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Advice for Beginners - consider this test from an audio club


ODS123

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2 minutes ago, Marvel said:

Longevity... the new tubes are rated to last about 40,000 hrs. At three hours a day, that would get me close to 40 yrs. You can get Chinese versions for $150 and up... , but they may now last as long. So ou can go from $150-$700 a tube. My 2A3s run about $80... and I haven't had to replace them in 10 years. Everything wears out at somepoint. Have you used your SS gear for 20-40 years? Probably now.

 

I wasn't referring to the tubes specifically.  ..I was referring to the amp in general.  ..What happens when a firm so small and so exclusive decides to close shop.  What happens to those who have their $60k (or whatever) amp and it needs repair?  

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6 minutes ago, ODS123 said:

 

I wasn't referring to the tubes specifically.  ..I was referring to the amp in general.  ..What happens when a firm so small and so exclusive decides to close shop.  What happens to those who have their $60k (or whatever) amp and it needs repair?  

 

=== in the heyday of audio buying/selling/trading i.e. the past 20 Audiogon years, how many “boutique” makers of amps and speakers do you suppose have come and gone? I’d venture more than you can count on your fingers and toes. As a consumer you take your chances with the flash in the pan newbies or as you did buy (Mcintosh) from decades old and time proven makers. Is it no different in any consumer purchase - buyer beware?

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13 minutes ago, richieb said:

 

=== in the heyday of audio buying/selling/trading i.e. the past 20 Audiogon years, how many “boutique” makers of amps and speakers do you suppose have come and gone? I’d venture more than you can count on your fingers and toes. As a consumer you take your chances with the flash in the pan newbies or as you did buy (Mcintosh) from decades old and time proven makers. Is it no different in any consumer purchase - buyer beware?

 

You are correct, of course.  ..But owning a pair Spica TC-50 speakers or a B&K 202 amplifier after those companies closed (as I did) wasn't terribly painful.  ..But after buying a $60k amp?  Yikes.  And yes this is partly why I gravitated toward brands like McIntosh, Klipsch, and Technics - all of which have been around for 40+ years.

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1 hour ago, ODS123 said:

 

Well, they were "Created For those of taste and distinction"  Curiously, they do not offer a pre-amp, apart from a phone pre.  

 

I'd be worried that a company with such incredibly low volume and small target audience is apt to fold and leave owners without a service network or available replacement parts.  In which case you have a very attractive boat anchor or expensive ammo for your trebuchet.

 

Beyond the Galactic Absurdity of a $62,000 pair of mono power amplifiers, ........

 

It sure it pretty!  I wonder it it is a flexible in torsion as it looks like it is? 

 

Most amps, whether tube or SS, use off the shelf components that will be available dozens of years later.  This is much like bus or semi-tractor.  Any competent electronic tech should be able to find and replace bad components.  I have a Technics SA-200, bought in college in 1979, and an SA-300 in daily service.  Both still work, correctly.  Surprisingly, the STK amp chips they use for output are still available, 40 years later.   I had a tech go through the SA-300 and clean, replace the caps, a transistor and a few resistors.  All of the parts were easily available, but I think he used caps of different physical sizes in a few places. 

 

No need to fear repairs for your Galactically Absurd power amp. 

 

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My mistake.  Corrected.  I suppose they are now half as absurd. 

 

Sad part is, if they were made the same and priced at $2k, the sound would suck and Stereophile wouldn't even test them.  If you can't brag about the price in audio, it is not good. 

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I believe the stereo model with a single 300B per channel is going to be about $5k. Those will be a far easier sell than the 91A models.

 

@JohnA   Want to go with me when I can arrange a tour? We can ask all the absurd questions.

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O.K.,  I don't know much about the electronic end of audio, so I'm confused.

  • The Western Electric mono-block is rated at 80 watts, RMS (or "RMS"), but the meter goes up to 600 watts for the highest peak.  (7.5 times the "RMS" power).
  • Back in 1977, a revised Dope from Hope (January 1977, v 16, #1) by Keele, talked about amps being capable of 10 dB over the average level (10 times the power).  In an earlier DfH the wording was a little different.  IIRC, the original read something like, "will pass peaks 10 dB above average, without clipping."
  • Yet the IHF Dynamic Headroom for good amps is usually around 3 dB
  • One renowned amplifier designer (I think it was Pass, but I'm not sure) said that with well designed amps, the headroom (or dynamic power? or peak power?) would be expected to be barely higher than the continuous power.

What's going on here?

 

 

 

 

 

 

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That's pretty funny... I'll ask about the meters when I get the tour arranged. I can assure you those are real amps. I saw a pair in on display in the repair shop on the first floor of the Western Electric office building.

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1 hour ago, garyrc said:

O.K.,  I don't know much about the electronic end of audio, so I'm confused.

  • The Western Electric mono-block is rated at 80 watts, RMS (or "RMS"), but the meter goes up to 600 watts for the highest peak.  (7.5 times the "RMS" power).
  • Back in 1977, a revised Dope from Hope (January 1977, v 16, #1) by Keele, talked about amps being capable of 10 dB over the average level (10 times the power).  In an earlier DfH the wording was a little different.  IIRC, the original read something like, "will pass peaks 10 dB above average, without clipping."
  • Yet the IHF Dynamic Headroom for good amps is usually around 3 dB
  • One renowned amplifier designer (I think it was Pass, but I'm not sure) said that with well designed amps, the headroom (or dynamic power? or peak power?) would be expected to be barely higher than the continuous power.

What's going on here?

 

Sheesh, you're right.  Excellent catch.   ..When I first looked at the watt meters I thought there must be a decimal.  ..Like 60.0 Watts.  ...But 600??  

 

I sure hope their explanation isn't, "Well, those meters were designed to also work w/ a much higher output amp that we might introduce later."  ..That would be forgivable in a $300 Behringer, crown, or  whatever budget-priced amp.  ..But definitely not a $60k amp.  ..McIntosh's watt meters are scaled appropriately for the output of each amp.   I would expect same in an amp this expensive.

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The zero to 10 watt range takes up the majority of the meter, but 10 to 100 is a small segment.  A more useful approach would have been to have the meter scaled with more range between 10 and 100.  The 600 doesn’t make any real sense, but it might make marketing sense.  

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2 hours ago, Khornukopia said:

The reason for the meters large margin, is so the needles always have smooth sweeps, even at full power. 

 

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Yeah, but McIntosh actually claims that their 2,000 watt, several chassis amp can actually produce genuine peaks of 8,000 watts, yet their Dynamic Headroom spec is only 2 dB.  

 

"The MC2KW monoblock amplifier is designed to exceed the demands of true lifelike playback levels, capable of delivering 2,000 watts of continuous power and 8,000 watts of peak power into 2, 4 or 8 ohm speakers. But sheer power output is just the beginning of the story."

 

As @glens said, it is probably "different intermixed terminology."   I have no clear picture of this terminology.  Apparently, given how McIntosh uses these terms, Dynamic Headroom is different than Peak Power.  From the above, it looks like Dynamic Headroom is (or can be) about 1.67 times the Continuous Power, while Peak Power can be 4 times the Continuous Power -- for the same amp!  I remember when I was but a lad, the specs in the mail away catalogs typically listed peaks as being 2 times rated power

 

It looks like duration is, at least partially, the key.  Are the peaks we are talking about 2ms, 20ms, 200ms, or even 1 second?

 

Does anyone have a nice little chart comparing the different ways of rating peaks?

 
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Not positive about all of this, but RMS is an average which is somewhat below the peaks of the waveforms.  I'm thinking RMS x 1.4 = peak (it's been a while...).  So you could express the peak power as 1.4 x the RMS power and be correct both ways.

 

Dynamic power can be either representative of clean power before the less-regulated power supply gets dragged down, or it can be less-clean power; possibly both.

 

The "standards" are being a little elusive tonight via web search...

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Dynamic power is a result of the Federal Trade Commission standards for home stereo equipment. During the FTC method of power rating the amp is run at 1/3 power for an hour before testing, then the power is measured up to a defined distortion level. That is the continuous average power rating, erroneously called "RMS power", of the amp. An amplifier may be able to put out more power than the FTC rating without the preconditioning at 1/3 power, for a shorter period of time, and perhaps at a different distortion level. That is the "dynamic power" of the amp. Unlike the FTC power rating, there are no standards for the dynamic power number. In general, amps with a stiffly regulated power supply will have less dynamic power output than amps with unregulated or less stiffly regulated power supplies.

 

Peak power for a sine wave is 1.4 times average (RMS) power. For non sinusoidal signals the crest factor of the signal is a determining factor in computing peak power.

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