What makes the Bloom around instruments . . .

The XA30.5 had a strong bass and good high frequency extension, BUT, the instrument that was so prominent that it was masking everything else was the drums.

I have never heard an effect like this with the XA30.5. I don't doubt what you are hearing, but I'm wondering if there's some kind of unhappy interaction between the amp and outboard crossovers/speakers that's resulting in a skewed frequency response.

On the other hand, when I think of drums overpowering other parts of a recording, I usually associate that with room modes. But presumably you would hear the same room modes with the Spectron amp, so I don't know what to think. I assume you did not change the position of the speakers when you changed amps.

Bryon

I own a Pass XA30.5. To my ears, it sounds pretty neutral. I'm not doubting you about the difference in bloom you heard between the Pass and the Spectron. But I am wondering whether the difference in bloom is attributable to something that the Pass amp ADDS or to something that the Spectron amp SUBTRACTS. Here are two possible scenarios:

1. The Pass amp ADDED bloom to the system, whereas the Spectron amp did not.

2. The Spectron amp SUBTRACTED bloom from the the system, whereas the Pass amp did not.

I don't know anything about the Spectron amp, other than its excellent reputation. But as an XA30.5 owner, I can say that it does not seem particularly additive, at least not in the way I associate with descriptors like "bloom," which makes me think of euphonic harmonic distortion. This observation about the XA30.5 is confirmed by Stereophile's measurements, which show that its harmonic distortion is mostly 3rd order, and that it is otherwise rather harmonically neutral.

In light of that, I am inclined to believe that scenario (2) is the more likely of the two, and that the Pass amp's advantage over the Spectron was that it was allowing the bloom from the recording, or from other components, to be heard, while the Spectron was masking it. Of course, this is speculative.

It would be interesting to hear more about the system used to audition the two amps.

Bryon

I also think Chuck's speaker cables and such are more resolving than your anti cables. So maybe more details/resolution are heard in Chuck's system.

Hi Joe. This is certainly possible, though I don't know that it effects the likelihood of either scenario I described in my last post.

I suppose there is an argument to be made that Chuck's system, if it is more resolving, might reveal characteristics of the XA30.5 that are inaudible in my system. But I have a hard time believing that any additional resolution would reveal "bloom" as a consistent characteristic of the amp. I could be wrong about that. I also could be wrong about what Chuck has in mind when he uses the term "bloom." It seems there is some difference of opinion about what that term means.

My description of the XA30.5 is based on hearing it in two different systems (mine and a friend's). I have also heard other Pass amps from the XA.5 series in other settings, including some systems that are very revealing by any standard. It is on the basis of those experiences that I have characterized the XA30.5 as "neutral," rather than having "bloom." Of course, other people familiar with the XA30.5 may have different experiences and different opinions, which I am certainly open to hearing.

Bryon

bloom: A quality of expansive richness and warmth, like the live body sound of a cello.

-From J. Gordon Holt's Stereophile audio glossary.

This is what I thought Chuck meant by "bloom." Maybe he can tell us.

Bryon

My question really didn't have anything to do with the quality of the XA30.5, only the Bloom that I got from it.

It probably would have been best if I hadn't mentioned the amp. I did it, not thinking, because that's where I had the Bloom and I really liked that part of the sound.

I didn't take you to be questioning the quality of the XA30.5, and even if you had been, it's no big deal. Nothing is perfect, and it's just stuff anyway. ;-) My comments were intended to offer the perspective of a person familiar with the XA30.5, not to defend it from any possible criticism.

FWIW, I'm guessing that the bloom you heard with the Pass amp in your system was a consequence of its interaction with other components, rather than being an intrinsic characteristic of the amp. But that may be academic at this point.

Bryon