[801evan]

The amp cannot present the front-to-back depth of the soundstage

End game sound doesn't have that front to back as ppl would think. This is a phase issue somewhere in the chain or wonky FR.

 

[theveterans]

Recorded with a singer or instrument in the centre between two mics, or mixed by the mastering engineer to put them in the centre? However, even many two-mic recordings will have a dedicated mic for the singer, such as the Chesky binaural and other recordings. If the singer is "extremely in the centre" and you don't pick up the spread of the sound of their voice in the venue (assuming the singer and other players were all in the same room), then, if the room isn't over-damped, you should hear some reflection of their voice. You wont be able to hear this clearly with ~$500 amps and DACs though.

As for amps, the Stealth has been good at revealing the limitations of the A90 Discrete I have in for review. The amp cannot present the front-to-back depth of the soundstage, and it's obvious, using high-quality recordings I’ve listened to many times, that a lot of micro detail is missing, such as the decay and reverberation of notes from stringed instruments. I would highly not recommend spending $4k on a Stealth, only to use it with average gear. That is a waste of money IMO.

Like the Susvara, the Stealth really needs to be run on quality solid state amp speaker taps to open up even if Stealth is much more sensitive than Susvara IMO. As for tubes, a really good SET amp with 8 ohm taps such as the DNA Stellaris should bring justice to Stealth's technical capabilities

 

[PointyFox]

I don't know how an amp with the dynamic range and frequency response extension of the A90D could "leave out details", but I don't recall the Stealth demo at Canjam NYC sounding more detailed, and I'm sure that was on some fancy amplifier/DAC.
Regarding using speaker amp taps, I've tried that before with the A90 and Emotiva A2m with the jumper in place and couldn't detect any difference after volume matching with a Hifiman He6se besides an elevated noise floor on the Emotiva.
What could cause a loss of details that wouldn't show up in measurements, and how could an amp with so many vacuum tubes in the signal path let through more detail than solid state?

 

[801evan]

I don't know how an amp with the dynamic range and frequency response extension of the A90D could "leave out details", but I don't recall the Stealth demo at Canjam NYC sounding more detailed, and I'm sure that was on some fancy amplifier/DAC.
Regarding using speaker amp taps, I've tried that before with the A90 and Emotiva A2m with the jumper in place and couldn't detect any difference after volume matching besides an elevated noise floor on the Emotiva.
What could cause a loss of details that wouldn't show up in measurements, and how could an amp with so many vacuum tubes in the path let through more detail than solid state?

What Currawong is saying about the Topping is really about the quality of the psu. The poor quality psu eats the detail away. And this is more related to having a poor noise floor and lack of speed to present true dynamics and true detail.

 

[PointyFox]

What Currawong is saying about the Topping is really about the quality of the psu. The poor quality psu eats the detail away. And this is more related to having a poor noise floor and lack of speed to present true dynamics and true detail.

Since when does the A90 have a poor noise floor? It has one of the lowest noise floors of any amp.
Lack of speed? You're talking about the A90, right?
You must have a ground loop issue if you can hear any sort of noise floor.

 

[801evan]

Since when does the A90 have a poor noise floor? It has one of the lowest noise floors of any amp.
Lack of speed? You're talking about the A90, right?
You must have a ground loop issue if you can hear any sort of noise floor.

It only uses 2 low quality smps internally. It's lack of speed will give a perceived lower noise floor. and this is also why ppl say the amp is anemic,thin...or on the glass is half full group, very detailed and clean.

 

[TubyAndWobbly]

It only uses 2 low quality smps internally. It's lack of speed will give a perceived lower noise floor. and this is also why ppl say the amp is anemic,thin...or on the glass is half full group, very detailed and clean.

Noise floor is something measurable and is objectively a strong point of the a90. Although that perceived ""cleanliness"" is a whole different deal.

 

[PointyFox]

It only uses 2 low quality smps internally. It's lack of speed will give a perceived lower noise floor. and this is also why ppl say the amp is anemic,thin...or on the glass is half full group, very detailed and clean.

According to everyone else not on Head-fi, amplifier "speed" isn't a thing.

Speed and resolution, like pace and timing or musicality are meaningless words used by sloppy subjective reviewers.

Speed, as in Slew rate, can be easily measured and ANY amplifier of hifi pretentions can comfortably perform adequately. Resolution similarly, if meaning signal to noise ratio, is more than adequate in every amplifier, but neither slew rate nor S/N ratio are what reviewers mean, it's an airy-fairy armwaving concept only they understand, and therefore of no validity whatsoever.

On speed, I think this is one of those random terms people use because they can't explain what they like better and just use that term. Again, this is a perception thing that goes away in *scary sciency word censored due to Head-fi rules*.

People say the closest thing to "speed" is the frequency response. If an amplifier is "slow" it won't be able to play high frequencies, and this certainly isn't the case for the A90.

 

[Arniesb]

Recorded with a singer or instrument in the centre between two mics, or mixed by the mastering engineer to put them in the centre? However, even many two-mic recordings will have a dedicated mic for the singer, such as the Chesky binaural and other recordings. If the singer is "extremely in the centre" and you don't pick up the spread of the sound of their voice in the venue (assuming the singer and other players were all in the same room), then, if the room isn't over-damped, you should hear some reflection of their voice. You wont be able to hear this clearly with ~$500 amps and DACs though.

As for amps, the Stealth has been good at revealing the limitations of the A90 Discrete I have in for review. The amp cannot present the front-to-back depth of the soundstage, and it's obvious, using high-quality recordings I’ve listened to many times, that a lot of micro detail is missing, such as the decay and reverberation of notes from stringed instruments. I would highly not recommend spending $4k on a Stealth, only to use it with average gear. That is a waste of money IMO.

''You wont be able to hear this clearly with ~$500 amps and DACs though''
You understand that these 500$ amp or dacs would cost 1000 or more from West companies... Probably would cost 1500 if made by Chord.
For you money charged = quality. Perhaps if it was badly engineered with a lot of distortions it would have better soundstage?
How come all amps with massive soundstages have ton of distortion?

 

[Arniesb]

It only uses 2 low quality smps internally. It's lack of speed will give a perceived lower noise floor. and this is also why ppl say the amp is anemic,thin...or on the glass is half full group, very detailed and clean.

These power supplies are lowest noise in the market and since those work at very high requencies you wont be able to hear any noise.
Why there is no huge amount of capacitor banks? Cause its so clean that filtering is almost not needed.

 

[801evan]

These power supplies are lowest noise in the market and since those work at very high requencies you wont be able to hear any noise.
Why there is no huge amount of capacitor banks? Cause its so clean that filtering is almost not needed.

Mehhhh

People say the closest thing to "speed" is the frequency response. If an amplifier is "slow" it won't be able to play high frequencies, and this certainly isn't the case for the A90.

If you think we're talking about that kind of speed...nevermind then. Have fun with ur topping amp.

 

[Arniesb]

Mehhhh

If you think we're talking about that kind of speed...nevermind then. Have fun with ur topping amp.

"Have fun with ur topping amp."
Damn u showed him! Keep it up champ!
People can give you facts and you still gonna talk rubbish.

 

[801evan]

N

"Have fun with ur topping amp."
Damn u showed him! Keep it up champ!
People can give you facts and you still gonna talk rubbish.

Not gonna waste my time with someone who has 2500+ posts and would make comments where they don't understand speed and how if it's not fast enough then it wouldn't resolve high frequency. Lolz.

 

[Currawong]

Like the Susvara, the Stealth really needs to be run on quality solid state amp speaker taps to open up even if Stealth is much more sensitive than Susvara IMO. As for tubes, a really good SET amp with 8 ohm taps such as the DNA Stellaris should bring justice to Stealth's technical capabilities

I've been enjoying them with the Studio Six the most. Much as I'd like to collect different tube amps, I'm already running out of room for any more gear.

I don't know how an amp with the dynamic range and frequency response extension of the A90D could "leave out details", but I don't recall the Stealth demo at Canjam NYC sounding more detailed, and I'm sure that was on some fancy amplifier/DAC.
Regarding using speaker amp taps, I've tried that before with the A90 and Emotiva A2m with the jumper in place and couldn't detect any difference after volume matching with a Hifiman He6se besides an elevated noise floor on the Emotiva.
What could cause a loss of details that wouldn't show up in measurements, and how could an amp with so many vacuum tubes in the signal path let through more detail than solid state?

This is a good thing to wonder, and you're not the first, by far, to ask such a question. But, basically, dynamic range and frequency response extension do not have anything to do with the ability to resolve low-level signals. It's like trying to reconcile the rev range of a car with its handling ability. Every amp seems to measure flat, but there are other ways to high changes to the perceived frequency response. The guy who ran Anything But iPod a decade ago knew this. I've seen a manufacturer reverse transistors in a circuit to change the sound, and I still have circuits sitting here that were tweaked to sound more or less spacious, with such things as a boosted bass or treble, but all had a completely flat FR.

There isn't a measurement that specifically relates to detail, and never has been. There are vastly greater types of measurements available on analysers than most people are aware of. Some manufacturers/engineers have a range of ideas what specific capabilities relate to the ability of an amp to resolve detail. It's something that is most definitely worth exploring, as the vacuum for knowledge about this seems to have been filled with bad science instead.

 

[PointyFox]

Ok, so if the A90 leaves out low-level signals that would be audible on a different amplifier, then I should be able to reduce the input signal to a point where the sound suddenly cuts out.
I attempted this and I heard no such cutoff. It continued to decrease until ambient noise overpowered it.
Thinking logically about this, I would expect the amplifier to be able to produce a signal so low that it won't be able to move the headphone drivers.

Then I though of a different test.
I set the Windows volume control to 1/100 and my software volume control to 1/100.
This represents an extremely low level signal, far below what is audible.
I then switched the A90 up to high gain and 100 volume and I could just barely hear it.

So either I don't understand what you mean or you're making stuff up.