You don't need close to 200wpc

ben62670

heiney9 wrote: »

THD is a meaningless spec. You don't need gobs of power for quality.

H9

Amen. The mods I did to my Denon SACD player probably raised the THD a hair, but the simpler circuits sound so much better than stock

zumbo

heiney9 wrote: »

THD is a meaningless spec. You don't need gobs of power for quality.

H9

I would respectfully disagree from a SS POV.

These days, I look at what the THD spec does when the amp is asked to drive a less resistive load. A SS amp of poor quality can get pretty nasty when asked to perform such a task, especially when asked to reach it's limits.

My Adcom 7605 will reach it's limit any time I put it to use. It gets pretty nasty. It does what it was designed to do, and that's about it.

But, take a look at the specs of something like Krell(just an example). Power doubles, and yet THD remains lower than most amps I've seen. When the amp is asked to perform, it does so with reserves. If you don't think that spec matters, then you are just missing-out.

I do understand that most of us will stick to what we believe, so no need to have a pissing contest.

heiney9

THD is a meaningless spec. The difference between the Adcom and Krell has nothing to do with the THD rating.

H9

zumbo

heiney9 wrote: »

THD is a meaningless spec. The difference between the Adcom and Krell has nothing to do with the THD rating.

H9

K

heiney9

The reason it's meaningless is because anything below 1% is inaudiable and most amps are well below this for THD. The more important factor is intermodulation distortion which is a more complex form of distortion and does far more damage to the musical signal than THD ever could and that is if THD started to reach 1%.

Get your read on here.

http://www.passlabs.com/pdfs/articles/distortion_and_feedback.pdf

H9

heiney9

zumbo wrote: »

so no need to have a pissing contest.

I agree, not my intention. But if you read the article I posted you'll see THD is really not that important since most amps measure well below what is considered troublesome. There is no audible difference between and amp that specs at .003% or .03% THD. (all other things being equal). The spec is also an average over whatever freq spectrum they test unless otherwise noted. It's also measured with a test tone or sine wave rather than real musical content.

H9

newrival

Then to be fair, H9, it appears your contention is that THD is a meaningless below 1%. Obviously if the THD was 3% you'd like to know that spec. This being the case, THD is hardly useless.

heiney9

Well for intents and purposes on this audio board I doubt anyone would entertain or ever own an amp that measures that poorly. Nor would any self respecting amplifier company ever print something in their specs that measured so poorly.

So how about this THD specs are meaningless. THD specs in an of themselves tell you nothing about the amp and how it will perform. Ergo, they are meaningless.

H9

shack

heiney9 wrote:

Nor would any self respecting amplifier company ever print something in their specs that measured so poorly.

Bingo!

heiney9

I know I am being literal and very narrow and beating this into the ground, but measured specs don't mean a whole lot in the real world of audio. They are rarely ever observed using a real musical signal, in a real listening environment. So when I see people raving about how something sounds and then quoting some meaningless spec I get a little bent out of shape because there are lots of audio components that don't measure well but sound great. And vice versa.

As Mr. Spock said, “Instruments only measure what they were designed to measure.”.

H9

heiney9

Everyone likes something slightly different when it comes to the sound of their audio equipment. Those difference's rarely coincide with what is printed on a typical manufacturer's spec sheet. There is soooooooo much more at play.

H9

heiney9

zumbo wrote: »

I would respectfully disagree from a SS POV.

These days, I look at what the THD spec does when the amp is asked to drive a less resistive load. A SS amp of poor quality can get pretty nasty when asked to perform such a task, especially when asked to reach it's limits.

My Adcom 7605 will reach it's limit any time I put it to use. It gets pretty nasty. It does what it was designed to do, and that's about it.

But, take a look at the specs of something like Krell(just an example). Power doubles, and yet THD remains lower than most amps I've seen. When the amp is asked to perform, it does so with reserves. If you don't think that spec matters, then you are just missing-out.

I do understand that most of us will stick to what we believe, so no need to have a pissing contest.

I will respectfully suggest you don't have a firm understanding of what Harmonic distortion is as it relates to the THD spec from the manufacturer. It has nothing to do with driving a gain device over its limits. Distortion added from clipping is a type of harmonic distortion but not the type of harmonics measured in THD. There is no direct correlation in the case you describe above.

Atleast I am assuming you are referring to clipping when you say "reaches its limits"

H9

newrival

Fair enough, it just seemed a little strange to me that you're categorically dismissing it. I understand the last comment you made, but while results may not typically be a result of specs (your opinion) there are times that it does. Furthermore, I believe that knowing the THD CAN be of some import given it's cumulative nature within a system, particularly vintage systems.

heiney9

newrival wrote: »

Fair enough, it just seemed a little strange to me that you're categorically dismissing it. I understand the last comment you made, but while results may not typically be a result of specs (your opinion) there are times that it does. Furthermore, I believe that knowing the THD CAN be of some import given it's cumulative nature within a system, particularly vintage systems.

Again I think you are referring to IMD intermodulation distortion, not THD total harmonic distortion.

But I won't put words in your mouth.

If you like to listen to simple music as played by an unaccompanied sackbutt, harmonic distortion figures might be perfectly relevant to you, but with a lot of music you will find that inter-modulation distortion becomes the elephant on the dance floor.

H9

zumbo

Meaningless to human perception, or hearing ability. Absolutely.

But, my tweeter goes to 32k.

Now, also take into consideration I am stating the amps ability to handle a less resistive load while keeping it's composure.

If you look around at the amps such as Krell I referenced, you will see how those high-end/high-power units have the ability to produce great amounts of power while keeping a very low THD.

While this doesn't matter in the schooling you are trying to give me, it matters in telling the person reading the specs the amps ability to deliver quality power.

If the specs didn't matter, amps like Krell wouldn't have these impressive specs to support their hefty price-tag.

heiney9

zumbo wrote: »

Meaningless to human perception, or hearing ability. Absolutely.

But, my tweeter goes to 32k.

Now, also take into consideration I am stating the amps ability to handle a less resistive load while keeping it's composure.

If you look around at the amps such as Krell I referenced, you will see how those high-end/high-power units have the ability to produce great amounts of power while keeping a very low THD.

While this doesn't matter in the schooling you are trying to give me, it matters in telling the person reading the specs the amps ability to deliver quality power.

If the specs didn't matter, amps like Krell wouldn't have these impressive specs to support their hefty price-tag.

All this has nothing to do with THD. Your last line is very comical as if impressive specs = high dollar gear = audio nirvana. You either like the Krell sound or you don't, no 1 page of specs will decide that for you, if it does that's just sad.

H9

zumbo

heiney9 wrote: »

All this has nothing to do with THD. Your last line is very comical as if impressive specs = high dollar gear = audio nirvana. You either like the Krell sound or you don't, no 1 page of specs will decide that for you, if it does that's just sad.

H9

The specs give the clear information I need to decide if the amp is of poor design. It's as simple as that.

I said nothing about sound.

zumbo

As mentioned, the Krell specs were just an example of my point.

treitz3

zumbo wrote: »

Meaningless.......it matters in telling the person reading the specs the amps ability to deliver quality power.

I have stayed out of the thread up until now but I just had to edit your post to where you actually made sense.

Have a nice day.

zumbo

And I don't know what is up with my sig.:biggrin:

zingo

Has anyone heard/used one of the new Luxman integrated amps? Their class A, low power design interests me, even though they are not cheap.

newrival

heiney9 wrote: »

Again I think you are referring to IMD intermodulation distortion, not THD total harmonic distortion.

But I won't put words in your mouth.

If you like to listen to simple music as played by an unaccompanied sackbutt, harmonic distortion figures might be perfectly relevant to you, but with a lot of music you will find that inter-modulation distortion becomes the elephant on the dance floor.

H9

No, I'm Referring to Total Harmonic Distortion, the %delta of varience from the liner amplification of the original waveform (in my words, may bot be exactly the best decription). It has a cumulative effect within a system, and THD in vintage components is not as low (generally speaking) as in modern components.

zumbo

treitz3 wrote: »

I have stayed out of the thread up until now but I just had to edit your post to where you actually made sense.

Have a nice day.

If you are going to quote me, please have the decency to keep the quote original.

Not very cool.

heiney9

zumbo wrote: »

The specs give the clear information I need to decide if the amp is of poor design. It's as simple as that.

I said nothing about sound.

That is hysterical. Thanks for a good chuckle

H9

zumbo

If the point of the thread was just to get one closed-minded POV, I see no point in the thread.

The fact is, you guys show me a highly regarded SS amp with high THD, and poor 4ohm performance. Also, be certain it has low power.

I will check in from time-to-time, but I doubt you will find it.

And I don't mean a highly reviewed amp. Reviews are advertisements.

I mean, find an amp that brings big bucks in an auction setting. I can tell you now, it will be very capable of a 4ohm load, while keeping an exceptional THD spec.

reeltrouble1

who cares sand stinks like dead fish parts scooped from last nights sushi party.

The most significant Spec ever at CP was the Dr.

RT1

shack

I buy everything based on the spec sheet...:rolleyes:

zumbo

And just to be clear, I am not one of those guys who thinks I own the best stuff.

I am not impressed by my Adcom amp.

I am not impressed by my over-reviewed, over-priced Marantz BD-8200.

I am very impressed by my Denon POA-2200.

heiney9

zumbo wrote: »

If the point of the thread was just to get one closed-minded POV, I see no point in the thread.

The fact is, you guys show me a highly regarded SS amp with high THD, and poor 4ohm performance. Also, be certain it has low power.

I will check in from time-to-time, but I doubt you will find it.

And I don't mean a highly reviewed amp. Reviews are advertisements.

I mean, find an amp that brings big bucks in an auction setting. I can tell you now, it will be very capable of a 4ohm load, while keeping an exceptional THD spec.

I own one

SPECIFICATIONS

Gain 20 dB balanced, 26 dB single ended

Freq. Response - 0.5 dB @ 2 Hz, -1.5 dB @ 100 KHz

Power Output 30 watts/ch @ 8 ohms, 40 watts @ 4 ohms

Maximum Output 25 volts, 5 amps

Distortion (1KHz) 0.2% @ 30 watts, 8 ohms

Input Impedance 47 Kohm single-ended, 52 Kohm differential

Damping factor 100

Crosstalk > -80 dB 20-20 KHz

Balanced Input Rejection -50 dB typical CMRR

Output Noise < 500 uV unweighted

Random noise floor 5 uV typical

DC offset < 100 mv

Power Consumption 200 watts

Temperature 25 degrees C. above ambient

Dimensions 17 " W x 15.5" D x 5.5" H

Shipping Weight 45 lb.

zumbo

heiney9 wrote: »

I own one

SPECIFICATIONS

Gain 20 dB balanced, 26 dB single ended

Freq. Response - 0.5 dB @ 2 Hz, -1.5 dB @ 100 KHz

Power Output 30 watts/ch @ 8 ohms, 40 watts @ 4 ohms

Maximum Output 25 volts, 5 amps

Distortion (1KHz) 0.2% @ 30 watts, 8 ohms

Input Impedance 47 Kohm single-ended, 52 Kohm differential

Damping factor 100

Crosstalk > -80 dB 20-20 KHz

Balanced Input Rejection -50 dB typical CMRR

Output Noise < 500 uV unweighted

Random noise floor 5 uV typical

DC offset < 100 mv

Power Consumption 200 watts

Temperature 25 degrees C. above ambient

Dimensions 17 " W x 15.5" D x 5.5" H

Shipping Weight 45 lb.

That's a mighty fine SS amp you have there.:rolleyes: Are you even reading my post?