16 ohm speakers: any amp sounds better with more resolution. speaker cables less critical.

Dear Raul you posted above {all the tube owners are listening ( no matters what ) something really away from what the recording microphones pick-up during recording sessions} and { Learn from all those honest gentlemans}  = Non-Sequitur ie Sweeping generalizations followed by special pleading The generalization is the fallacy here. The pleading follows it in order to avoid offense or some such measure.

" all due to distortion .." what are you talking about, where are your facts?

Your inability to understand the facts isn’t my fault. I’m writing this so you understand that I presented the facts *already*.


If you actually have a genuine interest in learning more of what I posted previously (instead of simply acting on a desire to make me wrong), google ’Gain Bandwidth Product’ and ’phase margin’ and read up. Then you will see why what I posted is correct. FWIW these are engineering topics and may be a little dry. For more information you might also read this article by Bruno Putzeys on feedback. In this one you don’t have to work out the math, if you allow yourself to trust that he did his math homework (in case you don’t know who he is, Bruno is one of the top designers of class D product in the world, responsible for the Purify and Hypex modules):
https://linearaudio.net/sites/linearaudio.net/files/volume1bp.pdf

After reading this article, you should understand why the Parasound is running insufficient feedback, and so has a brightness.

Ignorance is curable- stupid is forever. I’m pretty sure you’re not the latter, so now you have an opportunity.

Dear @atmasphere : Totallñy wrong about the quality level performance of the JC-1’s or today top SS amplifiers where almost all of them are non-feedback and many pure class A, the JC-1’s works in class A with its first 30 watts.ear .

Did you heard the Evidence’s mated with the JC-1’s or the top Soundlabs with those monobloks or with other top speakers?

" all due to distortion .." what are you talking about, where are your facts? as always only bla, bla, bla and low knowledge level audiophiles here and elsewhere think that because you are a tube manufacturer you are the bible on amps but about SS you have nothing and always you trying to diminish the SS alternative with no facts and the only reason you do it is that you are taking money as other tube manufacturers from low knowledge level audiophiles that unfortunatelly just have no idea how live MUSIC sounds at near field position. As all of us you are a member of the corrupted AHEE and unfortunatelly you are the darkness part of that AHEE.

Here it’s the measured " distortion " of the JC-1’s even at 1 ohm where puts nothing less than " 4.2kW into 1 ohm (27.2dBW, magenta). The latter is equivalent to an output current of 64.7A! "

https://www.stereophile.com/content/parasound-halo-jc-1-monoblock-power-amplifier-measurements

This is the J.Atkinson conclusion after he finished the measurements and along that it’s the review down there:

" This is excellent measured performance. The Halo JC 1 is not only the best amplifier to come from Parasound, it ranks up there with the best high-end heavyweights. "

If you don’0t have true facts/measures on what you said stop to spread your poison/false information and please learn that live MUSIC at near field position is everything but warm and it’s brigth, agressive, high dynamic power, with ryhtm, extraordinary at both frequency extremes, sometimes harsh ( listen to a trumpet/horn player at real SPL seated at 3 meters . ).

Recording microphones are " seated " at near field positions not at 20m-30m.

Warm, sweet, relaxed, and other ridiculous adjectives to explain the MUSIC sound in a room/systems is exactly what the corrupted AHEE teachs/teached for the last 50 years to audiophiles but that AHEE in this specific subject were and are only spreading lies deceiving/misleading audiophile gentlemans only to take their money and people like you even try to explain that kind of deceive with no facts.

I don’t care what the audiophiles like ( it’s a personal privilege. ) but with out any doubt all the tube owners are listening ( no matters what ) something really away from what the recording microphones pick-up during recording sessions and in the other side good SS electronics designs ( like the " old " JC-1’s. ) puts any one of use nearer and truer to the recording where tube is only a " caricature ".

Go a head making money, nothing wrong with that but stop to spread false information against SS that you can’t prove or proved and learn from other tube manufacturers that never post in any internet audiophile forums that totally false information in favor of tubes and against SS electronics . Learn from all those honest gentlemans.

R.

Ralph, What I recommended to Elliot is that he first experiment with the settings of the L-pads in his speakers until he arrives at a solution that he wants to live with long term. Doing this would automatically involve accounting for the driving ampifier and the length of speaker cable. Once that steady state is arrived at, do you see anything wrong with swapping the L-pads for high quality high wattage discrete resistors that represent the resistance across each L-pad after their final adjustment? Anyway, that is what I would do. My approach is based only on listening to my Sound Labs speakers (first the M1s, then the 845PXs) with vs without the Brilliance control in circuit. Big improvement in transparency and air without that L-pad.

I don't doubt it. But as I said, if you make changes in the amp or speaker cables you might find that you want to change the setting as well. Once you know what it is, of course a fixed resistor of good quality will be better.

JC-1’s are great monoblock amplifiers and is unfortunated that today are out of production because can compets or could be a true challenge to even names as FM Acoustics, Boulder, Gryphon, CH, Dartzeel and the like.

The JC-1 was a good solid state amp for its time, but like many other amps from that time didn't have enough feedback to really sound neutral- and that is why it can be a bit bright and harsh- all due to distortion. Combine that with an ESL and its going to be very bright... fortunately the Sound Lab has adjustments to allow you to adjust the speaker to the voltage response of the amplifier, so you can tone it down a bit.


The reason the distortion is there is due to insufficient feedback. This prevents the distortion caused when feedback is applied to be suppressed. Put another way, feedback suppresses distortion, but then makes some of its own. To allow the amp to get rid of that, you need more feedback, and most of the solid state amps of this era (and before) lacked the Gain Bandwidth Product and phase margins that were needed to run the required feedback. So they simply didn't.


So ya picks yer poison; harshness and brightness, or a little extra warmth but the highs are detailed and relaxed. This is why tubes are still around BTW; solid state is supposed to be 'neutral' but its hard to call it that when its bright and harsh.

Dear @mijostyn : JC-1’s are great monoblock amplifiers and is unfortunated that today are out of production because can compets or could be a true challenge to even names as FM Acoustics, Boulder, Gryphon, CH, Dartzeel and the like.


Years ago I meeted by first time to the JC-1’s that were handled a pair of superlative Dynaudio Evidence speakers in the room/system of a friend of a friend of mine.

I readed in those times about the Evidence speakers but never imagined that were handled by so " humble " Parasound amplifiers and was a glorious listening time with both friends and we reapeated that kind of listening session several times. Here the Evidence:

https://www.stereophile.com/floorloudspeakers/286/index.html

Now and this you can be absolutely sure that no tube amplifier can beats the Soundlabs/JC-1’s experience and you can be sure too that the Sounlabs- self powered subwoofers ( 80hz-100hz. ) combination is a must to do it no matters what.

Enjoy it.

Btw, the 16 ohms issue really matters to tube amp owners, not many 16 ohms speakers in a market with 90% ( at least ) of 4 ohm-8 ohm nominal impedance specs.

In the other side SS amps as the JC-1’s can handle from low to high impedances where you can’t detect the small increment in distortion level.

When a tube amp normally ( manufacturer spec. ) has 1% a SS amp with low or high impedance could goes to 0.2-3% when the manufacturer spec overall gives 0.01%.
Normally tube owners " can’t " listen 1-2% of distortion in their amps or just do not care about.

With a little of patience any one can buy second hand the JC-1’s for very good price. John Curl made very good design job with.

This is what I'm talking about:

https://www.stereophile.com/solidpoweramps/774/index.html

R.

Ralph, What I recommended to Elliot is that he first experiment with the settings of the L-pads in his speakers until he arrives at a solution that he wants to live with long term.  Doing this would automatically involve accounting for the driving ampifier and the length of speaker cable.  Once that steady state is arrived at, do you see anything wrong with swapping the L-pads for high quality high wattage discrete resistors that represent the resistance across each L-pad after their final adjustment?  Anyway, that is what I would do.  My approach is based only on listening to my Sound Labs speakers (first the M1s, then the 845PXs) with vs without the Brilliance control in circuit.  Big improvement in transparency and air without that L-pad.

It makes sense that only putting out half the power (vs 8 ohms) with the same power supply and current could relax an amp at times, but I suspect otherwise.

If you can find a solid state amplifier that makes more distortion into 16 ohms as opposed to 8 or 4, I'd be interested in hearing about it. Looking at hundreds of solid state amps over the years, I've not seen one.

The one pitfall that you might run into isn't related to the load impedance so much as it is the intention of the loudspeaker designer. If that designer was intending the speaker to be used with tubes (as is common with 16 ohm speakers) then the design could sound bright (less relaxed) in certain situations. This is certainly true of ESLs with solid state (but the brightness there is due to a low impedance at high frequencies, despite a high impedance at low frequencies).


@elliotnewcombjr 

Unless someone talks me out of it!!!

Be prepared to work with a variety of values if you really intend to remove the level controls! I'd leave them in place if I were you (I certainly have done so with my speakers). This is simply because the speaker is designed without foreknowledge of the voltage response of the amplifier (IOW its a Power Paradigm device), so the control is there to allow you to adjust it to match to the amplifier . One way this can cause an issue is if you run a really long speaker cable as opposed to a short one- it might require a different setting of the level control since the apparent voltage response of the amplifier will be affected by the speaker cable (in the case of a really long cable) in series with the amp. I personally stay away from long speaker cables as speaker cables have errors unrelated to their DC resistance, and these errors (due to something called 'characteristic impedance') get more profound with longer cables. So I run short speaker cables and long balanced interconnects to get around this issue, since balanced lines can be run some very long distances without coloration (if they are set up correctly).

Never really understood how it worked that way. Figured I’d jump into this one and see if anyone had a brief explanation, thanks. 

@cisgo  The J2 is current limited (helps keep the output device alive) and so power does not increase as the load impedance is reduced to 4 ohms. But because its output impedance is relatively low, its power output is dropping into loads above 8 ohms. This amp is best used with a higher efficiency speaker, and a 16 ohm speaker will allow it to behave as a voltage source as long as you don't overload it.

It's always interesting to learn things here. Of course I have heard of the highly respected Nelson Pass, but never checked anything out.

That is wonderful to hear Raul as I will be driving my Sound Labs with JC-1s at least for the time being. Dr West also highly recommends Atma-Sphere MA2's. The newer units have undergone significant changes in their interfaces. They do suffer from the same anomaly my old Acoustats had. Both designers were intent on making the speakers full range but for some reason that has to with transformer physics it is impossible to make a single transformer cover the entire audible range gracefully so both designers decided to use two transformers and a blending network to do the job. In my case I am crossing over to subwoofers somewhere around 100 Hz (125 Hz with the Acoustats) So, I do not need a transformer to go down low. Consequently I can get away with one transformer and no complicated blending network. This worked great on the Acoustats. I'll live with the SoundLabs for while before I start screwing around with transformers. Lewm relates that he bypassed the bass and brilliance controls. Dr West assures me there is no benefit in doing this. If it is easily reversible I'll give it a try. I am not fond on any additional stuff in the signal path particularly if it is not doing anything useful. 

I agree with lewm in that Nelson Pass used his First Watt designs to intentionally deviate from their siblings throughout the model line.
The J2 was designed as a single ended transistor amplifier using only 1 output power transistor per channel. Just as a SET amplifier utilizes only 1 output tube per channel.

So it makes sense that it will deliver less power into a lower impedance load if the circuit was optimized for an 8 ohm impedance speaker load. Some First Watt amplifiers are push pull and will behave differently. Basically whatever Nelson Pass was  trying to achieve with the given model. Each F.W. amplifier is quite distinct.
Charles

Elliot, What you say to Cisco (Cisgo) may be true for an SS amplifier but for a tube amplifier, especially a transformer coupled one, the reverse is more likely, for a given tap on the output transformer:  An amplifier that makes 12W into 8 ohms might make only 6W into 4 ohms.  This is not always the case, and actual measurement is in order.  Likewise, an SS amplifier is likely to double its power into 4 ohms vs 8 ohms, provided it can deliver the needed additional current, which depends upon the power transformer.  But Cisgo apparently owns a First Watt amplifier, designed by Nelson Pass, one of the best and most innovative of all designers of SS gear.  In the First Watt series, he is experimenting with different topologies and different types of output devices.  So if Cisgo's information about his own amplifier comes from NP, I would accept it as gospel.  And Cisgo, if you want to know why the power rating changes as you say, ask NP.

cisco,

did you get #'s reversed?

typical amp would be 12 wpc at 8 ohms, double at 4 ohms, i.e. 25 wpc at 4 ohms.

If your transformer does not have a separate 16 ohm winding, then if you hook up a 16 ohm speaker to an 8 ohm tap, _____ wpc?

sonically, this article says the mids would be boosted slightly

http://blog.hughes-and-kettner.com/ohm-cooking-101-understanding-amps-speakers-and-impedance/

A question I always was curious about. My amp (FW J2) rates at 12w 4 ohms and 25w into 8. Yet when I connect my 16 ohm speakers ( Spatial TM) they rate back to around 12w. Never really understood how it worked that way. Figured I’d jump into this one and see if anyone had a brief explanation, thanks. 

My 96dB/10ohm speakers sound much better on my amp's 16ohm taps than the 8 ohm.  The 4 ohm taps are almost unlistenable.  The 16 ohm taps bring out so much more richness, nuance, and detail.

Hi @danvignau, 
Reading Ralph's clearly written explanation it isn't difficult for me to understand why this is the case. As of yet I haven't come across a contrary explanation that reasonably refutes him.

An easier high impedance speaker load (Less current demand) would seem quite beneficial for all amplifiers. I don't see the rationale that a more difficult lower impedance (Higher current demand) to drive is a more positive circumstance for an amplifier. 
Charles 

RE_ 16 ohms:   It makes sense that only putting out half the power (vs 8 ohms) with the same power supply and current could relax an amp at times, but I suspect otherwise.

To me, Elliots findings make perfect sense.
1. A16 Ohm speaker will present a much milder load to any amp designed for 4-8 loads, usually resulting in less distortion. There are exceptions but very rare.
2. As the speaker’s impedance rises, the amp’s output impedance will become less of a factor, equivalent to higher damping factor. The amp will drive the speakers with more control. Frequency ranges where the speaker’s impedance drop even below 8 ohms will present no problem to the amp, again less distortion, more grip.
3. Because of the higher impedance of the speaker, the resistance and impedance of the cables will be less significant.

BR,
Davor, also a Covid recoverer :)
Take care

So I heard Raul and I don't disagree. Practically for a speaker you will need quite a few Vishays per channel which will make it more expensive and more bulkier to install but yeah if you have the money Vishays are supposed to be great and Mills good (like you said)

@luisma31 : Mills are good not great, great are the Vishay ones nothing can beats it.

R.

If you want to add a single resistor to replace the L pad and adjust brilliance (like Lew suggested) Mills are great, those are the ones I use on my speaker and are very transparent, 12W BTW 28 ohms in my case.
Edit: in your case of course you might want to measure the lpad setting for resistance and replace with same value, my 28 ohms is very specific to my room and driver

I’m gonna

1. remove the L pads
 
another advantage: the L pads in the back panel won’t be wired to the crossover/drivers inside, the back will come fully off.

2. annual tightness check (nothing ever loose, but, to sleep better ..)

a. confirm the drivers are tight to the front panel, and
b. the front panel tight to the case 
c. 15" Woofer off the front panel, I can check the paper cone’s condition, it’s been several years.
d. I might drill more mounting holes on the metal ring of the 15" woofer, 4 just doesn’t seem enough for that 37 lb monster (although it is never loose when I check)

3. make a new set of speaker cables using this:

https://www.ebay.com/itm/75FT-CAT7-S-FTP-Network-Outdoor-High-Speed-10Gbps-Shielding-Ethernet-Cable-...

OFC, S/FTP, 24 awg solid strands (8 conductors equivalent to 14 awg)
(might be 26 awg, equivalent to 17 awg, waiting for seller's answer)
12 feet long each, (2+, 2- : 50 foot roll will just do it) 16 ohm nominal.
McIntosh chart says 18 awg, 16 ohms, max 60 feet long.

Unless someone talks me out of it!!!

Problem is that speaker manufacturers never gives the whole impedance facts/measurements/charts. Tha’s why generalizations to say 8 ohm speaker spec means almost nothing. I choosed at random ( between hundred of ST measurement. ) and you can read there that your words are not exactly rigth with some of those speakers, same for maplifiers.

Whenever anyone asks if a speaker will work with our amps I take a look at the impedance curve if one is available. But if the speaker is rated 8 ohms or more I pay attention, and if the speaker is rated higher, like 16 ohms, I’ve yet to run into one that didn’t work. I’ve seen some speakers, like B&Ws, that are rated ’nominally 8 ohms’ but feature dual woofers, which are wired in parallel, although the midrange and tweeter array is certainly what I would call ’8 ohms’. The woofer array, even though it may have peaks at 8 ohms or higher, is something I would regard as more of a 4 ohm load. So you do have to be careful about this issue; but in the case of higher impedances it usually no worried at all.


The Sound Lab is not a speaker rated at 16 ohms or 30 ohms despite both impedances being present at some frequency. While it is difficult for most solid state amps to make power on this speaker owing to the 30 ohm impedance in the bass (which is why a tube amp of 150 watts can easily keep up with a solid state amp of 600 watts on this speaker), all this means is that you might see about 1/4 the power the amp is rated for into 8 ohms. However, and this is important, as the frequency goes up above about 5-7KHz, the impedance is dropping, to a low of about 1.5-3 ohms (depending on the setting of the Brilliance control) at 20KHz. Like almost any full range ESL, the impedance varies by about 10 or 9:1 from the bass to the highs. The issue here is that a good quality solid state amp will double power as impedance is halved. With a box speaker, this is fine because a peak in the impedance curve usually represents a resonance so this property is welcomed. But this isn’t the case with the Sound Lab. It needs about the same power in the bass region as it does in the high treble region to make the same sound pressure at that frequency. This means that an amp that can double power (and the Sound Lab does not challenge most solid state amps in that regard) will be excessively bright due to this property.

To get around that issue, the Sound Lab is equipped with a number of settings to modify the speaker’s response. The Brilliance control is there to deal with excessive brightness, the bass settings allow you to boost or cut the bass, depending on if you have a solid state amp (boost) or tube amp (cut). IIRC there are midrange settings too.


One nice thing about this speaker if using solid state is that the bass impedance (where the power is) is high, resulting in low distortion for nearly any amplifier. Low distortion means less harmonics from the bass notes, so an amusical harmonic like the 7th, 9th, 11th or 13th to which the ear is keenly sensitive, will be greatly attenuated. IME this is beneficial to all amps.


The mod that @lewm did seems a wonderful upgrade for the speaker!

For those who don't know, Sound Lab drive their full range ESLs using two audio step-up transformers wired in parallel, one for bass and one for treble.  Audio frequencies are divided by a first order crossover network (inductor in series with the bass transformer, RC network before the treble transformer) before being fed to the bass and treble transformers, respectively.  I have done impedance vs frequency curves for my 845PXs, measuring Z at 50, 100, 200, 500, 1K, 2K, 5K, and 10K Hz, with the original bass and treble transformers in place, with only the OEM SL bass transformer in place, with only the original treble transformer in place, and with the aftermarket full-range 1:90 ESL transformer alone and in combo with the OEM SL bass transformer.  I have the data in a notebook.  So I think I have a pretty good understanding of the impedance of an 845PX.   I use the speaker with the OEM bass transformer preceded by a small inductance, in parallel with my aftermarket audio step up transformer preceded by no filter at all.  Efficiency is hugely improved; I would wager it could easily be driven by less than a 50W amplifier.  My Atma-sphere amplifiers probably make 100W into a 16-ohm load, and they are coasting at high SPLs while driving the 845PXs, which appear in my system as about a 20-ohm load, using the generalization that Raul dislikes, but I can guarantee that Z never goes below 20 ohms below 5kHz. All ESLs are in effect giant capacitors, so it is inevitable that Z goes down as frequency goes up above 5kHz. As Ralph said, the big problem was the resistor in the RC network that was there to create a high pass filter for the (old) treble transformer.  That resistor, depending upon the vintage of the speaker, could be as low as 5 ohms, or in later speakers as high as 8 or 10 ohms.  The resistor creates an absolute upper limit of impedance at frequencies around the crossover point, because it is in parallel with the output of the amplifier.  Thus, if you were unlucky enough to have one of the older speakers with a 5 ohm resistor, you were dealing with 5 ohms or less impedance at around 500Hz to 2kHz.  That's also why you benefited from a very high wattage resistor in that RC network.  Raul has a point about the very high impedance in the bass region using the OEM bass transformer; it's way up around 100 ohms and maybe higher below 100Hz.  Yet, my OTLs drive it fine, as does Raul's friend's SS amplifier.

Elliot, For Sound Lab owners, the first thing I recommend is to bypass the "Brilliance" control, which is an L-pad in series with the treble transformer, much like the controls on your speaker.  Alternatively, if you feel you need some treble taming, you could use a discrete resistor of an effective value in place of the L-pad.  L-pad bad.  No L-pad good.

Dear @atmasphere  @lewm  and friends:  In reality " things " are not so " simple " as both of you posted to me.

The whole speaker impedance subject is a lot more than only the deviations through the frequency response of the speakers because we have to take in count to phase and angle that could " helps " to the amplifiers to develops even higher distortions and if you look to the amplifiers measurements I linked you can see that how good or not an amplifier can drive an specific speaker model.

If can be true that some SS amplifier can have some " problem " with some specific speakers ( I never found out one SS amplifier that had problems about or at least I just coul not detect it and I'm extremely demanding listener, not an easy one. ) where exist a higher trouble is with tubes even that the system owners are satisfied with and likes what they listen with.

Problem is that speaker manufacturers never gives the whole impedance facts/measurements/charts. Tha's why generalizations to say 8 ohm speaker spec means almost nothing. I choosed at random ( between hundred of ST measurement. ) and you can read there that your words are not exactly rigth with some of those speakers, same for maplifiers.

I love Soundlab speakers and for me is the only today electrostatic that I really like it.
My friend Guillermo ( a wealthy one gentleman. ) owned big Wilson that performed very good. Suddenly he took a fligth tp SLC in Utha and he bougth and brougth with him a pair of top of the line Soundlabs and the JC-1 amplifiers recomended by the designer him self.
For me was a surprise because never told me he wanted to change the Wilson, so and before I listen his new system and when both been at my place testing one of the tonearm prototype he told me about and I asked why and he told me that were the only speakers with the kind of sound quality performance levels that the very old ones in my room/system. For me was a true unexpected nice comment by him but when I listened at his place I really fall in love with Soundlabs/JC1 combination and if not exactly it sounds similar, obviously I like it.

This Soundlab measurements are not the today ones but more or less gaves an idea about and confirm that in the bass range what you said of very high impedance that for a SS amplifier is not " welcomed " however I heared no single trouble in those Soundlabs driving by the truly good JC-1 monoblocks:

https://www.stereophile.com/content/sound-lab-1-electrostatic-loudspeaker-measurements


R.

Now, getting back to the amplifier factor, it is quite likely that the old version of the 845PX could have been driven more satisfactorily at midrange frequencies using a typical SS amplifier, because of the lower output impedance exhibited by most SS designs, but then I wouldn't have the OTL-ness to which I am addicted. I was told that SL use SS amplifiers at their factory, which is probably why the problem went unnoticed for a while.

@lewm  I have customers with solid state amps and they report the same thing that our customers with tube amps do- that when the error in the backplate was corrected, the speakers instantly were easier to drive and sounding better at the same time.

Sound Lab was using a Boulder amplifier, which is why they may not have noticed a problem. But remember that resistor that got pulled out? It was a composite of eight resistors, totaling 200 watts! Obviously a lot of amplifier power was being used to heat those parts up. So its no wonder when that problem was corrected that the speaker got instantly better.

Elliott do bypass those L pads!!!!!!

Dear Raul, Of course you are correct that no speaker has a flat impedance.  Yet it's common practice to refer to speaker impedance with a single value.  I am guilty of that as is almost everyone else in the audio world.  If it were of some importance to me personally in the course of evaluating a speaker for purchase, I would demand to see the full impedance curve over the entire frequency range.  As you know, an impedance dip in the bass or midrange can be much more consequential than a falling impedance at very high frequencies, for the interaction of any speaker with any amplifier.  I don't argue with any of the points you made about speaker impedance.  Also, all remarks about speaker impedance are subject to the choice of amplifier to drive that speaker, unless the speaker is just crazily variable in impedance across the audio frequency range, which will be challenging for any amplifier.

Ralph, The older Sound Labs sounded anything but "transparent" in the midrange, using your OTLs to drive the unmodified version of my 845PX. I remember listening to Frank Sinatra during the first week or two after I bought the 845PXs and thinking to myself, "Is that Frank Sinatra?" Yes, Dr West did respond to our findings and our fix by revising his circuit and substituting the old treble audio step-up transformer for a new one that works down to lower frequencies, at least an octave lower.  This allowed him to make changes in the crossover such that it sucks less power and provides for a higher impedance at midrange frequencies.  I am told it's a big improvement.  I continue to drive my own 845PXs using a treble transformer capable of full-range response that does not require any crossover components at all to differentiate the input to the bass vs treble transformers.  Now, getting back to the amplifier factor, it is quite likely that the old version of the 845PX could have been driven more satisfactorily at midrange frequencies using a typical SS amplifier, because of the lower output impedance exhibited by most SS designs, but then I wouldn't have the OTL-ness to which I am addicted. I was told that SL use SS amplifiers at their factory, which is probably why the problem went unnoticed for a while.

I can't understand why you and any one else speak of 16 ohm, 8 ohm or 4 ohm speakers when the speaker impedance is not flat , it changes over its frequency range.

Simply put, a nominally 16 ohm rated speaker will be higher impedance than a nominally rated 4 ohm speaker.


It is true that no speaker has flat impedance, but the impedance variation is not so important as the overall. If the impedance is overall higher, the amp will be lower distortion. I suspect that this is one of the reasons the Sound Lab is so transparent, as in the bass region its 30 ohms. Any bass energy made by any amplifier will have less harmonic distortion simply because the amp will be lower distortion where the power is needed most. And for all that, the impedance of the speaker varies by about 9:1 from bass to 20KHz.

Dear @lewm : I can't understand why you and any one else speak of 16 ohm, 8 ohm or 4 ohm speakers when the speaker impedance is not flat , it changes over its frequency range.

The measurements made it by Stereophiles confirm it and it does not matters what the speaker manufacturer specs are.

We can't choose an amplifier ( tube or SS. ) founded by the manufacturer nominal impedance spec because this spec is away from reality and all those "" bla, bla, bla " in good shape opinions on lower or higher distortions and the like has no true value. Facts are the only reality.

Any kind of audio items measurements made it by Stereophile always are really enligthing and learning lessons for many of us, at least for me that I'm not an expert as other gentlemaNS HERE.

The OP  ask something on 16 ohm speakers when does not exist in the way he was and is thinking.

If we look these measurements of 3 way different amplifiers along the speakers measurements posted we can understand the whole subject  in a better way:

https://www.stereophile.com/content/ps-audio-stellar-m1200-monoblock-power-amplifier-measurements

https://www.stereophile.com/content/gryphon-essence-mono-power-amplifier-measurements

https://www.stereophile.com/content/balanced-audio-technology-vk-56se-power-amplifier-measurements


All those kind of measurements needs no words, are just facts. Self explained facts.

R.

spkrplus4

thanks, 

I get voltage, current, resistance, but don't understand inductance.

and used cable with plenty of conductor to do the job.

@atmasphere by plenty you mean AWG correct?

Yes. Bad editing.

@elliotnewcombjr  The level controls are there to allow you to adjust the speaker to your amplifier's voltage response. But to maintain the crossover point they should be the same value as the original.

@mijostyn If you're getting a new Sound Lab, Roger corrected for the issue to whicht @lewm was referring. So you shouldn't need to do any mods.

Elliott, Lewm is correct in that you have to measure the resistance of the L pads when they are in neutral position. It may not be zero. I think it is best to do what Lewm suggested. Set them up so that they sound good to you. Then measured the resistance and substitute the appropriate resistors.
Wires that run parallel to each other have the highest inductance. In other words one wire will induce a current in the next wire. Wires across each other at 90 degrees have the lowest induction. I believe the wire in cat 5 cables is parallel.  Wires in a twisted pair are always approximating 90 degrees to each other and therefore have very low induction. IMHO the best wire made for loudspeakers is Kimber Kable. It uses smaller gauge wire woven in a pattern that keeps induction very low and because the wires are very close to each other parallel resistance is low. As Ralph relates you keep series resistance low by keeping the wires as short as possible. For 16 ohm speakers 18 gauge twisted pair is more than adequate. If you want to go ballistic buy a set of the higher gauge Kimber Kables. My amps are right under the speakers and I use 3 foot runs of Kimber Kable 12TC.
Lewm, I finally ordered my Sound Labs!! They are a custom size, basically 845s the width of 645's, a little narrower. They will fit my situation better. Roger is supposed to be giving me an ETA today or tomorrow. You mentioned that you modified the interfaces. Did you just bypass the controls?

luisma31

everyone,

This didn’t start about sound, I am completely content with everything as is.

It was about bias controls, internal or external.

I was considering changing to a newer version of this Cayin A88T tube amp to get external bias adjustment, which my current version lacks. Those newer versions have dropped the 16 ohm taps.

Now that I have learned about the relationship of resistance to distortion, I’m sticking with this version, 16 ohm speakers to 16 ohm taps. Sticking with the internal bias controls.

Steve at VAS previously said he would adjust the bias while I waited.

https://vasnyinc.com/

He is only 1 hour away. Bill and I might go there together after the holidays.

Meanwhile, I am going to bypass the level controls, expecting no change or better.

thanks again, as always, for the shared experiences, friendly and knowledgeable advice.

and used cable with plenty of conductor to do the job.

@atmasphere by plenty you mean AWG correct?

lewm

thanks for your thoughts.

you know too much for my own good!

level controls are in the neutral position now, i.e. doing nothing.

I have been thinking of simply bypassing the level controls, on one speaker first, see how it compares with the other, any detectable changes. Then mess about with level controls other speaker, see if any 'improvement' can be found.

 No problem or better without the controls, then bypass the other.

I am not sure that generalization (16 ohms = lower amplifier distortion) would apply to every variety of solid state amplifier.

@lewm If you know of one that actually has lower distortion into 4 ohms as opposed to higher impedances I'd love to know about it. I've yet to find one, starting from primitive driver transformer designs of the 1960s to self oscillating class D amps of the 2020s. If there is one out there it is a very rare exception!

Dear friends: I respect all gentlemans opinions but this is what defines the amplifier need it. Not what said atmasphere or Dudley or Fremer or Teektonany one else  because one is the manufacturer theoretical impedance ( been 4ohms or 16 ohms. ) at the end it does not matters till we know what these facts shows us:


https://www.stereophile.com/content/acora-srb-loudspeaker-measurements

https://www.stereophile.com/content/g%C3%B6bel-high-end-divin-marquis-loudspeaker-measurements

https://www.stereophile.com/content/von-schweikert-ultra-55-loudspeaker-measurements

https://www.stereophile.com/content/magico-m2-loudspeaker-measurements

https://www.stereophile.com/content/wilson-audio-sasha-wp-loudspeaker-measurements

https://www.stereophile.com/content/monitor-audio-gold-300-loudspeaker-measurements

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

My amp has 4, 8, and 16 taps. If my speakers are 4, what strain, if any, on any of my amp tubes will that have?

If you put the speaker on the 4 ohm tap, none, but the output transformer will likely be losing some performance- they can often lose as much as an octave of bandwidth in the bass, and they will run warmer. That warmth is also causing the amp to make slightly less power, as the heat is coming from the power tube output.

And yet, the guy who designs some of the most fantastically successful speakers made anywhere in the world today says nevermind 16 ohms, even 8 ohms is obsolete.

As far as solid state is concerned, this may well be true from a marketing perspective. But this is high end audio, where minimizing colorations is important, and distortion causes most of the colorations we hear- for example the brightness/harshness of solid state. The 3dB more power thing is a really weak argument- put another way, if you want to get the **best sound quality**, your amplifier investment dollar is best served by a higher impedance speaker. OTOH, if **sound pressure** is your goal, then you have a 3dB argument for 4 ohms (as opposed to 8) **if** you have a solid state amp that doubles power into 4 ohms. But you really pay a price doing 4 ohms- not only do you have more distortion, but most amps will run warmer (even class D) and the speaker cable becomes critical. On that basis it would be a stretch to claim state of the art performance when the amplifier is thus compromised.

His demo is about loudness, saying 4 ohm will produce 3db more VOLUME than 8 ohm. IOW, it helps him with efficiency.

To be completely correct, it helps with **sensitivity** which is not the same as efficiency. Efficiency is unaffected. What the higher sensitivity number is saying is that the amp is now being asked to make twice as much power! That's completely different from a speaker that is 3dB more efficient- the latter would mean that an amp with half the power would play just as loud!


Like everything electronic, math is involved. Efficiency is stated as a certain sound pressure with 1 watt. Sensitivity is stated as a certain sound pressure with 2.83 volts.  Into an 8 ohm load 2.83 volts is 1 watt; into 4 ohms its 2 watts. This is a 3dB difference. Since tube amps don't double power as impedance is halved, efficiency is the more useful specification, but since the industry went solid state, the sensitivity spec has taken over. You can make any speaker seem more "efficient" by reducing its impedance though parallel drivers but what is happening is the sensitivity is being increased while the efficiency is unaffected. You do have to pay attention to this nuance when selecting a speaker to work with an amplifier!

1. how importance is bias to sound? (I don't care about heat or tube life).

......................

2. speaker cable inductance ..... gauge ____ awg

mijostyn said

" the wire you are using probably has high inductance. You should use 18 gauge wire that is a jacketed twisted pair like this".

Guage: Cat 5 8 strands is 15 awg. Two Cat 5's, 16 strands, is 12 awg.

https://www.wirebarn.com/Combined-Wire-Gauge-Calculator_ep_42.html

I don't really understand inductance. If speakers are high efficiency (mine are), and I/you have more than enough power from the amp, speaker

3. equiv 15 awg, is inductance an issue?

Inductance (Back EMF) might increase amount of current needed, but

4. enough power: does it have any effect on the music's frequencies?

Bias can be pretty important. Usually it is used to place the output device (tube or transistor) in the most linear portion of its operating curve. So it can have a noticeable and measurable effect on the sound.


The inductance of the speaker cable plays a role, but so does capacitance and DC resistance. I would not place too much importance on any one characteristic. In theory, the cable has what is called 'Characteristic Impedance' which is the character where the cable is properly terminated by the impedance specified. Put another way, if the cable has a characteristic impedance of 8 ohms, if an 8 ohm load terminated the cable, there will be no reflections from the load back to the source. In this case from the speaker back to the amplifier. But in practice, no speaker is a perfect resistive load, and the back emf from the speaker dominates the minor reflections, so what becomes more important is that the speaker cable simply be kept as short as possible so that its errors are minimized. This FWIW is why I developed a balanced line preamp, so the amps could be placed as close to the speaker as practical. When doing this you hear an immediate improvement in bass impact and resolution. In a nutshell- keep your speaker cables short and used cable with plenty of conductor to do the job.


The amount of power you have might affect how much bandwidth the amplifier has. This is particularly true of SET amplifiers, where power past about 7-8 watts falls short of the definition of 'hifi' (the smaller the SET, generally the wider bandwidth it is; this is why the type 45 power tube, which is only good for 0.75 watt, is the 'best' sounding). With push-pull tube amps this limit is more like 60-120 watts, but in both of these examples its assumed that there is an output transformer on the tube amp (some tube amps don't have output transformers so are not bandwidth limited at any power level). Some solid state designs don't scale well as power is increased, but most of those I've encountered are older designs employing coupling capacitors at the output of the amp. 

Reactance of the cable is also important. But now you’re starting a different topic.

McIntosh Speaker Wire Gauge/Distance/Resistance Chart (pdf pg 6)

http://akdatabase.com/AKview/albums/userpics/10004/MC2250%20Owners.pdf

Indicates: any given gauge: 8 ohm load allows double the length of a 4 ohm load. Presumably 16 ohm load would allow twice the 8 ohm allowable length (4 times allowable 4 ohm length).

I have to believe many if not most are using larger gauge than needed, however, some with 4 ohm speakers that dip to 2 .. some people might not be using a large enough gauge. And people are overly concerned about long speaker cables.

..............................

Text from my MC 2250’s manual:

"Selection of the proper gauge wire to connect the loudspeakers to the amplifier preserves the quality of sound reproduction for which the loudspeakers have been designed. If undersize wire is used, resistance is added to the amplifier/loudspeaker combination which adversely affects the performance. Added resistance causes depreciation of damping characteristics, modification of frequency response and reduction in power to the loudspeaker.

Use lamp cord or wire with similar insulation to connect the speakers to the amplifier. In all cases, the leads to and from the speaker should be twin parallel conductor or twisted pair.

When using 8 ohm speakers and for the normally short distances of under 30 feet between the amplifier and speaker, #18 wire or larger can be used.

For distances over 30 feet a larger diameter wire is required. Select the correct size from the chart below. The DC resistance of the speaker leads should be less than 5% of the speaker impedance. Resistance of the leads must be computed for the length of wire both to and from the speaker or speakers.

Wire lengths above represent the wire resistance equal to 5% of the speaker impedance. For multiple speaker operation, run separate leads from the amplifier to the speakers."

I am not sure that generalization (16 ohms = lower amplifier distortion) would apply to every variety of solid state amplifier. Tube amplifiers as a class tend to have a much higher output impedance than do solid state amplifiers.  This does give an advantage for 16 ohm speakers. What I abhor about "4-ohm" speakers is that they tend to be multi-driver arrays with very complex crossover networks.  This is a set-up for low input impedance and for power-sucking crossovers.  You can get a Pass or other high quality solid state amplifier to drive these beasts because they generally have an output impedance well below 0.5 ohms, and there will be some listeners who like the results.  Speaking only for myself, I never have.  But it is wise to think about the speaker first, and then to choose an amplifier well suited to driving it.  Once that process is done, I have always tended to prefer at least modestly efficient speakers with high input impedance that can be driven by tube amplifiers (my preference has always been for OTLs) or low power Class A solid state amplifiers.  Not everyone will agree, and that's fine.

Don't forget to get rid of those "rheostats", which are probably L Pads.  L pads sound terrible and one is always better off without them. Replace them with discrete resistors or no resistance at all. See my earlier post.

Roger Modjeski always recommended "light loading" his amps and gave numerous reasons why this was beneficial. Some were mentioned by @atmasphere in a previous post. On a pair of 8 ohm speakers I run my RM10 off the 4 ohm tap. The difference is very noticeable versus the 8 ohm tap. Roger often opined why 16 ohms speakers went out of style. Oddly enough in cleaning things up around Roger's shop I ran across a set of Chartwell speakers that are 15 ohms. Going to give them a try on my RM10.

charles1dad

Thanks for your reinforcement of Ralph and other's comments.

I knew the speakers were very high efficiency (horns), and needed little power (16 ohms is easier, I knew that), but I was unaware of the inherent advantages to the amp regarding lower distortion.

three_easy_payments

thanks, we agree about the video and advantages of 16 ohm reduced distortion.

In the beginning, when 4 ohm speakers showed up, some sounded very good, however they were small enclosures, and it seemed to me they needed a heck of a lot of power, the complete opposite of my goals. I didn't know about amount of distortion involved.

I encourage trying tube amps, and the way to save money/size/heat/cost of tube rolling/replacing, is to start with efficient speakers, thus you can stay in the 35/30/25 wpc world of tubes, even less if you use horn speakers or other highly efficient speakers. My friends system uses 8 wpc tube amps.

I remodeled my office recently, my friend has an unused pair of KEF's, I remember them sounding great, I was going to use my Carver Cube 200wpc, enough power for them. However they are 15" deep (to get more box volume, avoiding port(s) I suppose), sadly too deep for bookshelf use.

chakster

thanks. as usual, I wish you lived next door so I could hear your variety of speakers, equipment, ....

160 ohm resistor across the terminals. any idea what/why?

mijostyn

thanks for your comments.

turns out eight 24 gauge is equiv to 15 gauge. any other factors of cat 5 involved with 'inductance' concerns?

millercarbon

thanks for your comments. as I don't have power concerns, I'm sticking with 16 ohms for the inherent reduced distortion involved.

Elliot,
Your Qs followed by replies.

1. why/how do 16 ohm speakers make amps sound better, with more resolution?

For an estimated 99+% of amps the higher the load impedance the greater is the amp’s current capacity and the more pleasant and agreeable is distortion spectra. A 16 ohm speaker draws half the current of a 8 ohm speaker.

For SS amps, power/voltage is halved for each doubling of impedance, a potential negative for amps with borderline power. For tubes including OTL it’s all upside (at least up to 16 ohm); in some cases like Ralph’s lovely S30 OTL, power increases 50% (45W, +1.5 dB) @ 16 ohm vs. 30W @ 8 ohm. Interestingly, compared to S30 > 8 ohm, 16 ohm has more powerful bass and IIRC even lower bass cutoff! IIRC, with Ralph’s larger amps the 16 ohm power advantage is less than with S30.

2. why speaker cables less critical?

The sum total amplifier load = speaker impedance + speaker wire series resistance. The higher is speaker impedance the less (as a ratio of 100%) does the speaker wire contribute to the load. You hear less cable and more speaker because the latter contributes a higher ratio of the total load.

Lower speaker cable resistance can have similar effect as increased speaker load impedance; the caveat is that cable inductance rises with conductor thickness, so as usual it’s not a free lunch upgrade,

I didn't remember you had Sound labs Lew, wow, that is something I would love to listen to, my speakers made by Duke are very good but he is / was a Sound labs dealer dealer some eons ago and he still praises the sound

For the OP, if you have some small stand mounts Elacs B6 or such, attach these in parallel with your mains and let us know what happens to resolution of the mains, I have done it with both tubes and SS and in both cases lowers resolution and increases distortion