If only! My Quads have pretty much 4 ohms in the bass, 8 ohms in the mid, and 2 ohms in the treble (falling to 1 ohm at ~18KHz). The current required in the treble will be 4x that of the mids (8x at ~18KHz). Of course, this assumes all sorts of things which I'm sure aren't really valid... reactive vs. capacitive loads, etc.

Another complication with my Quads is that being electrostatics, they are not driven by current but by voltage. The Soulution outputs 31V RMS, which I'm sure is fine for 'normal' magnetic speakers. My Magtech outputs 62V RMS, which the Quads should prefer.

EDIT: This voltage I guess is dependent on the operating voltage of the amp. High voltage parts are more expensive, so it's not in an amp manufacturer's interest to have a high operating voltage... unless they were designing an amp for electrostatics 

Mani.

Hi Adrian, thanks for this - much appreciated. I've looked into Audionet before but have never heard any of their gear. I remember the owner of Wilson Benesch recommending Audionet with my then Chimera speakers, which were hard to drive. I'm not sure how easy it is to get hold of, and sell if/when necessary, an Audionet in the UK.

From a purely technical point of view, I guess what I'm looking for is the following:

- high voltage output (is there any other good audio amplifier that operates at 90V and not 30V?)
- at least 100W into 8 ohms
- power that doubles with every halving of impedance (down to at least 2 ohms) - to keep control at frequency extremes with the Quads
- ~500V/µs slew-rate (and therefore high bandwidth) - although many people would say this is 10 times higher than is necessary...
- low THD* at 100W ouput
- something that won't depreciate massively and that I can sell if/when necessary

* Unless it's a true single-ended output amp. You see, you can theoretically reverse the speaker polarity and use the amps HD to cancel that of the speaker, which should have a similar HD spectrum to a single-ended amp. But, I've never come across a single-ended amp that has all of the other requirements above.

Any thoughts anyone?

Mani.

A slightly different topic, but I think I'll keep it in this thread...

Yesterday, I was testing some other old amps that I have lying around, and I ran out of interconnects. I went down to the basement and pulled out the only pair of XLR interconnects that I could find - 'PureNote Epsilon' interconnects. These have ultra-high purity silver conductors housed in a stiff a metal sheath. I bought these ICs years and years ago, tried them, didn't like their forward/bright sound and put them away for I guess 8-9 years! I convinced myslef that silver was a bad metal for audio. But you know what, they sound incredible now, with much better low-level detail than any other ICs I have. And they just sound 'faster' - better transients and overall boogie factor.

Does anyone have any idea as to why a silver cable might sound 'faster' and more detailed than a copper cable? I'm not sure I buy into the simple "better conductivity" argument, because you can always just increase the amount of copper in a cable for significantly less cost...

Mani.

Hey Peter, thanks for your thoughts. I know you're busy, so appreciate your spending time on my 'obsession'.

I don't think 130W into 8 ohms is a problem - the Magtech is 500W into 8 ohms.

Actually, I think the slew rate is 31V/0.33µs = ~90V/µs. Now the Magtech operates at plus/minus 92 volts and is quoted as having a slew rate of 500V/µs. The operating voltage becomes important when considering an amp for electrostatics because these speakers are 'voltage operated devices'.

Now this is where I'm getting a little confused. In the recent Stereophile review of the 710, John Atkinson ends his measurements by saying, "... the Soulution 710 is definitely one of the best-measuring amplifiers I have encountered." I've attached some of his measurements - any comments about these?

Incidentally, the Magtech's noise is also rated as, "More than 110dB below rated output."

Yeah, but I need an amp that will drive my Quad 2905s 'properly'. On paper, they're pretty benign. But their impedance dips sharply at the frequency extremes and I'm sure that this is why they sound woolly low down and too smooth up top with most amps. But the Magtech seems to cope very well.

I think with your help, I'm on the road to convincing myself to buy another Magtech... and save >10K UKP! Thank you!

But any additonal thoughts (from Peter or anyone else) would be really welcome. I have to make a decision as to whether I buy the Soulution pretty quickly.

Cheers, Mani.

That's the problem with summer. I usually have a few weeks off work and try to spend as much time at home as possible. But on Thursdays and Fridays, my wife goes to work and my 20-month old son goes to nursery. I'm at home... with way too much time on my hands...

My two NOS1s should be back at some point and I'm eager to get everthing ready for them. One of the tasks is to get an ultra-fast amp sorted for my office system, with my small Quad electrostatics. I've been looking at some possible solutions, but the one that I keep on coming back to is to simply buy another Sanders Magtech amp for my office, just like the one I already have in my main room, with my big Quad electrostatics. I've tried a number of amps in my main room now, and none of them sound as good as the Magtech with the Quads. The sound comes alive with the Magtech - it's 3-dimensional, tight and really quite dynamic (for electrostatics at least).

But buying an identical amp just seems too boring. So the search recommenced today. Of course, this is nothing new for me. I've been at this before (http://www.phasure.com/index.php?topic=1274.0). But this time, I'm looking for a real end-game, so that I can focus on other elements of my system. Anyway, to cut to the chase, I have an opportunity to buy a used (but absolutley mint) Soulution 710 amp (http://www.soulution-audio.com/en/serie7/710/index.php). The idea would then be to put the Magtech in the office (with the small Quads) and the 710 in the main room (with the big Quads).

But even used, the 710 will cost me 14K UK pounds! Now, I'm not a rich man and this is a totally absurd amount of money for me. But, I can just about afford to buy it without putting my family in a state of total poverty.

Someone... anyone... please give me a compelling arguement as to why I shouldn't do this. Please...

... but you've got to convince me that the USB-NOS1/710/Quad combination won't be heaven on earth, because I'm totally convinced it might well be.

Mani.

Hi Lee. I'm assuming you've read my thoughts on the NOS1 (original) vs. the Pacific Microsonics Model Two here http://www.phasure.com/index.php?topic=1549.0?

I've got a couple of potentially really important caveats to my thoughts though:

1) I've always been aware that my Model Two was one of the earlier ones, used as the in-house demo unit by PM for a couple of years. But I've recently learned that my unit is actually a pre-production unit. Some people believe that the later 'Euphonix' units sound better than the earlier PM units. However, Dave Peck (production manager at PM, now at Avid) assures me that my unit meets all the PM2 standards... and his measurements confirm that my particular unit has state of the art ADC and DAC performance).
2) I don't have a Mykerinos card, considered by some to be the best way of interfacing a Model Two to a computer. Nor do I have a Lynx AES16. Rather I use either a Weiss AFI1 firewire unit (upgraded with a linear Paul Hynes PS) or an RME AES-32 PCI card. I've done extensive tests comparing the 'direct' ADC->DAC path with the 'indirect' ADC->computer->DAC path. I'm convinced that the PM2 itself set to 24/192 is pretty much completely transparent. However, I'm not sure that either of my AES interfaces are completely transparent.

With these caveats in mind, my thoughts in the aforementioned thread stand 100%. The NOS1 is a better DAC than the PM2. Not just my thoughts, but the thoughts of others who have compared the two at my place also.

Oh and by the way, cut out the cr*p about marketing. If you knew Peter, you'd know that he's not like that. And of course, it's totally against my interest to be potentially eroding the market value of my own PM2!

EDIT: Forgot to mention that I have three Zalman TNN300 PCs. Two with Gigabyte cards (with an E8600 and an i7 - the latter a total bugger to fit and get working in the TNN300!) and one with a Asus PQ5-EM (with an E8600).

Mani.

In the past, I've blown up the bass drivers of pretty expensive speakers a couple of times playing the 1812 SACD. This has artificial (I believe) cannons that really are waaaay too loud compared to the 'real' music. I think this sort of dynamic range is ridiculous. The Reference Recording 24/176.4 that I cited earlier (DR 15) is verging on too much DR for practical listening (especially because the very dynamic bits are pretty low frequencies).

I tend to agree with the PMF guys - a DR of 14 is a good target to aim for for (non-techno/dance) music.

EDIT: From the PMF site - "Because of the not considered macro dynamics, values higher than DR14 doesn´t make much sense."

Mani.

Chris, you've no doubt already looked at the link that Russ provided. But just in case you haven't had a chance to yet, here is the main description:

"The DYNAMIC RANGE METER displays the inner dynamics of a recording in whole numbers or more precisely the inner grade of compression (micro dynamic). The macro dynamic (difference from pianissimo to the fortissimo in a song) is not considered, because it wouldn´t deliver usable information about the degree of density.

... this is the average cumulative difference between peak and loudness (RMS) over a specific period of time (duration of a song or album) and is a whole number value given in decibels. Just the top 20% of the loudness are taken into consideration to ensure that songs with a long intro and and over compressed refrain doesn´t appear with a too high DR value."

The highlight is mine.

So it's not the difference between the loudest and the softest but rather the loudest and the RMS, which is a more useful number... and also explains why it's nowhere near as high a number as the actual medium can accomodate (e.g. 96dB for CD).

Mani.

Hey Russ. I was an SACD early adopter and actually have the following DMP titles on SACD:
- DMP Does DSD
- Manfredo Fest, Just Jobim
- Beck & Ryerson, Alto
- Flim & The BB's, Tricycle
- The Steve Davis Project, Quality of Silence

I don't own a very good SACD player anymore (I never liked the sound of SACD), but it might be fun to transfer these to PCM (via the analogue outputs - I don't have the time or inclination to get a DSD stream out of a PS3 working) and see what their respective dynamic ranges are.

Meanwhile, will let you know if I come across anything with a DR>23!

Mani.

Haha, my vinyl recordings have a higher dynamic range than most of the hires downloads I've purchased!

Mani.

Yes, the CD is louder.

HOWEVER... this has nothing to do with the hires having a very loud peak or anything. It just doesn't have any louder peaks than the CD. I'm assuming that if you have 24 bits of resolution to hand, you simply don't need to go anywhere near the peak limit. With 'only' 16 bits, it becomes a bit more necessary.

But really, 96dB is already a lot. Even the best vinyl played on the best turntable would come nowhere near this!

The highest dynamic range I have come across is indeed the 1812 on SACD. I will attempt to transfer this to 24/192 and see what the dynamic range comes out as. But for now, here's the dynamic range on a Reference Recording 24/176.4 transfer from analogue tape.

EDIT: I don't think you'd want more dynamic range than a recording of a tom tom drum I have.

Mani.

OK, last analysis from me 

The CD rip has a higher dynamic range than the hires!!!

Mani.

There are just so many of these versions going around! But I believe I have the same one that Chris has. Now if you compare the CD waveform that I posted earlier to the one attached below, you'll see that both seem to have a similar dynamic range, although the hires has a lower SPL. I've tried to adjust for this lower SPL in the second attachment (using a simple zoom) and if you align the two jpegs, you'll see that they're virtually identical.

I prefer the sound of the CD rip to the hires. I now agree with Peter that the tapes must have deteriorated in the last 20 years or so.

Mani.

Hi Chris. Yes, I'll post my thoughts there.

Having listened to both for a while now, I'm not sure I would continue to say that the CD version sounds 'more digital'. Rather, I'd say it actually sounds a lot cleaner... and way more life-like.

I'm kind of coming around to Peter's thoughts that maybe the tapes had deteriorated quite a bit between the original 1987 digital remastering and the latest 24/192 one. Also, it occurs to me that the Sony PCM1610 used for early CD remasters couldn't have been that bad...

Mani.

Looks like I have the same version as Chris. From the attachment you'll see that there's no compression.

Peter, I think we have the original version and you have a (very-well) remastered version...

Mani.