Lets talk Amps

[Max2]

With the lack of HIFI stores  and not being able to demo equipment these days and not having friends that have equipment, what's a individual to do to pick out an amp?    How much stock do you put in SNR ratios and THD numbers?   If you have a super clean pre and are looking at amps with 10+ db lesser on the SNR, are you shooting yourself in the foot?   McIntosh has great numbers on their not so old amps to the tune of 113db or so SNR and THD which is shown at .005% at rated power or below.  The majority of the mainstream amps are in the .03% range on THD and have similar SNR ratios.   Ok, I have stellar specs, but what about the sound?   Is the negative feedback input so great that my THD numbers are stellar, but once again, how does it sound?  Outlaw boasts amps that have .03% THD and a whopping 122+ db SNR, but what dictates its sound?

Where is the compromise with designing an amp?  I know many here don't put any stock in specs, but don't numbers add up?  It is numbers that tally how close to perfection you can get in electronics and speaker building or is it?

 

My big question here is, Can you suck all the musicality from an amp chasing after numbers only to leave a clinical, sterile sound?

 

I have heard of zero negative feedback tube amps and others adding positive feedback distortion, which I think is the old McIntosh tube topos. There obviously isn't a clear winner or manu's would be shooting for it and buyers would only be after it.

 

I can read numbers and articles, but I don't know amps. I don't see how someone can say they do know an amp without spending a good bit of time with it in their own setup, unless of course its obviously very ugly or very different right out of the gate.

 

 

Any Amp gurus want to throw their 2 cents in?

Edited March 24, 2015 by Max2

[Cut-Throat]

Yup, Specs mean almost nothing...You have to listen to them. There has got to be some forum members near you who could give you an audition.

[joshnich]

Somewhat timely topic. I obviously would concur that listening is the best way to judge if one likes an amp or not. Who knows what other people hear! Having said that I recently auditioned the relatively new Benchmark AHB2 amplifier. The specs are off the charts.

 

"The dynamic range of the AHB2 is 132 dB, making it 10 to 30 dB quieter than the typical reference-quality power amplifier. The frequency response extends beyond 200 kHz."

 

I have to say this is the best amplifier I have ever heard. It is truly remarkable. It now has a permanent home in my system and I couldnt be happier - not because of the specs because truthfully I dont know what they mean, but because of how it sounds.

I have auditioned many fine ss amps and none have lasted more than a few minutes!  This is a whole new kettle of fish. Truly a game changer - at least to my ears!

 

Josh

[babadono]

Would love to hear this AHB2. Low gain, I like it. You can use the headroom your preamp or pre/pro or mixing board has.

[tube fanatic]

I can tell you, after decades in the field, that specs don't mean anything!  As was pointed out by C-T above, you have to hear the amp in your own system.  There is simply no other way to determine whether it will satisfy you.  In fact, I wouldn't even look at specs of a prospective amp before auditioning (assuming you aren't trying to power something like Apogee Scintillas with a 1 watt SET) as the numbers can easily poison your perception.  Whenever possible, I don't even discuss power or whether an amp is a SET or SEP (the only types I'm currently involved in) when doing demos.  I simply put the person in a chair and let them listen.  After a decision is made then some specs can be discussed, although it often isn't necessary since the person says "that's what I want."  In the absence of a dealer from whom you can borrow equipment for audition, or friends/acquaintances who can bring something over, the only other alternative is to purchase from dealers who offer a return privilege (such as Decware).  Yes, it will cost you a few dollars in shipping charges, but that's a small price to pay for being able to live with an amp for 30 days in your own system.

Maynard

Edited March 24, 2015 by tube fanatic

[USNRET]

About 30 years ago I used to buy and brag on equipment based on advertised specs; no longer. I must admit that this past week I have been researching specs as I was buying headphones and a headphone amp and being illiterate I did try to find a place in that madness.

Edited March 24, 2015 by USNRET

[Schu]

I think I can not agree 100% with the statement, Specifications mean nothing... they do mean something. whether or not it's 1 watt or 132db of dr, they all mean something.

 

one thing is for sure, it not only depends on who did doing the measuring, but how those spec's integrate with everything else in your system... they don't call it a system for nothing.

[Schu]

I do have to say... that the spec's of the benchmark have me really intrigued even though they are close to my class D.

 

[Max2]

Thanks for the reply guys.  I have completely modded my K's, yet I want to keep my 5.1 setup. Im still 99% a two channel listener, but still delve into multi channel Blu Ray audios, SACD's, DDA's and what not. I am torn with an all out 5 channel amp or use a two channel for the fronts and the AVR for the rears. Of course I want to get a quality processor in time, but can't pull it all off at once.  I read where someone had pretty good results running MC 30's through a Yamaha AVR.  Having no tube experience in my setup, its tough to drop the dough on something only to figure out a total different direction is needed.   

[PrestonTom]

I think I can not agree 100% with the statement, Specifications mean nothing... they do mean something. whether or not it's 1 watt or 132db of dr, they all mean something.

 

one thing is for sure, it not only depends on who did doing the measuring, but how those spec's integrate with everything else in your system... they don't call it a system for nothing.

I agree with Schu. There are some important numbers, just not the unqualified THD numbers. Have a look at input sensitivity, does the wattage double when the impedance of the load is halved (approximately).

 

Fortunately, Klipsch speakers usually do not present a difficult load and they usually have tons of efficiency (which also means any hiss or hum will come through). So reviews done with lower efficiency speakers or difficult loads (electrostats etc) are not very useful.

[Max2]

I do have to say... that the spec's of the benchmark have me really intrigued even though they are close to my class D.

 

 

 

Why haven't the manu's dropped Class A/B  for the G and D setups?  I know Rotel did for a while, but I noticed they have started offering the A/B topos again in their integrated amps.

[Max2]

 

I think I can not agree 100% with the statement, Specifications mean nothing... they do mean something. whether or not it's 1 watt or 132db of dr, they all mean something.

 

one thing is for sure, it not only depends on who did doing the measuring, but how those spec's integrate with everything else in your system... they don't call it a system for nothing.

I agree with Schu. There are some important numbers, just not the unqualified THD numbers. Have a look at input sensitivity, does the wattage double when the impedance of the load is halved (approximately).

 

Fortunately, Klipsch speakers usually do not present a difficult load and they usually have tons of efficiency (which also means any hiss or hum will come through). So reviews done with lower efficiency speakers or difficult loads (electrostats etc) are not very useful.

 

 

 

Well said. Nothing hides from a horn and 104+ efficiency.  

[joshnich]

 

I do have to say... that the spec's of the benchmark have me really intrigued even though they are close to my class D.

 

 

 

Why haven't the manu's dropped Class A/B  for the G and D setups?  I know Rotel did for a while, but I noticed they have started offering the A/B topos again in their integrated amps.

 

The Benchmark combines Class H and Class A/B technologies with something they call feedforward error correction developed in concert with THX.  Again, I dont know a thing about the techology but when reading the info it all seemed to make sense. And once again the proof is in the sound.

http://benchmarkmedia.com/blogs/news/14680625-the-ahb2-a-radical-approach-to-audio-power-amplification

[Cut-Throat]

 

I think I can not agree 100% with the statement, Specifications mean nothing... they do mean something. whether or not it's 1 watt or 132db of dr, they all mean something.

 

one thing is for sure, it not only depends on who did doing the measuring, but how those spec's integrate with everything else in your system... they don't call it a system for nothing.

I agree with Schu. There are some important numbers, just not the unqualified THD numbers. Have a look at input sensitivity, does the wattage double when the impedance of the load is halved (approximately).

 

Fortunately, Klipsch speakers usually do not present a difficult load and they usually have tons of efficiency (which also means any hiss or hum will come through). So reviews done with lower efficiency speakers or difficult loads (electrostats etc) are not very useful.

 

 Well, certainly Specs make a difference. But they tell you Absolutely Nothing on whether you will like the amp or not.

[derrickdj1]

I like the flow of this thread, hearing is the most important factor.  The preamp has a major impact on the what you hear at the end of the audio chain.  I use an Acurus with my avr and prefer it to separates.  The avr /amp combo is a good option.  Flagship avr's have an economy of scale advantage over smaller companies making separate preamp.  A good preamp can cost a few bucks.  Also, Flagship avrs may offer many features not available on a lot of preamp.  I use my system mostly for music.

[PrestonTom]

 

 

I think I can not agree 100% with the statement, Specifications mean nothing... they do mean something. whether or not it's 1 watt or 132db of dr, they all mean something.

 

one thing is for sure, it not only depends on who did doing the measuring, but how those spec's integrate with everything else in your system... they don't call it a system for nothing.

I agree with Schu. There are some important numbers, just not the unqualified THD numbers. Have a look at input sensitivity, does the wattage double when the impedance of the load is halved (approximately).

 

Fortunately, Klipsch speakers usually do not present a difficult load and they usually have tons of efficiency (which also means any hiss or hum will come through). So reviews done with lower efficiency speakers or difficult loads (electrostats etc) are not very useful.

 

 Well, certainly Specs make a difference. But they tell you Absolutely Nothing on whether you will like the amp or not.

 

Well, when I was looking at amps to use with a "passive" pre-amp (simple potentiometer), it turns out that the input impedance and sensitivity were important factors. These are specs. I agree that it was not the entire story, but they were important factors.

[Bubo]

You can go on E-bay tonight and buy a 200WPC THX Ultra rated amp from Parasound for approx $250.

 

THX specs and bench testing mean something and test not only optimal operating parameters, but sub optimal and fault conditions.

 

If you don't like, you can sell it the next day and be out one way postage.

 

Parasound has made several versions, if you go to their web site they have all the manuals for download.

 

The used THX amps may be the best deal out there.

 

http://www.ebay.com/itm/Parasound-HCA-1000-2-Channel-High-Power-Amplifier-350-180-Watts-THX-/131464355255?pt=LH_DefaultDomain_0&hash=item1e9be2ddb7

[joshnich]

You can go on E-bay tonight and buy a 200WPC THX Ultra rated amp from Parasound for approx $250.

 

THX specs and bench testing mean something and test not only optimal operating parameters, but sub optimal and fault conditions.

 

If you don't like, you can sell it the next day and be out one way postage.

 

Parasound has made several versions, if you go to their web site they have all the manuals for download.

 

The used THX amps may be the best deal out there.

 

http://www.ebay.com/itm/Parasound-HCA-1000-2-Channel-High-Power-Amplifier-350-180-Watts-THX-/131464355255?pt=LH_DefaultDomain_0&hash=item1e9be2ddb7

Not sure if this is directed at the THX reference in the Benchmark post ....but I have owned the parasound HCA 1000 as well as a highly modified parasound HCA 2200 MK11. We are talking a different animal here all together. The HCA 1000 was a nice amp that I replaced with a Hafler and never looked back. The HCA 2200 lasted about 30 minutes before my wife said "whats wrong with the stereo?"  The technology from THX in the Benchmark is well beyond simple certification.

 

Josh

[erik2A3]

PrestonTom. Precisely. While specs and measurements will not always reveal how one may subjectively respond to a given design, specifications of input/output impedances and input sensitivty are not only important, but really mandatory in determining fundamental electrical compatibility between components. In designing a preamp or power amplifier, for example, those same specs are required for determining interstage impedance relationships.

While it's true that it's difficult to make a decision about the sonic qualities of those components that share similar specs on paper, in my view it is arguably beneficial to consult basic operating parameters of pieces of gear in order to begin the auditioning process.

A more mundane example: When I go out to buy a pair of shoes, there will be a million varieties of the size 10 species, and knowing my size requirements, size 10 is what I will ask for as a starting point. We all know that shoes labeled the same will not always fit the same, so we look for the size (which may be a half or even whole size up or down) that best fit our particular needs.

[Deang]

You all is hearing things.