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Old 18th August 2007, 07:37 PM   #1
lmcyee is offline lmcyee  Hong Kong
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Default Question on X250.5 and X350.5

I would be grateful if some one can help me understand the difference I heard during a recent audition between the X250.5 and X350.5. Whilst this might not be a new topic, I have yet to find any definite answer/discussion on the web in this regard.

What I have been told by the Pass dealer and from reading difference sources is this: the two amplifiers use the same circuit, and therefore their sonic difference is minimal. The power difference would only be apparent when used in a room of significant size. In an average room, both amplifiers would produce very similar results.

During a a recent audition of these two amps, their sonic nature did sound very similar to me. Nevertheless, it was obvious the X350.5 provided significantly better control on all ranges of the sound (whether it is treble, midbass, or bass) when compare with the X250.5. The X350.5 excels in all areas, with much better image, more clarity on instruments, and much finer details on timbers of instruments, and a lot more subtlities. I noticed it immediately at the first note played after switching from the X250.5 to the X350.5.

This is not the kind of difference I would have expected based on what I was told/have read. I would be much grateful if some one familiar with these two amps can explain it to me.

For your information, the audition system used included a pair of Dynaudio C2, a Pass X1 pre-amplifier, and a Metronome CDP. Only classical music was playedm which included Bruckner 9th, Mahler 5th, Bach Organ concerto, Brahms choral works, Bach violin partitas, Debussy preludes. It was auditioned in a room of about 150 sq ft.

Your thoughts would be much welcome. Thank you.
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Old 18th August 2007, 09:40 PM   #2
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Location: Columbia, SC
Though the circuits are similar, the power supply in the 350 is going to be bigger (good for dynamics), and have higher rail voltages (something which makes MOSFETs happy). More output devices in parallel also factor in (better control of bass).
Don't overlook the benefit of more muscle when playing power pieces like the Bruckner.

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Old 19th August 2007, 12:01 AM   #3
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The amount of class A watts is different also.
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Old 19th August 2007, 08:52 AM   #4
lmcyee is offline lmcyee  Hong Kong
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Join Date: Aug 2007
Thanks for your reply.

I think it means that contrary to what I was told/read, the difference in power in the X250.5 and X350.5 is apparent regardless of room size or the type of music played. It does not request the full tutti of an orchestra to demonstrate the difference. Even the single violin in Bach, and the first few notes of the trumpet solo in the Mahler 5th, confirmed the more weight and composure of the performance. The result far exceeded my expectation.
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Old 19th August 2007, 10:17 PM   #5
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The X350.5 has a larger output stage, power supply, more
heat sinking, and runs at considerably higher bias. As a
result, it tends to sound better at lower power levels.

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Old 21st August 2007, 09:58 PM   #6
mert is offline mert  Turkey
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Default x.250.5vs. x350.5

I have X250.5 and not thinking to upgrade it to 350.5 Simply because it will not yield marginal benefit. My system: Willson Sophia 2, Boulder 810 Pre, Accuphase Dp-78 Cd/Sacd, Exact Power Ep 15A.
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Old 22nd August 2007, 05:48 PM   #7
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Default Re: x.250.5vs. x350.5

Originally posted by mert

I have X250.5 and not thinking to upgrade it to 350.5 Simply because it will not yield marginal benefit. My system: Willson Sophia 2, Boulder 810 Pre, Accuphase Dp-78 Cd/Sacd, Exact Power Ep 15A.:whazza:

You know? There are people following the more the better.
Papa knows it for his commercial purpose (positive meaning).

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Old 8th September 2010, 05:24 PM   #8
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What happened in the bass region when you do un upgrade to X350.5?
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