SS Amp Performance Characteristics

[Holmz]

I was curious about getiing a sub $10,000 SS amp. Thing is, I really have no idea how to assess how they voice. I don't know what is good or bad. In my mind, they all seem to sound about the same. I generally hear about the same thing from the systems I hear them in. I personally attribute the variation in sound from system to system to speakers and their placement.
I am assuming there must be some pretty large variation in tone and performance. There sure is a massive spread in pricing.

So whats going on with SS amps. What do you look for that makes one stand out as great where another is only OK. Or maybe bad.

More than half of it is the speakers.
If you have good easy to drive speakers, then the amp is not very stressed.

Low impedance speakers and wild phase swings cause hell for the amp.
And long high capacitance cables can be hell as well.

To make things more confusing, One can read a glowing customer review on one forum. Well written and decent comparisons. But another forum has members saying the product is good. Kind of sweet and slightly warm. Well, is it great, or is it about the same as every other SS amp out there.

With 100 speakers, I would suspect that 50% sound the same, 25% great and 25% bad.
(Maybe it is 60, 30 and 10%).

How do people assess a SS amp and conclude one is great or just ok.

Rex

Let’s go back to the speakers and placement in the room.
That is worth a lot IMO.
Once that is worked out, then get the amps to suit the speakers.

Some speakers are notoriously difficult to drive, to the point where it is almost a marketing badge of honour.
(180 degrees out from what horn users say; “where horns are almost all - just super easy to drive.”)

 

[Kingrex]

Given the damping factor of most SS amps, I would not consider them ideal for open baffle because of the loss of bass that will ensue. Of course if you add subs then that is a thing I guess. It is similar in a way for horn bass, a high damping factor amp will dry up the bass to the point of leaving it dessicated.

Why would you loose bass??? Doesnt higher damping mean more grip on the drivers. Faster start and stop. Why would that dry out bass?

 

[morricab]

Why would you loose bass??? Doesnt higher damping mean more grip on the drivers. Faster start and stop. Why would that dry out bass?

Because you have no cabinet to act as a resonator. Normal box speaker make bass because of the drivers and cabinet loading. How that is tuned affects whether bass needs “grip” from a high damping factor amp or not. Horns and OB do not want to have high electrical damping…they are already damped or at least not loading a resonator. Bass will be dramatically less than with an amp that has a low damping factor.

 

[mtemur]

Bass will be dramatically less than with an amp that has a low damping factor.

I can say that my experience is quite different. I always hear more bass with low damping factor amplifiers compared to high damping. Moving drivers isn’t hard, but stopping them in a split second is very difficult—that’s where a high damping factor comes in. When a bass driver can’t be stopped due to the amplifier’s low damping factor, it keeps producing bass. The driver also moves farther when the amplifier isn’t in control, which results in higher amplitude compared to the original signal—hence, more bass. An amp with high damping stops the bass driver on a dime, which translates to less bass but more quality.

This may also apply to open baffle speakers, but what I’ve written is based on regular, boxed speakers.

 

[Ron Resnick]

When a bass driver can’t be stopped due to the amplifier’s low damping factor, it keeps producing bass. The driver also moves farther when the amplifier isn’t in control, which results in higher amplitude compared to the original signal—hence, more bass. An amp with high damping stops the bass driver on a dime, which translates to less bass but more quality.

This sounds correct to me.

 

[bonzo75]

I can say that my experience is quite different. I always hear more bass with low damping factor amplifiers compared to high damping. Moving drivers isn’t hard, but stopping them in a split second is very difficult—that’s where a high damping factor comes in. When a bass driver can’t be stopped due to the amplifier’s low damping factor, it keeps producing bass. The driver also moves farther when the amplifier isn’t in control, which results in higher amplitude compared to the original signal—hence, more bass. An amp with high damping stops the bass driver on a dime, which translates to less bass but more quality.

This may also apply to open baffle speakers, but what I’ve written is based on regular, boxed speakers.

I agree with Brad on this, that it depends on the driver's damping factor. This is not universal. With Altec you will choke off the bass by gripping it. It requires low grip. high output impedance amp. It depends on the QTS of the driver. That said, very few drivers are this way, and mostly vintage, so I doubt that Kingrex's PAP have that issue.

 

[mtemur]

I agree with Brad on this, that it depends on the driver's damping factor. This is not universal. With Altec you will choke off the bass by gripping it. It requires low grip. high output impedance amp. It depends on the QTS of the driver. That said, very few drivers are this way, and mostly vintage, so I doubt that Kingrex's PAP have that issue.

Which one is preferable — high or low damping — and with which driver is another matter. More pleasurable, natural sound and driver-amp synergy are not necessarily what I’m addressing here.

My point is: regardless of whether it sounds dry or not, a high damping amplifier produces less bass compared to a low damping amp. This is, of course, with a demanding load.

 

[ashandger]

I have a newly updated version of Klaus’ Kismet amplifier (Odyssey).
Mine has upgrades not yet offered on the website.
That being said, In my system and to my ears it was clearly better than my Pass XA amp.
Highly recommended.
I leave my amp on all the time. (weather be damned).

May I ask which Pass Labs XA amp you had? Many thanks

 

[morricab]

I can say that my experience is quite different. I always hear more bass with low damping factor amplifiers compared to high damping. Moving drivers isn’t hard, but stopping them in a split second is very difficult—that’s where a high damping factor comes in. When a bass driver can’t be stopped due to the amplifier’s low damping factor, it keeps producing bass. The driver also moves farther when the amplifier isn’t in control, which results in higher amplitude compared to the original signal—hence, more bass. An amp with high damping stops the bass driver on a dime, which translates to less bass but more quality.

This may also apply to open baffle speakers, but what I’ve written is based on regular, boxed speakers.

This is what I said, please read again…I said bass is dramatically less for high damping vs. Low damping.

 

[mtemur]

This is what I said, please read again…I said bass is dramatically less for high damping vs. Low damping.

Ok.

 

[Kingrex]

It sounds like a low damping amp would produce tubby, inaccurate bass as there is a lack of control. It sounds like the driver is just flopping around.

 

[morricab]

It sounds like a low damping amp would produce tubby, inaccurate bass as there is a lack of control. It sounds like the driver is just flopping around.

Depends on the driver

 

[microstrip]

Why would you loose bass??? Doesnt higher damping mean more grip on the drivers. Faster start and stop. Why would that dry out bass?

Amplifier damping is related to amplifier output impedance. A low damping amplifier will have an higher output impedance, the signal seen by the speaker will also depend on the impedance curve of the speaker. In many cases, the changes in frequency response due to impedance peaks and dips can't be ignored and affect the perceived subjective bass grip.

The relation between damping and "fast bass" - a dubious word, IMO - is not clear. For example, amplifiers known for an excellent grip, such as the D'Agostino Momentum's have a middle damping value actor - around 50.

 

[Kingrex]

Will do. The A-2 will replace my YBA amplifier (Yves Bernard Andre of France) and Jeff Rowland Pre-Amp. They are both SS, but quite dated so I'm not sure the differences to the A-2 would tell you much, but I'll let you know what I hear after break-in. Previously, long ago, I had a few tube and hybrid components, but no real aural memory that could be considered useful in light of other changes to my system.

Lacking pre-amp out, the A-2 would probably not be a first-choice for a 5-Ch system, but it will serve my needs for 2-Ch. It was easy to me to buy into Soulnote's philosophy of design by listening rather than designing to a spec, and the many reviews emphasizing strengths in tonality and musicality clicked with me.

Agree on the A-3 reviews but out of my price range. As I understand, the replacements for the A-2 and A-1 are coming in a few months, hence the close-out pricing on them. Purportedly, the A-3 is not in the works for immediate replacement.

Well???? How long has it been playing. Any initial thoughts.