Can anyone validate my subjective findings?

[rdenney]

Good info, given that old SAE amps are class HG, they are a lot more efficient then AB amps, I can't be motivated to go to Hypex unless someone tells be I will hear a big difference especialy using active crossovers and 3 stereo amps..

You won't hear a big difference (or really any reliable difference) between Hypex modules and any other competently designed amp, as long as you operate it within its design envelope, meaning not current-starved from difficult loads and not clipping from being overdriven.

But if you are driving that many amps using active crossovers, then you'll appreciate the form factor and power efficiency of the better Class D modules.

Rick "which is why ATI started using them from high-channel-count amps" Denney

 

[Jim Taylor]

I wish I could, but with my limited knowledge, I have to go imperical manipulations.

You can learn more. The members here have shown themselves as being willing to help you do that.

Jim

 

[Theta]

You can learn more. The members here have shown themselves as being willing to help you do that.

Jim

Of course I meant to say "technical Knowledge" Jim. That is why practicaly all my post are in the form of a question. Here are 2 things I have learned so far: 1) Why would anyone bother with passive speakers? 2) Why would anyone buy a 15000 dollar Dac? 3) Why would anyone buy a tube amplifier?

 

[SIY]

True, but I have one of his Vendetta preamps and it has been in service for most of those 50 years and is still working to spec.

I have one as well that I repaired for a friend and will (one day) drive it back to him. Performance is OK, good enough for phono. Of course, it's not hard to design something with an order of magnitude better performance at an order of magnitude lower price...*

*I will confess to publishing two phono preamp designs which will outperform a Vendetta but at level of expense far higher than they needed to be since I used tubes for voltage amplification. So mea culpa.

 

[Jim Taylor]

Here are 2 things I have learned so far: 1) Why would anyone bother with passive speakers? 2) Why would anyone buy a 15000 dollar Dac? 3) Why would anyone buy a tube amplifier?

Which two of those three things have you learned so far?

Just teasing you, @Theta . I've done similar stuff.

Jim

 

[MaxwellsEq]

Low output impedance of an amplifier does not automatically mean that the amp is capable to deliver the requested (maximal) current to the load.

That's indisputable.

 

[tjf]

True, but I have one of his Vendetta preamps and it has been in service for most of those 50 years and is still working to spec.

"SIY said:
John is purely a huckster. He's been flogging the same circuit for half a century."

So -- do we paint JC (interesting initials, no?) with the broad brush of criticism and disdain because he makes a living in his final years letting Parasound (the "Pacific Stereo" Richard Schram's Parasound) use or "license" his FET designs in various "High End" Halo "JC" preamps/amps?

I say YES!

Don't forget -- when he was producing the "Vendetta" products in the early 80s -- he also designed and lent his name (for a fee) to a high end electronic X-over design for the "Symmetry" brand (also sold under the "Vendetta" label) -- Symmetry was made/run by one Noel Lee of Monster Cable -- the Symmetry line also had a large passive radiator subwoofer from VMPS -- and a Symmetry branded set of electrostats from Roger West and Sound Lab -- sold as a Stat/Sub/Xover package back in the early 80s...by...Monster Cable!!!!

 

[SIY]

So -- do we paint JC (interesting initials, no?) with the broad brush of criticism and disdain because he makes a living in his final years letting Parasound (the "Pacific Stereo" Richard Schram's Parasound) use or "license" his FET designs in various "High End" Halo "JC" preamps/amps?

No, we paint him as a huckster because he's a huckster. I know John quite well, and have for over 20 years. His licensing deal with Parasound for the use of his name is irrelevant to that.

 

[Mr. Widget]

Performance is OK, good enough for phono.

I think we often lose sight of what is important for an intended application. Can virtually anything be improved upon? Generally yes, but at what cost?

I particularly appreciate stable performance and long term reliability. Aesthetics, human factors, and products that are nice to the touch are also appreciated... a $10 plastic box with stellar electrical performance but unlikely to maintain that electrical performance over time is of no interest to me. Filling up the world's landfills with cheap junk while it may keep people employed, is not sustainable.

 

[Schollaudio]

I use Chevin and Ashly MOSFET amps. The Chevin is all around great sounding and the Ashly is great on top boxes, good but not great on subs. I use the Chevin on subs and the Ashly above 80hz.

I borrowed an SAE amp and preferred the Ashly on a 15" 2 way.

I use class D amps on the upcycled Snell E4s with very good results. Have not tried an Ashly

I used to use a cheap DIY class D on the outside system but we had a neutral failure on our power inlet that blew it out. I replaced that with an Ashly with notable improvement.

 

[AuricGoldfinger]

Of course, A double blind test would be ideal, but too difficult to set up for every piece of gear mentionned.
As a non technical person, I was intriged the many discutions by the "amp design gurus"(John Curl, Nelson Pass and a few others recent like the engineers at Shitt Audio)...

You don’t need a team in lab coats to set up the test. You can simply use a voltage divider on each channel to connect the device under test to an audio interface. I use approximately 1200 Ohms in series then a smaller resistor to drop the level and record from the output of an amplifier, while it is also driving the speakers directly. If the amplifier is class D balanced drive, this method however cannot be used as described. Thereafter, you may record anything, from test signals to music programme, which may then be AB tested in a music editing program, even Foobar 2000.

P.S - Be careful of gurus and their claims. Being famous in the audio niche does not automatically make one correct. No one is above reproach.