2. amps-preamps
  3. 1353688456

Merrill Audio VERITAS Amps: Any other experiances?

Despite the Sandy Hurricane interruptions, Merrill was kind enough to provide me the opportunity to audition his Merrill Audio Veritas Mono-block amps with my system. He delivered the amps and I listened for approx 48 hours over a period of three days. It should be noted that never once in this time frame did I or anyone else listening experience listening fatigue.

The Veritas units were temporary replacements for my ARC VTM200 MONO-blocks and other than a short experience with my neighbors ARC 610 Mono-Blocks which really brought my Maggies to life, it was a reawakening as to what my Maggies can do given sufficient power. It's not that the VTM200 don't do a good job, its that financially, moving up with more powerful tube amps is out of the question.

Basically , I was overjoyed with what I was listening to. With the Veritas supplying 700 watts per channel vs the 200 tube watts, which is fundamentally 3 and one half times the power I had been feeding them, it was the first time I heard the Maggies with the power they were recommended to be supplied with other than the 610 experience. It should be noted that every piece of electronic audio equipment I have is TUBE centered. The presentation of the Veritas into the system was the first time a pure solid state unit had been introduced to the system and the lasting impression was WOW...just like the web site stated!

We listened to vinyl as well as CDs...Jazz and full orchestration as well as solo piano, cello and violin. Beside myself and occasionally my wife, the listening panel included Blaine Handzus of the NJAS as well as an interested neighbor along with Merrill.

If and when I replace the ARC VTM200s, the Veritas would be at the top of the list.

Having heard Class D amps at other systems, I had never been totally satisfied with what they delivered but the Veritas units presented a completely satisfying and different audio presentation. In short, the 'you are there' effect the Maggies are famous for with the proper watts was stunning.

Simply put, the Veritas are an audio achievement, with extremely accurate front to back definition as well as a superbly accurate soundstage presentation. The holographic effect of instrument position within the orchestra was excellent.

But more to the point, the sounds of the instruments themselves were very accurate. My wife, who listens to live music on a daily basis, both strings, keyboard and horns made the comment that she "could hear the cellos and violas breath".

It was a sad hour when Merrill came back to take his amps away!
128x128jafo100

Showing 3 responses by dan92075

dan92075
23 posts
 
I was curious so I looked up Brostrom (Abletec) patent applications

Earlier these were touted as a new revolutionary class D design

Here are some of my observations:

1). the design clearly still relies on feedback, contrary to earlier assertions
(as a side note, is it even possible to do something as nonlinear as Class D without any feedback?)

2). it appears the design still relies on pulse width modulation

3). it does seem that he is using some similar principles to ncore in not allowing his feedback filters to saturate - he is doing it a slightly different way - limiting the gain - cant say which technique is best but they both are addressing the same key issues it appears

At the end of the day, this seems like an improvement over the existing art but certainly not as revolutionary as was claimed earlier - and also would not jump to the conclusion these are better than ncore - definitely a listening test would be in order
dan92075
23 posts
 
Audiozon,

His patent application lists him as Patrik Brostrom of Abletec, I will take your word for it that is a typo and he is Patrik Bostrom of Abletec.

But one thing that is absolutely clear from the diagrams in the patent is that his design uses pulse width modulation. In fact, google it and read the patent yourself - he actually says himself he is presenting a new way of doing pulse width modulation.

I think perhaps the confusion is that for the feedback and input structures that feed the Class D switch, he uses a phase shift modulation.
This is actually not novel - this is described in papers 7 years old by Bruno - and I doubt he invented this either - its probably been around for a long time.

But at the end of the day all Class D amps are a switch to a positive voltage rail and a switch to a negative voltage rail followed by a LC filter, switching around 400-500kHz speed. The only way to create the desired audio signal is to pulse width modulate the switches.
The art is in how you space out the switches to create the best quality audio signals - what kind of feedback scheme you use, how you modulate the input, etc

You peaked my engineering curiosity though that this may be something radically new - even though it was not it was fun to look into! :)
dan92075
23 posts
 
Audiozen,
The Bel Canto amplifiers that are replacing the power module with a linear supply instead of a switching supply are still keeping the class d amp the same module.
This means its a class D pulse width modulated amplifier.

I wish you would stop claiming that every new class D amp is no longer a pulse width modulated amplifier - pulse width modulation is pretty much intrinisic to a class D audio amp.
More to discover