I was basing my comments on my experience with the sound of bass from amps that have a rising distortion in the bass due to output transformer core saturation. It fits well with Fremer's comments on the Lamm's bass and my experience with many SETs on many types of speaker. The Diana has none of that...it has SS like slam and goes very deep on the Thiels. I was speculating that probably the core saturation in the Diana is either non-existent or at least minimal. Given the size of the OPTs in the Diana (18Kg each!!) this should be the case. So, my comments were based more on my understanding of the data and observations available than a direct comparison. Sorry if I was a bit short in the response above.
Windsor Hifi Show - simple systems ruled
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I was basing my comments on my experience with the sound of bass from amps that have a rising distortion in the bass due to output transformer core saturation. It fits well with Fremer's comments on the Lamm's bass and my experience with many SETs on many types of speaker. The Diana has none of that...it has SS like slam and goes very deep on the Thiels. I was speculating that probably the core saturation in the Diana is either non-existent or at least minimal. Given the size of the OPTs in the Diana (18Kg each!!) this should be the case. So, my comments were based more on my understanding of the data and observations available than a direct comparison. Sorry if I was a bit short in the response above.
I have heard Diana bass on Tune Audio Anima. It is less than what you can get from a more powerful amplifier (in that case a direct compare was done with a modded jolida, apart from the fact that I have heard Animas with multiple other amps many times.
The Diana was much better than the Jolida overall, but not on the lower bass and bass SPL, probably due to the lower power
The Diana was much better than the Jolida overall, but not on the lower bass and bass SPL, probably due to the lower power
Neither have I. I am addressing this comment and just wanted to know what is the speaker that was used to listen to the Diana evidencing these good qualities :
Is the Animas bass a horn? I have heard them always with some kind of subwoofer. At least with my horns the bass was not that powerful but with conventional speakers it was awesome. My Ayon Crossfire III has great bass on my horns but probably doesn't have the same slam on the Thiels (haven't tried it out yet).
I don't think that this horn can go very deep in the bass...it is too short as it is not folded I think.
Hi, how does anyone separate out speaker and amp distortions in a new room without comparing another amp or changing something? Can others do this as well, and rely on that? I would rather A/B
They sound quite different so I don't think it is anything magical. Sure if there are other pieces of gear to swap in and out you will be able to pick out more aspects of those different distortions but that doesn't mean you need that to hear main effects.
A friends Golden Jubilee Quad iis had better bass than any 845 SET I've tried - and they are only 15w. If the Jolida was P/P, I'm not surprised.
Push/pull or SET it doesn't really matter. What matters is the quality of the output transformers. A PP amp with too small output trannies will also saturate and give a loose, bloated and poorly defined bass of varying degrees depending on the severity of the problem. You can see this easily in distortion measurements made by Stereophile and Soundstage, which shows that most tube amps are plagued this way. Even some VERY expensive ones show clearly from the data that the distortion in the bass is increasing significantly. Only a few, really well done PP and SET amps avoid this issue completely. With PP, you can get away with smaller transformers because you don't have the DC component energizing the core but people still try to get away with a smaller core than is needed, probably to save costs (this makes no sense with some "cost no object" designs but you still see it).
A recent example from stereophile:
http://www.stereophile.com/content/...er-amplifier-measurements#gj7YHurd5vqU3HHh.97
Look at Figure 7 and you see the sharp rise. This is core saturation and I can tell you from hearing Prima Luna amps that they have a soft rather "tubey" bass. Tubey bass is really core saturation...anyone who has lived with good OTLs can tell you that they don't have soft, rounded bass like most transformer coupled amps.
This is just one example and from an affordable amp. What about really "high end" amps?
http://www.stereophile.com/content/...er-amplifier-measurements#kiapAZBfFWGAb20b.97
Not as severe but still saturating.
I can show you similar things with SET but here is one SET that has a minimal issue with it:
http://www.stereophile.com/content/...er-amplifier-measurements#BDvzQpsVr4Y8RDSK.97
Essentially no saturation and the LAMM ML2.2 has very good bass.
Agree somewhat, although they were Audion Black Shadows so very good iron. I've also owned/demo'd Sophia Electric, Melody, and Tri.
of course, Quads measure quite well (on the right speaker) - so it maybe more the Quads, than the SETS
http://www.stereophile.com/content/...er-amplifier-measurements#2UQkjTFyv0vxkLoR.97
of course, Quads measure quite well (on the right speaker) - so it maybe more the Quads, than the SETS
http://www.stereophile.com/content/...er-amplifier-measurements#2UQkjTFyv0vxkLoR.97
Hi Morricab,
thanks for posting these 3 links showing distortion characteristics and how in 2 cases, the distortion curve moves up dramatically below 100hz. The only question i have is about the absolute distortion levels. In the case of the Lamm, the distortion curve is FLAT...BUT it is also 0.5% to 1% across the board at 8ohms. By contract the ARC150 with the steep curve has all of the distortion pretty much below 0.1% distortion and never rises above 0.5%.
Do you prefer flat distortion across the spectrum (0.5%-1.0%) or steeply curved distortion (0.03%-0.5%) when all the distortion is measured lower than the 'flat distortion' amp?
You say the Audion Black Shadows have good iron but what data are you basing this on? My experience with Audion is that their products are quite lightweight, which would indicate possibly insufficient output iron core size. I have not seen any measurments of any of their amps to confirm that they use a large enough transformer to avoid or at least to minimize core saturation. I have never heard the Black Shadow (but I would like to) nor seen any measurements.
IMHO the overall picture is not so simple as suggested by these measurements. In order to reduce core saturation transformer manufacturers can introduce gaps, such as usually done in SET transformers. However this reduces drastically transformer inductance, also affecting its performance in other areas - I remember reading long ago about the subjective effect of using gaps in transformers.
From my experience the best bass subjective performance I had with tubes was when using the Audio Research REF150 - better than the few OTLs and SET I have used. OTLs have great bass, but not as articulate as the ARC. Surely all IMHO and IMMV, these opinions depend a lot on system and amplifier/speaker matching.
PP amp transformers though have no gap. The best way to reduce the saturation is a larger core. That has issues though with frequency response at the high frequencies unless the winding is done with lots of layering between primary and secondary to get good coupling.
The load of the speaker for sure matters as that will impact how much current is flowing through the transformer ultimately. The power generated matters a lot too fo rthe same reason...more power is more current flow through the transformer. With some amps you will see at 1 watt that the THD vs. frequency is pretty flat and then at 10 watts it curves up sharply.
Of just as great concern though is a rise in distortion at higher frequencies.
Ideal would be flat from 20 to 20 and no dependence on power other than the whole line is increasing uniformly. A curve upwards in the bass or highs implies not only an increase in the existing distortion but the creation of new distortion products because something just got a lot less linear. This means the whole character of the amp changes with frequency and power...not a winning combination.
I am much more concerned about sudden non-linearities than with a consistent but higher distortion. If you look at the FFT from the Lamm it is mostly low order harmonics dominating this has been shown to increase with the power but it is pretty much the same kind of distortion throughout the whole audio band. This means you will get a consistent sound at all levels below clipping. The problem is that the nature of the distortion has just gotten a whole lot less linear when you see a sharp curve upwards. That means more high order harmonic content, which is never good for sound quality.
When you have a sharp increase in distortion in the bass or in the highs, it means that you will be reflecting this in an uncontrolled way through the audio band. The ear is sensitive to things like this more than something that is homogeneous and consistent with level. A sharp increase in distortion in the highs might bring images forward and flatten the 3d effect that stereo is capable of creating and foreshortening the soundstage depth. A sharp increase in bass distortion might make bass sound lumpy, soggy or soft and indistinct. It might also make it "bloom", which some people seem to like though.
As long as we part from ideal we are mostly guessing unless we listen.
Fortunately the main sound character of an amplifier is in general independent of power within its normal use range - use it with a 82 or 95 dB/W speaker and it keeps its main caracteristics. The power delivery changes a lot with frequency as the impedance changes significantly with it - sometimes a 10 times fold. Just looking at the measurements at 2, 4 or 8 ohm shows that there is much more than this simple analysis - otherwise the sound character would vary significantly in a piano reproduction!
We can consider the case of the Jadis amplifiers, known for the excellent, large, heavy and over specified output transformers. Tubbey bass, as you called it it, IMHO. The main sound characteristic is due to the circuit. In many tube power amplifiers the tubbey bass is also due to power supply.
Unless someone with great expertise also analyzes the distortion spectra with detail it is almost impossible to guess the sound of an amplifier. And fortunately there are too many winning combinations, I can not see how simple measurements can systematically identify them.
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