Was wondering if anyone has when from the Citadels to the new 1.5Citadels? What is the diffence in sound? Do the new ones sound better if so in what way? Thanks!

Evolved technology
Most notable, the revamped amplifier features a completely new circuit board designed to facilitate exotic components, better current conduction from realigned copper buss bars, user accessible rail fuses on the rear panel and locking, gold-plated XLR jacks.

With all that it should sound better. :D



THD+Noise: <2%

Signal to Noise Ratio: (unweighted) >103dB

(-3dB points @ full power) 0.2 Hz - 400 KHz.

What are with these specs? SNR is horrible and THD is through the roof. Should it not be 40KHz instead of 400?

Was wondering if anyone has when from the Citadels to the new 1.5Citadels? What is the diffence in sound? Do the new ones sound better if so in what way? Thanks!

I luv my Enterprises. Got a great deal pricewise on them. Don't even wanna think about how good the Citadels 1.0 would sound let alone the 1.5. That's downright scary!!!!

With all that it should sound better. :D



THD+Noise: <2%

Signal to Noise Ratio: (unweighted) >103dB

(-3dB points @ full power) 0.2 Hz - 400 KHz.

What are with these specs? SNR is horrible and THD is through the roof. Should it not be 40KHz instead of 400?

Where did you get the above specs from? Here's the weblink to the specs and I don't see the 40KHz that you're talking about even listed:

http://www.thetadigital.com/product/citadel/specs.htm

Where did you get the above specs from? Here's the weblink to the specs and I don't see the 40KHz that you're talking about even listed:


The same page you linked to, it says 400KHz.

I have owned the Enterprises too! They are very nice!

The same page you linked to, it says 400KHz.

Woops. I can't read!!! Looks like a typo, quite obviously.

Looking for few people who have had the old and new Citadels. I just would like to know there opinion about the two. Just because they upgrade and amp doesn't mean its better.

But why is the THD so high and the SNR so low?

Hi Steve, no typo. This high bandwidth is correct. Zero feedback allows for a damn fast amplifier.

The -3db points for the Citadel are 0.2 Hz at the low end, and 400 KHz at the high end.

Its the use of feedback that gives the .000.... harmonic distortion specs we see for most amplifiers today. The human ear hears the degradation feedback causes. There has been much written about this over the last thirty years.

Here's Theta's secret page on amplifiers: http://www.thetadigital.com/ThetaHistoryp5.html and here is the even more secret Theta page specifically on feedback in amplifiers and why we use no global negative feedback: http://www.thetadigital.com/ThetaHistoryp6.html#Feedback.

The 103 dB S/N ratio is unweighted. "A" weighting would increase this by another 5-10 dB. Most manufacturers use "A" weighting, and many do not indicate so. Still, a high power amp will have higher noise than a low power amp. We are past the point where one will perceive noise or its effects.

Citadel, in playing music will normally have distortion well below 1%. The ear doesn't readily hear harmonic distortion at this level. At the high levels at which our ears will perceive harmonic distortion, it doesn't necessarily sound "bad". Think violin with a little more rosin on the bow rather than the grunge of Nirvana's guitars.

There are no measurable differences between the Citadel 1 and 1.5, by the way. All the changes are certainly audible.

I wasn't part of the listening team making all the sonic decisions that led from Citadel to Citadel 1.5. I do remember though how excited members of the listening team were as the newer amp was reaching completion.

Neil took home a set of Enterprises for his own use before the work on the upgraded Citadel started. He told me that while Citadel was obviously better than Enterprise, the level of improvement was more on a cerebral level than an emotional one. He had difficulty justifying the larger size and cost. Since the newer Citadel was finished, he's been trying to talk me into taking his Enterprises so he could justify Citadel 1.5s.

Neil took home a set of Enterprises for his own use before the work on the upgraded Citadel started. He told me that while Citadel was obviously better than Enterprise, the level of improvement was more on a cerebral level than an emotional one. He had difficulty justifying the larger size and cost. Since the newer Citadel was finished, he's been trying to talk me into taking his Enterprises so he could justify Citadel 1.5s.


Evelyn, you should take Neil up on that offer. I LUV THE ENTERPRISES.
And as you point out, a characteristic of No Negative Feedback is a fast amplfier, and you ain't a kidding. My friends and I have all noticed this. I comment that with bullets, explosions, etc. that the Enterprises are so quiet and then "boom" and then so quiet - so darn natural and fast. Last night I watched "The Unit". This particular show had lotsa land mines, gunshots, etc.
and I was just delighting in the sounds and feelings thanks to my Enterprises/Aerial 9s and of course Theta CB3. Much more so than with my prior Bryston 7B/Aerial 10Ts. Pretty Amazing!!!@@@ Scary to think of how good the Citadel 1.5s would sound. (I was lucky to get my wife to let me get the Enterprises - if I got the Citadels I would be out of the house and my hoem theater and into my own private tiny citadel)!:D

Hi Steve, no typo. This high bandwidth is correct. Zero feedback allows for a damn fast amplifier.

The -3db points for the Citadel are 0.2 Hz at the low end, and 400 KHz at the high end.

Its the use of feedback that gives the .000.... harmonic distortion specs we see for most amplifiers today. The human ear hears the degradation feedback causes. There has been much written about this over the last thirty years.

Here's Theta's secret page on amplifiers: http://www.thetadigital.com/ThetaHistoryp5.html and here is the even more secret Theta page specifically on feedback in amplifiers and why we use no global negative feedback: http://www.thetadigital.com/ThetaHistoryp6.html#Feedback.

The 103 dB S/N ratio is unweighted. "A" weighting would increase this by another 5-10 dB. Most manufacturers use "A" weighting, and many do not indicate so. Still, a high power amp will have higher noise than a low power amp. We are past the point where one will perceive noise or its effects.

Citadel, in playing music will normally have distortion well below 1%. The ear doesn't readily hear harmonic distortion at this level. At the high levels at which our ears will perceive harmonic distortion, it doesn't necessarily sound "bad". Think violin with a little more rosin on the bow rather than the grunge of Nirvana's guitars.

There are no measurable differences between the Citadel 1 and 1.5, by the way. All the changes are certainly audible.

I wasn't part of the listening team making all the sonic decisions that led from Citadel to Citadel 1.5. I do remember though how excited members of the listening team were as the newer amp was reaching completion.

Neil took home a set of Enterprises for his own use before the work on the upgraded Citadel started. He told me that while Citadel was obviously better than Enterprise, the level of improvement was more on a cerebral level than an emotional one. He had difficulty justifying the larger size and cost. Since the newer Citadel was finished, he's been trying to talk me into taking his Enterprises so he could justify Citadel 1.5s.

Do you work for Theta? Do you have any idea how the Citadels would mate with Revel Salon - Gen I's?

Evelyn is the ex-wife of Neil Sinclair, former Theta owner. Theta was sold to ATI some months later than the above post.

There are no measurable differences between the Citadel 1 and 1.5, by the way. All the changes are certainly audible.

Excuse me!?

But why is the THD so high and the SNR so low?

No global negative feedback design. Global negative feedback makes for better spec but some would argue worse sound. I do not know.

No global negative feedback design. Global negative feedback makes for better spec but some would argue worse sound. I do not know.

I don't think that no global negative feedback and good specs have to be mutually exclusive; e.g., Krell Evo 900 amp:

Signal-to-noise ratio
>122 dB, "A"-weighted

Total harmonic distortion
<0.02% at 1 kHz, at 900 W, 8 Ohms
<0.15% at 20 kHz, at 900 W, 8 Ohms

But then again, I don't really believe in specs anyway..... ;)

Thanks Rider. I do not recall seeing such low feedback used,only 8db and getting specs that good.

Thanks Rider. I do not recall seeing such low feedback used,only 8db and getting specs that good.

IIRC, all the Evo amps are like the Evo One: there's no global negative feedback - the 8dB feedback is locally nested in the final gain stages.