2. amps-preamps
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Soundstage drastically worsened when I replaced a solid state AV amp with tubes.

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Hello. I am streaming music with Qobuz and Apple Music through a McIntosh MX123 A/V processor, into a McIntosh MC8207 7-channel solid state amplifier (200 watts x 7 channels), into Klipsch La Scala speakers (105 dB sensitivity). (I also have an SVS 2000 sub-woofer.) (The components are behind the wall in the photo.) With that setup, I had a 180 degree soundstage, extending laterally well beyond my speakers and from ceiling to floor in height. I wanted to see if tubes would improve the system for music listening, so I added a McIntosh MC275 amp to power the front L and R LaScalas. Now the MC8207 is used only to power the surround speakers. The MC275 improved the warmth of the music and greatly increased the bass. However, the lateral soundstage is gone. I now have a deeper soundstage focused perfectly between the speakers, but the lateral and height extensions are gone. It is as though I am back in the 1950s listening to a single mono speaker directly in front of my listening position. The music is beautiful, but I miss the soundstage. Other than replacing the amp for the LaScalas, everything else is the same. I did have to temporarily add an extension chord to the McIntosh power cord until I can get one of the proper length, so that could be the culprit. Otherwise, does anyone have any ideas regarding why the soundstage so drastically changed? I expected the soundstage to improve with the tubes, but it worsened. Thanks for your thoughts!

therandyman
mulveling's avatar
mulveling
1,774 posts
 

Are you 100% sure the mode switch on the MC275 is set to stereo and not mono?

It sure sounds like OP is inadvertently getting mono output, whether by erroneous switch setting or miswiring (even internally - wonder if the amp has been worked on?).

mike4597
53 posts
 

I recently switched from a SS amplifier (the excellent Benchmark AHB2) to tubes (Rogue Stereo 100 Dark) and had the opposite experience—significantly wider and deeper soundstage, but only modest change, if any, to vertical dispersion. The real change, however, is that the SQ has improved in terms of realism—it seems more “organic” and less dry.  As others have suggested, the MC275 (which I considered before buying the Stereo 100) could have a fault if the SQ has collapsed to seem mono.

rbertalotto
138 posts
 

Wouldn't the Crosstalk specification of different amplifiers, preamplifiers and source affect soundstage?

zlone
463 posts
 

If the MC275 is new, you need to give it some time. I experienced the same thing with a new solid state amp, it took a couple weeks of continuous play to establish the soundstage. 

therandyman OP
33 posts
 

More great comments, thanks.  To answer some questions:  The amp was purchased as new, but had been on the dealer's floor as a demo.  The amp itself is well burned-in.  The tubes are new, but have been left "on" for a few weeks prior to installation at my home.  They probably need another 50 or so hours to properly burn in.  There is no photo because I did not know how to properly attach it to my post.  I copied it, pasted it, it appeared on my pre-posting screen, but evaporated when I entered the post.  I also realized that I have different balanced cables running from the amp to the processor.  I'll look into that as well as the power cord.  Thanks again for all the thoughtful, non-judgmental responses!

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