What makes the Bloom around instruments . . .

My definition of 'bloom' is very close to Holt's/stereophile's listed in Bryon's post. I would describe it as a warm,euphonic sound quality that doesn't sacrifice or mask details. I like the earlier poster's analogy of a topograhic map of the music -very descriptive. If Chuck is looking for a warmer. more euphonic quality, then I would suggest trying a tube preamp (I don't see one on his system page so I'm assuning he's using the Wadia).
I may be totally wrong, but I thought you needed tubes somewhere in the signal path
(tubes in a cdp,preamp, amp,dac or even a line buffer) to introduce any 'bloom'. I was seeking this special quality in my system a few years ago and added a tubed preamp to replace a ss. It worked immediately. I replaced the stock tubes with NOS Mullards a year later which added a touch more magical 'bloom'. I'd even like a bit more if it comes in a powerful enough ss or digital amp to drive my inefficient speakers. So, based on your comments above, I might try out some other ss and digital amps.
I'm always learning new things from the guys and gals on Agon and just wanted to say I appreciate your knowledge and time. But I didn't want to hijack this thread. Chuck, did any of this and the above help you?

I have, with the Atma Sphere S30, what Holt's take on bloom is in my system. Having lost it with a SS amp/tube pre I went with the AS amp and recovered it.

From multitude owners of TRL SS amps I have been told that if brought into my system I would not lose that bloom I have with the AS amp.

I was convinced that a SS amp will not produce that bloom a tube amp can deliver. I hope to be wrong.

When I do get the SS amp in my system the AS amp will sit by and wait for the verdict.

That definition of bloom by J. Gordon Holt correlates perfectly with Baranyi`s experience with his father`s violin comparisions.This presence of bloom is real and I`m aware of it when listening to live acoustic instruments be it a concert or friends practicing(piano,guitar,horns etc.)A good recording can capture some of this quaility and very good systems can reproduce it in your home. Based on the OP`s descrition aboveit seems the Pass amp has superior low level resolution/lower sound floor that`s allowing him to hear the natural bloom. The Spectron amp for what ever reason is`nt as resolved despite it`s other apparent advantages.

Rob (Rtn1) posted this to my system accidently and has asked me to move his thoughts to this post, if some of you don't know Rob, he is one of the ultimate audiophiles on Audiogon.

"Hi Chuck,

If one deconstructs a single note played on an acoustic instrument, such as piano/violin/cello, the concept of bloom can be better understood. As the musician transfers mechanical energy into the instrument, the body goes from rest to vibration. This transition is the leading edge of a note. The note will then reach its peak, and evolves depending upon how much energy was used. The evolution is due to individual parts of the instrument interacting with one another, to reinforce or cancel the vibration. This results in a complexity of sound and hue that is still part of the main vibration. Next, the instrument will come to rest, and the note will decay and fill the space of the hall.

The brain processes all this information and passes judgment as to whether it sounds ‘real’. If the leading edge or decay is too short, or if the evolution is too simplistic, the result is mechanical, analytical, fatiguing, etched. If it does not have the correct decay, the result is the dreaded black background. If the leading edge or trail is too long, the result is syrupy, hazy, boring. If these elements are correct, the sound is natural, and has a paradoxical detail. The detail is a sense of roundedness, texture, depth, and a floating sensation. Because the brain perceives the sound as natural and right, it has more agreeable detail compared to the analytic sound described above.

What is the basis of this natural sound? As others have surmised, part of it is recorded and part of it is introduced by components and cabling. I no longer understand the concepts of neutral, colored, distorted, etc. The goal is to have a sound that is real and right. Just as with a great dish, it takes many ingredients.

You are correct that the Pass XA.5 has this element. That is why I believe this amp is so special. I do think there are other ways there.

1) Tubed preamp ($$$$): Lots of good choices out there. Less if you wish to run balanced, which I recommend because of the Wadia. I believe this is the most important missing piece in your system. I also am convinced that at a volume level <90, the Wadia suffers from lack of detail and dynamics.
2) Jade Audio Cables ($$): JD uses fine gauge, multistranded gold and silver wire to create this bloom. His cables are all about that natural bloom, and I have yet to hear a IC or SC that does this better. His cables are close to adding a tubed preamp, with none of that syrupy mid, rolled treble, or muted bass.
3) NVS Sound Power Cables ($$$): Nathan is using some very special wire and techniques to create this decay and sense of space. You should speak with him and describe what you need.
4) HiFi Tuning Gold Fuses ($): I tried the silver fuses, and they were mechanical. The gold ones are just right in my system.

Best of luck on your new obsession. This element has been my obsession for the past year."

Chuck

Thanks to everyone! Now my heads spinning trying to explain my thoughts about what the Bloom is to me.

I have a soundstage that is detailed, wide, deep and layered. I think that the Bloom that I'm wanting is the glow or highlighting around each instrument. It does seem to be highlighted by a blacker void around it, which brings out even more minute aspects of the tones, making it more realistic sounding.

It sounds like you've all got me seeing that the most important ingredient is lowering the background even more to let the micro pieces show themselves first. Then maybe enhancing it further if I need to with either mods or upgrades.

Thanks again to everyone!
Chuck