# Van Alstine ABX Switch for Two Systems



## Sonnie (Apr 11, 2006)

Frank Van Alstine has finally released (or taking orders for builds) his second revision of the ABX Switch box, which is suppose to be the king daddy of ABX switching. It sure looks promising. We have looked at one for doing some AB testing between various pieces of equipment. I figured while it is lying around, perhaps I can put it to good use.

View attachment Van Alstine ABX Switch Manual Rev2.pdf


I am thinking about using it to run two systems with a different source, preamp and subwoofers between the two systems, but use the same amp and main speakers for both systems.

The music system would be sourced from the music server output to a 2.1 channel preamp, which would output to input A of the ABX box. The 2.1 preamp would also run preout to two individual powered subs (possibly a pair of SVS SB13-Ultras) that would only be used for music, crossed over at about 40Hz. I will use JRiver to equalize this system.

The movie/TV system would be sourced from the OPPO and DIRECTV units output to the Onkyo 5509, which would have the L+R Front speaker preouts running to input B on the ABX box. The Onkyo also feeds the other surround and sub channels directly. Audyssey will be used to equalize this system.

Then I will use one of the ABX preouts to the L+R input channel of the Emotiva XPR-5, which will be powering the MartinLogan Montis. This way I can switch between 'A' (music system) and 'B' (movie system) using the same amp and main front speakers for each system, however be able to also use different subs for each system.

With this setup I will not use any of the speaker terminals on the ABX box. Only two inputs and one preout (pairs L+R).

There is one potential issue that I see... as it is right now, when I switch between sources, such as between the OPPO and the server, one or the other source is no longer output from the Onkyo, there is no output from that unused source. The switching is all contained within the Onkyo. When I setup the new dual system and I switch between preamps on the ABX box from the Onkyo to the 2.1 preamp, at that point the center, surround and sub channels are still being output from the Onkyo, because they are not routed through the ABX box... so they are still playing (that is if I still have the DIRECTV box on or the OPPO playing a disc). I suppose the easiest solution might be to setup a macro program with the remote to have the Onkyo switch to an empty source input when I switch to the 2.1 preamp, so that the movie subs and surround speakers will no longer be output. Then setup a macro to switch back to the appropriate input as necessary when going back to the Onkyo. I am already going to have macros setup anyway for switching between the two.

Anyone else see any other potential issues with this setup?

Sorry to pick your brains so intensely to trace the inputs and outputs, but hoping someone can confirm the routing and connections. The manual link above will show you the inputs/outputs.


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## NBPk402 (Feb 21, 2012)

Why not just set the input on the AVR for Stereo and use that one for stereo only listening?


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## Sonnie (Apr 11, 2006)

That is what I am doing now, but I can't run different subs with my mains this way. I am looking for a way to be able to use different subs for music than with movies.


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## NBPk402 (Feb 21, 2012)

Sonnie said:


> That is what I am doing now, but I can't run different subs with my mains this way. I am looking for a way to be able to use different subs for music than with movies.


How about getting a second ABX switcher for the subs?


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## Sonnie (Apr 11, 2006)

A second one? I don't need another one... I also don't want the processing of the subs thru the Onkyo. I want to create my own equalization for music.

This isn't really about finding an alternative... I am simply wanting to make that I am not missing anything in the connections. We will have this unit for testing, so if I can put it to use while not testing, may as well.


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## ajinfla (May 10, 2009)

I was going to nominate this for "Most bizarre use of an ABX box, evah..", but I figured, hey, if you own it and aren't doing ABX at the time, why not put it to use.
However...



Sonnie said:


> That is what I am doing now, but I can't run different subs with my mains this way. I am looking for a way to be able to use different subs for music than with movies.


Is this the main issue? I'm way to simple to figure out the connection/routing entanglement scheme you described above, so...
If it is, then it seems to me, that a simple, remote line level switch for your Onkyo sub outs would do the trick. Am I missing something? Are the HT subs crossed higher than 40hz?
Have you been reading my ramblings about stereo bass, or better yet, perceptual research regarding LF reproduction in rooms? 

cheers


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## Sonnie (Apr 11, 2006)

No doubt it is bizarre.

Yes... different subs are the main issue. While I can live with it like it is, I think I can improve on the bass with music by having a slightly different placement of the subs. Also I take the sub level for movies out of the picture, and I can introduce my own equalization for music, which I could probably do that with JRiver and the current subs.

No... where are your ramblings about stereo bass at? What I have in mind, and based on the testing Wayne and I did with the SVS sub for music a while back, this new setup will basically give me more of a stereo subs setup.

Most of the line level switches I have seen have several inputs and one output, where I would need one input and two outputs. Are these line level switches bi-directional?


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## ajinfla (May 10, 2009)

Sonnie said:


> Yes... different subs are the main issue.
> 
> Most of the line level switches I have seen have several inputs and one output, where I would need one input and two outputs. Are these line level switches bi-directional?


No remote, but: http://www.parts-express.com/rolls-ss32-miniroute-3-passive-stereo-signal-switcher-3-in-1-out--245-1180?utm_source=google&utm_medium=cpc&utm_campaign=pla

cheers


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## Sonnie (Apr 11, 2006)

Useless for this scenario... plus I gotta spend more money to get it.


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## ajinfla (May 10, 2009)

Sonnie said:


> Useless for this scenario... plus I gotta spend more money to get it.


Eh? It's <$60 and would allow you to switch between subs, manually of course. I just read it and indeed, the text is confusing (wrong actually), but you input your Onkyo sub outs into the "Common" and then switch between either A, B or C outputs.
You've experienced it doing exactly that .

cheers


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