2. amps-preamps
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Please tutor me on some integrated amp basics.

I’ve recently purchased Magico A3 speakers and a VPI Classic 2 SE turntable with an Ortofon Black 2M moving magnet cartridge. I have a Marantz SA 8005 CD/SACD player to play the few (maybe a hundred or so) CD’s in my possession.
I’ve mostly vinyl albums and no streaming sources. I’m next going to upgrade my old amp/preamp purchased back in the late 70’s with a new, probably integrated, one and am starting to do some research.

Here’s where I need some tutoring. A lot has changed since the seventies with the advent of digital technology. As well as I need to learn more about amplification components in the high end of audio technology. I keep running across terms I don’t understand. I’ll give you a list and if someone would be kind enough to explain these basics I’d be obliged.

For instance I was reading about the Hegel H360 integrated amp that Magico’s Alon Wolf recommended for their A3’s. The review mentioned they were a Class A/B amp, another person commented Class A’s were better, and a third person said he didn’t care for Class D amps. What do these classes signify? 

A second question is about DACs. I generally understand their purpose of the DAC, converting a digital to an analog signal. However my only digital device, the Marantz SA 8005 already has a DAC, ostensibly of good quality. The turntable ’s Ortofon cartridge would not need to play through a DAC, I presume. Would I bypass the CD’s players DAC if I purchase the higher quality Hegel H360 integrated amp?. Or could I find an equivalent integrated amp without an integral DAC?

On the other side of the equation I understand the turntable’s cartridge cannot play through the Hegel without first going through a phono stage. My old Phase Linear 4000 preamp you just plugged the turntables RCA cables into the back of the preamp and you were done. What’s that about? Do they make equivalent integrated amps to the Hegel H360 with integrated phono stages already in place, so I can just plug my turntable in as I’ve been able to do before. The amps don’t seem to be well integrated at all if you have to add a pricey phono stage to make them work, and end up having an extra DAC. That’s just me whining.

Third question is what are monoblocks, how are they used, and what are their advantages to a system? They were used at one of my speaker auditions.

I figured out the answer to what amplifier damping was myself, so I’m sparing you that one, but what does the term impedance mean? I keep coming across that.

Thank goodness I don’t have to figure out the cabling nightmare yet. Thanks for any help.

Mike
skyscraper

Showing 8 responses by terry9

terry9
931 posts
 
It's all about bang for the buck, as assetmgr said.

I suggest that you include a record cleaner in your budget. Perhaps the best bang for buck. I went to ultrasonic.

Least bang for buck, IMO, is cables. I went to the trouble of building theoretically optimal interconnect cables (virtually zero capacitance, virtually zero dielectric absorption, gold plated fine silver) inside a Faraday cage cabinet (for noise rejection), and found them no better than star quad microphone cable (Canare, Mogami) with decent termination (ETI, Klee).

When you open up a high priced component, you'll see why - they use internal wiring which is no better than microphone cable in terms of noise rejection and dielectric absorption, and very little better in terms of capacitance, three key physical properties. I suggest that you buy cheap, real cheap, and upgrade only when some one can demonstrate a better sound in your system.

Let the hate mail begin.
terry9
931 posts
 
Mike, I really do mean cheap, as in $10 or $20 a pair. $100 max. You can just laugh and throw them away when someone demonstrates better.

I run a six figure system on premium microphone cable and ETI connectors, maybe $75 a pair to solder up. Speaker wire is a special case for me, but when I was using stock speakers, I used Goertz speaker cable at about $10 / ft. Current system is vinyl and ESL.

Exotic power cords are bettered by an isolation transformer, IMO.

Yes, US cleaning makes a big difference. I use a German commercial unit made by ElmaSonic (80KHz) and a spinner made by Vinyl Stack. The difference between cleaning with the VPI 16.5 (now sold) and US is about equivalent to moving from $5000 speakers to $10,000 speakers. Not to mention wear on your stylus. IMO. YMMV.

Good luck!
terry9
931 posts
 
@kosst, a very clear post. Nicely put.
terry9
931 posts
 
Chinese quality

The Quad ESL's are now made in China; I bought some. As soon as they were out of warrantee I opened them up to take a look and begin to modify. I couldn't help but notice the build quality. 

The Quad 2805's were a bit rough, but the 2905's were of good fit and finish. Parts quality was pretty much as it always had been, that is, could be better. I made it better, it sounded better.

Not all Chinese stuff is junk. Quite a lot of it is quite good, as the Quads testify.
terry9
931 posts
 
RE Chinese theft

If I remember correctly, the Chinese were handed modern technology with aerospace deals under Reagan. It was all in the open, above-board and, what must now be obvious to everyone, was not to US advantage.
terry9
931 posts
 
You describe serious issues with power, Mike.

I have reasonably good power out of the wall, but even so I use Siemens in-panel surge protectors as well as isolation transformers. You could probably do with lightening arrestors as well. Talk to a local electrician.

The thing with isolation transformers is that they hum when they are doing their job, which is protecting your equipment. So they should be sited outside the listening room, perhaps beside a sub-panel. Plitron makes a good transformer, and they sell to the public.

Turntable add-ons are typically low power, so completely unsuitable for isolating an amplifier. TT motors are all over the map. Some are single phase, some are multiphase, some are DC. Multiphase and DC need their own controller, which can be as simple as a phase-shifting capacitor, but can be (and should be!) quite complex. A universal TT box might be a regenerator, or a constant voltage transformer, or just a few inductors and capacitors. In any case, unsuitable for an amplifier.

All power sources have imperfections, like a distorted sine wave for AC. The only question is how much. So if you are considering a regenerator, look for a picture of the "sine" wave produced, like an oscilloscope trace, and see how much it resembles the classic sine wave from your calculus text. Also look for specifications like total harmonic distortion (THD).

Considering your situation and your coming investment, I think that your first priority should be power conditioning. You are wise to think of it when most would not. Good luck!
terry9
931 posts
 
One more thing about isolation transformers: they replace the need for lesser devices such as exotic power cords or regenerators.

I did the experiment years ago. 5 conditions: Isolation transformer alone VS isolation transformer plus exotic power cord VS isolation transformer plus regenerator  VS  regenerator alone VS  exotic power cord alone.

The results were: first three conditions indistinguishable, then a step down to regenerator alone, then a big step down to exotic power cord alone. This was good evidence that the isolation transformer made the big difference. The electrical inspector opined that the circuits protected by the isolation transformer provided power as clean as any he had ever seen, even at the power plants of major utilities.
terry9
931 posts
 
@cleeds 

I should have said, "TEND to hum ..."
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