Preamp for Aesthetix / Atma-sphere


Hi

I have the Aesthetix Io Eclipse with volume and dual power supplies, Atma-sphere MA-1 monoblocs (140 watts) and Audiokinesis Dream Maker (93 db sensitive) speakers. These are great components. My question is about system synergy, how to make them play together.

I have been running the Io direct to my amps since I first bought the Mk2 version back in 2004. At the time, I had a Krell FPB600, and in that context, it was a blessing, and a great step up from the Krell KAV 250p preamp. I'll never forget my first impression with the Io - it was like going from the wooded hills up into the mountains. There was no going back.

With volume, the Io functions as a preamp. It looks like a preamp. Someone here on A-gon said going direct is best - which I interpreted as: it IS a preamp! So I thought, OK I have a combined phono and preamp - problem fixed. But it wasn't.

From recent testing I have finally become convinced that the Io does benefit from a separarate preamp. Even if clarity and detail is better going direct from the Io to the amps, the punch and "here-ness" of the music is clearly better with a preamp in the chain, at least in my system.

Trouble is, which preamp? I am testing a small solid state Musical Innovation preamp, which helps with the punch but veils the music. An optimal solution might be the Aesthetix Callisto, preferably with dual power - but I don't have the space, and I already have a lot of tubes and tube heat. I have space for one or possibly two boxes.

From what I have heard so far, a solid state might do the job well (in my tube-rich context), however it should not impart any s-state artifacts or reduce the resolution from the Io Eclipse.

The ideal would be to test a few tube and s-state preamps, and then decide. However, this is difficult where I live, so advice is welcome.

My question relates to my own setup of course, but is relevant for everyone with a top phono stage on the one hand and amps on the other. What is best in the middle?

From recent testing I have learned that problems that I thought were related to the speakers, the phono pre, the pickup and so on, were in fact related to the preamp issue. For example, the Dream Makers straight from the Io may sound a bit lazy and washed out in the bass, very clear in mid and treble but not fully embodied. Plugging in the solid state pre, the situation becomes dramatically different, now the speakers are driving, propulsive. Very enjoyable, but some detail is lost and some transistor things added that I don't want.

So I am looking for a solution with most of the plusses, and not much of the minuses. The preamp must be fully balanced with XLR in / out.
-
o_holter
I have two close friends that run various iterations of the Io phono stage, and both use them in combination with the Callisto line stage preamp. Obviously these are made to work together and I can attest to the amazingly high quality sound that they produce. The word 'magical' comes to mind in the way that they can transport you to the musical event with good recordings.
From recent testing I have finally become convinced that the Io does benefit from a separate preamp. Even if clarity and detail is better going direct from the Io to the amps, the punch and "here-ness" of the music is clearly better with a preamp in the chain, at least in my system.

Absolutely, I've been saying that for years, I ran the IO + Callisto in my system for a decade and the IO benefits significantly from adding preamp.

Based on your description of sound and your preferences I would go for Aesthetix Callisto with single power supply. You should be able to find a near perfect one used here at Audiogon and although you must deal with more tubes there are countless options to tune that combo to best effect with your speakers.

I don't personally think a solid state will deliver what you are after. I've done quite a bit of listening with IO and Callisto as well as countless tube swaps (easy to find old posts here at Audiogon).

I think what attracts you to your current sound is the density and musicality of the IO so you need to play to that strength.
Ditto Albert's suggestion. Albert is one of the few people I know who've been able to critically audition both the Io by itself and the Io through a Callisto. As an alternative, I wouldn't discount using a used Atma-Sphere MP-1 as the linestage preamp for your system.

I think you risk playing major havoc to the very things you value most to introduce a SS linestage into things.
Thanks! It's like I suspected. In the ideal world I could have tested both the Callisto and the MP-1. Would have been interesting. Well, anyway, I will have to start saving.
I agree with Albert and Rushton, try a high quality tube line stage. I believe that this is the path to the realism and natural sound you're seeking. The two models suggested should be excellent in your current system.
Best of luck.
Charles,
With the Atma-sphere MP-1 you would get an extra phono stage too. Has anyone ever compared it to the IO.
I have not heard the Atma-Sphere MP-1 in my own system in many years.

My suggestion for the Aesthetix was based on what O_holter had already chosen. Safe bet that Aesthetix preamp and phono are a great match up, I know from ten years in my own system.

As Charles1dad and I both pointed out, it's about the tubes. Aesthetix and Atma-Sphere fill that order but the only way to be absolutely sure is to own both. That's difficult at best and why I suggested used Aesthetix (or Atma-Sphere) here at Audiogon.

Purchase at a fair price and take care, you can live and listen long term and see if the magic is there. If it fails you can put it back up here and get most or all your money back.
I am also using the IO and Callisto Eclipse, both with dual power supply, and it is a magical combination!

As Albert has mentioned, adding the Callisto to the IO do improve on the dynamics considerably. Even with my previous Callisto Sig with 1 power supply, this improvement could be heard very easily.

To me, with stock tubes, I found the combo slightly too warm to my liking, so I have just started tube rolling on the units. My first step was to put a pair a Telefunken CCa in the V1 position of the Callisto, resulted in tighter imaging, better separation, more air and a slight reduction on the warm, exactly what I was looking for.

Then, I put another pair of Telefunken CCa in the V7 position of the IO and get similar, but much more subtle, result. My next step will be working on those 12AX7s.

Usually, I am not an advocate of NOS tubes, but in this situation, it works!
I have ended up with a used Einstein The Tube mk2 preamp, since I could get it for a good price (in Europe). It may not be ideal (compared to Callisto or Mp-1) but is what I could afford right now. The Io/The Tube combo sounds very good, clear, quite 'muscular', and even if I perhaps don't get 100 percent from the Io, it beats every other combination I have tried (including Io direct to the amps). Perhaps I get the chance to try a Callisto later. (I have the heat allready, the Einstein contributes by running hot.) I agree with the NOS comments. Selected Telefunken ax7s work very well in the gain stages of the Io, notably better than the stock tubes, and I plan to get some (2 6922s and 1 au7) for the Einstein also.
I had a similar experience as Thekong with the Callisto with different tube mono blocks. Of course its all synergy and taste.

I found a Purity preamplifier to be more to my taste. In your case a conversation with the manufacture regarding compatibility would seem like a must.

http://www.purityaudiodesign.com/contact.htm
The reason we created the MP-1 is that we needed a preamp that used the same direct-coupled technology at its output that our amplifiers use (and were looking for the same transparency thus granted by that approach). This makes it very different from most tube preamps.
Clearly, a listening test would be interesting! That's my summary of comments so far. The Callisto, the MP-1 and Einstein The Tube all sound very good - but which is best, using the Io Eclipse as input, and Atma amps as output? There are two potential synnergies here, both with the phono (get the Callisto) and with the amps (get the MP-1). Or The Tube is actually right there up front. Who knows? Comparisons would be useful.
So far, the verdict has been in the direction of Callisto, but I like the OTL sound (or lack of it) so I am open to the MP-1 also. For now, for a lower price, the Einstein serves me well, also in the sense that I hear more of my phono and amp upgrades. The grip on the speakers is excellent. Perhaps a bit too muscular, not as refined as some preamps, can't judge, but a big step up for me. Budget did not allow the others (or, ideally, comparing all three). Albert, you are right that I am drawn to the Io Eclipse sound, all the more so since I changed from a worn Lyra Titan to a new Atlas nine months ago. This really sounds excellent. For some reason (German engineering?), with the new preamp, I have especially loved the sound with new elektro music like the "Vermont" LP. BTW I thought that a one-box solution would give less heat, but that is not the case, The Tube runs very hot, perhaps the equal to a Callisto with one power supply. I measure 75 degrees Celsius at the top of the transformers, but Einstein support says don't worry. The preamp can be improved by a pair of NOS 6922 tubes for the relevant input, in my case, the Io phono stage, and perhaps a NOS au7. I will order some tubes, to try. For now, this is clearly the best I have heard, from my system as a whole.
Congratulations on your much improved sound performance! A high quality active preamp again demonstrating their value in obtaining improved enjoyment, music reproduction and emotional connection.IMO they are essential.
Charles,
Thanks. You need fork, knife and spoon to enjoy the meal. For a long time I used only knife and spoon. Phono preamp direct to amps. No preamp. So I am happy with this investment, and the somewhat muscular effect of the Einstein, being "half-blood" solid-state (in the power supplies), is interesting and perhaps quite a good thing in my context. Although the Callisto or MP-1 might give an even more refined sonic picture.
So far, the verdict has been in the direction of Callisto, but I like the OTL sound (or lack of it) so I am open to the MP-1 also. For now, for a lower price, the Einstein serves me well, also in the sense that I hear more of my phono and amp upgrades. The grip on the speakers is excellent. Perhaps a bit too muscular, not as refined as some preamps, can't judge, but a big step up for me. Budget did not allow the others (or, ideally, comparing all three). Albert, you are right that I am drawn to the Io Eclipse sound, all the more so since I changed from a worn Lyra Titan to a new Atlas nine months ago. This really sounds excellent. For some reason (German engineering?), with the new preamp, I have especially loved the sound with new elektro music like the "Vermont" LP. BTW I thought that a one-box solution would give less heat, but that is not the case, The Tube runs very hot, perhaps the equal to a Callisto with one power supply.

I had the IO Eclipse here and ran it paired with Einstein The Tube, Ypsilon PST 100 preamp, The Messenger, an Allnic L-3000 (original small transformer) model and Aesthetix Callisto Eclipse.

The part you need to know is the Einstein gets a massive upgrade when you remove the 12AU7 tubes and replace with 5814 CBS Hytron.

I don't think you can prepare for what that does to the Einstein, you might be happy for a long time. This takes away a bit of the electronic but preserves the dynamics and resolution. It's different than what the others I mention bring to the balance but all are very good quality pieces.
@ Albertporter, Hi, Will the 5814 CBS Hytron tube go in the place of any 12AU7 tube socket that is used in other name brands of componets, never heard of this tube, where is it made, and by who, what is the projected life span, where do you get them from, Is there a specific year that is very good?
Thanks, Albert, for interesting advice, which I will follow. You probably mean the one 12AU7 tube (only one in The Tube mk2). Do you remember the type of 5814 CBS Hytron? There are some at Ebay, some with orange and some with blue letters. Some are called "CBS Hytron 5814 A Black Plates D-Getter". These may be the same tube, not sure.
I did some more listening with the Einstein at low-moderate levels (since the family protested last night). It doesn't evoke the grand passions of the higher level but it still sounds very good.
I wonder, would it sound even better if I turned the amp gain a bit down. If I remember right, it is possible to do this in the MA-1, simply by taking out a pair of output tubes.
Interesting,

I have the Io with 2 supplies and Volume controls. I have never been wanting for dynamics. The whole system interface & efficeincy considered + room = jump or dynamics. I am not talking about sound pressure.

I run electrostats mostly but I am familiar with the big dynaudio C1, Revel , Wilson and Avalon etc. You don't miss want you don't have but my exposure to these other systems tells me I am ok.. with Beveridges it is actually startling on dynamic contrasts... again I am not talking SPL.

I can't argue with the quality of your equipment. It is surprising .

With its warts, the Io is still probably one of the best phono stages I have heard ( Klyne, ASR, Zanden + more) so I would have tried for an Atma or Callisto to trial if at all possible and see where you land.. It is an interesting and expensive with variable outcome in terms of the journey.

Good Luck
You would need to remove a specific driver tube from each amp (don't know which one) and replace each with a special shorting tube socket that Ralph sells. Gain on my M60s is reduced by 12 db (supposedly)using this tactic.
Thanks, Albert, for interesting advice, which I will follow. You probably mean the one 12AU7 tube (only one in The Tube mk2). Do you remember the type of 5814 CBS Hytron?

I thought I remembered there were two in the Einstein but perhaps I remember wrong. I looked for nearly an hour today to find that tube, I know it's around here somewhere.

I know the box was military type, brown cardboard and very old. Perhaps 1940s (or 1950s at latest).

Audiolabyrinth
@ Albertporter, Hi, Will the 5814 CBS Hytron tube go in the place of any 12AU7 tube socket that is used in other name brands of components, never heard of this tube, where is it made, and by who, what is the projected life span, where do you get them from, Is there a specific year that is very good?

Audiolabyrinth, this tube will work where 12AU7 is called for. I checked the Sams tube manual and it's electrically fully compatible.

CBS Hytron is an old USA brand, found at specialty tube dealers and Ebay. Life span is determined by the circuit it's placed in, some equipment is easy on tubes and some are brutal, making for short life.

The tube is extremely high quality as are most USA and Euro tubes from 40s and 50s.
I have ordered a pair of Siemens Halske 6922 gold pins from the 1960s for the phono input + 1 Telefunken 12AU7, from Brent Jessee. Quite expensive but I know he delivers quality (last year I bought Telefunken 12ax7s for the Io from BJ, working great, very low noise). Also, based on Albert Porter's advice, I have ordered a Hytron from ebay seller Greengirl613: "Vintage CBS Hytron 5814 A Black Plates D-Getter Stereo Tube 1959". It may not be the exact same, but seems close. Will be interesting to try the Tele vs the Hytron.
I was preampless for a few years and realized the error of my ways. added an ayre for $1800 and my rig sends me to new places. Saving up for a used KXR.
Cerrot; yes its a tough life - glad to hear you found a way.
Nkj: I certainly recognize what you are describing. The Io Eclipse with dual power can sound breathtaking direct to the amps. Dynamics. Clarity. I used it with a Krell FPB600 to great effect, and later the Atma MA-1s. It was only gradually that I came to realize something was missing, especially after a friend who works with recording / pro audio had visited and said "something is wrong - the system doesn't grab the speaker drivers in the right way". I gradually understood that problems attributed to other causes had to do with the lack of a preamp. So I tested with some pro preamps borrowed from my friend, and went up the line, ending with the Einstein for now. It is hard for me to put the finger on it, exactly. I can only say, the music feels more "right". I know that Aesthetix uses the term "headroom" to describe the difference by adding a preamp - they say it will be better, provided that the pre is absolutely top class (think of a Jupiter moon).
Thankyou Albertporter for your reply, very imformative!, I will write down this info and the Telefunken info, I do not like going down this rabbit Hole of tube rolling, Exspensive going thru so many tubes to get it right!, so I am going to attemt to get it right the first time, My player consist of three 12ax7 tubes, and one 12au7 tube, Do they make a cbs Hytron for the 12ax7?
@ O_holter, I look forward to your comparison of the CBS Hytron versus the Telefunken tube, what year and type of Telefunken 12AX7 tube do you have?
When I did own Callisto Sign. I had a lot of problems to find amps which matched. Of course, I heard something, but there was no bite, no speed, no kick, no grip, a touch lifeless, always...and such a result I had with Atma-Sphere M-60 with a 98dB speaker Design. I can't recommend such a pairing (based on my kind of Listening Standard). I think, the Preamp from Atma-Sphere for the MA-1 is the way to go. Had nothing to do with the speaker, the X-Over was very simple and the speaker was easy to go, the M-60 had more than enough power...I don't share the Aesthetix enthusiasm, when you want to go for it, I recommend to loan it somewhere first.

My player consist of three 12ax7 tubes, and one 12au7 tube, Do they make a CBS Hytron for the 12ax7?

Like many vintage tubes, not all types are created equal. I prefer other 12AX7 over the CBS Hytron but which brand depends on circuit design.

For the Aesthetix IO it was Telefunken in 12AX7 position, Mullard 6922 in the 6DJ8/6922 position and (ONLY) the RCA red base 5692 in the 6SN7 position.

There are other options and only listening will tell what suits your taste and system best but these are top flight contenders and should be considered.
Hi - thanks for informed responses!
Audiolabyrinth: I ordered ultra low noise Telefunken NOS ax7 tubes from Brent Jessee. Smooth plate from the 60s I think. They were costly but elevated the Io to a new level. I can turn up the volume to four o'clock before hearing any noise problems and the sound is marvellous. They totally smash the stock tubes, especially after I replaced the secondary gain stage too. Right now I cant remember what is in the third gain stage and 6922 positions but it is American NOS and helps too. I could probably go on and change tubes in the power supplies but have not done so yet.
Syntax: I have no special preference, Aesthetix or Atma-sphere, I own both, and have no commercial interests. Both the Aesthetix Io Eclipse and the Atma-sphere MA-1 are on the top, from what my ears have heard, so far. It may be, I give a little nod to the Io. But then i have not heard the MP-1.
The "dark horse" that I brought into this, Einstein's The tube, surely does not sound washed-out or no bite. Rather, it is very dynamic, perhaps a bit flat. I will find out more, with better tubes.
For the interest of all - I will report back, since direct comparison is so difficult for most of us.
@ Albertporter, wow!, You are a asset to me, Thankyou so much!, I am doing extensive modds to a vincent cd-s7 player which single handily out performed the double the price Ayon cd-2s player in the vincent player's stock form,I am changeing the XLR out-puts to Furetech Ft-785m, and implementing a real balanced circuit inside the player, going with Tara Labs Internal Gen 2 insulated 24 awg wire, changeing the IEC to Furetech, changeing the Recepticle at the wall to Oyaide R-1 recepticle with carbon plate, and I Have The Tara Labs cobalt power cord with top Oaide IEC and plug on the power cord, The tube recommendations you have given are being noted to try, what year and type Telefunken 12AX7 tube is best in your opinion?, Thankyou.
Albertporter, I believe I have a 6z4 tube in the power supply of the player I have, what do you believe will be a good recommendation for that roll?
Hi Albert Porter - you wrote "the Einstein gets a massive upgrade when you remove the 12AU7 tubes and replace with 5814 CBS Hytron" - do you remember, what 12AU7? I got the Hytron today, and have tried a few hours. Promising. It turned out, there was a Sylvania 5963 (green label) sitting in the 12AU7 position.
Thanks Oystein
Apropos tube rolling: in this case I got a preamp that according to the seller was bought new in 2011 or so, has been left on mostly, and has not had any tube change. So that is 3-4 years of running. Is "best practice" in this case, take out all the tubes, clean sockets and pins, and put them back? Or leave them be?
I would consider removing the tubes and reinstalling them.

A greater concern would be: what is the condition of the tubes? You might want to get them tested.
Thanks Atmasphere. With so may tubes in my system I should probably have gotten a tube tester long ago. I will check possibilities.
Audiolabyrinth
@ Albertporter, wow!, You are a asset to me, Thank you so much!, ....The tube recommendations you have given are being noted to try, what year and type Telefunken 12AX7 tube is best in your opinion?, Thankyou.

There are not as many variations of Telefunken 12AX7 as some tube brands. Just be sure the bottom of the glass has the diamond embedded in the glass so you know it's not re branded.

Second, know your vendor or have provision to test it yourself and be sure the tube is as new or near new.

There are lots of tubes floating around that have been sold and resold as each customer filters out the best and passes on the duds.

Last, don't take my recommendation as gospel. The correct 12AX7 is what works in THAT device. I've seen variation depending on circuit design and implementation. Could be the Mazda, Mullard or even the Siemens is better in the device you're testing.

I gave advice on Aesthetix because I owned it for more than ten years and know pretty well how it responds to various tubes. Your Vincent player is not familiar to me so don't hesitate to test beyond my recommendations to discover what's best.
06-08-14: Audiolabyrinth
Albertporter, I believe I have a 6z4 tube in the power supply of the player I have, what do you believe will be a good recommendation for that roll?

I don't recall ever owning a piece of equipment that used the 6Z4 tube.

The Radio Museum, http://www.radiomuseum.org/tubes/tube_6z4.html

Indicates 6X5 was a successor. Check with the manufacturer to determine if this is a drop in replacement for that circuit. If so, I may have some suggestions.

06-10-14: O_holter
Hi Albert Porter - you wrote "the Einstein gets a massive upgrade when you remove the 12AU7 tubes and replace with 5814 CBS Hytron" - do you remember, what 12AU7? I got the Hytron today, and have tried a few hours. Promising. It turned out, there was a Sylvania 5963 (green label) sitting in the 12AU7 position.
Thanks Oystein

It's been awhile since we did those listening tests but we got the Einstein from Brian Ackerman who was the official importer at the time.

Unknown if that was the tube in our test but I remember the CBS was more organic and removed some of the splash in the treble that I had issue with.

Could be the caps or circuit have changed since then or perhaps the tube your's came with is an improvement from when I had my sample here.

The value of these discussions is to instill the desire to TEST. Don't be afraid to put good quality tubes in there and see what works.

Go slow, listen long term, be sure to allow warm up and break in time before making your final judgement.

Last, be sure the tubes you're auditioning are genuine and in top condition. It's amazing how some sellers behave. I've seen tubes with as much as 20% transconductance loss with claim as NOS. At 50% loss a tube can be a real duds and some sellers claim there is plenty of life left at that point.

If you can, test the tubes yourself.

If you cannot, be sure the seller verifies you what you're buying. This can be the make or break detail on your final decision.
Again, many thanks! I agree about testing, going slow, and taking time. I will compare the Sylvania, the Hytron and soon also a Telefunken 12au7.
Thankyou Albertporter for the reply.
CBS Hytron - Albert, I think you are right. I just listened, quite loud, to Chicago Transit Authority: Poem 58. Utterly amazing. Right there. The tube stays.
As well as other tests:
Deep Purple, Shield (from Book of Taliesyn LP) - wow!
New Vermont LP - same - best sound so far
Diana Krall and various jazz - also very good
The Einstein The Tube preamp perhaps excels even more in the "energetic" than in the "refined" area, but this can be modded with tubes etc.
Albert, when you tested the preamps, you obviously found them all good, but they brought some different plusses and minuses to the table. Could you tell a bit more, regarding The Tube?
Experiences from other Audiogon members regarding The Tube, especially in combination with good tube phono stages and amps, are of course very welcome too.
Ditto HMS Donovan, the original Dawn double LP - amazing, an overlooked gem. This preamp makes Donovan a folk singer, quite rightly, but I can hear him rock out too, no problem. Donovan took the consequence of "the youth revolution" and created a double album partly to children, and with children's music, but it seems, this was too much at the time, it was ignored. His guitar work is rich, melodic and unique, especially on his 'adult' songs. This is his Sgt Pepper - taken to a different place.

Albert, when you tested the preamps, you obviously found them all good, but they brought some different plusses and minuses to the table. Could you tell a bit more, regarding The Tube?
O_holter (System | Threads | Answers | This Thread)

There was almost unanimous opinion on order of to rank but you're correct, each of these were high quality and performance. The Einstein sounds more solid state than tube but your trial with CBS Hytron shows it can be more musical.

Our test involved ten different preamps and/or phono stages plus combinations of brands to find what effect that would bring. We did our best to find tubes that brought out the best in each design. I have hundreds of tubes on hand, making that part easier.

There is noting wrong with the Einstein, it has a personality as does every piece of equipment. The goal is to achieve best sound and final decision involves the room, the speakers and all the other components.

The Einstein phono stage was judged better playing into Aesthetix Callisto than it's "mate" The Tube. Oddly, the Einstein single ended phono was chosen over the XLR version.

Something not mentioned so far, the Einstein responded to AC cable as much as interconnect, so don't be afraid to borrow and try a few brands.
Try the RCA 12BH7 tube in the Einstein's 12au7 socket. Magic magic magic when I tried this during an audition of the Einstein Line Stage vs. the Callisto Sig. I had at the time.

The coolest thing about the Einstein was that you can optimize the tube for each line input
Thanks Jafox - I will try. I also have a Tele au7 and a pair of Siemens 6922 coming. Will be interesting. Did you try the Hytron? Are you saying, you preferred the Einstein to the Callisto Sig?

Albert - thanks, very interesting. If I had known that The Tube sounded s-state, I might have reconsidered. Before I got into tubes I went up the whole Krell line. However, like you say, these preamps have personality, and I think a good idea, whatever choice we make, is to listen for what is good, and not so much, what is bad or missing. "Smell the roses". For example, I imagine that the bass handling of the Einstein compared to the Callisto would show some of the typical traits of good s-state, like iron fist on the bass, no softness or bloat, and similar. Although I might in the end prefer the benefits of an all-tube design. Don't know, since I have never heard the Callisto (or the Atma MP1).
An A-B test
Playing Ane Brun: These days (from the It all starts with one LP)
(System: Lyra Atlas / SME V / Hanss T30 / Io Eclipse / Einstein The Tube / Atma-sphere MA-1 / Audiokinesis Dream Makers)
A - direct from Io Eclipse to MA-1 amps
B - through Einstein The Tube
The song is a good test case, an upfront but intimate and partly subdued female singer, plus heavy drums and bass work. It is the balance of these elements that make out the song.
Case A:
This is the first time I have tried direct to the amps since I got the new preamp four weeks ago. As often before, at first, I am amazed just how good the Io is direct into the amps. Delicate, intricate, organic, detailed. The vocal is right there. It is only after a while that I recognize the problems. Sound is detailed but not quite right. Body and drive and punch is missing. The voice is a bit ghostly. Turning up the volume doesn't help, it only means more of the same. Almost like a very high-quality photo, that hasn't been fully developed yet.
Case B:
With The Tube into the chain, some detail may be lost, but not much, and the whole thing feels right. Bass, vocal, everything is more filled out, working better together. The drama in her voice and in the band as a whole is better captured, making a more consistent and convincing picture.
My wife was listening during this test. Her verdict was: B is clearly better. So I would say, the Tube passed this test with flying colors. YMMV etc.
Jafox, do you have more details on the RCA 12BH7 that worked magic - ? These tubes can be found, but I am not sure is it the right one.