Zed audio on my MS275
http://www.caraudiomag.com/features/cae ... index.html
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ZED Audio Gladius The "Thinking Man's" Amp - Testing
ListeningRegular readers know I do my listening sessions in my quiet lab on a high-end reference system that I'm familiar with. But before I get into the details of my listening session with the Gladius, I thought it would be good to share some facts with you. Some of you will understand this instantly, and others may not want to believe this, but I promise you it's the truth. I measure and listen to about 130 different amplifiers a year, including car, home and pro products. I've been doing this for well over 20 years, so you can trust me on this one.
I don't believe that out of the box, without corrections, all amps sound the same. They don't. Yes, many good ones can sound indistinguishably similar, even if they are very different kinds of amplifiers. In fact, many years ago, I did demos to classrooms full of people who proved to themselves they couldn't tell the difference between an IC amp in a head unit from a well-known "sound Q" amp. These were simply very different amps that sounded very similar. The only "setup" in that scenario was very careful gain matching, and never driving either one into clipping. But amps simply don't all sound the same out of the box. Some are better than others and some are actually pretty awful. Yes, with careful EQ and gain corrections applied they can be tweaked to sound about the same, but they don't get that careful correction in real life.
Just how does a good amp sound? To start, it doesn't color the music. It doesn't add or subtract anything from the original signal, and it allows the recording engineer's vision of the intended sound to be fully reproduced. The frequency response is very flat and doesn't roll off prematurely on either end of the spectrum and the amp has the ability to drive the load properly without adding audible distortion or noise. There will be very little difference in the amount of gain on each channel. All these things can create audible differences.
Over the years, I've measured brand new "famous name" amps with frequency response variations of greater than 3dB! Sure, sometimes it was actually intentional, as the brand was creating their "sonic signature." I've also seen amps with a single ganged gain pot controlling a stereo pair of channels, with more than 4dB of difference between channels at certain places in the pot's rotation. That's never intentional.
By now it must be obvious why they simply can't all sound the same out of the box.
This is one of those amps that made me remember just why I made the decision to do in-lab listening in the first place. If I had been evaluating amps in a car all along, I might have put some of my impressions of the sonics of this amp down to an exceptionally unusual day in the car. But in the lab, with controlled conditions, when an amp sounds really good or bad, it's quickly evident. And this amp sounds uncommonly good.
The Gladius reproduced high frequencies with smoothness and exceptional detail. It wasn't brittle or hard-sounding. The best way I can think to describe it, is "natural." The amp sounded flat and very linear with respect to frequency response. The bass was deep, low and tight. The bass EQ provided a bit too much boost at adjacent frequencies and to make it more useful I'd prefer a high filter Q factor but that's a personal preference. Female vocal, piano, saxophone and acoustic guitar sounded natural and clean. The amp produced a good soundstage, which is a testament to good control of both the inter-channel gain, and the phase response of the amp. There was no audible turn-on or turn-off noise and during the duration of the test, the amp barely got warm. I listened to this amp for well over four hours, playing everything from Bach to ZZ Top and I came away very impressed. This thing just sounds natural and transparent, precisely the way a good amp should. I'll say this, if I were to recommend a 12-volt amplifier based solely on sound quality, the Gladius would make my Top 5 list. Don't let the economical price fool you, right out of the box this amp sounds very good.
Performance
On the bench, the Gladius met or exceeded every specification outlined in the owner's manual. It developed more than rated power, both 4 and 2 ohms per channel, and the power remained constant to the last watt - even with a battery voltage of 12 volts. As I suspected, after listening to it the inter-channel gain difference was very close at less than 0.1dB, and there was only 0.2 degrees of phase difference between channels at 20kHz. Signal to noise was exceptionally good, as was the stereo separation number. The frequency response was almost ruler flat from below 10Hz to above 100kHz.
The amp handled reactive loads with ease, and even the very difficult load presented by a pair of large electrostatic loudspeakers (I tried 'em just for fun) was no problem for the Gladius. During testing on the bench, with repeated full power runs and all the assorted measurements, the Gladius didn't heat up significantly, which I attribute to having more than the average amount of heatsink for the power levels reached. The amp showed no sign of stress and should be very reliable.
Conclusion
The company espouses unpopular but true notions in it's product manual and builds a very modest amp with sound quality to rival anything out there. The Zed Audio Gladius left me quite impressed and has become an additional point of reference for sound quality from a 2-channel mobile amplifier.
(...)
ZED Audio Gladius The "Thinking Man's" Amp - Testing
ListeningRegular readers know I do my listening sessions in my quiet lab on a high-end reference system that I'm familiar with. But before I get into the details of my listening session with the Gladius, I thought it would be good to share some facts with you. Some of you will understand this instantly, and others may not want to believe this, but I promise you it's the truth. I measure and listen to about 130 different amplifiers a year, including car, home and pro products. I've been doing this for well over 20 years, so you can trust me on this one.
I don't believe that out of the box, without corrections, all amps sound the same. They don't. Yes, many good ones can sound indistinguishably similar, even if they are very different kinds of amplifiers. In fact, many years ago, I did demos to classrooms full of people who proved to themselves they couldn't tell the difference between an IC amp in a head unit from a well-known "sound Q" amp. These were simply very different amps that sounded very similar. The only "setup" in that scenario was very careful gain matching, and never driving either one into clipping. But amps simply don't all sound the same out of the box. Some are better than others and some are actually pretty awful. Yes, with careful EQ and gain corrections applied they can be tweaked to sound about the same, but they don't get that careful correction in real life.
Just how does a good amp sound? To start, it doesn't color the music. It doesn't add or subtract anything from the original signal, and it allows the recording engineer's vision of the intended sound to be fully reproduced. The frequency response is very flat and doesn't roll off prematurely on either end of the spectrum and the amp has the ability to drive the load properly without adding audible distortion or noise. There will be very little difference in the amount of gain on each channel. All these things can create audible differences.
Over the years, I've measured brand new "famous name" amps with frequency response variations of greater than 3dB! Sure, sometimes it was actually intentional, as the brand was creating their "sonic signature." I've also seen amps with a single ganged gain pot controlling a stereo pair of channels, with more than 4dB of difference between channels at certain places in the pot's rotation. That's never intentional.
By now it must be obvious why they simply can't all sound the same out of the box.
This is one of those amps that made me remember just why I made the decision to do in-lab listening in the first place. If I had been evaluating amps in a car all along, I might have put some of my impressions of the sonics of this amp down to an exceptionally unusual day in the car. But in the lab, with controlled conditions, when an amp sounds really good or bad, it's quickly evident. And this amp sounds uncommonly good.
The Gladius reproduced high frequencies with smoothness and exceptional detail. It wasn't brittle or hard-sounding. The best way I can think to describe it, is "natural." The amp sounded flat and very linear with respect to frequency response. The bass was deep, low and tight. The bass EQ provided a bit too much boost at adjacent frequencies and to make it more useful I'd prefer a high filter Q factor but that's a personal preference. Female vocal, piano, saxophone and acoustic guitar sounded natural and clean. The amp produced a good soundstage, which is a testament to good control of both the inter-channel gain, and the phase response of the amp. There was no audible turn-on or turn-off noise and during the duration of the test, the amp barely got warm. I listened to this amp for well over four hours, playing everything from Bach to ZZ Top and I came away very impressed. This thing just sounds natural and transparent, precisely the way a good amp should. I'll say this, if I were to recommend a 12-volt amplifier based solely on sound quality, the Gladius would make my Top 5 list. Don't let the economical price fool you, right out of the box this amp sounds very good.
Performance
On the bench, the Gladius met or exceeded every specification outlined in the owner's manual. It developed more than rated power, both 4 and 2 ohms per channel, and the power remained constant to the last watt - even with a battery voltage of 12 volts. As I suspected, after listening to it the inter-channel gain difference was very close at less than 0.1dB, and there was only 0.2 degrees of phase difference between channels at 20kHz. Signal to noise was exceptionally good, as was the stereo separation number. The frequency response was almost ruler flat from below 10Hz to above 100kHz.
The amp handled reactive loads with ease, and even the very difficult load presented by a pair of large electrostatic loudspeakers (I tried 'em just for fun) was no problem for the Gladius. During testing on the bench, with repeated full power runs and all the assorted measurements, the Gladius didn't heat up significantly, which I attribute to having more than the average amount of heatsink for the power levels reached. The amp showed no sign of stress and should be very reliable.
Conclusion
The company espouses unpopular but true notions in it's product manual and builds a very modest amp with sound quality to rival anything out there. The Zed Audio Gladius left me quite impressed and has become an additional point of reference for sound quality from a 2-channel mobile amplifier.
[b]Chaplin[/b]
-
dBincognito
- Randy Bo-Bandy
- Posts: 3301
- Joined: Fri Feb 06, 2009 11:32 pm
Meh. Maybe its regional but Ive seen an absolute shit ton of his stuff around here under many differnt brands. Some people here might remember my zed us acoustics system I ran last summer even.Eric D wrote:No offense to Stephen, but I think the record speaks for itself. I have never once in my life seen one of his amps in a car, or even in a competition car (not to say they are not there, just I don't see them). I know I have ran across plenty of his old stuff from all sorts of companies, and plenty of it sat dead on the Soundbuggy test bench.
In the case of PG I have seen countless local systems using their equipment, and I have seen plenty of competition cars using their equipment. Now maybe PG has better marketing, but I really don't think that is the case. We on the forum have been pissed off for years now concerning PG's complete lack of marketing. ZED has been around so long, if they have all the answers, they would also have a solid understanding of marketing and their products would be everywhere.
Yep I have a bunch of the old US Acoustics amps. Nice and sturdy, but no comparison to an MS or similar
I think Zed makes some good, robust, amps with minimal flair. The board layouts are usually quite clean, with good thick traces where they need to be.
Of course the output sections have always left me with more to be desired. Not a lot of headroom, but good reliable power otherwise.
I think Zed makes some good, robust, amps with minimal flair. The board layouts are usually quite clean, with good thick traces where they need to be.
Of course the output sections have always left me with more to be desired. Not a lot of headroom, but good reliable power otherwise.