[Eisener Bart]

Thanks John. I have been enjoying an STA 9 for 8 months now and am just considering to get another and bridge or go to the ST 10. I am aware of the basic sound differences between  the two. I remember once you saying that the STA 9's sounded even better in bridged mode and just wondered with more time if you still felt that way. Tons of system variables I know. I'll just go ahead and order another 9 and make up my own mind which is what matters anyhow, thanks.

I am wating ST-10 for reviewing. 

[John Casler]

So instead of term "aggressive" better use "more detailed", neh? 

Yes, keep in mind this was a relative comparative evaluation.

The ST-10 while it was initially called a "near reference" component, in my mind is certainly "reference class".  This has been demonstrated by the professional reviewers, and the owners who have spent time with it.

It is more aggressive at mining detail, and producing micro and macro dynamics with immediacy, than the amps below it.

This is opposed to "more subdued", or more "laid back", which it is not. (by comparison)

I might add, that I tend to "prefer" more aggressive amps, with those qualities, over the more soft, smooth, warm, soothing, laid back sonics.

[John Casler]

Thanks John. I have been enjoying an STA 9 for 8 months now and am just considering to get another and bridge or go to the ST 10. I am aware of the basic sound differences between  the two. I remember once you saying that the STA 9's sounded even better in bridged mode and just wondered with more time if you still felt that way. Tons of system variables I know. I'll just go ahead and order another 9 and make up my own mind which is what matters anyhow, thanks.

Yes, as has been stated and posted many times, there seems to be something unique to the STA-9 and the K-38 technology/topology, that "improves" the sound a bit when bridged.

This is in comparison to older amps that when bridged suffer from reduced stability, increased distortions, S/N.

Of course part of this is simply increased headroom from the additional power, but it seems like more than this.  I believe Jason posted the technical reasons a few months ago.

[Eisener Bart]

Yes, as has been stated and posted many times, there seems to be something unique to the STA-9 and the K-38 technology/topology, that "improves" the sound a bit when bridged.

This is in comparison to older amps that when bridged suffer from reduced stability, increased distortions, S/N.

Of course part of this is simply increased headroom from the additional power, but it seems like more than this.  I believe Jason posted the technical reasons a few months ago.

STA-9 has interesting THD+N:
0.02% (Stereo) / 0.01% (Mono). 

[Eisener Bart]

Yes, keep in mind this was a relative comparative evaluation.

The ST-10 while it was initially called a "near reference" component, in my mind is certainly "reference class".  This has been demonstrated by the professional reviewers, and the owners who have spent time with it.

It is more aggressive at mining detail, and producing micro and macro dynamics with immediacy, than the amps below it.

This is opposed to "more subdued", or more "laid back", which it is not. (by comparison)

I might add, that I tend to "prefer" more aggressive amps, with those qualities, over the more soft, smooth, warm, soothing, laid back sonics.

Thus, Ref-20 will be the aggressivist NuPrime's Power Amp. 

[John Casler]

STA-9 has interesting THD+N:
0.02% (Stereo) / 0.01% (Mono). 

That is exactly what I was talking about.

In most amps distortion "doubles" and stability worsens. 

With the STA-9 and K-38, it seems this is not the case.

[John Casler]

Thus, Ref-20 will be the aggressivist NuPrime's Power Amp. 

 

[rustydoglim]

Typically bridging is done by using OpAmp to invert one set of signals, which resulted in more distortion.
Our bridging circuit is done by using transistors.  Transistors are the fundamental building blocks of electronics circuit but many engineers don't design circuit with transistors anymore (similarly, who writes in assembly language? Most software engineers write in object oriented language and scripts). Many high level functions are integrated into complex chips as building blocks. There are literally unlimited number of circuits that can ben created out of transistors but it requires more experience and in-depth understanding of various transistors. Fortunately our chief engineer has decades of experience.

[Eisener Bart]

Typically bridging is done by using OpAmp to invert one set of signals, which resulted in more distortion.
Our bridging circuit is done by using transistors.  Transistors are the fundamental building blocks of electronics circuit but many engineers don't design circuit with transistors anymore (similarly, who writes in assembly language? Most software engineers write in object oriented language and scripts). Many high level functions are integrated into complex chips as building blocks. There are literally unlimited number of circuits that can ben created out of transistors but it requires more experience and in-depth understanding of various transistors. Fortunately our chief engineer has decades of experience.

Thank you, Jason!

[Bill_Bill]

Hi Lim and other members, just wandering can the sta-9 use T3.15A fuse as replacement for the original T3A as the T3.15A has more choice, any negative affect? And can anyone please advise what is the main difference in sound quality compare to stereo mode and in bridge mode (mono block)? Thanks a lot!

[John Casler]

Hi Lim and other members, just wandering can the sta-9 use T3.15A fuse as replacement for the original T3A as the T3.15A has more choice, any negative affect? And can anyone please advise what is the main difference in sound quality compare to stereo mode and in bridge mode (mono block)? Thanks a lot!

Not sure regarding the fuses, that is a tech support determination.

But, I think most have confirmed that the "bridged" STA-9 has improved sonic properties.

These are generally mentioned as, Better and Deeper Bass, Improved Dynamics, more Relaxed Presentation, Blacker Backgrounds, slightly more Transparency, and Better Imaging and Soundstage.

Much of this is due to two primary factors:

1) Bridging increases Power from 120wpc to 290wpc
2) Bridging actually improves Noise/Distortion Numbers.

Seldom does anyone purchase a single STA-9 anymore, or they grab a second soon after.

[Bill_Bill]

Thanks John! Now thinking might get another sta-9.

[akopperl]

Deleted

[srb]

If you connect the amp in mono mode, the manual states to use the top speaker outputs (both posts red).  In this scenario, which post is the + terminal and which is the - terminal?

They're marked + / - separately for BTL mode.

 

Steve

[Rx8man]

Does the STA-9 go into 2ohms like my Ref9 V2SE's?

I'm thinking of auditioning two STA-9's to compare.

If they retain the liquid sound I'm getting, with the additional power and "modern" technology, that'd be nice.

[rustydoglim]

No problem with 2 ohm.

[zwizardofoz]

Is the gain the same over both RCA and XLR @ 22dB ???

I think 22 is quite low as most amps I see are are in the 28-29 range. Similarly is the same over when in bridged mode?

It would be really nice to see data posted like Emotiva does of the Precision Audio measurements data on many of its amps http://emotiva.com/resources/media/xpa1/XPA-1gen2_8Ohms_2013-08-09.pdf

[Eric Gustafsson]

Use, and trust, your ears instead of comparing a lot of technical data.

[zwizardofoz]

I do but the engineer in me wants to know more details so when I do the selling its backed up with the numbers 

[mrthib]

I am looking for nuprime amp to feed my Regas speakers.
Could you tell me how the sta 9 sound compared to the nuforce sta-100 and sta-120 ?