2 Panels per side? Were those visible while the Atriums were demoed? Sorry for off-topic!
Ron’s New System
- Thread starter Ron Resnick
- Start date
But it wasn’t addressed…it was still there even with 40 mA bias…which is probably close to class A for that amp. You can hear VERY low levels of this type of distortion.
He is mistaken about class B. Class B is very difficult to actually achieve; by definition, it is when one device (tube, transistor, etc.) goes into cutoff and so only amplifies half of the waveform. In the example of the video, we see that what is actually happening is the output tube is cutting off less than halfway.
By definition, that makes it class C.
This is a super common misconception, one of which I've had myself until quite recently, that such amps as in the video are class B.
So when you are increasing the bias current to get rid of crossover distortion, you are going from class C to some sort of class AB or A.
The last statement above is an example of what I posted earlier: Brad uses out of context examples such as Howard's above to seem to prop up his position. But of course no-one is 'adding all odd harmonics'. Its well-known that odd ordered harmonics are unpleasant; so it might be surprising to learn that the amps that make the most of them are SETs. The reason we don't perceive them as harsh is because of a principle called masking.
What happens is if the lower ordered harmonics, the 2nd and 3rd, are of high enough amplitude, the higher ordered harmonics are masked. The only way I know to get an amp to make such prodigious harmonics is by having either a quadratic or cubic function involved in the amplifier. To do that the amp is one of two things: entirely single ended (SET) or fully differential/balanced. The latter tends to cancel even orders although if one uses measurements you see that in reality, the even orders are simply diminished due to slight imbalances that are unavoidable except in 'modelling'...
So you can see Boyk and Sussmann's studies do not apply here for the simple reason that modelling a differential circuit does not tell the whole story. Further, they ignored the fact I already mentioned, which is the harmonic decay of a differential circuit uses a cubic function, which means the higher orders fall off at a faster rate (exponential), one to which our ears are well adapted.
Norman Crowhurst pointed out 60 years ago that when you combine a single-ended input circuit with a push-pull output, you tend to get more of the 5th harmonic. I'm very sure this is one reason SET lovers like SETs; the 5th is not particularly musical. But if you avoid such circuits then its no worries. But 99 and 44/100ths percent of the time, when SET lovers compare to PP, this kind of amp is the kind used in the comparison. Its apples and oranges.
@ Ron Resnick Glad you got it sorted!!
I think the Aria needs a rear support strut on the bass panel as it is just plain wobbly. I said so to one of the reps.
The MRT tower has one, oddly.
They could put one in for you was the hint I got if I were to buy a pair. No plans to.
Atrium was an interesting listen.
I should point out something you are not taking into account.
1) Guitar amps are not built to be hifi. There is often intention to build the amp to make distortion rather than to avoid it.
2) When any tube is driven, for example a power tube, the input capacitance increases with the drive. If the driver circuit isn't adequate to the task you will see crossover distortion in a push pull design. That is a design criteria; IOW a design flaw if the amp is meant to be hifi.
The video does not use much in the way of examples; your remonstration thus based on a logical fallacy.
We went round and round on this very topic on this thread yet you persist. I put you on ignore for this sort of thing; since there are two problems, the first famously outlined by an American author named Samuel Clemens. The second problem is when you are presented with technical information, you simply ignore it. I am hoping this is not done out of malice but the alternative, by Hanlon's Razor, isn't great either. You can chose ignorance or you can chose to learn. Its up to you.
Thank you for the information, Ralph. Yes, I thought the amp in the video may not be the best design, as I suggested in my answer to Brad.
Basically you say, in a well-designed push-pull amp crossover distortion is not an issue.
The persistence of not wanting to learn is something that I also notice in digital vs analog discussions. No matter how often you refute the notion, people will always come up with the "staircase" fallacy (refutation here) because they do not want to put the effort into understanding how digital really works. They'd rather dwell in their biases and preconceptions, as part of what is called "motivated reasoning".
Regarding the LP vs digital thing, if you are arguing either position is might be useful to know this particular weakness of the LP, which is that most of its 'distortion' arises in playback and does not exist on the record side. IOW the media itself is quite low in distortion (my mastering system wrapped 30dB of feedback around the cutter head and cutter amplifiers; see Bruno Putzey's writings to see what that much feedback does to distortion).
But there are problems in tonearms, platter pads, phono cartridges and how phono sections react to out-of-band noise (including RFI). Of course most people fail to set the playback system up correctly. But the actual LP itself is very low in distortion.
These days I'm quite happy with digital playback.
Munchen teached me vinyl when done right is well above digital regardless of price .
It got me even wondering it might be better then tape
It got me even wondering it might be better then tape
Could you expand on this? Are you talking about your listening impressions from the latest Munich show? Can you give examples?
You'll need a signal generator, oscilloscope, and a dummy load. Then increase the amplitude until the amplifier starts clipping, then turn it back a bit until you have a clean sine wave again. Next, adjust the bias so that there is no longer any shift between positive and negative half-wave the zero crossing. Be careful with the bias: keep an eye on the maximum anode power dissipation of the tube you're using. After that, crossover distorsion hardly plays a role anymore.
Yes mainly the demonstrations by manuel Huber FM acoustics just phenomenal presentations even with lower quality vinyl which he uses anyway .
But also the fine inner detail i heard on Prince and pink Floyd at the touraj moghaddam/ vertere demo .
Especially at the FM demo i just did nt want to leave lol.
I ll be buying that gear in the future .
Good indicator is when the time flies by while listening
You hear the actuall musicians intent .
Digital presents a facsimile instead some sort of smoothed over version of the truth.
Thanks. I have nothing against LP -- I love great LP playback -- and have often defended it against idiot-level "digiphiles" who come up with bogus arguments against it. That includes dynamics which are often brought up as an "argument" against LP, but in practice can be fantastic on LP.
Me too.
It has been better than tape since the inception of the stereo LP in 1958 when the Westerex 3D cutter head was introduced. It has greater dynamic range (and less noise), greater bandwidth (typically about 10Hz to past 40KHz) and far less distortion. Tape was only used because it can be re-recorded in case musicians make a mistake or the like.
Quite often LPs can sound better than the digital release for the simple reason the master tape degraded between the release of the two. This is very common with anything released prior to the inception of digital recording in the late 1970s with the first digital machines from 3M; for those recordings if you really want to hear what the recording was about you'll need to get the original LP pressing from the country of origin.
If the driver circuit is properly designed you need not be so careful. I've seen amps without any bias control at all (Mac MC40 comes to mind) and no crossover distortion at any power level down to as low as measurable. EV made such amps in the 1950s that were regarded as 'class B' although they were really just extremely lightly biased class AB amps and they show no crossover distortion either.
When I was working at Allied Radio Shack in the service department, I often encountered Realistic receivers that were biased into the C region. I would run them on the bench slowly advancing the bias until the audible crossover distortion was gone. Usually they measured within 10% of their nominal idle spec after that. I think Realistic was less expensive than other brands simply because they didn't have a tech spend as much time testing.
Put simply a lack of crossover distortion isn't something unique to SETs; any good solid state, push pull tube amp or class D can do just as well in that department. As most here know, its really all about that first Watt and many amp topologies can do that.
The real question is how far can you push it? Audiophiles crave the answer to that question, if my own experience is any example.
great vinyl is great....but.....tape is still tape. but both sides have many levels....hardware and media.
the ratio of my tapes bettering my vinyl has been fluid over the last 20 years. in 2006 when i started with tape, 100% of the tapes i first acquired were better than my vinyl as that was how i decided to buy the tape. that is the tape exceeded the vinyl performance or i would not buy it.
over the last 20 years my tape did advance a few times; such as when i got the King Cello to add to the Studer's. but mostly my vinyl improved a number of times. by 4 years ago the ratio of tapes better than vinyl was around 50%. but my vinyl was then pretty awesome. so maybe 80% of my tapes would be better than very good but more normal level vinyl performance. then two years ago i acquired the hot-rodded Ampex ATR-102/MR-70 decks and now 75% of my tapes are better than my awesome vinyl. but the ATR/MR70 is rarified air. and a very particular case.
so this equation has to do with how far you have taken both sides. and how great are your tapes and pressings. and is not any fixed thing. most users would get a boost over their vinyl with tapes. and a strong case can be made that if you are a digital person; that very high level tape decks and a few tapes would take you higher than any vinyl but be much cheaper and easier to keep optimal. especially if analog would be an occasional thing for special moments and not a steady daily diet.
OTOH if you have 12,000 compelling reasons to love vinyl like i do, then the music talks very loudly on where the focus is.
Last edited:
+1
As I mentioned earlier the biggest problem with LPs is in the playback. Its a problem for tape machines too per your testimony.
Many LPs are pressed from dubs of the master tape called a working copy, especially if the LP is not pressed in the country in which the recording was made. You know as well as I do what a second generation sounds like compared to the master.
Mike, do you think you are at the end of your road road with vinyl? Have you explored the hardware end as far as you would like to? I remember when you were contemplating reducing your collection down to one supreme table.
At class AB transistor amps easy two diodes gives bias when the signal is 0 no crossover distorsion any more. Is a old trick this prevents the transistors from being blocked from 0.7 to - 0.7volt
mine, yes.
like to? i will always 'like to'. yet.......
Peter, i'd say i am at my vinyl performance destination. when i listen to it i am consistently taken by it. the superb musical connection is fresh and new to me. i realize there are likely some mini steps out there to be had if i were still on the hunt. would i hear a difference between what i have and those next steps? maybe, probably. but maybe not. they would be very expensive and not compatible with my retirement lifestyle. would they be worth worrying about? unlikely. but vinyl development is probably not done. nor do i want it to be.
i moved from the Saskia to the Esoteric T1 so i could have three arms and it could be my last tt. i do view it as my end game. also love the CS Port too for it's own sake.
until i processed (cleaned and curated) my acquired 3000 pressing classical collection last summer i did feel i wanted to acquire more great sounding classical pressings. but now that itch has been fully scratched and i'm not looking for more pressings. i am more than fulfilled. so i feel i'm also at my vinyl media destination.
my urge to think about better vinyl gear can never be quieted. i'm hard wired that way. so i still dream sometimes, but then lay down till that feeling passes. or listen to my lovely vinyl. or go out and sit in my motorhome.
Last edited:
 | Steve Williams Site Founder | Site Owner | Administrator |  | Ron Resnick Site Owner | Administrator |  | Julian (The Fixer) Website Build | Marketing Managersing |