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My Steg MSK Class A, MS 2125,275, M 50, ZPA .5 SQ test

Posted: Mon Sep 25, 2017 10:36 pm
by Virtue
Hope you enjoy the read!

Thought I would throw this up here. So many times I have read people who say there is no difference in sound quality from amp to amp, or very little difference. I was curious for decades and finally sat down and did a side by side SQ comparison. Here are my findings. These are my amps that I own.
The signal was coming through my home audio set up which consists of a Rega Saturn CD player, Pass Labs 'Aleph P' pre-amp with modified caps internally, and custom Focal tower speakers I made with very high end crossovers. The sound was very different through all amps. I ranked them from best to worst.

Steg MSK Class A
-the sound that came through was incredible. It had a detailed sweetness that all other amps could not produce. It was able to produce the 'leading edge' of the music. The sound stage was very wide. It sounded as if you were part of the concert right in front of you.

ZPA .5
-The sound that came through was detailed. The sweetness was not there. The sound was right in your face, which was not enjoyable. Harsh one could say. Almost like someone yelling in your face. It was able to produce the leading edge of music. The sound stage was very wide.

MS 275
-The sound was good, not as detailed. The sound was very similar to the ZPA .5 with the sound being right in your face. Was not able to produce the leading edge of the music. Softer detail I would describe it as. Sound stage was wide.

MS 2125 and MAC 500
-The sound was good, not as detailed. The sound was very different from all the other amps. All mid-range sounds were very distant. Like if you were at the back of the concert hall. Pleasant though, but the MS 275 would be just as loud when vocals were in the music even though the MS 275 had a lot less power. Was not able to play the leading edge of music. Sound stage was wide, but distant. One could play this amp at loud volumes and not get fatigued.

M 50
-The sound was well, ok... I am very surprised how the over all sound is disappointing compared to the MS 275. Even though the 2 amps share the same components... Was not able to produce the leading edge of music. The sound stage was not wide. It played music I guess one could say. Not badly but, not with excitement either.

Over all this was quite an eye opener. Some will have there opinions, but, this is what I personally heard. I would say the Steg was as close to my Krell house amp as possible. I was shocked! It is very difficult for pre-amps and amplifiers to reproduce the leading edge of music. The Steg and ZPA was able to do this. I would say that if one replaces the op amps in the MS and M series amps they would get better sound. But at an added cost... This is the down fall of many amps, it's their op amp filled electronic crossovers and line drivers. I did not have a crossover or line driver in front of any amp. The ZPA's sound would degrade if this was the case and believe me, it needs a line driver... All other amps do not require any with a decent head unit.
This is obviously a test in house, not a car. Head units will really effect sound. Patch cords will effect sound. The width of sound stage will not really be noticeable in a general car. But the leading edge of music and depth of music, you will hear if the mids are of a good quality and placed up high near the dash.

The quote I read says: "ZPA's will have the same sound essentially as you get from the MS, they just feature a bigger shinier set of balls." Not so true...

Re: My Steg MSK Class A, MS 2125,275, M 50, ZPA .5 SQ test

Posted: Tue Sep 26, 2017 1:59 am
by Mr. Wild
Nice test!

i will only comment that with old amps the sound may or may not be same as new from factory.

Re: My Steg MSK Class A, MS 2125,275, M 50, ZPA .5 SQ test

Posted: Tue Sep 26, 2017 2:39 am
by ttocs
sounds like a fun a-b.

Re: My Steg MSK Class A, MS 2125,275, M 50, ZPA .5 SQ test

Posted: Tue Sep 26, 2017 11:36 am
by Virtue
It was a fun comparison. I've wanted to do it for a long time. Yes, The STEG is a newer amp and design. I just threw it in there for fun. But as for older amps and their components degrading over time, just the electrolytic caps start to dry up. In many cases no sound goes though them and if so, they use mylar caps. The sound is 'their sound'. None in the ZPA's will have this issue since they use WIMA film capacitors for the signal areas.

Re: My Steg MSK Class A, MS 2125,275, M 50, ZPA .5 SQ test

Posted: Tue Sep 26, 2017 8:26 pm
by Bchester6
Nice job... Not all amps are created equal and that's just how it is. My Xtant amps sound alot different than my PG and Audison amps when hooked up to the same components in the same vehicle.

Re: My Steg MSK Class A, MS 2125,275, M 50, ZPA .5 SQ test

Posted: Fri Sep 29, 2017 3:50 pm
by Eric D
Your test would only be useful if you played the amplifiers at the same level (gain matched). In this case you will likely find you cannot distinguish the difference between any PG amp (those which you mention have nearly identical circuit designs). You still will probably hear differences between brands (different circuit designs can sound different).

When you don't level match, I would guess 80% or more of the time the most powerful amps will sound the best. Humans tend to "push things" and the more powerful amps will have more control with less distortion, in regions where the lower power amps will be overly stressed to compete.

I do find it pretty striking you found the ZPA0.5 and MS275 were better than the MS2125 and MAC500. I would expect just the opposite, as the MS2125 and MAC500 are dual mono designs, and the ZPA0.5 and MS275 have a shared single power supply. Although all 4 have the same circuit design, the dual power supply models should have a competitive edge in sonic performance.

Re: My Steg MSK Class A, MS 2125,275, M 50, ZPA .5 SQ test

Posted: Sat Sep 30, 2017 11:54 am
by kg1961
I agree with Eric but I did like my steg amps very nice

Re: My Steg MSK Class A, MS 2125,275, M 50, ZPA .5 SQ test

Posted: Sun Oct 01, 2017 3:30 am
by Bchester6
kg1961 wrote:I agree with Eric but I did like my step amps very nice nut love of also???
:shock: Huh? LOL!

Re: My Steg MSK Class A, MS 2125,275, M 50, ZPA .5 SQ test

Posted: Sun Oct 15, 2017 11:36 am
by Bertje
I did a test like this also, with Genesis DM, Celestra RA220, Audison Sedici and a few other PG amps. I found the ZPA0.5 the best PG amp on sound in my home system. The difference with other PG amps is the pre-amp stage, there are no opamps in it. Just my opinion...