Does It Really Sound The Same?

[xnor]

You can change the sound of an SS amp simply by increasing the output impdeance. This can be achieved by adding a single resistor at the output for each channel. 0.1 ohms sounds different from 1, 10, 20, 100 etc. But does that make the amp sound different? Well, it depends.
 
Some amps allow you to choose between high and low output impedance, most have a fixed one however. Some opamps need a decoupling resistor (or make use of other techniques) at the output to prevent instability when driving headphones directly, others do not. When you're forced to do so I consider the resulting coloration as part of the amp -> the amp clearly sounds different.
 
Other designs use buffers wrapped in the feedback loop so you get very low output impedance plus high current capabilites. I think this is one topology which Willakan refers to as well-designed.
Since the output impedance is close to zero it doesn't interact with the complex headphone impedance (see voltage divider, as mentioned before) and you can use dummy loads such as resistors to measure the performance of the amp.
 
Frequency response is usually flat from 20 Hz to beyond 20 kHz, distortion doesn't matter if it's 0.0001% or 0.001% because headphones will dominate this with 0.01% min. Crosstalk is no problem either as described before. Those tiny phase shifts you see in well-designed amps also don't matter since our hearing has a hard time detecting even huge phase shifts. What else is there? The noise created by jitter usually is also down below -100 dB.
 
All in all, I see no reason why such designs should sound differently (same goes for expensive cables).

 

[Head Injury]

Quote:

You may disagree strongly with my statement that such beliefs are unfounded, but until you are able to offer, at least, some rudimentary diffMaker proof, it remains nothing more than "your" viewpoint.
 
...
 
As a final thought for this post, Bob Carver was able to win the "Challenge" by altering the sound of his SS amp to match that of a Mark Levinson tube amp*.  This in itself demonstrates that SS amps can sound different from each other.  And IIRC, Carver went on to market and sell "t" versions versions of his SS amplifiers which duplicated the sound of both Mark Levinson and Conrad Johnson designs.
 

Why don't you supply diffMaker results of your own? You are the one who suggests that amps sound different. You seem like the perfect volunteer.
 
After Bob Carver altered his amp, did it still measure well, and were the opamps still operating within their limits?
 

 

[upstateguy]

Quote:

You can change the sound of an SS amp simply by increasing the output impdeance. This can be achieved by adding a single resistor at the output for each channel. 0.1 ohms sounds different from 1, 10, 20, 100 etc. But does that make the amp sound different? Well, it depends.
 
Some amps allow you to choose between high and low output impedance, most have a fixed one however. Some opamps need a decoupling resistor (or make use of other techniques) at the output to prevent instability when driving headphones directly, others do not. When you're forced to do so I consider the resulting coloration as part of the amp -> the amp clearly sounds different.
 
Other designs use buffers wrapped in the feedback loop so you get very low output impedance plus high current capabilites. I think this is one topology which Willakan refers to as well-designed.
Since the output impedance is close to zero it doesn't interact with the complex headphone impedance (see voltage divider, as mentioned before) and you can use dummy loads such as resistors to measure the performance of the amp.
 
Frequency response is usually flat from 20 Hz to beyond 20 kHz, distortion doesn't matter if it's 0.0001% or 0.001% because headphones will dominate this with 0.01% min. Crosstalk is no problem either as described before. Those tiny phase shifts you see in well-designed amps also don't matter since our hearing has a hard time detecting even huge phase shifts. What else is there? The noise created by jitter usually is also down below -100 dB.
 
All in all, I see no reason why such designs should sound differently (same goes for expensive cables).

I think the 1985 Carver Challenge demonstrates that SS designs can sound different from each other and by the same token, Dacs can also be made to sound different from each other as well.
 
 

 

[upstateguy]

Quote:

Why don't you supply diffMaker results of your own? You are the one who suggests that amps sound different. You seem like the perfect volunteer.
 
After Bob Carver altered his amp, did it still measure well, and were the opamps still operating within their limits?
 

I didn't make the claim that all amps sounded the same, that all opamps sound the same or that all DACs sound the same.  The burden of proof is on the one making the claim, just like it is for those making claims about cables.  I'm not making any claims, I'm just asking for the kind of proof that is customary in Sound Science.
 
Regarding Bob Carver, I am just relating historical facts, rather than making unproven claims.....
 
FWIW, Carver went on to market and sell the amps he created for the challenge as the "t" amps.  There were a lot of people, back then, who would have loved to find fault with them.
 

 

[Head Injury]

Quote:

Originally Posted by upstateguy /img/forum/go_quote.gif
 
I didn't make the claim that all amps sounded the same, that all opamps sound the same or that all DACs sound the same.  The burden of proof is on the one making the claim, just like it is for those making claims about cables.  I'm not making any claims, I'm just asking for the kind of proof that is customary in Sound Science.
 
Regarding Bob Carver, I am just relating historical facts, rather than making unproven claims.....
 
FWIW, Carver went on to market and sell the amps he created for the challenge as the "t" amps.  There were a lot of people, back then, who would have loved to find fault with them.

You are making claims. You claim that your amps sound different. Your claims are going against the science already provided by those who claim that all opamps sound the same when utilized properly (you still seem stuck on that "all" thing). You are the one who has experienced the amps in question. You need to provide evidence, too. Don't dump all the evidence on the science crowd. You won't believe any of it anyway at this rate.
 
If you have no measurements of Bob Carver's amp, and no information on what he did to make to make it sound different, then it has no place in response to Willakan's post. It only serves to mislead. You need to provide statistical information, as much as anyone else.
 
If he's marketing the amps, you should be able to retrieve information about their construction (and maybe even measurements) fairly easily.

 

[xnor]

Quote:

I think the 1985 Carver Challenge demonstrates that SS designs can sound different from each other and by the same token, Dacs can also be made to sound different from each other as well.

Sure, nobody said you cannot make SS amps sound different. Actually, in my previous post I said just that (lol?): you can change the sound simply by increasing the output impedance by adding a single resistor per channel. That's what Carver did too. You can change the FR for example by changing the capacitor in an AC-coupled design to cause bass roll-off. You can cripple the power supply or add noisy pots, like he did. You can add a bass boost circuit.
 
Does any of these practices have something to do with well-designed, accurate amps? Not really, in my opinion.
The stereophile crowd might enjoy the amps with lots of distortion, sub-par power supplies, loudness tuned frequency response etc. - amps designed to sound 'nice', but in no way accurate.
 
I found this quite entertaining:

On the face of it, what Bob Carver pulled off should be impossible. You can't make a silk purse from a sow's ear.

 
They fail to see that Carver's amp was the silk purse and their "reference" nice sounding amp the sow's ear. After all he had to make use of some of the practices explained above to "degrade" his amp until it sounded as "nice" as the reference.
 
Also, something like this has been mentioned before, where's the proof for the differences the stereophile crowd claim to hear? Just because two amps don't null (in order words: measure differently, for example because of tiny, inaudible phase shift differences) doesn't mean they sound different.

 

[upstateguy]

Quote:

You are making claims. You claim that your amps sound different. Your claims are going against the science already provided by those who claim that all opamps sound the same when utilized properly (you still seem stuck on that "all" thing). You are the one who has experienced the amps in question. You need to provide evidence, too. Don't dump all the evidence on the science crowd. You won't believe any of it anyway at this rate.
 
If you have no measurements of Bob Carver's amp, and no information on what he did to make to make it sound different, then it has no place in response to Willakan's post. It only serves to mislead. You need to provide statistical information, as much as anyone else.
 
If he's marketing the amps, you should be able to retrieve information about their construction (and maybe even measurements) fairly easily.

 
I am not making claims, I am questioning them.
 
Grasshopper, The Carver Amp Challenge is history.  I'm surprised that you don't already know about it.  Google is your friend.  Look it up.  It will add to your knowledge base.

 
 

 

[xnor]

Quote:

Originally Posted by upstateguy /img/forum/go_quote.gif
 
I am not making claims, I am questioning them.

You're also questioning facts, it seems.
 

 

[upstateguy]

Quote:

Sure, nobody said you cannot make SS amps sound different. Actually, in my previous post I said just that (lol?): you can change the sound simply by increasing the output impedance by adding a single resistor per channel. That's what Carver did too. You can change the FR for example by changing the capacitor in an AC-coupled design to cause bass roll-off. You can cripple the power supply or add noisy pots, like he did. You can add a bass boost circuit.
 
Does any of these practices have something to do with well-designed, accurate amps? Not really, in my opinion.
The stereophile crowd might enjoy the amps with lots of distortion, sub-par power supplies, loudness tuned frequency response etc. - amps designed to sound 'nice', but in no way accurate.
 
I found this quite entertaining:
 
They fail to see that Carver's amp was the silk purse and their "reference" nice sounding amp the sow's ear. After all he had to make use of some of the practices explained above to "degrade" his amp until it sounded as "nice" as the reference.
 
Also, something like this has been mentioned before, where's the proof for the differences the stereophile crowd claim to hear? Just because two amps don't null (in order words: measure differently, for example because of tiny, inaudible phase shift differences) doesn't mean they sound different.

xnor, you're just being silly. 
 
Carver holds 15 patents, and is a design genius in the audio field.  What might your credentials be for critiquing him?
 

1. U.S. Patent 3,727,148 Amplifier with Protective Energy Limiter Circuit Components, filed January 1972, issued April 1973
2. U.S. Patent 3,989,897 Method and Apparatus for Reducing Noise Content in Audio Signals, filed October 1974, issued November 1976 (auto-correlator noise reduction)
3. U.S. Patent 4,218,585 Dimensional Sound Producing Apparatus and Method, filed April 1979, issued August 1980 (sonic holography)
4. U.S. Patent 4,218,660 Audio Amplifier and Method of Operating Same, filed November 1978, issued August 1980 (magnetic field coil power amplifier)
5. U.S. Patent 4,309,570 Dimensional Sound Recording and Apparatus and Method for Producing the Same, filed April 1979, issued January 1982
6. U.S. Patent 4,415,768 Tuning Apparatus and Method, filed May 1981, issued November 1983
7. U.S. Patent 4,4,450,95 Audio Amplifier, filed February 1982, issued April 1984
8. U.S. Patent 4,457,012 FM Stereo Apparatus and Method, filed June 1982, issued June 1984 (asymmetrical charge coupled stereo detector)
9. U.S. Patent 4,484,150 High Efficiency, Light Weight Audio Amplifier and Power Supply, filed September 1982, issued November 1984
10. U.S. Patent 4,586,002 Audio Amplifying Apparatus and Method, filed June 1984, issued April 1986
11. U.S. Patent 4,808,946 Lightweight, High Power Audio Amplifier and Power Supply, filed December 1986, issued February 1989
12. U.S. Patent 4,815,141 Apparatus and Methods for Removing Unwanted Components from a Communications Signal, filed December 1986, issued March 1989
13. U.S. Patent 5,748,753 High Power Audio Subwoofer, filed January 1996, issued May 1998
14. U.S. Patent 5,937,074 High Back EMF, High Pressure Subwoofer, filed August 1997, issued August 1999
15. U.S. Patent 6,166,605 Integrated Audio Amplifier, filed September 1998, issued December 2000

 

 

[xnor]

Quote:

xnor, you're just being silly. 
 
Carver holds 15 patents, and is a design genius in the audio field.  What might your credentials be for critiquing him?

 
I don't critique him.
 
Either I'm too tired to make any sense of your replies or it's you who's being silly.

 

[xnor]

*double post*

 

[bigshot]

Upstate, you're missing the point of Carver's test. He was proving that a solid state amp could be made to sound just as colored and inaccurate as a tube amp. He wasn't trying to make the solid state amp sound better.

Of course amps and DACs can be designed to sound however you want them to sound. But why would anyone want one that was colored, noisy and inaccurate when they can easily be made to e flat, clean and balanced? The goal of sound equipment is to provide accuracy.

 

[Mad Max]

 
Quote:

Upstate, you're missing the point of Carver's test. He was proving that a solid state amp could be made to sound just as colored and inaccurate as a tube amp. He wasn't trying to make the solid state amp sound better.

Of course amps and DACs can be designed to sound however you want them to sound. But why would anyone want one that was colored, noisy and inaccurate when they can easily be made to e flat, clean and balanced? The goal of sound equipment is to provide accuracy.

There's plenty of colored-sounding gear and plenty of people who love that.  They do not hide in little caves or anything that you can't find them posting their opinions throughout the internet.
You can have a clean, mildly inaccurate amp thanks to all the various circuit designs and so many flavors of capacitors out there to color up the sound the way you want.  A lot of people find a little coloration to make equipment's sound more "musical" and pleasant to their ears.
In fact, isn't the more neutral equipment the minority in the market?

 

[Grahame]

Quote:

 

There's plenty of colored-sounding gear and plenty of people who love that.  They do not hide in little caves or anything that you can't find them posting their opinions throughout the internet.
You can have a clean, mildly inaccurate amp thanks to all the various circuit designs and so many flavors of capacitors out there to color up the sound the way you want.  A lot of people find a little coloration to make equipment's sound more "musical" and pleasant to their ears.
In fact, isn't the more neutral equipment the minority in the market?

 
Do you use the same set of coloration for all source material?
 


 
 

 

[upstateguy]

Quote:

Upstate, you're missing the point of Carver's test. He was proving that a solid state amp could be made to sound just as colored and inaccurate as a tube amp. He wasn't trying to make the solid state amp sound better.

Of course amps and DACs can be designed to sound however you want them to sound. But why would anyone want one that was colored, noisy and inaccurate when they can easily be made to e flat, clean and balanced? The goal of sound equipment is to provide accuracy.

I'm not missing the point.  The contention was that all SS amps sound the same.  All I did was to point out some that didn't.  That they were tested by Stereo Review and Carver winning the challenge is enough to put to rest that contention. 
 
His challenge was not to make the solid state amp sound better, but to make it sound like Stereo Review's $12,000 reference amp.  That he did this, shows that all SS amps do not sound the same and was all I was trying to do.  You may or may not like 300B tube amps, but that is not the subject of our discussion.
 
The amp he duplicated, btw, was The Conrad Johnson Premier Five, which was one of the most highly regarded amplifiers at the time and to refer to it as a colored and inaccurate tube amp does it a great injustice, but that is not under discussion either.
 
As usual you bring up an interesting point. "... why would anyone want one that was colored, noisy and inaccurate when they can easily be made to be flat, clean and balanced?"
 
The only answer I can think of comes from something you said the other day, .... that most recordings are engineered for flapping paper, situated in rooms, whose frequencies are not flat, clean or balanced.  I'm guessing now, but maybe a 300B amp flaps the paper in a very pleasant way, with typical recordings, played in typical rooms.