there is room for phono inputs, best answered by Frank.

W

rustneversleeps · « **Reply #37 on:** 12 Apr 2008, 10:15 pm »

It is a nice concept, but the only source device that can put out right +, -; and left +, - is Frank's differential DAC. I don't have a tuner, turntable, CD player, or tape deck that can do that, that means the differential preamp will have to split up the right + -, and the left + - internally, and differentiate it internally to the outputs, does it do that? Then from output of the differential preamp, with four outputs, go to two identical stereo amps in bridge mode, then to two speakers.

I hope I didn't misread anything.

The bottom line is the cost, double everything, I am sure there will be a differential phono amp, splitter for tuner, and tape deck. Oh, double your patch cables, how do we manage the cables?

Also there will be refinement follows the first generation of the differential product. Since I am still perfectly happy with Frank's product from 1993, I think I can wait for a few more years.

It IS a nice concept.

BrianM · « **Reply #38 on:** 13 Apr 2008, 10:52 am »

Somewhat relieved to learn that the hybrid differential setup will cost 6 grand before the double amp requirement. That puts it conveniently beyond the realm of temptation at this time... (Not that I would need a kilowatt of power for standmounts in a small room anyway...) I like the idea of the Omega combined pre/DAC and single amplifier chassis, i.e. 2 pieces. The question is, if starting from scratch, does one spend $5000 on the Omega differential setup, or a little more than that for the "non-differential" Ultra setup....

Toka · « **Reply #39 on:** 13 Apr 2008, 03:17 pm »

Quote from: BrianM on 13 Apr 2008, 10:52 am

The question is, if starting from scratch, does one spend $5000 on the Omega differential setup, or a little more than that for the "non-differential" Ultra setup....

Welcome to my world!

Just when I thought I had it all figured out...oh well, good "problem" to have I guess. An Ultra differential setup is beyond my grasp for the foreseeable future, alas.