ARC LS25 with PASS X250 - bad match? Seems bright.


I just switched my amp from an arc VT100mkII to the PASS X250. Upon doing so, I heard more brightness and even harshness in my system. I have heard that the PASS amps are not bright, so I am suspecting either a system mismatch, or that the X250 is more linear and is revealing another source of brightness in my system, that the tube amp perhaps was masking.

System:
Rockport Mira Monitors
Wisdom SCS Subwoofer
PASS X250
Audio Research LS25 mk I
Bryston 10b Sub crossover
Cambridge DacMagic
PS Audio GCPH
J.A. Michell Tecnodek
Dynavector 10x5
Cardas 100b microtwin balanced interconnects
Cardas Cross speaker cables

I am having a feeling that maybe my source components are not up to par with the rest, and that may be the cause of the harsh brightness at times. Or, that the PASS does not like the ARC LS25. What do you think?

Thanks!
Mark
marktomaras
Some people may disagree but I think part of the problem is the X250. I had one in my system and complained that it had too much midrange and high energy. Great bass control WOW!!! I have also heard the VT100 and loved it. Night and day difference between it and the 250. The X .5 series is supposed to be much smoother than the original series from my understanding. Overall I didn't keep the X250 very long. Also I think it depends on other factors but your cabling is on the smoother side so its hiding even more of the brighter aspects of the 250. Personally I would keep the VT100 and try more neutral cabling to open things up more. You might be surprised. I had the Cross speaker cables and while they were a step up from my older cables they are not known for neutrality or openness. Cabling is very important or at least has been for me. Just my 2 cents.
Steveaudio makes a good point about the Cardas cabling. Once I upgraded to better cabling the sound really opened up. The VT100 is a very nice amp.
Thank you very much for the advice and thoughts. I thought I would try the pass x1 with the x250. The sound is still harsh in the highs. I thought that is what bright means, but perhaps my lingo is not precise or accurate.

We are talking the high frequencies of vocals, some high drums, definitely cymbals, and other treble. It sounds harsh, and well, bright!

So, enter the X1. Still sounds similar. Harsh highs. But now I am lucky, that though my audio research amp and preamp are for sale, they haven't sold yet. So I will set all of them up and do a proper comparison between the arc amp & preamp and the pass amp and preamp.

My sources still may be contributing, but at least I'll know which amp-preamp combo I prefer. I sort of really want to love the pass gear. I am attracted to the significantly less maintenance they require over the tube gear. But who knows, if the audio research stuff sounds way better, maybe I have to rethink about which units to sell!

I'll do this test on Friday, and I'll let you know what happens.
ARC products are bright sounding, more like solid state. Pass is not a bright amp.
Agree with Samzx12. I have an ARC LS25 Mk I with GNSC ref mod driving the Pass X350.5. Speakers are Verity Parsifal Encores. No problem with impedance issue. Prior to getting my amp, I had listen to it in a side-by-side comparison with the X-350 at a friend's house. Speakers were Avalons. We had also compared the ARC Ref 2 Mk I and the Pass X0.2 driving the X350.5 at a later date.

Next to the X350.5, all 4 guys conducting the test that day agreed that the X350 sounded bright, cold, and "solid state", while the .5 version had the signature warmth and musicality that Pass had been known for. The difference, we all thought, warranted more than a ".5" upgrade status.

The X0.2 preamp sounded more tube like than the stock ARC Ref 2 Mk I. All the other 3 panelists voted for my friend to keep the Pass pre and ditch the ARC. But I voted for the ARC. My reason was that if he replace the Sovtek tubes with some NOS tubes, the ARC would have more of that tube magic in the midrange.

I've just had that experience myself. I had just moved back into my house in May after a 2-year major remodel. My system now sits in a dedicated room. I had plugged in some early Rusian tubes into my LS-25 and forgot all about it. I thought my system sounded a bit lifeless and dry in my new room. About a month ago, while I was cleaning I realized that I had Russian tubes in my pre. I swapped them out with some Amperex 6DJ8s and now it sounded much better.

FrankC