So what DOES make for a good amplifier?

[Bassman2]

I keep seeing that just about everything the manufacturers tout as great amp design... ultra wide bandwith, high current power supplies, etc, really don't make any difference to the sound quality of an amp or receiver. There are a few very well done editorials on this site alone explaining what DOESN'T make a great amp....So what DOES make a good sounding amplifier?

 

[Swerd]

I keep seeing that just about everything the manufacturers tout as great amp design... ultra wide bandwith, high current power supplies, etc, really don't make any difference to the sound quality of an amp or receiver. There are a few very well done editorials on this site alone explaining what DOESN'T make a great amp....So what DOES make a good sounding amplifier?

Good question. In the small world of DIY speaker building, I once met an electrical engineer named Bob Cordell who had past experience in audio amplifier design. There is a brief interview of him on the internet http://members.aol.com/_ht_a/pjay99/guruscordell.htm where he describes what he thinks makes a good amp. Take the time to read it, and tell us whether it answers any of your questions.

I had previously believed that "big iron" amps were overkill, but in a series of demonstrations, Bob convinced me that amps, in the 150+ watt per channel range, were needed to play most music at moderate or higher levels through speakers that are moderately or more efficient without any clipping. Despite the common use of the term "amplifier clippping" most of us (myself included) do not recognize what clipping sounds like.

 

[wire]

Good question. In the small world of DIY speaker building, I once met an electrical engineer named Bob Cordell who had past experience in audio amplifier design. There is a brief interview of him on the internet http://members.aol.com/_ht_a/pjay99/guruscordell.htm where he describes what he thinks makes a good amp. Take the time to read it, and tell us whether it answers any of your questions.

I had previously believed that "big iron" amps were overkill, but in a series of demonstrations, Bob convinced me that amps, in the 150+ watt per channel range, were needed to play most music at moderate or higher levels through speakers that are moderately or more efficient without any clipping. Despite the common use of the term "amplifier clippping" most of us (myself included) do not recognize what clipping sounds like.

Very good artical .

If you look at the design of the 4b , it didnt change until recently(it got more power) . The ppl. at Bryston kept the basic design the same for 20+ years .
On the same subject of design . I often visit the Carver forum . One man was talking to a worker in the Carver factory before it shut down and had a demo of the lastest Carver amp on some Amazing speakers , he told the man that he has the same speaker and his 1.5t Carver amp ( yet this amp was a updated version ) sounded better , the man said , yes the 1.5T does sound better . Then asked why , the man said , i dont know . ( note all Carver amps sound abit different ) .
Even Bob Carver was asked , what was the best amp you ever designed , he repleyed the 4.0T , this was recently . So he likes that amp better than the newer Sunfire stuff .
There canbe alot of variables in the designs of Amps , even if made by the same company . If the company updates the amp , it could make the amp sound totally different .
My example with the 4b is a company that left it alone for along time , why mess with a already good thing .

 

[wire]

Good question. In the small world of DIY speaker building, I once met an electrical engineer named Bob Cordell who had past experience in audio amplifier design. There is a brief interview of him on the internet http://members.aol.com/_ht_a/pjay99/guruscordell.htm where he describes what he thinks makes a good amp. Take the time to read it, and tell us whether it answers any of your questions.

I had previously believed that "big iron" amps were overkill, but in a series of demonstrations, Bob convinced me that amps, in the 150+ watt per channel range, were needed to play most music at moderate or higher levels through speakers that are moderately or more efficient without any clipping. Despite the common use of the term "amplifier clippping" most of us (myself included) do not recognize what clipping sounds like.

When i was younger , i would see my 4b go from green to red once and awhile , running my Polk 2bs .

 

[Swerd]

When i was younger , i would see my 4b go from green to red once and awhile , running my Polk 2bs .

Have you become color blind now, or do you play them at lower levels ?

 

[Bassman2]

Good question. In the small world of DIY speaker building, I once met an electrical engineer named Bob Cordell who had past experience in audio amplifier design. There is a brief interview of him on the internet http://members.aol.com/_ht_a/pjay99/guruscordell.htm where he describes what he thinks makes a good amp. Take the time to read it, and tell us whether it answers any of your questions.

I had previously believed that "big iron" amps were overkill, but in a series of demonstrations, Bob convinced me that amps, in the 150+ watt per channel range, were needed to play most music at moderate or higher levels through speakers that are moderately or more efficient without any clipping. Despite the common use of the term "amplifier clippping" most of us (myself included) do not recognize what clipping sounds like.

GREAT article. However....

It states both that big juicy power supplies and high damping factor are important factors when these are two of the things that I've read here aren't important, so....

Otherwise it was very informative. When he says..."large heat sinks that allow transistors to be well-biased and still run reasonably cool." I assume this means biased "hot" or high current/voltage?

 

[Swerd]

It states both that big juicy power supplies and high damping factor are important factors when these are two of the things that I've read here aren't important, so....

I thought "big juicy power supplies" were the one thing that everyone agreed was important to have. Who said they (and high damping factors) were not important? As Bob Cordell pointed out, there is a lot of voodoo associated with many of the "Big $ Big iron" amps.

When he says..."large heat sinks that allow transistors to be well-biased and still run reasonably cool." I assume this means biased "hot" or high current/voltage?

I read that as "large heat sinks that allow transistors to remain well-biased and still run reasonably cool."

 

[Swerd]

I guess now is the time to add that I did ask Bob what makes of amplifier he though were good ones that didn't cost an arm & a leg. He named several that I can remember, and quite a few more that I can't remember:

B&K
Bryston
Hafler (when it was owned by David Hafler)
Parasound (those models with MOSFET output transistors)
Denon (their older stand alone 2-channel amps)
AVA (Audio by Van Alstine)
Marsh
​

He added that used versions of these amps were a very good way get them without paying too much. I bought my used B&K amps through Audiogon.

 

[Warpdrv]

Good question. In the small world of DIY speaker building, I once met an electrical engineer named Bob Cordell who had past experience in audio amplifier design. There is a brief interview of him on the internet http://members.aol.com/_ht_a/pjay99/guruscordell.htm where he describes what he thinks makes a good amp.

Thank you for the link to that conversation, it was intriguing to get a glimpse of what an amp designer thought about amps/power in general....
I would be interested if he ever had a list of amps he had tested, and what results he came away with.. Which company's amps are better and which are just Botique with a big name that made mistakes/had flaws in their designs...

Once again I walk away another day with more knowledge about Audio...

Also thanks to Bassman2 for asking the question, revealing another mystery or common misconceptions flowing about...
Warp

 

[dave1490]

Very good artical .

If you look at the design of the 4b , it didnt change until recently(it got more power) . The ppl. at Bryston kept the basic design the same for 20+ years .
On the same subject of design . I often visit the Carver forum . One man was talking to a worker in the Carver factory before it shut down and had a demo of the lastest Carver amp on some Amazing speakers , he told the man that he has the same speaker and his 1.5t Carver amp ( yet this amp was a updated version ) sounded better , the man said , yes the 1.5T does sound better . Then asked why , the man said , i dont know . ( note all Carver amps sound abit different ) .
Even Bob Carver was asked , what was the best amp you ever designed , he repleyed the 4.0T , this was recently . So he likes that amp better than the newer Sunfire stuff .
There canbe alot of variables in the designs of Amps , even if made by the same company . If the company updates the amp , it could make the amp sound totally different .
My example with the 4b is a company that left it alone for along time , why mess with a already good thing .

im not a fan off carver,when i wanted to upgrade my bose 1801 250 a side to the carvers m1.5 300 a side.the bass just wasnt thier,granted you have to listen to them with = speaker,s not the show room s**t and = setting,s to make a fair comparison.but for bass i like my bryston,s the best.ps i cant turn it up past 10.30 with the subsionic sys off but that just the lack of speaker,s. granted that is 30 +db bass,50 with the sys.

 

[tubesaregood]

There are numerous factors to consider in my opinion. Low distortion, high bandwidth, sufficient power, load capabilities, power supply, quality of components, etc. The list goes on.

Most important for me are ability to deliver power at low distortions and overall sound quality (ie, not coloring the sound, stereo separation).

Many people here will tell you that upgrading your speakers will make the biggest difference in your overall sound quality. While I won't contest this, I do believe that different amps can mean the difference between giving a speaker a mediocre review and a good one. Case in point - I have a pair of KLH 9915 floorstanding speakers. I own the likes of Audio Pro, Epicure, and Electrovoice, and Kloss-designed KLH so I know what good sound is. The KLH speakers, when connected to my Denon PMA-300V, sound really fantastic for the price. The tweeters have a very balanced but powerful presence, and overall the speakers are clear and articulate (except the bass - but you get BIG bass at the expense of controlled bass). Acoustic guitars sound *almost* lifelike with this setup! On a crappier amp, they would sound crappier.

 

[dave1490]

There are numerous factors to consider in my opinion. Low distortion, high bandwidth, sufficient power, load capabilities, power supply, quality of components, etc. The list goes on.

Most important for me are ability to deliver power at low distortions and overall sound quality (ie, not coloring the sound, stereo separation).

Many people here will tell you that upgrading your speakers will make the biggest difference in your overall sound quality. While I won't contest this, I do believe that different amps can mean the difference between giving a speaker a mediocre review and a good one. Case in point - I have a pair of KLH 9915 floorstanding speakers. I own the likes of Audio Pro, Epicure, and Electrovoice, and Kloss-designed KLH so I know what good sound is. The KLH speakers, when connected to my Denon PMA-300V, sound really fantastic for the price. The tweeters have a very balanced but powerful presence, and overall the speakers are clear and articulate (except the bass - but you get BIG bass at the expense of controlled bass). Acoustic guitars sound *almost* lifelike with this setup! On a crappier amp, they would sound crappier.

Electrovoice is good comparable to jbl pro,s.you missed 1 dampaning factor.the ability to start and stop a woffer.no one want,s mud.

 

[gene]

It states both that big juicy power supplies and high damping factor are important factors when these are two of the things that I've read here aren't important, so....

I don't ever recall publishing an article on Audioholics stating power supply is NOT a factor. Damping factor is a nebulous term since it all depends on how it was measured which is why output impedance is something you should look more closely at.

If you look at any of my amplifier reviews, you will notice I measure:
Full bandwidth continuous power at 0.1% THD + N
Bandwidth linearity at various power levels
Output Impedance
FFT Distortion at full power
SNR @ 1 watt where the amp spends most of its time
Slew induced distortion at full power

These are some of many of the attributes that determine good amplifier design. Channel to Channel isolation is another which I will be including in future reviews.

 

[Bassman2]

I don't ever recall publishing an article on Audioholics stating power supply is NOT a factor. Damping factor is a nebulous term since it all depends on how it was measured which is why output impedance is something you should look more closely at.

If you look at any of my amplifier reviews, you will notice I measure:
Full bandwidth continuous power at 0.1% THD + N
Bandwidth linearity at various power levels
Output Impedance
FFT Distortion at full power
SNR @ 1 watt where the amp spends most of its time
Slew induced distortion at full power

These are some of many of the attributes that determine good amplifier design. Channel to Channel isolation is another which I will be including in future reviews.

OK, that one may have been from somewhere else I'll have to check. But I do recall the very high damping factor not being useful one.

I mainly wanted to know what DOES make a difference, as nearly everything I've read from manufacturers is busted as myth most of the time. That left me thinking that no one knew what they were doing except maybe the boutique guys, and they too can get a little crazy.

 

[Bassman2]

Here's what I was thinking of in relation to power supplies...

Conclusion
From the math and what we know about the basics of how amplifier and loudspeakers perform we can now conclude that High Instantaneous Current is a non-issue and it has no application to driving contemporary and even most of the not so contemporary loudspeakers. In the past, a number of so-called simulations of what music is supposed to represent have been tried to more accurately gauge amplifier power. They have all been dismal failures due to the nature of classical/symphonic music, which has a stunning ability to throw a wrench into just about any generalization. Since many soundtracks use symphonic music this is just as important to Home Theater enthusiasts as well as classical music lovers.


It is the authors firm conviction and experience in designing, building and selling amplifiers that the watts rms into a given load, (8 ohms, 4 ohms, 2 ohms, etc., etc.) over the audio bandwidth of 20 Hz to 20 kHz, is the only accurate and representative way to measure power for this application. For those of you who prefer peak power measurements just remember this: If we multiply the watts rms figure times two we get peak power. So yes, the good old watts rms measurement is also a measure of peak watts.


Special thanks to Dan Banquer of www.redesignsaudio.com

http://www.audioholics.com/education/amplifier-technology/the-high-instantaneous-current-spec

 

[dave1490]

I don't ever recall publishing an article on Audioholics stating power supply is NOT a factor. Damping factor is a nebulous term since it all depends on how it was measured which is why output impedance is something you should look more closely at.

If you look at any of my amplifier reviews, you will notice I measure:
Full bandwidth continuous power at 0.1% THD + N
Bandwidth linearity at various power levels
Output Impedance
FFT Distortion at full power
SNR @ 1 watt where the amp spends most of its time
Slew induced distortion at full power

These are some of many of the attributes that determine good amplifier design. Channel to Channel isolation is another which I will be including in future reviews.

i noticed that,the carver z-1 coupler i used was 75ohm and the crown ic-150 is 600ohm,s never really gave it a second thought.

 

[Bassman2]

If you look at any of my amplifier reviews, you will notice I measure:
Full bandwidth continuous power at 0.1% THD + N
Bandwidth linearity at various power levels
Output Impedance
FFT Distortion at full power
SNR @ 1 watt where the amp spends most of its time
Slew induced distortion at full power

They should put that on a plaque somewhere.

 

[Seth=L]

There are numerous factors to consider in my opinion. Low distortion, high bandwidth, sufficient power, load capabilities, power supply, quality of components, etc. The list goes on.

Most important for me are ability to deliver power at low distortions and overall sound quality (ie, not coloring the sound, stereo separation).

Many people here will tell you that upgrading your speakers will make the biggest difference in your overall sound quality. While I won't contest this, I do believe that different amps can mean the difference between giving a speaker a mediocre review and a good one. Case in point - I have a pair of KLH 9915 floorstanding speakers. I own the likes of Audio Pro, Epicure, and Electrovoice, and Kloss-designed KLH so I know what good sound is. The KLH speakers, when connected to my Denon PMA-300V, sound really fantastic for the price. The tweeters have a very balanced but powerful presence, and overall the speakers are clear and articulate (except the bass - but you get BIG bass at the expense of controlled bass). Acoustic guitars sound *almost* lifelike with this setup! On a crappier amp, they would sound crappier.

I heard some KLH speakers powered by a lower line Kenwood and it sounded good considering they were KLH speakers. I was impressed by the loudness and slam they seemed to have. KLH makes speakers to go loud, be efficient, and not take large amounts of current, so they should sound about the same with adequate amplification.

 

[gene]

--------------------------------------------------------------------------------

Here's what I was thinking of in relation to power supplies...


Quote:
Conclusion
From the math and what we know about the basics of how amplifier and loudspeakers perform we can now conclude that High Instantaneous Current is a non-issue and it has no application to driving contemporary and even most of the not so contemporary loudspeakers. In the past, a number of so-called simulations of what music is supposed to represent have been tried to more accurately gauge amplifier power. They have all been dismal failures due to the nature of classical/symphonic music, which has a stunning ability to throw a wrench into just about any generalization. Since many soundtracks use symphonic music this is just as important to Home Theater enthusiasts as well as classical music lovers.


It is the authors firm conviction and experience in designing, building and selling amplifiers that the watts rms into a given load, (8 ohms, 4 ohms, 2 ohms, etc., etc.) over the audio bandwidth of 20 Hz to 20 kHz, is the only accurate and representative way to measure power for this application. For those of you who prefer peak power measurements just remember this: If we multiply the watts rms figure times two we get peak power. So yes, the good old watts rms measurement is also a measure of peak watts.


Special thanks to Dan Banquer of www.redesignsaudio.com


http://www.audioholics.com/education...s-current-spec

That article was written to debunk a bogus spec that some receiver manufacturers boast about instantaneous current. It does NOT negate the importance of a solid power supply or an amp with REAL world headroom.

I plan on doing some more articles on this topic when time permits.

 

[wire]

im not a fan off carver,when i wanted to upgrade my bose 1801 250 a side to the carvers m1.5 300 a side.the bass just wasnt thier,granted you have to listen to them with = speaker,s not the show room s**t and = setting,s to make a fair comparison.but for bass i like my bryston,s the best.ps i cant turn it up past 10.30 with the subsionic sys off but that just the lack of speaker,s. granted that is 30 +db bass,50 with the sys.

Yeh
The some of the Carvers dont have the great bass , because of the T mods .
I have a TFM 35 for a backup ( for the 4b ) and using in my HT (center channel amp) , it matches well with my polks and my Center , Not quite a 4b and yes the 4b's have good bass and depth , but the Carver better than alot of power amps out there , my Carver amp also is T modded , i like like the mid and highend ( good soundstage ) on these amps. I also have a M240 Carver car amp in my truck , that thing is crystal clear on mids and highs .
All i was pointing out on the Carver examples above was a little change can make a different sound and sometimes its a crap shoot and you end up with a great amp .