[zybar]

GEEEZZZZEEEE!!!!!!

 Getting kind of expensive just to tunes!

                                             Cheers
                                             Charlie

I have four channels now with my current speakers and yes, it "can" get pricey depending on what path you want to take.

George

[richidoo]

wayner:
  From what I see in your diagram mono amps won't work. That leaves me out. I've got a pair of CIA D-200 mono amps.

                                               Cheers
                                              Charlie

Charlie, your D200s are fully differential monoblocks. See if Dusty can convert the input back to XLR for you if you have RCA input jacks. You can still use them single ended with an adapter.   I assume the new AVA balanced preamp has balanced XLR outputs...

A stereo single ended amp needs to be duplicated to be stereo differential, but not amps which are already balanced.

Congrats on the new designs Frank. Looking forward to hearing them in Denver.
Rich

[avahifi]

Well!  I see this thread is drawing some interest.  Now to try and answer a few questions.

The least expensive way to get into our Differential system is with an OmegaStar Preamp/DAC and add one more stereo power amp to match the one you already own.  There will be no trace of "solid state" sound, guaranteed!

The OmegaStar Differential Amplifier costs more than two OmegaStar 240EX amps because of the increased power supply required and some other detail changes such as much higher current capacity output sections.  Obviously two OmegaStar 240EX amps will work nearly as well if you have the space for them.

No, you cannot use "monoblocks" unless they are bridge mode designs already - -  having two identical stereo channels internally and both left and right hot outputs.  I am not aware of any done this way.  I am dubious of using two monoblocks per channel in any event as it will be difficult to get a good common ground between them and they may be hum producers because of that.

Note that even the performance of stereo DACs, Tuners, and Phono will be significantly improved feeding them into an Ultra Differential Preamp because their signals will be converted to differential mode in the preamp and will gain the advantage of differential operation from thereon to the speakers, assuming differential power amplifier operation too.

Is the system more expensive?  Unfortunately yes.  It does require four active channels from one end to the other.

Another alternative of course is to just continue to enjoy our normal stereo equipment until the Tax Rebate checks start getting a lot bigger. 

Hear it all at the AudioKarma show in Detroit this weekend.

Regards,

Frank Van Alstine

[Frank S.]

No, you cannot use "monoblocks" unless they are bridge mode designs already - -  having two identical stereo channels internally and both left and right hot outputs.  I am not aware of any done this way.  I am dubious of using two monoblocks per channel in any event as it will be difficult to get a good common ground between them and they may be hum producers because of that.

Regards,

Frank Van Alstine

Some monoblock amplifiers are designed this way.  My Theta Digital Citadel monoblocks are.  Each channel is a balanced bridge amplifier with both the positive and negative speaker outputs "hot".  They give multiple warnings in the owner's manual about this design and the fact that the "- negative" speaker output terminal is not a ground.

I think it's great you are designing your components this way.  I've always loved true fully differential mirror imaged balanced circuitry in audio components. 

[Charles Calkins]

So if I got this right two same kind stereo amps are needed. Not necessarily two of Franks special differential amps. Right? Do the amps have to have XLR inputs?

                                         Cheers
                                         Charlie

[Wayner]

Yep, 2 identical stereo amps with common ground mode.

Wayner

[Charles Calkins]

wayner:

 Now there you go again!!!!
 What do you mean by "common ground mode"?

                                      Cheers
                                     Charlie

[rlee8394]

Common ground mode is where the amps have a hot side for the positive output signal to the speakers, and the negative side of the speaker is connected to ground. All of Frank's amps except for the new differential amps, are common ground mode. Most amps are designed this way. All of the Dynacos, Haflers, and most other mainstream amps are common ground. Amps that were not common ground were the Carver amps as well as most if not all of the amps designed for mobile use, e.g. car amps.

When Frank speaks of his new differential systems "nulling out" all noise and distortion, he is referring to noise and distortion that is "referenced" to ground, also known as "common." Since most noise in a common ground system occurs between the power supply voltage and ground, it can creep in to your system components and then to the output signal on to the speakers. Now instead of connecting the speaker between the hot signal and ground, we connect it between two hot signals, one of which is 180 degrees out of phase with the other. Therefore any "common mode" noise, that being noise generated between the power supply voltage and ground, is effectively "nulled" or cancelled out. A side benefit is that since the voltage is doubled due to the fact that one signal swings in one direction while the other signal swings in the opposite direction, greater output power is achieved. Theoretically four times as much, but more often it is closer to three times depending on the available current of the power supply.

So how does one get this kind of operational performance from a common mode stereo amp? Simple, you drive one channel with a normal signal while simultaneously driving the other channel with the same exact signal 180 degrees out of phase, otherwise know as inverted. This is the function of the two AVA Phase Inverter Bridges. This of course provides you with a very powerful and quite amplifier channel for a speaker, a single speaker mind you. That is why you need a second amplifier, to provide the same configuration for the other stereo channel. Thank goodness quadraphonic never really caught on. We'd have to double up this configuration again. Now that would take a bit of cash!!!

I hope this explanation helps out a bit. Go to the AVAHIFI site and download the Audio Basics 1986 back issue set, ab1986.pdf. Start on page seven, column three, about two -thirds of the way down. Frank gives a very good explanation of this concept in much greater detail than has been done in this forum. It's a good read. The new systems are basically an extension of this principle starting at the source (differential DAC) level and continues through the entire audio chain to the speakers.

I'm psyched!

Ron

[carusoracer]

Nice reply Ron!

[Charles Calkins]

Do you know of any other audio manufacturers that offer this in their line of audio gear? I'm thinking probably not because of the final cost of such gear.

                                                             Cheers
                                                           Charlie

 

[Wayner]

Common Ground mode is the negative of the left and right channels are tied together.

Wayner

[Charles Calkins]

Wayner:
 As I remember when I had a pair of Nad 218THX amps when I wanted to run them in mono there was a switch on them to convert them from stereo to mono. Then the speaker wire was hooked up to the positive posts. No speaker wire hook up to the negative posts. Is this similar as to what Frank's setup will be?

                                         Cheers
                                       Charlie

[Wayner]

Charlie,

Now your gettin' it. Frank's design turns a stereo amplifier into a mono amplifier, summing the power of both channels. That is why you need 2 identical amps. Actually it about tripples the single channel wattage of your current amplifier. So let's say you had a 100 watt RMS per channel amp. It would become about a 300 (Frank can correct me here) watt mono block amplifier. You would hook the positive terminal of you speaker to one channel of the amplifier's positive output terminal and the negative terminal of the speaker would go to the other positive output terminal of the amplifier. There would be no connection to the negative terminals of the amplifier.
To keep the speakers in correct phase you would simply observe which channel of the amplifier fed the positive and which fed the negative and duplicate that for the other side.

Hope that clears it up for ya'.

Wayner

[Charles Calkins]

Wayner:

  Sure do. Thanks. But!!! When I tried all kind of different setups with the Nad amps it all sounded the same to me. I started out with one stereo amp. Got another and ran them in mono. Bought a pair of Paradigm speakers and there was a diagram about vertical biamping. Tried that. All sounded the same to me. I'm not trying to put a damper on this differential system. Just telling what I've heard in my listening. Maybe Franks new pre for this system is the key to better sound.


                                                   Cheers
                                                   Charlie

[rustneversleeps]

rlee8394,

You explained how noise got canceled due to noise spikes are positive going signals. But you did not explain how the actual signal got doubled very well. I thought a sinewave got chopped in two halves, + and -, the - got inverted and become +, then both +'s added algebrically and become double. During the - cycle, in works the opposite.

[plaf26]

Wow!  Does the OmegaStar Differential Pre-amp/DAC have phono inputs and line outputs for a self-powered subwoofer?

Also does it have a headphone amp like my T8?

[dB Cooper]

maybe you have to wear two pairs of headphones 

[mateo]

maybe you have to wear two pairs of headphones 

Or drive them balanced recabled with a pair of XLRs, as is now standard...

[Wayner]

I'm not sure if the new Differential Preamp/DAC will have a headphone jack or not. I'm still waiting for Frank to finalize this so we can get the new faceplate going. We'll have to wait and see for the final outcome.

Wayner

[pardales]

I heard both the solid state and tube differential systems driving Salk speakers at AKFest this weekend. The systems sounded really, really good. The systems had very clear, relaxed sound I could have listened to for hours. I think Frank has something really fine going here.