Zyx Universe. O.24 mv vs .48 mv with low eff spkrs


I have a dilema

My Zyx Universe .24mv cartridge appears to be loosing its suspension characteristics. I believe an arm bearing not moving freely put too much wear on it.

I have 84 db speakers and have to crank at pretty high levels to get my volume up far enough to resolve things.

I know a .24 mv is going to have slightly more resolution and speed but woud I be better going with the .48 and having less stress on the amplification and higher output volumes?
audiotomb
How much gain does you phono stage have? If you were happy with it before the suspension problem, why not send it to Andy Kim at the Needle Clinic he does excellent work with a fast turnaround. Recently had my cartridge repaired and it only took a couple of weeks for him to complete the repairs and he is very reasonable. Best of Luck
Amplification is a chain to your speakers. And it is useful when you realized that Volume and Gain (internal amplification) are 2 different things.
I think you will have a proper Amp to drive your speakers, then the next critical detail is the matching between Preamp output to Input Amp. When the amp needs a stronger input signal than your preamp can deliver, you will have a loss in Gain and you can only compensate it with the volume poti. But this is something you can check on your own. When they match then you are normally with the volume poti at 09.00....
Same is for your Phonostage connected to your Preamp, they should match, too. A 0.24mV cartridge needs normally Phono Gain in the area of 62-65dB. When this is not sufficient then you can only compensate that with a better Preamp, or with a higher Gain setting in your Phonostage.
When your phono gain is probably at 55dB max, a 0.24mV Cartridge is too weak (or your Phonostage is too weak), this means, all the advantages of a low output MC Cartridge are useless because you will never hear it.
That is the reason why a lot of carts are offered with higher outputs, 0.5mV+
When you made this controlling, you will know what you can do to improve that. Normally it is the cheapest way to switch to a cartridge with higher output (a different Preamp or Phonoamp is generally more expensive when you look for something serious).
No matter what will be, a Preamp (and a connected Phonostage) are the brain of the System. They are responsible for a lively or a static performance). Amplifier power is cheap and there are a lot of good units out there. But good Preamps are much harder to find. But, when you made the right decision and only the internal Phono gain is too weak, So, go for a higher output MC when you don't want to change parts of the hardware...
0.24mV carts are better BUT you need the right working area for these.
The cartridge will be riding low - too close to the record if indeed the suspension were collapsed. What arm are you using and how did you come to the assumption that it isn't free to move enough? If the cartridge looks ok when playing a record, I would look at your electronics first.
Tom,

Many thoughts and questions...

Can you give a bit more info? Has this need to crank up the gain come on gradually over time? Or is this suddenly out of nowhere?

Are you sure some tubes aren't going? Have you tried swapping in new phono stage or power amp tubes? Much cheaper than buying a new UNIverse.

I don't know anything about your Salk speakers or power amps, but your Doshi pre has oodles of gain, so the problem "shouldn't" be there. I know you had it modded by Nick. You might check with him to see if he has any insights. Gain and impedance matching between amplifier stages is one of his specialties.

If your supposition about faulty/sticky arm bearings wearing out the suspension is correct, then clearly the first thing to do is remedy that (duh).

Once you've got a properly functioning tonearm then presumably there's no risk of wearing out your next cartridge early. In that case, if a new cartridge is needed and the .24mv UNIverse gave you sufficient output before, I can't recommend going with the .48mv. I've heard both, as you know, and there's really no comparison. It's not just detail that's lost with the HO version. Dynamics and speed suffer greatly too. The music sounds (comparatively) dead and dull. Read Arthur Salvatore's original (.48mv) and followup (.24mv) UNIverse reviews for detailed comparisons. I discouraged him from bothering with the .48mv but he wanted to try it first. He wasn't that impressed, finding it only slightly better than his LO Airy 3. When he switched to the .24mv UNIverse... bingo!

If you go for another UNIverse, DO order the UNIverse II. It's head and shoulders better than the original. One of the improvements is increased dynamics and punch, which should help ameliorate any need to crank it up.
To summarize what I think Doug and Syntax are saying, don't do it. If your phono stage had sufficient gain for the 0.24 version of the UNI in the first place, then you will gain nothing by switching to the 0.48 version, and the latter is not as good sounding. If the phono gain was never sufficient, by criteria described by Syntax, then you may need to have it modified or replaced. If you really think you have a bad bearing in your tonearm, then first and foremost you need to have it fixed or replaced.
Lewm, that's exactly what I was saying.

Further, I'm confident that Tom's Doshi Alaap (phono + line preamp) has (or at least had) ample gain for a .24mv ZYX. You heard the UNIverse/Alaap combo at the home of our mutual friend and your neighbor, Michael K****. I'd wager that inadequate gain and dynamic compression were the furthest things from your mind.

Something's clearly amiss, but we need more info.

***

@Audiotomb,

Try this experiment: reduce your VTF drastically... like to 1.30-1.50g. If the cartridge tracks cleanly and dynamics open up, your supposition that the cartridge suspension is giving out is confirmed.

thanks guys for the insights

here is what happened and why I was questioning my options
Do I choose more volume (but less resolution in the zyx) or higher output stage?

How much less of a cartridge is the .48? thanks for your comments and experiences

I didn't know just how big of a difference the .24 and .48 would be musically and really appreciate your insight. I love the resolving power of the .24, can't give that up

the more volume part of the equation is that the Salk Soundscape 10s are 84db efficient and I have to have my Doshi in the top several clicks to get sufficient driving volume where you really separate out things. It wasn't a problem till I switched to the lower efficiency speakers. The Doshi is a step down attenuator so it isn't clipping being near the top end of it's range.

In addition woofer pumping takes a lot of wattage away from the music and makes a hard load to drive

The cartridge is on a triplaner arm - I was fighting woofer pumping for a while. With help from Richard Gray locally, Doug Deacon, Mehran and Thom Mackris of Galibier we were able to isolate this with a feather test. A feather should be able to lift a properly functioning arm. The arm bearing wasn't working and so the cantilever was doing all the up down motion and causing subsonic woofer pumping and damage to the suspension.

Tri totally reworked my arm and all was well the last year. The pumping has returned but the arm is tracking correctly vertically.

I believe the cartridge issue is one of two things
The suspension has finally given way from all the arm rigidity abuse or I was not properly using my magic eraser, just barely lightly rubbing slowly from back to front (Richard Gray freaked out). He showed my how to dip the cartridge in the eraser a few times instead.

Universe II - tis tempting - ouch on the price. I've read all your reviews on it Doug and I listen to a broad range of music from the period piece chamber ensembles we both love so well, symphonies, acoustic jazz, rock, folk, everything really. Especially acoustic instruments in space. I play upright bass and my son is in several symphonic groups

Tell me more about Andy Kim. Does he work on ZYX?
Maybe the cartridge can be salvaged.
Perhaps sending this back to Mehran is in the cards
You have a number of wise responses here. My question is about the sound at the high end of your volume control.

1) Does being so high on the attenuator create any sonic drawbacks? Added noise, feel like the system is running out of steam, straining too much?

2) Do you ever want to crank the volume beyond the highest setting you have available?

If the answer to these questions is "no" in both cases, then get that cartridge looked at and fixed or grab another .24 mV ZYX.

If the answer to either of the above questions is yes, then I personally would try to address the gain issue somehow other than by getting the HO cart. Do you use an SUT? You could get one that gives more boost to the voltage. Otherwise, I'd think about adding gain either in the phono stage, preamp or power amp.
1) no the Doshi behaves very well at the top end

2) getting close to wanting to, it is usually just enough for my louder listening, but I have to use a hi watt amp (Van Alstine 600r)

it was great volume synergy before dropping to lower efficiency speakers

think we have the answer
the move to the .48mV is too high a drop in performance
deal with the volume issues another way
Lose those speakers.
it was great volume synergy before dropping to lower efficiency speakers...

Think so, too. With your amps I would use Electrostats.....I know, there are very strong tube amps out but see it with a car explanation, a low efficiency speaker is like a fat car, for example a Mercedes 500, your amp is like a strong engine. When you accelerate, all is fine but when you drive small, curvy rads with a lot of speed changes, the MB500 can do that but it is work and you will feel, it is not made for that. Same engine in a car with half weight (= a high sensitive speaker) and all those accelerations, curvy driving is easy like breathing. You have much more fun with driving, or with listening to subtle details. OTL are a match for Stats (or Horns) based on their Design. Here you get the best out of it.

Normally are Zyx carts durable, but a defect Arm kills every suspension. I did never trust Triplanar for example, my choice is Graham Phantom.
You're using OTL's with 84db speakers? Why?

I never understood the point of low efficiency speakers. They put such demands on the amplification chain that sonics are bound to suffer. Show an amplifier an easy load and it'll dance or whisper or roar, as the music demands. Weigh it down with inefficiency and difficult impedance levels and, well, it just won't.

A pair of Krell monoblocks could drive those speakers easily... but you'll never hear what a UNIverse is capable of through a SS amp. Time to re-assess your priorities?
I agree with Doug Deacon. You are using the wrong amp with this speaker. Atmospheres really do not like loads below 6 ohms and with this low efficiency you really need at least 200 tube watts. I would not like the match of these two pieces as they have the same sonic character. The Salk speakers are very open but tend to be on the lighter side and this is the same signature of the atmaspheres. Oh boy what a poor synergy. Thats why you see atmaspheres with Sound Labs because Sound Labs are on the warm side of neutral and the atmaspheres are on the leaner side. I'm not judging you as you make like this kind of sound. I wish you the best.
Do you ever want to crank the volume beyond the highest setting you have available?
getting close to wanting to, it is usually just enough for my louder listening, but I have to use a hi watt amp (Van Alstine 600r)
As a point of information, the 84 db/2.83 volts/1 meter/4 ohm specs of the speaker correspond to only 81 db/1 watt/1 meter.

The Van Alstine amp, having a solid state output stage, will presumably be capable of delivering considerably more power into 4 ohms than the 300 watts it is rated at (presumably into 8 ohms). But I suspect that the power capability of the MA-1's will not be a whole lot greater than their 140 watt/8 ohm rating regardless of what transformation ratio you choose on the Zeros you appear to be using with them.

140 watts into 81 db/1W/1m speakers will just get you to maximum SPL's of around 95 to 98 db at a listening distance of around 10 feet, neglecting room reflections, and less than that at greater distances. That will be enough for most listeners for most recordings, but I suspect it will not be enough to cleanly handle the dynamic peaks on some of the symphonic recordings you mentioned that you listen to.

So using those speakers with the Atmasphere amps + Zeros may leave you with a power shortfall even if the gain issue were somehow resolved. While with the Van Alstine amp you have a gain marginality and probably also some degree of sonic compromise. Depending on the input impedance of the Van Alstine amp you MIGHT be able to resolve the gain marginality, without introducing significant additional sonic compromise, by putting a suitably chosen Jensen transformer having a 2:1 step-up ratio between the preamp and power amp. Doing that would give you close to 6 db of additional gain (equaling the volume increase that would result from going to the HO version of the cartridge), but would result in the preamp seeing a load impedance equal to the input impedance of the power amp divided by 4, which may or may not be acceptable. (There does not appear to be a spec on the input impedance of the amp).

However, given the extremely high quality of your turntable setup, your preamp, and of the Atmasphere amps you apparently still have, I would have to agree with the previous posters that what would make the most sense is to replace the speakers with ones that are both more efficient and higher impedance (and are also known to work well with OTLs), and selling the Van Alstine amp.

Regards,
-- Al
So they're actually just 81db efficient when stated with industry standard specs? Ouch.
Very good discussion here and with wise opinions.
Syntax, your heavy/light car analogy for high/low efficiency speakers is a excellent illustration. I've never understood the prevalence of inefficient difficult to drive speaker that require behemoth amplification. This results in poorer sound quality in my opinion. In this case the Salk-Atmasphere isn't a good pairing, one or the other has to go.High End audio moved away from high efficient-high impedance speakers a couple of generations ago. This was a wrong turn and not a good direction to follow.
Charles,
05-21-14: Dougdeacon
So they're actually just 81db efficient when stated with industry standard specs? Ouch.
Doug, "industry standard" is probably ambiguous in this context these days, as specifying speaker SPLs relative to an input of 2.83 volts rather than 1 watt is pretty common. Measurements presented in reviews often do that as well.

For an 8 ohm speaker (that is really 8 ohms) it makes no difference, as 2.83 volts into 8 ohms corresponds to 1 watt. But 2.83 volts into a 4 ohm speaker corresponds to 2 watts, which results in the SPL number being 3 db higher if the input is 2.83 volts rather than 1 watt.

Since a high quality solid state amp will usually approach or equal being able to supply 3 db more (twice as much) power into 4 ohms than into 8 ohms, specifying relative to 2.83 volts arguably has a somewhat reasonable basis. But tube amps can't do that, of course, so the 2.83 volt "specmanship" can be particularly misleading when a tube amp is paired with a low impedance speaker.

Best regards,
-- Al
If you are married to those speakers, I agree with all the others; you need to select a different amplifier. As a long time Atma-sphere devotee, I would instead choose a speaker better suited to the amplifier. For me, I don't know which came first, because I have been listening to OTLs driving ESLs all my audio life, as a matter of preference. If you should choose to switch to Sound Lab ESLs, I have many useful ways in which to improve dramatically the match between an Atma amp and an SL speaker. In this case, the word "dramatically" is an under-statement, not an exaggeration. I am driving my Sound Lab 845PXs with my highly modified Atma OTL amplifiers, but the modified speaker can be driven to very loud levels by ANY 50W tube amplifier, after modification. In addition to a vast upgrade in efficiency, the modifications also increase the impedance across most of the audio band, not less than 20 ohms from 50Hz to 5kHz. A win-win. Just let me know if you want input on that subject.
Efficiency is pretty important if you want tube power, as tube amplifier power is more expensive. It also does not pay to work your amplifier hard regardless of the amplifier, not if you want to hear the best the amp has to offer.

In my room with speakers of this efficiency I would need over 1000 watts!

I might make a recommendation- talk to Duke at Audiokinesis. He makes reasonably priced loudspeakers that are extremely musical, and also easy to drive with most tube amplifiers. This will solve your sensitivity issues with the preamp and phono cartridge at the same time.
I didn't know the thread was going to weave off into the amplifier end but should have anticipated it

1) I really wanted to go Atmasphere when I heard a friend's M60s - absolutely no grain

2) I found a deal on M1s and bought a pair with Zero Speltz
I should have realized this was a bad match

3) I tried to run the M1s with the Salks and it was clipping but sounded lush on warm acoustic music (think Norah Jones).

4) I bought a volume adjustable QSC 1,500 watt amp to bi-amp the bass freq by ear. Still too much load on the mid and high drivers

5) I bought a Van Alstine 600r 300 watt / 600 into 4 ohm
lots of authority with the Salks (Jim and Frank work together at shows). Robust bass sounds good, but not the Atmaphere musicality.

6)I am looking at Daedalus Ulysses
High efficiency cones not horn
96 db and very natural sounding
Many pair them with Atmaspheres

My Salk's are a museum piece - just beautiful craftsmanship
They are an engaging totally moving speaker and Jim is one of the most stand up guys in audio. I just really like what the Atmas can do

This is an example of thinking through every steep of upgrading and thankfully (if able to) not selling any pieces until you find the right synergy. Buying gear used at good prices and being willing to flip it at a slight loss
I believe the move to Daedalus is the right direction and these speakers also have a very good reputation for sound quality.
05-21-14: Charles1dad
I believe the move to Daedalus is the right direction and these speakers also have a very good reputation for sound quality.
Well, as a very happy Ulysses owner I'll certainly second that.

BTW, Tom, they are spec'd at 98 db/1 watt/1 meter, rather than 96. Also, although their impedance curve is exceptionally flat, and impedance phase angles are apparently very benign, you might still find it to be sonically preferable to utilize the Zeros with your MA-1's, most likely connected to provide a 2:1 impedance transformation. I say that particularly because while Lou's website does not indicate the impedance of the currently produced Ulysses version 2, the Ulysses v.1 which I have were spec'd as being 6 ohms. But either way (Zeros or no Zeros) I'd expect the Ulysses and the MA-1 to be a fine match.

Best of luck as you proceed. Regards,
-- Al
Well the Ulysses are getting the V2 upgrade right now
I cant wait to hear this synergy

We swapped in another cartridge today and no woofer pumping, arm is tracking vertically just fine

Looks like I will need a repair or step up to Universe II

Thanks for all the insght

Tom
Hi all:

The reasons why a designer may want to make low-efficiency speakers is usually because he needs to make a lot of bass from a small enclosure, or is striving for a very flat frequency response, and is using the crossover to burn off (correct) the resonant areas of the speaker drivers.

Also, maximizing the signal-noise ratio of an audio system requires that the first component in the signal chain has the most signal gain, and each following component has a lesser amount of gain. This is because each component amplifies the noise of the earlier components along with the signal, and the higher the gain of the following components, the more the noise and hum and buzz of the earlier components will be amplified.

Since speaker efficiency is also a kind of gain, using a low efficiency speaker makes sense if the overall goal is low noise. Conversely, super-high efficiency speakers (the maximum that I have ever encountered was 116dB) can take a very long time to get right, and require ultra-meticulous choosing of all of the amplification components.

I am not trying to imply that lower speaker efficiency is better than high efficiency, but rather than each is a tool, with its unique advantages and disadvantages. Either path involves trade-offs of some kind.

Incidentally, moving your listening position closer to the speakers is minimal-cost way to gain more listening volume, dynamics and resolution (since air is an effective filter).

Regarding the Universe, typically (but not always) the suspension is secured by a couple of tiny grub-screws inside a metal tunnel, which allows it to be moved fore and aft (together with the cantilever and coils). Pushing the suspension deeper into the cartridge body firms up the compliance by compressing the damper discs more, while pulling the suspension out more loosens up the compliance by compressing the dampers less. IOW, if no components have been damaged by the punishment inflicted by Tom's faulty tonearm bearings, it may be possible to correct the cartridge suspension through a readjustment only - without replacing any internal components. And if no component replacements are required, it could be that ZYX is willing to do the readjustment work for free, or for a nominal fee.

No doubt that ZYX understands their own designs far better than a third party retipper who will not have access to any of the correct replacement parts, nor the detailed documentation that describes how the cartridge needs to be built and repaired, nor the knowledge why it was designed the way that it was designed.

If I were Audiotomb, I'd describe the situation to Mehran and see what ZYX's reply is. It is free to ask.

kind regards, jonathan
Almarg,

Thanks as always for your willingness to share technical knowledge. Most of my postings are based on what I hear and seat of the pants "thinking". It's always helpful to hear from someone who actually understands what he's talking about.

Jcarr,

Great post. I concur with your suggestions, particularly the one that the best repair/adjustment of a UNIverse is likely to be provided by ZYX. Aside from Nakatsuka-san himself, there are 2 or 3 people in the world who are fully trained on the inner workings of ZYX cartridges. They're all in Japan and they all work for him. As an official ZYX distributor, Mehran has access to them.

If this were an entry level model, a third-party repair might make sense. But this is one of the world's premier cartridges (by performance, regardless of price) and Tom has already stated that he's unwilling to give up what it does for the music.

Anything's possible, but I wouldn't expect someone other than ZYX to have the knowledge to bring it back to original condition, if possible, or even to know what the original condition actually was.

There's certainly no harm in asking Mehran about an inspection before deciding to replace.
05-22-14: Dougdeacon
Almarg,

Thanks as always for your willingness to share technical knowledge. Most of my postings are based on what I hear and seat of the pants "thinking". It's always helpful to hear from someone who actually understands what he's talking about.
Thanks, Doug. And likewise with respect to your uncommonly knowledgeable posts about turntables/tonearms/cartridges/vinyl.

Best regards,
-- Al
I will second that on Doug, Almarg and everyone in this thread

This is what I love about the online audio community

I heard what I needed to hear, the .46 mv isn't going to cut it and my course is moving in the high efficiency speaker / tube amp domain

choosing highly desireable pieces of gear can be an issue if they are not in a symbiotic synergy. Lesson learned.

thanks everyone

I plan to touch base with Mehran, we have been down this road before

All the best

Tom
Send my best to Mehran!

I totally agree about what wonderfully helpful folks we have here on Audiogon, and you are getting great feedback from some of the best: Almarg, Doug, Lewm, Syntax, Charles1dad
My guess is that once you hear the Atma amps w a suitable speaker, your only argument will be w yourself, for not doing it sooner. IMO, the Salk speakers are beautiful, real craftmanship, but clearly designed for high power SS amps. A high(er)/flat impedance, high(er) efficiency speaker designed for tube amps is the way to go w the Atma amps. My own experience is that you do have to be somewhat concerned about hum and noise when you go to very high eff speakers; the higher eff the more careful you have to be; there's a reason why many low power amps (likely to be mated w high eff speakers) have hum pots!
Swampwalker- i bought my Atmas 8 months ago and held onto them
because i heard what a pair of M60s did in my friend's system

Even tried to biamp the top with the Atmas

Doug - talked to Mehran, always a pleasure
generous exchange policy - I am upgrading to the ii. !!!
Audiotomb, you lucky guy! Enjoy the II! Send my best to Mehran.
I haven't heard the UniII, but having heard the Uni in Doug's system, I can only imagine how good it is. Now go out there and get some speakers that are designed for that kind of an amp...look out!!!! You may not be getting much sleep for a while.
swampwalker

I have Daedalus Ulysses on the way which are right getting Lou's V2 upgrade

I never get much sleep with all my hobbies
usually it's live music
Audiotomb- Never heard the Daedalus at any length but I know Almarg loves his. Enjoy. And don't miss any live music to listen to the hifi. It's great fun but it's not the real thing, as I am sure you know.
05-23-14: Swampwalker
My own experience is that you do have to be somewhat concerned about hum and noise when you go to very high eff speakers; the higher eff the more careful you have to be....
Relevant to this point I see that the MA-1's description (under the "order" tab) indicates that the following are available:
Jumper plugs for high efficiency speakers -- Replaces tube in the voltage amplifier section of Atma-Sphere power amplifiers, thus reducing gain for high efficiency speakers. Recommended when efficiency of speaker is over 100.
As I indicated earlier the efficiency of the Ulysses is spec'd at 98 db/1W/1m, and I suspect that you won't have any issues with hum or hiss. But considering the high gain of your preamp I wouldn't completely rule out the possibility that you might find yourself operating the volume control undesirably close to the bottom of its range. In which case these jumper plugs would appear to be a solution.

Enjoy! Regards,
-- Al
Those jumpers are an under-appreciated option on Atma amps. Did wonders in my system when I had an S30.
Audiotomb quite the upgrade new speakers and a new cartridge. I upgraded to ZYX about three weeks ago and cannot imagine it getting any better, hope you enjoy the cartridge as much as I am. Make sure to post up and let us know how it turned out. Best of Luck
Doug - talked to Mehran, always a pleasure
generous exchange policy - I am upgrading to the ii. !!!
Woo-hoo! I figured he'd be generous to a repeat customer, that's always been his way. Mehran's one of the true good guys in audio.

When all the new goodies settle in, please update us on your impressions.

If you feel like taking the time, it would be instructive to hear how the UNI2 behaves with your Salk speakers. My guess (only that) is that it would slightly improve the perceived lack of dynamic headroom.
Al - I'm having the V2 upgrades being done by Lou at the moment (I found a great deal on a used pair)

I will definitely look into the jumpers

I've been so enamored by the original Universe I can't imagine what a ii will do.

I recently did Thom Mackris' Galibier upgrades - armboard and new motor pod. Thom really nailed it with both of those, low level detail, tight focus, dead solid
Thanks for the update, Tom. I recall, as you're probably aware, that Thom uses the Ulysses as his reference speakers.

Enjoy! Regards,
-- Al
Al

love your room - that wood looks gorgeous with the Ulysses

I first heard the Daedalus in 2011 at RMAF

I went into that room to finally meet Thom. What a pleasure. We were chatting quietly in the back corner and I was amazed at how wonderfully the Ulysses filled the room and had a great tonal balance. As an upright player I was taken, as Esperanza Spaulding sounded like she was in the room
Doug wrote

If you feel like taking the time, it would be instructive to hear how the UNI2 behaves with your Salk speakers. My guess (only that) is that it would slightly improve the perceived lack of dynamic headroom.

Doug will do
maybe I mislead everyone somewhat, I have headroom with the Van Alstine, just wanted to see if it was worth getting more as I was on the upper range of my Doshi volume knob. Hence the .24 vs .48 mv question

The Atmasphere will not work with low efficiency speakers

I will add in one piece at a time, most likely the ZYX will arrive first

perfect indoor fun for the hot summer that hasn't quite hit New Orleans yet

I cleaned 30 lps with my Kl Audio ultra sonic yesterday evening in preparation for the anointing

yes Mehran is the best!
Audiotomb, there should be no issue if the volume knob is near the end or all the way up. Usually, all that a volume control does is attenuate the strength of the incoming signal, which the preamp circuit then amplifies by a fixed amount of gain. The only concern with the preamp circuitry should be the level of the signal input, the fixed (maximum) gain of the preamp, and the preamp's maximum output level.

If the signal going into the input jacks is 6V and you use the volume to reduce the input level to 1/10 (0.6V), or if the signal going into the input jacks is 1.2V and you use the volume to reduce the input level to 1/2 (0.6V), both are the same thing to the preamp circuitry. Whatever the input signal level ends up at, the preamp circuit will amplify that by its fixed (maximum) gain, which does not change with volume position.

I know that many audiophiles show a psychological adversion to having the volume turned all the way up, but as long as the preamp output isn't clipping or distorting, the physical position of the volume is a needless worry.

kind regards, jonathan

PS. There may be one or two unique preamps (such as Ayre's KX-R) where the volume does alter the internal gain, but such designs are quite rare.
My guess is that once you hear the Atma amps w a suitable speaker, your only argument will be w yourself, for not doing it sooner. IMO, the Salk speakers are beautiful, real craftmanship, but clearly designed for high power SS amps. A high(er)/flat impedance, high(er) efficiency speaker designed for tube amps is the way to go w the Atma amps. My own experience is that you do have to be somewhat concerned about hum and noise when you go to very high eff speakers; the higher eff the more careful you have to be; there's a reason why many low power amps (likely to be mated w high eff speakers) have hum pots!

Swampwalker, I am guessing you've not heard our amps in a while! At the Munich show we did not use the jumper plugs as described on our website, yet to hear any artifact from the electronics at all, you had to have your head inside the horn of the loudspeaker, which was 107 db. Even then it was a gentle hiss.
My apologies to all, but esp. to Atma. My last post was poorly worded. The reference to being more concerned w hum and noise was based on two things. One, just an electrical/acoustical fact of life. A higher eff speaker will reproduce the inherent hum and noise in a system at a higher SPL than a lower one. At least I think that's a fact of life. Second, my recent experience w both push pull and and PSET amps (but not w the Atma OTLs). When switching between two speakers of differing efficiencies, I always heard more tube rush or hum or noise from the higher eff speaker. I was not in any way trying to say that Atma amps were noisy when mated w high eff speakers. My bad.
Since I generally can't stand horn speaker distortions, listening with my head deep inside the horn is often the only way I can tolerate them. Swampwalker's advice and Ralph's clarification are spot on!

<:-)
Swampwalker's advice and Ralph's clarification are spot on!
+1, in both cases.

With the slight qualification that the hum and noise which will be reproduced at a higher SPL by a speaker having higher efficiency is hum and noise that is generated or introduced at points in the signal path that are "after"/"downstream of" the volume control.

Best regards,
-- Al
The speakers at the Munich show were Hornfabrik:

http://my-hiend.com/leoyeh2/2014b/IMG_3428ss.jpg
Since the jumpers used in the Atma amplifiers to reduce gain do reduce gain by converting the voltage amplifier stage from a dual-differential cascode to a simpler dual-differential topology, it is entirely possible that the signal to noise ratio might well go UP rather than down with vs without the jumpers. Cascodes have a pretty darn good signal to noise ratio. But in either case, there would likely be no problem except possibly with ridiculously efficient speakers, i.e., >105db. (I chose a number out of thin air.)

On the subject of speaker efficiency: I think the benefits of efficiency, if you define that as 90 or 92db and up, are huge, provided the speaker is otherwise well designed and pleasing to its owner. I do not care for much less efficient speakers, if they come by their inefficiency by virtue of a multi-way complex crossover, regardless of how huge and powerful the driving amplifier may be. I don't find that huge power can overcome the sluggish behavior of such speakers. On the other hand, horns are not my cup of tea, either. They invariably sound great for the first 15 minutes, however. This is purely and only my own opinion.
Lewm, the big problem on horns usually is not the noise of the amp but the noise of the preamp. If you knock the gain down in the power amp you thus make big strides in reducing the noise floor.