XPA-2 gen 1 vs. BasX A2

[ausman]

when using an avr i would choose rca however given the choice KiethL I'd use xlr where possible

you notice the difference between the avr's amps vs basx

so to compare basx to an xpa it would likely sound tinny because you are at 250 watts @ 4 ohms vs 490 watts @ 4 ohms..

on my jensens..

just my opinion for main seven channels i'd use xpa and likely use basx as effects channels..

though I do have to wonder why there isn't an option in basx with xlr inputs as i know most other vendors in 1u-2u amp space have xlr options in this space??

I've always been taught the xlr is the best connection as it is earthed and rca isn't though rca is more common on consumer grade stuff because it is a common interface type in both stereo and the av world..

i've playing about in audie and av world since i was 14 as we had access in the home...

whilst xlr has been more prosumer/pro audie choice between processors and amps.. it is more more common to use that xlr standard for inter connects between processors and amps since the i was a kid.. and if you were in the money to afford a processor in the 1st place

[KeithL]

An RCA connector in fact is "earthed".

On an unbalanced connection the inner wire carries the signal and the outer shield wire is the ground.

With an XLR connector, the two inner wires carry the audio signal and the third wire is the ground.

XLR cables also often include a shield which is isolated from the signal ground... and which may then be tied to the case separately or to the signal ground.

(But, if you happen to be using plastic XLR connectors, there is no metal case on the connector, so all you have is two signal connections and a ground.)

To be quite honest, while the circuitry required for a balanced connection is slightly more complex, that is not really why they are rarely used for "consumer" equipment.

One reason is that, since RCA connectors have been the de-facto consumer standard for so long, they are more likely to be what you will find on what you are connecting to.

Part of the reason that XLR connectors were historically reserved for "pro" gear was price... in times past XLR connectors were a LOT more expensive than RCA connectors.

(In 1975 a low cost RCA panel jack cost about 25 cents - while an XLR panel jack cost about over $10.)

Another reason is that, while they are more secure, XLR jacks take up a lot more space on the rear panel, and the connectors on the cable are bulkier and require a lot more clearance.

And, finally, balanced connections were simply deemed unnecessary on consumer gear.

"Pros" used them because they were often required to run gear in noisy environments, with long cable runs, and near noise sources like light dimmers and motors.

Since balanced cables were pretty well necessary for microphones, this allowed them to use the same cables for both purposes.

And, of course, strong locking connectors were a major benefit in an environment where people tripping over your cables was a problem.

None of these reasons were considered to be important for HOME audio systems.

And, as a post-script, since audiophiles have started looking for them, balanced connections are seen as a sort of "premium feature".

(Since they are usually omitted on lower cost gear they provide one more premium feature which can be offered as an upgrade on the more premium models.)

Oct 14, 2021 11:52:21 GMT -5 ausman said:

when using an avr i would choose rca however given the choice KiethL I'd use xlr where possible

you notice the difference between the avr's amps vs basx

so to compare basx to an xpa it would likely sound tinny because you are at 250 watts @ 4 ohms vs 490 watts @ 4 ohms..

on my jensens..

just my opinion for main seven channels i'd use xpa and likely use basx as effects channels..

though I do have to wonder why there isn't an option in basx with xlr inputs as i know most other vendors in 1u-2u amp space have xlr options in this space??

I've always been taught the xlr is the best connection as it is earthed and rca isn't though rca is more common on consumer grade stuff because it is a common interface type in both stereo and the av world..

i've playing about in audie and av world since i was 14 as we had access in the home...

whilst xlr has been more prosumer/pro audie choice between processors and amps.. it is more more common to use that xlr standard for inter connects between processors and amps since the i was a kid.. and if you were in the money to afford a processor in the 1st place

[audiobill]

And that balanced connectors are a different thing than balanced circuitry internally.

[ausman]

this seems anal Keith, I was asking why not provide it may be I might want to waste money on basx mono's given the cost to deliver xpa's to australia it be nice to have xmc-2 or the rmc-1 with connection to low profile amps..

what is the point to offer a processor with xlr's yet not offer the whole amp product lines with xlr

though my point was is ever competitor within the u1/u2 rack space is providing xlr on their amps why isn't emotiva???

[KeithL]

In simplest terms, balanced inputs and outputs are generally considered to be a high-end feature, which is expected on high-end models, and usually not included on lower cost models.

(We would have to charge more for the BasX amps if we included balanced inputs and, since many people use them with processors or preamps that lack balanced outputs, we decided to avoid doing so to keep the price as low as possible.)

Our RMC-1, RMC-1L, and XMC-2 come with balanced XLR outputs.

And our XPA and XPA-DR amps, which are normally considered to be "the amps that go with those processors", also include both balanced and unbalanced inputs.

However, if you want to connect an RMC-1, RMC-1L, or XMC-2 to an amplifier with only unbalanced inputs, like one of our BasX models, you can do so by using simple passive balanced-to-unbalanced adapters or cables (with no loss at all in audio quality) .

The BasX amps are very capable and good sounding amps and all you need to use them with an RMC-1 or XMC-2 is that set of adapters or cables. 

(Some of our customers use BasX amps for their main channels; and many use an XPA amp for the main channels and a BasX amp for the surround or height channels.)

Oct 15, 2021 12:10:25 GMT -5 ausman said:

this seems anal Keith, I was asking why not provide it may be I might want to waste money on basx mono's given the cost to deliver xpa's to australia it be nice to have xmc-2 or the rmc-1 with connection to low profile amps..

what is the point to offer a processor with xlr's yet not offer the whole amp product lines with xlr

though my point was is ever competitor within the u1/u2 rack space is providing xlr on their amps why isn't emotiva???

[ausman]

why go from balance to unbalance Kieth

when the idea is to balanced between the amp and processor?


I do understand the logic to have the xpa and other amps with xlr..

though when factoring in international transport costs of xpa and ilk, basx and the UPA's before it would be an a attractive option if the consideration due to weight and cost of transport it makes them and option for the processors


looking at my current physical limitations

i would likely have to have the xpa amps shipped in a rack from the USA..

where as i could likely rack mount BasX myself without issue..

sourcing emotiva gear from an Australian supplier at present is next to impossible due to covid lockdowns

[leonski]

Oct 14, 2021 11:52:21 GMT -5 ausman said:

when using an avr i would choose rca however given the choice KiethL I'd use xlr where possible

you notice the difference between the avr's amps vs basx

so to compare basx to an xpa it would likely sound tinny because you are at 250 watts @ 4 ohms vs 490 watts @ 4 ohms..

on my jensens..

just my opinion for main seven channels i'd use xpa and likely use basx as effects channels..

though I do have to wonder why there isn't an option in basx with xlr inputs as i know most other vendors in 1u-2u amp space have xlr options in this space??

I've always been taught the xlr is the best connection as it is earthed and rca isn't though rca is more common on consumer grade stuff because it is a common interface type in both stereo and the av world..

i've playing about in audie and av world since i was 14 as we had access in the home...

whilst xlr has been more prosumer/pro audie choice between processors and amps.. it is more more common to use that xlr standard for inter connects between processors and amps since the i was a kid.. and if you were in the money to afford a processor in the 1st place    

IF both amps are equally capable of driving whatever speaker is being used for the test.....the difference between 250 watts and 500 watts is ONLY 3db.....Not much, in the larger scheme of things.
Where it gets weird is IF the speaker represents a more difficult load.    In that case?   IF the lower powered amp is 'better' into that load, it may actually SOUND better then the amp of 2x the power....

The ONLY time I'd get wrapped up in Balanced V RCA is when the entire signal chain is one of the other......Souce output is Balanced.   Pre/Pro is a true balanced design with I/O of all balanced and the AMP is likewise, a balanced design with the approproiate inputs.

When 'mixing' amps?   I'd make cerain the Gain was the same on the different amps.   OR have a means of correcting, maybe REW or such.....
Most HT speakers are not a bad load.   This means that most any reasonable amp will perform ok.    With a 7 channel system NEEDING 100 watts per speaker?   Are you down the block when listening?

AVRs typicaly have terrible amps.    Not really CAPABLE of top-notch performance which tells me XLR V RCA in that case is the LEAST of your worries.    And given how some of the power numbers on AVRs are arrived at?
I'd expect the BassX to outperform in MOST cases, and for sure with speakers which 'dip' down to near-4 ohms.....

[housetech]

Amp power- wattage, is not just about decibel levels, it's about the amp's ability to control the speaker drivers especially in lower frequency range. There are quality 50 watt amps (Rotel, Audiolab. etc) that have better driver control than amps @ 2x the wattage
Where the XPA amp excels is it ability to keep woofers under control.
There's nothing about 3 digit Yamaha integrated amps (Yamaha A-S801 @ 100w) that I like until the 4 digit amps (Yamaha A-S1200 @90w) insignificant output level, but big difference in sound quality.
btw my Denon ARV5700 (140w 2ch) had as good of sound quality & driver control as any integrated I've heard  @ $1500 (or more).

I keep hearing people say receivers suck- WRONG. The only difference between an integrated amp and receiver is the added tuner. The reason integrated amps were popular decades ago was the interference of the RF stage. (I'm not discussing low price junk) Today's receiver are much cleaner than they were but people can now stream radio stations to an integrated.
I'll take a quality integrated amp over separates (amp-preamp) today without hesitation. If anyone wants to donate a Music Fidelity M5si or M6si, I'll take it. 

[leonski]

For THAT matter? If you need FM? the OUTLAW RR2160 o the new RR2170 would be obvious choices. Please distinguish between STEREO and HT. HT receivers have notoriously poor amp sections.....

But the 'power controls the woofer' thing is sort of a red herring. IF the woofer was a pure resistor is would be true. Amp power is measured into a resistor and so can be compared that way.

But amplifiers of the same power are not all the same into REAL speaker loads. When speakers become 'weird' some amps.....and that is virtaully ALL HOME THEATER (not stereo, necessarily) amplifiers.....

You see HT receivers which have no 4ohm speaker ratings and some have that ridiculous switch for lower impedance speakers....Which these days for HT receiver purposes works out to 6 ohms....!

So what DOES constitute 'driver control'? LOOK at this link.....It will explain a LOT if you take the time to look at the graphics and effort to try to understand.

www.linkedin.com/pulse/how-test-your-new-audio-amplifier-design-powercube-basics-ohlen

If you 'd like to 'test' your Denon? I'd be more than happy to blow it up for you as it fails to drive my 4 ohm VERY low sensitivity panels......Sure.....might actually BE 140x2 @8 Than you start addding channels and using it as a HT piece and the

power drops. What do they claim? 110x5? I don't know and don't have time to dig it up....but I know the PS is not capable of 5 channels or 7 channels of 'full power' output. And if they follow the pattern of Other HT gear? Don't look for 4 ohm ratings.

There is a reason...and a good one....for MOST speakers intendedfor HT use to be modest loads of reasonable sensitivity and maybe 100watts or so power handling. (another red herring spec)

The last Rotel (and only) that I owned? The RB1070 of 135x2 into 8. INCAPABLE of properly driving my panels. I sold it in 3 months. NO 4 ohm rating but did have a 'bridged' rating of I think 360 8 ohm watts which implies 180x2 @4 ohms.

My current Parasound A23? 125x2 @8 and a much more robust 200x2 @4 ohms......But I also have ONE amp per speaker..not bridged.....

I suspect the XPA is good into reactive loads or less than 'optimium' loads. And should be better than the BassX series...especially as impedance drops. So, the 3db is into a resistor, NOT a real speaker where the difference would be MUCH greater......But for typical HT use?

Not so much, especially for 'back' channels which I understand to not be as demanding as the front Three.....

The main take away? It isn't 'ohms', which is a DC measure, or its cousin for AC, Impedance, but rather PHASE which is REACTANCE measured by Capacitance or Inductance......which is what REAL speakers use for

crossovers.....Amplifiers see THIS not just a pure resistive load. some amps....even some fairly well ragarded amps, simply fall down when given some of the wackier loads of real speakers.

[KeithL]

What you're talking about is NOT exactly wattage.

The ability to control the speaker is a matter of damping...

An amplifier with a higher damping factor will control the speaker more precisely... (within limits).

A dynamic loudspeaker acts as both a motor and a generator.

When you feed power into the voice coil it generates a magnetic field which pushes against the speaker's magnet's field and causes the cone to move.

Then, when you stop applying power, momentum causes the come to want to continue moving, so it acts as a generator.

The amplifier must then "absorb" the back EMF - thus acting as a "magnetic brake" that forces the speaker to stop.

Older speakers, intended to work with tube amplifiers, which have very little damping, had more internal mechanical damping, and so relied less on the amplifier to provide damping.

Modern speakers, designed to work with amplifiers that have a lot of electrical damping, tend to have less mechanical damping, because they expect the amplifier to provide the damping required to control the driver.

The ability to absorb back EMF does vary between amplifiers... and more powerful amplifiers... and amplifiers with a higher damping factor... tend to be able to do it better.

Many amplifiers that can deliver large amounts of output current also handle this better than some with limited current capabilities - but the relationship is not totally simple.

Also note that this is not at all an issue with electrostatic panels - which do not generate back EMF via this mechanism.

Oct 18, 2021 15:03:45 GMT -5 housetech said:

Amp power- wattage, is not just about decibel levels, it's about the amp's ability to control the speaker drivers especially in lower frequency range. There are quality 50 watt amps (Rotel, Audiolab. etc) that have better driver control than amps @ 2x the wattage
Where the XPA amp excels is it ability to keep woofers under control.
There's nothing about 3 digit Yamaha integrated amps (Yamaha A-S801 @ 100w) that I like until the 4 digit amps (Yamaha A-S1200 @90w) insignificant output level, but big difference in sound quality.
btw my Denon ARV5700 (140w 2ch) had as good of sound quality & driver control as any integrated I've heard  @ $1500 (or more).

I keep hearing people say receivers suck- WRONG. The only difference between an integrated amp and receiver is the added tuner. The reason integrated amps were popular decades ago was the interference of the RF stage. (I'm not discussing low price junk) Today's receiver are much cleaner than they were but people can now stream radio stations to an integrated.
I'll take a quality integrated amp over separates (amp-preamp) today without hesitation. If anyone wants to donate a Music Fidelity M5si or M6si, I'll take it. 

[KeithL]

I'm not sure I understand the question...

Our XPA amplifiers are a more expensive, and more "premium", product than our BasX amplifiers,

A balanced input is simply one of the premium features which we offer on our XPA amps and not on the BasX amps.

In the case of our XMC-2, RMC-1, and RMC-1L processors...

The easiest way to think about it is that, since they are our premium processor models, they include both balanced and unbalanced outputs.

But you need to use a balanced-to-unbalanced adapter to "access" the unbalanced outputs.

(If you use one of our balanced-to-unbalanced adapters to connect one of those processors to an amplifier with unbalanced inputs you are getting exactly the same signal as if we had included unbalanced output connectors on the processor.)

Our lower cost processors, including the now-discontinued MC-700, and the new model which will soon replace it, have ONLY unbalanced outputs.

(Again, as a lower cost product, that is one of the premium features which we omitted from them.)

Oct 17, 2021 2:50:01 GMT -5 ausman said:

why go from balance to unbalance Kieth

when the idea is to balanced between the amp and processor?


I do understand the logic to have the xpa and other amps with xlr..

though when factoring in international transport costs of xpa and ilk, basx and the UPA's before it would be an a attractive option if the consideration due to weight and cost of transport it makes them and option for the processors


looking at my current physical limitations

i would likely have to have the xpa amps shipped in a rack from the USA..

where as i could likely rack mount BasX myself without issue..

sourcing emotiva gear from an Australian supplier at present is next to impossible due to covid lockdowns

[leonski]

Oct 19, 2021 10:59:42 GMT -5 KeithL said:

What you're talking about is NOT exactly wattage.

The ability to control the speaker is a matter of damping...

An amplifier with a higher damping factor will control the speaker more precisely... (within limits).

A dynamic loudspeaker acts as both a motor and a generator.

When you feed power into the voice coil it generates a magnetic field which pushes against the speaker's magnet's field and causes the cone to move.

Then, when you stop applying power, momentum causes the come to want to continue moving, so it acts as a generator.

The amplifier must then "absorb" the back EMF - thus acting as a "magnetic brake" that forces the speaker to stop.

Older speakers, intended to work with tube amplifiers, which have very little damping, had more internal mechanical damping, and so relied less on the amplifier to provide damping.

Modern speakers, designed to work with amplifiers that have a lot of electrical damping, tend to have less mechanical damping, because they expect the amplifier to provide the damping required to control the driver.

The ability to absorb back EMF does vary between amplifiers... and more powerful amplifiers... and amplifiers with a higher damping factor... tend to be able to do it better.

Many amplifiers that can deliver large amounts of output current also handle this better than some with limited current capabilities - but the relationship is not totally simple.

Also note that this is not at all an issue with electrostatic panels - which do not generate back EMF via this mechanism.

Oct 18, 2021 15:03:45 GMT -5 housetech said:

Amp power- wattage, is not just about decibel levels, it's about the amp's ability to control the speaker drivers especially in lower frequency range. There are quality 50 watt amps (Rotel, Audiolab. etc) that have better driver control than amps @ 2x the wattage
Where the XPA amp excels is it ability to keep woofers under control.
There's nothing about 3 digit Yamaha integrated amps (Yamaha A-S801 @ 100w) that I like until the 4 digit amps (Yamaha A-S1200 @90w) insignificant output level, but big difference in sound quality.
btw my Denon ARV5700 (140w 2ch) had as good of sound quality & driver control as any integrated I've heard  @ $1500 (or more).

I keep hearing people say receivers suck- WRONG. The only difference between an integrated amp and receiver is the added tuner. The reason integrated amps were popular decades ago was the interference of the RF stage. (I'm not discussing low price junk) Today's receiver are much cleaner than they were but people can now stream radio stations to an integrated.
I'll take a quality integrated amp over separates (amp-preamp) today without hesitation. If anyone wants to donate a Music Fidelity M5si or M6si, I'll take it. 

Actually?   You can TEST this with nearly any dynamic speaker and a PAPER CLIP.

First?   Remove the speaker wires from the back of the speaker.    Than?   Around 'front', go ahead and 'flick' the edge of the river with a finger snap.     It'll make a certain noise.    Put that noise in Short Term Memory.

Second?  Short the speaker terminals WITH the Paper Clip.    Go back around front and REFLICK.    Very much different noise.....

If you look at transistor specs?   You will see something called RdON.    Resistance of the device when ON.    This is a VERY low number.   This resistance will be related to HOW MUCH of the BACK EMF the amplifier 'absorbs' and tuns into HEAT.   The remainder?    Basicall goes BACK to the speaker in the form of a SHORT which instantly consumes the energy.......This is HIGH DAMPING.

Now?   this is historically fairly a recent development.   Tube amps have a VERY high resistance when compared to Transistors.   And the speakers?    Had a LOT MORE self-damping.     This is the source of some BASS PROBLEMS where you run a certain speaker and either the bass is 'Tubby' or 'Missing In Action'.....depending of if you are running a speaker which would PREFER a tube or Transistor amp on 'the other one'.......

[KeithL]

Mostly correct... but you have a few of the details backwards.

Yes, if you simply short the terminals of any dynamic speaker, you have the equivalent of connecting it to an amplifier with a very high damping factor.

And, if you simply leave the terminals unconnected, you have done the equivalent of connecting that speaker to an amplifier with a very low damping factor.

(Always remember that a high output impedance equals a low damping factor and vice versa.)

And, if you tap on the speaker cone, you will hear a difference that will let you hear how much that particular speaker is affected by amplifier damping factor.

And, yes, if you replace your paper clip with a transistor, and apply enough current to the base to turn that transistor fully on, the resistance across those terminals will be pretty much equal to RdON.

(It's actually a bit more complicated because you generally have two transistors, and the current involved is AC current, but the math works out pretty much the same.)

BUT your assertion about "the remainder of the current going back into and absorbed by the speaker" is not exactly correct.

Back EMF is a voltage...

The output stage of the amplifier is closing the circuit and providing a path for current to flow...

And, the lower the impedance of that circuit path, the more current that will flow, and the more "braking force" on the speaker movement that will result.

A lot of the energy not absorbed by the amplifier in this way is sort of trapped in the speaker in the form of mechanical energy...

Which is why speakers designed to work well with this sort of amplifier have plenty of mechanical damping to absorb that energy...

And why, when used with amplifiers without much damping, speakers that also lack mechanical damping tend to sound "sloppy and boomy"...

The speaker has energy stored in the form of momentum...

And, without anything to absorb that energy electrically through damping, it simply causes the cone to continue to bounce back and forth and generate sound after the signal driving it has stopped.

And, depending on the mass of the cone, that movement may continue for some time before the energy completely bleeds off.

It's the same reason why the speaker sounds boomy when you tap it without its being connected to anything...

When you tap it you are dumping energy into the cone...

And, without any sort of damping to dissipate that energy, the speaker continues to bounce back and forth until that energy is used up (either as heat or sound)...

However you are also neglecting another especially important factor... feedback.

In an amplifier without feedback the minimum output impedance is indeed pretty much the same as the on resistance of the output devices.

But most modern amplifiers have feedback applied around the entire amplifier.

And, when feedback is applied, the "apparent output impedance" is reduced by a MULTIPLE equal to the amount of feedback being applied.

Not only is the distortion reduced by a similar factor but the apparent output impedance is ALSO reduced by a similar factor.

Rather than simply providing a passive current path for current due to back EMF, the output device is part of a servo loop, and is ACTIVELY sinking the current from the speaker.

This is how an amplifier can have a damping factor that equates to an output impedance FAR lower than the on resistance of its output devices.

If an amplifier has an open loop gain of 2000x (which would be unexceptional for a solid state amplifier)...

But its "overall gain"" has been set to 20x using feedback...

We have applied feedback that reduces the gain by a factor of 100x (we usually specify feedback in dB).

And, as well as reducing the gain by a factor of 100x, that feedback will also reduce the apparent output impedance by the same factor of 100x.

(So the output impedance, as seen by the speaker, will now be 1/100 of the on resistance of those output devices.)

Rather than "pulling the back EMF to ground by shorting the current it generates" we are now actively DRIVING it to ground because that point is inside our "servo loop".

This is all part of "the standard theory of operational amplifiers"...

And virtually all modern solid state amplifiers are really just pretty much giant op-amps...

Your final summary is spot on... although opinions vary as to whether the time when tube amps ceased being current technology was "relatively recently" or "in ancient times"...

Speakers designed to work well with tube amps tend to sound "overdamped" or "dry" when used with modern amplifiers with a high damping factor...

And speakers designed to work well with modern amplifiers, with relatively high damping factors, tend to sound "sloppy" or "tubby" when used with amplifiers that have relatively low damping factors.

Incidentally... for those not familiar with the numbers here...

A typical tube amplifier will have a damping factor of around 4 or 5 (with 8 being considered quiet high)...

Whereas most solid state amplifiers have a damping factor of 500 or more (with 100 being considered quite low)...

(In practice any number much over 50 or 100 really doesn't make much difference.)

Oct 19, 2021 15:40:36 GMT -5 leonski said:

Oct 19, 2021 10:59:42 GMT -5 KeithL said:

What you're talking about is NOT exactly wattage.

The ability to control the speaker is a matter of damping...

An amplifier with a higher damping factor will control the speaker more precisely... (within limits).

A dynamic loudspeaker acts as both a motor and a generator.

When you feed power into the voice coil it generates a magnetic field which pushes against the speaker's magnet's field and causes the cone to move.

Then, when you stop applying power, momentum causes the come to want to continue moving, so it acts as a generator.

The amplifier must then "absorb" the back EMF - thus acting as a "magnetic brake" that forces the speaker to stop.

Older speakers, intended to work with tube amplifiers, which have very little damping, had more internal mechanical damping, and so relied less on the amplifier to provide damping.

Modern speakers, designed to work with amplifiers that have a lot of electrical damping, tend to have less mechanical damping, because they expect the amplifier to provide the damping required to control the driver.

The ability to absorb back EMF does vary between amplifiers... and more powerful amplifiers... and amplifiers with a higher damping factor... tend to be able to do it better.

Many amplifiers that can deliver large amounts of output current also handle this better than some with limited current capabilities - but the relationship is not totally simple.

Also note that this is not at all an issue with electrostatic panels - which do not generate back EMF via this mechanism.

Actually?   You can TEST this with nearly any dynamic speaker and a PAPER CLIP.

First?   Remove the speaker wires from the back of the speaker.    Than?   Around 'front', go ahead and 'flick' the edge of the river with a finger snap.     It'll make a certain noise.    Put that noise in Short Term Memory.

Second?  Short the speaker terminals WITH the Paper Clip.    Go back around front and REFLICK.    Very much different noise.....

If you look at transistor specs?   You will see something called RdON.    Resistance of the device when ON.    This is a VERY low number.   This resistance will be related to HOW MUCH of the BACK EMF the amplifier 'absorbs' and tuns into HEAT.   The remainder?    Basicall goes BACK to the speaker in the form of a SHORT which instantly consumes the energy.......This is HIGH DAMPING.

Now?   this is historically fairly a recent development.   Tube amps have a VERY high resistance when compared to Transistors.   And the speakers?    Had a LOT MORE self-damping.     This is the source of some BASS PROBLEMS where you run a certain speaker and either the bass is 'Tubby' or 'Missing In Action'.....depending of if you are running a speaker which would PREFER a tube or Transistor amp on 'the other one'.......

[leonski]

If the output devices are very low resistance 'on' and the speaker produces a back EMF, where does it GO? It passes with little restriction thru th output devices but the voice coil will have a substantial....by comparison ......resistance.

My 'test' is meant to show the range of possibles. Such a test is a way to learn about damping. Than you can go to the 'next level' and worry about transformers and SS output. A speaker with 'trapped' mechanical energy will express it when

the cone returns to 'rest' and at that point turn (inefficiently, for sure( this stored energy as electrical......Some heat, too, for that matter. Old school 'box' speakers.....like BOZAK and ALTEC VOT and several others use other than electrical means as damping.

Maybe stuff suspensions?

I actively didn't want to get into feedback. While neat to talk about, doesn't help with th basic idea of damping. My Maggies are similiar to 'stats also. They don't need much amp damping and work well with EITHER tube or SS.......

[Boomzilla]

My experience: The Emotiva BasX line is the best value in audio. The components sound within striking distance of "the best" regardless of cost. Can you buy better sound? Sure. Can you buy better-built and more-reliable components? Sure. But for the dollars spent, I'd put the BasX line up against anything. And regardless of cost, the BasX line is still worth considering. With some speakers, the amps just sing. The inexpensive PT1 preamplifier is now the center of my system. It's being used with FAR more expensive amps & speakers, but still holds its own.

My current system consists of:

Roon on a Mac mini computer with external USB HDD for the library
Emotiva Big Ego+ USB DAC
Emotiva PT1 preamplifier
Any of the following amps on any given day: Crown PSA-2, Emotiva PA-1, Heathkit tube monos, Black Ice F22
Any of the following speakers on any given day: Klipsch RP-600M, B&W 702, Harman Kardon bookshelf - all with Klipsch 12" sub

For the $$$ invested, this system amazes me and keeps me wanting to hear more.

Boom

What would I upgrade?

If I find a pair of Dahlquist DQ-10a speakers locally or a pair of Thiel 5i speakers, I'd buy those. I might even consider a Fried H system...
If I find a better subwoofer locally, I'd get that (but may buy an Emotiva one instead)

Note that the front end & amplification is already "as good as it gets" IMHO.

[leonski]

Boom......with APPROPRIATE speakers, I have little doubt you have found a good place.....

It is at the 'edges' where you will begin hearing differences which may or may NOT make you wonder.

Me, I'm thinking one of the VTA tube amps.....Maybe the Mono 125s for my panels. Panels don't need a LOT of damping and while

low sensitivity,, I rather doubt I'd make real use of more than 10 watts EACH with 10db (100 watt) peaks.....But I may not even use

THAT much power......