[KJ]

Actually, your $5500/pair IS buying a lot of amps. If you are just comparing 200W to 200W then you are totally missing the picture. EACH Ampzilla monobloc has a 2.4 kVA torroid and 100,000 ufd of filtering. When you compare this to some of the other "powerhouse" amps you will get a better understanding of how the Ampzilla stacks up:

Julian - this is the type of information I have been looking for.  Since I haven't seen any formulas calculating kVA and wattage together, I can only assume there isn't a metric demonstrating the overall capacity of an amp.  That being said, is there a ratio of kVA and wattage that statistically yields better results?  Or is it a simple case of more of each is better?  Of course, listening is probably a better judgement of anything overall, but...the geek in me is curious.

While we're on the topic of specs, the Ampzillas report what appears to be a significant difference in distortion compared to the other products listed.  Is this not as important as it would appear?

John - did the Bryston fall from the shootout list?  (Couldn't find the kVA specs for the SST line btw).

-KJ

[Sedona Sky Sound]

From a pure Electrical Engineering perspective kVA = wattage/(1000*Power Factor).  Here is a site that gives the full details: http://www.ibiblio.org/obp/electricCircuits/AC/AC_11.html

For simplicity sake, you can guestimate that kVA=kW for these transformers (but in reality kVA>kW). So theoretically, the Ampzillas could drive a .75 ohm load with 2.4 kWatts. However, a 200W amp measured at 8 ohms that only had a 750VA transformer would max out before it even got to 2 ohms.

As to what is the "best" combination/ratio, that is a highly debatable subject. Once you drop the transformer into the amps chassis, all the other "stuff" connected to it becomes equally or even more important. A bad design is a bad design no matter how big the transformer. Things such as dampening factor, input/output impedance, balanced/unbalanced design, class A vs AB, etc. all have a big impact on how the amp will act in a particular sytem.  

As a general guideline, if you have hard to drive speakers (i.e., most planars, any of the larger VMPS speakers, etc.) then look for an amp that doubles-down in power to at least 2 ohms (1 ohm is better). They will likely (but not always) have the umph to take control of the speaker. If you have easy to drive speakers (which is not necessarily the same thing as highly efficient speakers), then you will likely save a lot of money since having a "big engine" is not that important. As I have mentioned in past threads, I somewhat prefer using a 100W Marsh amp over the Ampzilla for my 626Rs (the Ampzillas are just overkill in that case from both a power and a cost perspective).  

Personally, I believe amp specs are fairly important. There are very, very few amps that have better specs than the SoA (the Halcros are the only ones that readily come to mind). Check out the graphs on the website and be prepared to be amazed. The Ampzilla 2000 specs/graphs I have seen are not quite as good as the SoA but still highly respectable.  

Of course, as pointed out previously, the above discussion is for standard SS speakers and is not relevant to the newer digital switched amps. While I have definitely not heard every digital amp made, the ones I have heard have so-far been totally unbearable to me (during a demo of one "high-end digital amp" that many folks rave about, I had to tell the manufacturer to stop the disc half-way thru a song since it was literally hurting my ears). I guess that I am just hypersensitive to the type of distortion that they put out. Digital amps have their advantages and will possibly take over in the future, but for me that looks to be "later" rather than "sooner". However, I try to keep an open mind (and ear), so I also look forward to the upcoming shootout.    

Julian
www.sedonaksysound.com

[zybar]

The Son of Ampzilla is an amazingly natural sounding amp and is what you hear in my demo room when I play speakers for customers.

You do have to reterminate your interconnects into the amp with phone plugs (most IC manufacturers are willing to do so).  The RCA to phone adapters supplied with the amp are not very good.

I have retired my wonderful Jadis JPL tube pre and run the Wadia 27ix directly into the Son.  That means just one pair of IC's between source and amp.  The sound is faultless.

Brian,

A single SOA drives the 40's without any issues?

George

[jgubman]

I've heard the SON drive a pair of RM-40s to very high SPLs w/o issue on several occasions.

It's a great amp.

[zybar]

Thanks.

Brian also just let me know that he is using the single amp.

George

[shokunin]

Damn, that's mighty impressive.  We didn't push the SoA to it's limit since we didn't know how far we could push him.  Looks like he can take a beating.

[perfectionist]

Actually, your $5500/pair IS buying a lot of amps. If you are just comparing 200W to 200W then you are totally missing the picture. EACH Ampzilla monobloc has a 2.4 kVA torroid and 100,000 ufd of filtering. When you compare this to some of the other "powerhouse" amps you will get a better understanding of how the Ampzilla stacks up:

$3000 (each channel) - Parasound JC-1 = 1.9 kVA running 1 channel rated at 400W
$4795 - CINEPRO 2K6(4) = 2.3 kVA running 6 channels rated at 300W each
$6750 - Theta Dreadn ...

I'm seriously considering AMPzilla 2k for my next amps.  But, something that concerns me is the actual rating of the torroid.  I can't find it on John's website, SSS says it's 2.4kva and the review by Anthony Cordesman says it's 2.0kva (which sounds more correct to me).  This is not a small descrepancy in my eye's.  One problem I have with different manufacturer's is that they don't always list all the spec's or they're listed in a different mannor, e.g. speaker sensitivity @ different voltages.
Someone care to clear this up  

[zybar]

The SST website says this:

The new Ampzilla 2000 uses a completely new variation of the Forward Gain topology to achieve unprecedented improvements in linearity. As a matter of fact, the new circuit is so smooth, that it can be actually listened to OPEN LOOP, WITH NO FEEDBACK. Of course, we aren’t going to make it that way. The PROPER use of feedback is necessary in order to tie down all of the operating points so there will be no variations in performance from unit to unit. The new Ampzilla 2000 uses 12 250-watt output devices per monobloc. This is 3 times more devices than the original Ampzilla. In addition, since it is a monobloc, there is a separate 2000VA transformer for each. In addition, the amount of heat sink radiating area is 3 times greater than the original meaning that there is NO fan. Also, the B+ and B- supply fuses are EXTERNAL. Also, The entire circuit is totally balanced from input to output although there is a totally and uniquely new un-

balanced to balanced converter for single ended inputs. Each monobloc has 100,000 ufd of power supply filtering with dual rectification as pioneered in the original Sumo's.


The nominal specifications are as follows and are very conservative:

Power output –200 watts into 8 ohms at less than .05% of any kind of distortion known to man.

Frequency response-- +/- .1db at any power level from 20Hz to 20kHz.

Rise time – less than 2usec at any power level up to rated output

Hum & noise – Better than –110db below full output

Gain – Balanced inputs – 42x (32.5db) with +/- 1 volt RMS input

Unbalanced 42x(32.5db) with 1 volt RMS input

Load capability – will drive any load conceived by man

So now I am really confused...what is the real size of the transformer?

The info above can be found here:

http://www.ampzilla2000.com/Amp_History.html

George

[perfectionist]

The SST website says this:

So now I am really confused...what is the real size of the transformer?

The info above can be found here:

http://www.ampzilla2000.com/Amp_History.html

George

George, that answers the question.  It wasn't listed in the specs (should be) so I missed it.  2000va=2.0kva, K meaning thousand.

SSS mis-qouted (I'm sure not intentionally) the size of the torroid as 2.4kva.  My Aragon 8008BB has two 1.1kva torroids, one for each channel, just as an example.

So, now we know.  A 2.0kva torroid is still quite massive, especially given the A2k's small chassis.

[John Casler]

I will check with James, but all I have read says the transformer is 2Kva.

One each in the AMPzilla 2K and a single in the SoA.

While many question the "beauty" of the Ampzilla this pic below is certainly a good look



It comes from the German Dealer and he has even posted pics of the "former" Son from the 80's (look below)



It is a very good site and can be visited here:

http://www.exciting-audio.de/default.htm

[zybar]

Just got off the phone with James (nice guy BTW) and he says it is a 2.5Kva in each Ampzilla 2000 and obviously a single one in the SOA.

I agree that in either case it is pretty darn big.

George

[Marbles]

Just got off the phone with James (nice guy BTW) and he says it is a 2.5Kva in each Ampzilla 2000 and obviously a single one in the SOA.

I agree that in either case it is pretty darn big.

George

I don't beleive it!!!

















Someone calling Bongo nice  


OK, he IS a nice dresser!

[perfectionist]

Something's awry here

I have also spoken with James, and he is a nice guy and quite the character (see wardrobe).

But, now we have three different numbers being tossed around here.

James, if you read this, I'd like to see it in print, specifically on the spec page for A2k.  I'm sorry if I'm coming off like a shmuck, but I'm down to two choices for my next monoblocks, A2k's or JC-1's.  

So I take my torroids seriously  
Size does matter

[Sedona Sky Sound]

Actually, not a misquote on my part. The pair I have are 2.4kVA. When the Ampzillas were originally designed, their spec was for a minimum of a 2.0kVA transformer (and thus the 2000 designation on the name). As far as I know, all production models actually went out with 2.4kVA transformers up to recently.  Just as Brian is always tweaking the drivers for the VMPS models, James is always looking for better sources and designs for his transformers.

I have had many conversations with James about his transformers. James is very, very, very finicky about what he uses. His transforms are precision wound with a very high flux density and per him "cost me 3 times as much as the crap low flux transforms used by the other high-end audio companies". I had talked to him several months ago and he mentioned that he had found and was testing a "better" transformer. I guess he is now using a 2.5kVA version of that one.

Hope that clears things up.  

Julian
www.sedonaskysound.com

[John Casler]

Something's awry here

I have also spoken with James, and he is a nice guy and quite the character (see wardrobe).

But, now we have three different numbers being tossed around here.

James, if you read this, I'd like to see it in print, specifically on the spec page for A2k.  I'm sorry if I'm coming off like a shmuck, but I'm down to two choices for my next monoblocks, A2k's or JC-1's.  

So I take my torroids seriously  
Size does matter

I'll post James the thread and see if I can lure him over.

I think Julian's explaination is accurate.  All printed material (manuals, articles, reviews, etc) have the 2Kva number.

Some of the originals had the 2.4Kva and the current runs have the 2.5Kva.

Maybe James will add a bit of "color" if I can get him to drop by.

[ekovalsky]

and he is a nice guy and quite the character (see wardrobe).

I got to meet him at CES.  Had I not seen him in pics from previous shows I would have thought he was just another Vegas pimp daddy.  He was very nice, at least once he learned I owned a pair of RM/X.  Guess that made me worthy in his eyes  

Of course I didn't mention I chose a switch-mode amp instead of his Ampzilla  

[doug s.]

i'm not sure that transformer size is the *main* item of importance.  implementation is also important.  take electrocompaniet amps, for example.  their "ftt" technology, which they claim delivers twice the current of a conventional power supply.  their smallest stereo amp, the aw220, rated at 70wpc into 8 ohms, is also rated at >60a current output, & is stable w/loads <1.0 ohms.  here's info on their aw180 monoblocks (w/650va transformers):

AW180 - Technical specifications -
--------------------------------------------------------------------------------
 All measurements are made at 120V / 240V  //50Hz / 60Hz
Amplifier section  
 
Output Impedance
(20 Hz - 20 kHz)
 < 0,008 W
RCA (single) input impedance 220 kW
XLR (balanced) input impedance 110 kW
Input sensivity for rated output 1 V
Max. peak current > 100 A
THD (measured at 1 kHz
half power, 8 W) < 0,001 %
THD (measured at 1 kHz
-1 dB, 8 W) < 0,001 %
Noise
(measured with both inputs shorted)
 400 Hz - 30 kHz : 90 µV
10 Hz - 30 kHz : 100 µV
   
Rated output power  
 
8 W 180 W
4 W 350 W
2 W 650 W
   
Power consumption
(no load or signal)
 115 W
   
Dimensions    
Width 215 mm / 8.5 inches
Depth 470 mm / 18.5 inches
Height 288 mm / 11.3 inches
Weight 22 kg. / 48.4 lbs.
--------------------------------------------------------------------------------
that was from their website:  http://www.electrocompaniet.no/nyweb2/index.asp   they also have the nemo monoblocks & the aw250r stereo amp, which are even more powerful.  while i prefer tubes, ec is my fave for s/s amplification.  while not tubes, they don't have a typical s/s sonic signature, yet still have all the detail & drive of the of best s/s.  i'm not sure i will ever let go my older aw75dmb's...  mebbe in a coupla years when digital amplification is fully developed.

doug s.

[John Casler]

Hi All,

James finally posted me with his response below in typical Bongiorno style:

Dear John,
This is all really very redundant. Transformers are rated according to temperature rise. Without this factor, the number per se, is meaningless. Also, the MOST important thing is the AC regulation of the TX. My transformers have 1% AC regulation which is better than anyone elses' on the planet. Also, I rate my units at a core temperature rise of 65 degrees C, which is also very stringent. There are of course a multitude of additional factors (secrets, if you wish) which I will not divulge. Officially, the TX in both my amps can be stated as 2.5 KVA.
James
P.S. By the way, I design all of my transformers NOT the TX company.

[sbcgroup1]

Personally, I believe amp specs are fairly important. There are very, very few amps that have better specs than the SoA (the Halcros are the only ones that readily come to mind)

I just went to the Halcro website. The specs on those amps are incredible. It seems like they're the best ss amps ever made.... I wonder how their character compares to the SOA's. And all that may not matter with VMPS because the Brian himself tweaks according to Ampzillas.

Have you compared the two's tone characteristics?

-Ed

[KJ]

While we're on the topic of specs, the Ampzillas report what appears to be a significant difference in distortion compared to the other products listed. Is this not as important as it would appear?

Re-posting my question.  Wasn't sure if it got lost among all the good info or if it was generally unknown.

-KJ