about Citation XX
Citation XX is 99% as philosophy like citation 22 ,XII ,also in 7100,990 and others you can see the same engineer thought.The think that make xx so excellent is the assebling (temperature distorsion ,high currenr source ,RF ecc).Also on the power PCB you see particular attention to bias( 2 relays,8 transistors ,in direct contact with immense heatsink).Lets try to find the driver and power schematic from some service center ,especially in USA or Japan. Harman kardon has made 1000-1500 only pieces and MILLER ,OTALA(is death?), and a japanese named Shirasura ,they dont want to publicate there creation!!!.We can make a clone ,because find that amplifier is impossible think.A photo from near distance is enough. Dont remember 30 year evolution in semiconductors can make a better unit...Also a revolution amplifier for his semplicity and design is accoustat ,all mosfet tnt 200 or 120.billkunavas@yahoo.gr
I haven't George, never even seen it, let alone auditioned it. However, I have heard what it caused. When ti was introduced, it's key advantages as advertised were peak current delivery of 500 A (later toned down to "just" 150 A, practically zero TIM, a nice voltage slew rate of 200 V/uS, with a rarely wide bandwidth for the day. Not explicitely called so, but strongly sggested as virtually indestructable.
Well, looking over the specs of the H/K PA2400 power amp I listen to for 16 hours every day, I see shades of the XX, specs al,ost the same, except that mine moves a current of measily 100 A, but has a better THD and IM specs, and with a possibly lower NFB factor of just 12 dB. It is very smooth and civilized, and imparts a feeling of being a bottomless power reserve, as if it had endless oodles of power. Bear in mind that my speakers are an exceptionally easy load to drive and are reasonably efficient at 92 dB/2.83V/1m. working in a 14 m2 room. That, with PA2400's nominal power rating of 200 W/8 Ohms, delivers all of the dynamics I can wreak out of my system no problemo.
Do you think such an amp would have been possible without H/K model XX as its cornerstone predecessor?
Well, looking over the specs of the H/K PA2400 power amp I listen to for 16 hours every day, I see shades of the XX, specs al,ost the same, except that mine moves a current of measily 100 A, but has a better THD and IM specs, and with a possibly lower NFB factor of just 12 dB. It is very smooth and civilized, and imparts a feeling of being a bottomless power reserve, as if it had endless oodles of power. Bear in mind that my speakers are an exceptionally easy load to drive and are reasonably efficient at 92 dB/2.83V/1m. working in a 14 m2 room. That, with PA2400's nominal power rating of 200 W/8 Ohms, delivers all of the dynamics I can wreak out of my system no problemo.
Do you think such an amp would have been possible without H/K model XX as its cornerstone predecessor?
I'm not so sure about no feedback There is a link from the outputs back to a differential pair at the input. The whole thing is pretty convoluted in the drawings, typical of Tandberg. Still interesting. Thanks for sharing.
I audited both the 3016A and the ML No23 in 1987, the Madrigal power amp had the more authentic sound imo.
Coincidentally, one of the German audio magazines tested the Levinson 23 in august '87, the Tandberg in october '87, and derived at the same outcome as moi.
Seemed to suggest that there's more than one way to make a record scream than skipping global nfb, for the non-holistic.
(Retail of the ML-23 was 60 percent higher though, the 3016A listed at DM 8K in 1987. US gear was terribly expensive in Europa back then, due the high dollar exchange rate and added import taxes for American manufacture)
Last edited:
I'm with Demian on this. While I owned Tandberg gear, a colour TV set, I never really liked their audio gear, it somehow always let me down a bit as I kept finding it on the lean side of things.
Also, God knows I tend to prefer audio gear which has a lower (than usual) NFB factor, but I have yet to hear zero NFB gaer which will not leave me feeling that somehow it had not been quite completed yet, as if something was always missing. It seems my ears always need SOME global NFB, currently at 12 dB as in my H/K P2400 and older 6550 integrated amp from 1993.
This corresponds well with what Jacco says of his impressions. Plus a big ditto for the prices, US gear no matter how good was wildly overpriced across Europe.
Also, God knows I tend to prefer audio gear which has a lower (than usual) NFB factor, but I have yet to hear zero NFB gaer which will not leave me feeling that somehow it had not been quite completed yet, as if something was always missing. It seems my ears always need SOME global NFB, currently at 12 dB as in my H/K P2400 and older 6550 integrated amp from 1993.
This corresponds well with what Jacco says of his impressions. Plus a big ditto for the prices, US gear no matter how good was wildly overpriced across Europe.
Last edited:
That is interesting , I have found the the opposite to be true.
The difference was astounding and immediate. There is a possibility that the improvement was due to topology because the amps without global nfb were always class-A. A similar effect I noticed on well engineered class-d (Ti's tpa311x ) so is it a systemic crossover issue and not nfb?
I guess that is a raging debate and can only speak for my ears.
On Tandberg , I keep pics of anything of Dieter Rams influence in my design reference. (the clean functional lines etc.)
-
Could be several possible rteasons, or any combination thereof. I spoke only from my own experience, which covers only a fraction on what's offered out there, so it's hardly conclusive proof.
Yet overall, I stand by my initial statement - the best sounding amps I am aware of, or even own, actually use very modest amounts of GNFB, typically 12-16 dB, however, I also own such a low GNFB amp which looks great on paper, but doesn' sound so great in real life, in fact it's rather mediocre.
Interesting when a practicing EE parses the schematics and makes a comment he/she is usually ignored. The Otala amps are nice why they do what they do is obvious. For one thing the overbias in the OS can not be ignored (IIRC far beyond the "Oliver" point).
Last edited:
Its simply a matter of available time and not to ignore.
I stick with my opinion based on listening experiences.
The open loop amps sounded superior , no question about it.
The samples auditioned happened to be class-a.
I threw them together to see if there was anything worth pursuing.
Although an excellent sound and I could have proceeded to develop Pass type BUT that waste heat is a show stopper. That was 11 years ago.
Enter the tpa311x , now that is a real game changer. (disruptive technology)
-Bruce
Thats it.
I stick with my opinion based on listening experiences.
The open loop amps sounded superior , no question about it.
The samples auditioned happened to be class-a.
I threw them together to see if there was anything worth pursuing.
Although an excellent sound and I could have proceeded to develop Pass type BUT that waste heat is a show stopper. That was 11 years ago.
Enter the tpa311x , now that is a real game changer. (disruptive technology)
-Bruce
Thats it.
The stuff like low open-bw over and over, Bob Cordell, I, and others have addressed this numerous times and it keeps coming back. It wasn't aimed at you, but you were responding to a comment where a simple look at the circuit would have yielded the answer.
Last edited:
I read through the article. The author is a cinema projectionist. You could say he has no audio development expertise whatsoever. His main argument is that nobody can't determine from the confusing measurement curves whether the audio is good or bad. The statement is proof that he has no idea about the subject. Thread closed.
I reply to my post from 2014, to reignite conversation in this thread. =] =]
- Status
- Not open for further replies.