Newbie Here Tubes vs SS Question

[latenite3]

Hi. I have been reading your forum for a while and have gathered much valuable information. It's priceless to have access to so much knowledge thanks to you guys. Thanks so much!

My equipment consists of:
McIntosh c2200 pre
McIntosh mcd 201
2- McIntosh Mc275 IV in mono
Tyler Acoustics Linbrook Sig 1 (4ohm)

I have never heard Pass Labs, just good things about them and
I would like to know if replacing the amps with Pass Labs X150 would be an improvement? My set up has plenty volume, but my problem is the low bass. At low to moderate volume it's great, but when I start increasing the volume the bass looses definition and and sounds muddy. Would the amp exchange help me and would I still have plenty of power or is the X150 not enough and I should be looking bigger? I don't normally listen at high volumes, but I want it there when needed. Any and all thoughts welcome.

Thanks in advance for your help.

Regard,
latenite3

[GRollins]

This is a difficult question to answer. All things being equal, the bass control would probably improve. However, the X amplifiers are not necessarily going to be as tube-ish sounding as the McIntosh. Depending on your preferences, that might be a problem.
In terms of a tube-ish sounding solid state design, I would suggest the Alephs (not current Pass product, but available used or DIY) or the XA designs rather than the X. Compared to the XA amps, the X will likely have better control in the bass. Compared to the McIntosh, either the X or XA would be have better bass control. As to whether the XA would be tube-like enough for you...that's up to you.
As far as power goes, tube amplifiers are often regarded as sounding "more powerful than their ratings." I generally think in terms of 1.5 to 2 times the power when going from tube to solid state. Shooting from the hip, I would say that your perception of available power would be about the same.
The classic solution for a situation like this is bi-amping, solid state on the bottom, tubes fro the mids and top. That, in turn, depends on the speakers.

Grey

[anatech]

Hi latenite3,
I agree with Grey here. Bi-amping is the best solution depending on what you want. It's possible you don't really know right now.

You bass problem could be your speakers. Have a friend bring over another pair to test before you do anything. McIntosh amps I've rebuilt normally don't get a complaint of not enough bass.

-Chris

[JCM]

...my problem is the low bass. At low to moderate volume it's great, but when I start increasing the volume the bass looses definition and sounds muddy.

A problem I am somewhat familiar with. But I don't know anything about your amplifier - is it Class AB bias ? If so, I think it is understandable.

I had the experience of creating a small Zen-like amp and mating it with a BoZ (the gain had to be increased) and simple LC tone controls. For some reason, the bass Never crapped out, not only that, it seemed to have a clean, somewhat effortless sound - the result of Class A bias, I believe. Such a circuit, with high distortion, poor damping factor and all else against it cannot possibly drive a speaker with power-hungry-looking woofer and sound good (not that it would have the same success with other speakers) - yet it did. I believe that such an arrangement, scaled up to the level of an Aleph amp, would perform very well.

I go so far as to believe that whatever the power level of the amp you would choose, as long as it's Class A bias, you won't experience this sonic deterioration.

If your amp has tone controls - I have a dim view of the vast majority of them, and maintain that they are responsible for tremendous misery, and that the cure is a simple LC network with 12 or 18 dB / octave slope centered anywhere from 70 to 100 Hz, preferrably switch selectable. Alternately, op amps can be used with LC arrangements or as active low and high pass filters with a differential stage. (I posted my thoughts on this in the last page of the "JFET BoZ thread.)

I may be off base, but these are my suspicions of the problem.

[anatech]

Hi JCM,
Hmmm. I've seen many class AB1 and class B amps that had no problem here. Damping factor (or a lack of it) will cause the bass to get muddy at higher levels. So will thin speaker wire.

If your amp has tone controls - I have a dim view of the vast majority of them, and maintain that they are responsible for tremendous misery,

If they are in the feedback network - yes!
If they are in an equalizer like arrangement (electrically) - yes!
If they are well made, but abused - yes!

If the loudspeaker system Q is higher than 1 for the bass driver - yes!! Even if there are no tone controls. This is more common that you really want to know.

-Chris

[JCM]

All valid points, Anatech. I could be mistaken, but the problem sounded familiar to me. Without knowing more about the amp in question, it's hard to say. If it's class AB bias, the critical part is how robust the power supply is.

[anatech]

Hi JCM,
True. If you are dealing with a cheap amp, all bets are off anyway.

I suspect your problem was from something other than the class of amplifier. Often I have seen the capacitor in the feedback network that goes to ground go open. You lose the bass first.

-Chris