[maty]

Audio by Van Alstine ABX Comparator Review, Part 1: Audio Store & Wiring by Doug Schroeder | April 2015

-> http://dagogo.com/audio-by-van-alstine-abx-comparator-review-part-1-audio-store-wiring






Audio by Van Alstine ABX Comparator Review, Part 2: Trials

-> http://dagogo.com/audio-by-van-alstine-abx-comparator-review-part-2-trials





Audio by Van Alstine ABX Comparator Review, Part 3: New Twists & Conclusion

-> http://dagogo.com/audio-by-van-alstine-abx-comparator-review-part-3-new-twists-conclusion

Addendum, April 20, 2015: In a conversation with Frank just before this article was sent off, I discussed with him my findings regarding the ABX Comparator and amps. As I had reached my conclusions in the article and he had not seen the finished article, I have not gone back to edit the article, but instead add the discussion here.

Frank gave insight about the uniformity of amplifier sound, noting that in his shop he uses two very different speakers, through which differences in amps can be heard. However, he noted that the differences are very subtle, and the speakers he uses are quite different; Philharmonic Audio’s Philharmonic 3 and Janzen zA2.1 electrostatic speakers. Recall that I commented that it would be expected for different technology and/or sized speakers to sound obviously different. This would shed light on my findings, that with nearly identical speakers amps could not be distinguished, but with Frank’s obviously different speakers they could...

[maty]

The AVA ABX Comparator Switchbox

-> http://www.avahifi.com/index.php?option=com_content&view=article&id=271&Itemid=238

[JoshK]

I just learned of this component.  Very cool.  I am super tempted, particularly more for speaker comparisons, but amps would be cool too. 

Just a quick question, as I didn't see it answered upon quickly skimming your review.   Does it has a built in tone generator for setting levels like the QSC ABX did?

Josh

[avahifi]

No - no built in tone generator.

We use a white noise CD track and a sound level meter to match system outputs for really serious testing.

However it is pretty easy to match levels by ear for quick testing in the system "lights off" mode.

Want more info?  Give your e-mail address and I will send you the complete user manual.

Frank

[danielgk]

The very first prototype had a built in tone generator plus dummy load plus test points for a digital multimeter.  It only worked properly when 1 set of speakers was used.  Once different efficiency speakers were involved, it was pretty much worthless as there was no way to measure the actual acoustical output from the speakers, and even if we had something it would be next to impossible to accurately account for left / right.  Since this approach didn't solve the problem for half the setups the ABX box could be used in, we decided to scrap the idea.  Good riddance.   


Dan

[avahifi]

The first two sections of the our ABX Comparator review has now been published at Dagogo.com

Here is the link:

http://dagogo.com/audio-by-van-alstine-abx-comparator-review-part-1-audio-store-wiring

The review is very long and is interesting reading.

By the way danielgk is our electrical engineer and he does great work for us.

Frank

[JerryM]

The very first prototype had a built in tone generator plus dummy load plus test points for a digital multimeter.  It only worked properly when 1 set of speakers was used.  Once different efficiency speakers were involved, it was pretty much worthless as there was no way to measure the actual acoustical output from the speakers, and even if we had something it would be next to impossible to accurately account for left / right.  Since this approach didn't solve the problem for half the setups the ABX box could be used in, we decided to scrap the idea.  Good riddance.   


Dan

By the way danielgk is our electrical engineer and he does great work for us.

Frank

Welcome to AC, Dan!

[acninja]

what is one of these babies gonna cost?

[tesseract]

I found the Comparator to very useful in a recent ABX amplifier evaluation, feeling that it gave me a good handle on what I was hearing.

http://www.hometheatershack.com/forums/home-theater-receivers-processors-amps/115674-home-theater-shack-2015-high-end-amplifier-evaluation-event-reporting-discussion-thread.html

[JerryM]

what is one of these babies gonna cost?

$999.00 USD.  http://www.avahifi.com/index.php?option=com_content&view=article&id=271&Itemid=238

Have fun,

Jerry

[maty]

Audio by Van Alstine ABX Comparator Review, Part 2: Trials

-> http://dagogo.com/audio-by-van-alstine-abx-comparator-review-part-2-trials

[poseidonsvoice]

Sorry if this has been answered elsewhere but is this an AB comparator or ABX comparator? The idea being that if you can determine which of the switch positions  correspond to A and which to B with significantly better than 50 % accuracy, you’re hearing a difference.

Nice Price!

Thank you,
Anand.

[Tone Depth]

See the AVA website:  http://www.avahifi.com/index.php?option=com_content&view=article&id=271&Itemid=238

Sorry if this has been answered elsewhere but is this an AB comparator or ABX comparator? The idea being that if you can determine which of the switch positions  correspond to A and which to B with significantly better than 50 % accuracy, you’re hearing a difference.

Nice Price!

Thank you,
Anand.

[DS-21]

The first two sections of the our ABX Comparator review has now been published at Dagogo.com

Here is the link:

http://dagogo.com/audio-by-van-alstine-abx-comparator-review-part-1-audio-store-wiring

What an unfortunate review for an interesting product!

The reviewer does not seem to understand the basic rule of experimentation: change one variable, keep everything else constant.

[poseidonsvoice]

What an unfortunate review for an interesting product!

The reviewer does not seem to understand the basic rule of experimentation: change one variable, keep everything else constant.

Agreed. Of note, there is a 'random' mode by reading the manual so there is that use for this product. So it is an ABX comparator, not just AB comparator.

Best,
Anand.

[avahifi]

The third installment of the Dagogo.com review of our ABX Comparator is now posted.

Here is the link:   http://dagogo.com/audio-by-van-alstine-abx-comparator-review-part-3-new-twists-conclusion

Some of you are not going to like the conclusions.

Anyway, if you are thinking about a $20,000 or $50,000 power amp, try ours first and save a whole lot of money.

Frank Van Alstine

[dB Cooper]

Frank, I suppose it is safe to assume that not only level matching has an effect but differences in clipping behavior between amps of different power being driven to similar output levels. Obviously the amp not clipping should sound 'better'. Last year at Capitol Audiofest I heard the very efficient Salk Exoticas driven by your 600R. It sounded like the amp was loafing at even the highest levels. I assume that, say, your 90W integrated heaving its guts out into, say, HT3's in a big room might be audibly struggling. No reflection on the quality of the integrated; just a question of the right tool for the task. Does this sound fair?

[Odal3]

That's an interesting product. Wish I will have a chance to test it one day.

The reviewer does not seem to understand the basic rule of experimentation: change one variable, keep everything else constant.

I guess that depends on what question you are trying to answer. Sometimes one wants to know how complete systems compares,but it looked like further detail was provided in the third part:
"Just as I had compared individual components, I also compared the amps in isolation, that is, with one set system of components, speakers and cabling, and only the amps being switched."

I think it would be great if the author or other reviewers would continue using the comparator - perhaps in the same way a referee sometimes resort to video playback to ensure the right call is made.

BTW: What is the the best way to level match? SPL meter set to C-weighting with the microphone facing up towards the ceiling at ear height in the primary listening position?

[Rusty Jefferson]

...BTW: What is the the best way to level match? SPL meter set to C-weighting with the microphone facing up towards the ceiling at ear height in the primary listening position?

The proper way to level match is with a volt meter at the speaker binding posts while playing a 1khz tone, or an oscillator tone.  We match it to +/-  0.003 volts.  You need a good volt meter, and hearing protection while you do it. We generally match in the .75-1.0 volt range.

Somewhat sadly, I'm being convinced that careful, double blind (and A/B/X) tests show that any 2 amplifiers that have flat response from 20hz-20khz, low output impedance, high input impedance, and are sized for the load (don't clip), are indistinguishable regardless of the cost. It's been a recent eye opener for me.

He's been saying it for years, I needed to literally hear it for myself.
http://www.theaudiocritic.com/audio-legacy-2/

[R Swerdlow]

The proper way to level match is with a volt meter at the speaker binding posts while playing a 1khz tone, or an oscillator tone.  We match it to +/-  0.003 volts.  You need a good volt meter, and hearing protection while you do it. We generally match in the .75-1.0 volt range.

That works if comparing different electronics while the speakers are the same.  But you'll need a SPL meter when comparing different speakers.

Somewhat sadly, I'm being convinced that careful, double blind (and A/B/X) tests show that any 2 amplifiers that have flat response from 20hz-20khz, low output impedance, high input impedance, and are sized for the load (don't clip), are indistinguishable regardless of the cost. It's been a recent eye opener for me.

An amplifier designer named Bob Cordell once was asked whether all solid state amps sound the same.  His answer:

"No, because they all misbehave differently.  However, well-designed SS amps operating well below clipping, that are not misbehaving, and which have high damping factor across the band, will tend to sound the same."

See the entire interview http://www.helarc.com/guru/guruscordell.htm

I'm not an EE, but I get the impression that Frank Van Alstine might agree with most or all of what Cordell said.