I do like Steely Dan, and Donald Fagin's nightfly, which for years was one of my demo records, despite of course being digitally recorded
. Ah the days when I used to go into stores and listen to stuff..
@atmasphere. I feel somewhere along the line you are mixing correlation with causality, but I am not an audio historian. You are claiming that the invention of acoustic suspension in 1954 changed the way amplifiers were designed. Hopefully someone who either was there or has studied it can confirm/deny this.
For the record, due to some extended gestation on my latest project I am nursing an aged awful tube/Mosfet hybrid with no global feedback around the output stage. at normally listening levels around 0.5% distortion, so worse than the radford it replaced, but despite being rubbish it still plays music, at least until the bias supplies finally burn out.
For the record, due to some extended gestation on my latest project I am nursing an aged awful tube/Mosfet hybrid with no global feedback around the output stage. at normally listening levels around 0.5% distortion, so worse than the radford it replaced, but despite being rubbish it still plays music, at least until the bias supplies finally burn out.
I used cuts from that great Don Fagen album as demo material to great effect, especially New Frontier. It's one of those that sounds great on systems with limited bass extension, better still with more.I do like Steely Dan, and Donald Fagin's nightfly, which for years was one of my demo records, despite of course being digitally recorded
Where are these bad amps? I'm almost tempted to concoct one, at least in sim, to show how bad amps can be. Putzeys mentions them without specific identification in the F-Word article, and I can recall some very negative reviews, but no specifics.OK, point taken, I will next time insert a REAL high feedback example amp
Jan
Embarassed to say never listened to it full range. Another excuse to get the sub working
I'm in an apartment so bass extension needs to be limited---although this doesn't seem to be much of a consideration with the adjacent manager, who apparently delights in video games. I could make a stink but in other respects they aren't a bad lot.Embarassed to say never listened to it full range. Another excuse to get the sub working
I also listen to a lot of music with minimal low bass, like baroque music.
Interestingly, John made reference to a short piece he authored (erroneously
attributed to Audio Critic, but actually in Sound Advice) showing results of TIM testing.
The two "winners" were the ElectroResearch and the Threshold 800A. The "losers" were
Phase Linear and Audio Research (solid state).
Jon Inverson's (ER) philosophy was maximal feedback - "you can never have too
much", and the Threshold was "moderate - 20 dB or so". I don't have data
on the amount of feedback in the ARC amplifier, but the Carver would
belong in the "immodest" category I think.
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How surprising! <roflmao>... but the Carver would
belong in the "immodest" category I think.
Thanks Nelson.
An excellent point but one that is unfortunately ignored by most designers....
The trade-off we make is to accept an increase in local higher-order distortion, in return for the convenience that local degeneration brings
and then squash these later with gnfb. And so the story goes....
Don't the SET designs qualify, such as 45 types when asked to do power at usable levels? I was SPICEing a while back on some SET designs, 2% at 5W is doing really good wth the smaller tubes. I also played with a physical triode strapped EL34 design (11 claimed watts, 4.5 actual 5%HD watts). Based on voltage gains and known drive levels, it sounded loud (and really, not bad at all) when it actually ....wasn't.
One example of SS zero GNFB from the 80's, Denon PMA-737. Sounds great (fast, exciting, involving) with my Tannoy K2558, but is intolerant of thin loudspeaker cables. Needs 2,5mm2 (AWG13) to sound right. This is the most picky amp as far as loudspeaker cables are concerned, that I know.
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Hi,
with regard to '155 and 159:
That amp would see a very pure capacitance load only.
If as typical a Audio Tranny is involved the shape of the impedance curve changes to Gaussian-Bell-like from the lows up to the mid highs.
So with rising frequency the ESL impedance curve appears inductive first and changes to capacitive.
At the very top end of the audio range the stray inductance of the tranny goes into resonance with the panel´s capacitance, leading to another peak in the response, with an inductive raise, followed by a capacitive fall.
The Amplitude response also shows this HF-peak with a following -12dB/oct drop (older MartinLogan and Audiostatics: Fpeak ~12-15kHz).
One can easily dampen that peak by connecting a low-valued series resistor between amp and Tranny (or a higher valued R between tranny and ESL-panel).
As the series resistor before the tranny not only tailor´s the HF-amplitude response but also acts as kind of a protection for the amplifier against the close to a shortcut load at LF and HF it´s the commonly used measurement.
As many SETs, especially Tube amps feature a output dc-impedance of a couple of hundreds of milliohm they may dampen the ESL´s HF-peak/brightness sufficiently.
So this is the main reason for a different sonic behaviour of (Tube-)SETs against feedback Voltage-amplifiers.
A second reason could well be the fact that the electrical phase response curve can take on large negative values.
The more so, the better the quality of the tranny (I measured up to -86° with my ESLs. Despite their marketing words most ESL manufacturers used low quality trannies to keep the phaseshift values low enough for typical amps).
This phase shift reduces the phase reserve of a global feedback amp and may even send it into oscillation.
But even long before the phase reserve approaches critical values the amps step response is spoiled by ringing.
In any way if it is that mechanism or some other, the sonic performance deteriorates.
After my experience the impression of stage becomes 2-dimensional and the sound rather ´dry or dead´.
A ´technical note´ enters the sound picture that our brain always recognizes as listening to a conserve, a technical playback and not the real life stuff.
Most prominent is the playback of voices that suffers.
Is it a colorful 3-dimensional person singing or a grayscale printout?
Now ESLs microdynamics and distortion levels are so far superior to dynamic speakers, that they can present such effects while most any dynamic speaker I know of is far less sensitive, equalizing amplifier differences to close to not recognizeable.
jauu
Calvin
with regard to '155 and 159:
That´d be true only if the ESL would be driven directly with a HV-amp.
That amp would see a very pure capacitance load only.
If as typical a Audio Tranny is involved the shape of the impedance curve changes to Gaussian-Bell-like from the lows up to the mid highs.
So with rising frequency the ESL impedance curve appears inductive first and changes to capacitive.
At the very top end of the audio range the stray inductance of the tranny goes into resonance with the panel´s capacitance, leading to another peak in the response, with an inductive raise, followed by a capacitive fall.
The Amplitude response also shows this HF-peak with a following -12dB/oct drop (older MartinLogan and Audiostatics: Fpeak ~12-15kHz).
One can easily dampen that peak by connecting a low-valued series resistor between amp and Tranny (or a higher valued R between tranny and ESL-panel).
As the series resistor before the tranny not only tailor´s the HF-amplitude response but also acts as kind of a protection for the amplifier against the close to a shortcut load at LF and HF it´s the commonly used measurement.
As many SETs, especially Tube amps feature a output dc-impedance of a couple of hundreds of milliohm they may dampen the ESL´s HF-peak/brightness sufficiently.
So this is the main reason for a different sonic behaviour of (Tube-)SETs against feedback Voltage-amplifiers.
A second reason could well be the fact that the electrical phase response curve can take on large negative values.
The more so, the better the quality of the tranny (I measured up to -86° with my ESLs. Despite their marketing words most ESL manufacturers used low quality trannies to keep the phaseshift values low enough for typical amps).
This phase shift reduces the phase reserve of a global feedback amp and may even send it into oscillation.
But even long before the phase reserve approaches critical values the amps step response is spoiled by ringing.
In any way if it is that mechanism or some other, the sonic performance deteriorates.
After my experience the impression of stage becomes 2-dimensional and the sound rather ´dry or dead´.
A ´technical note´ enters the sound picture that our brain always recognizes as listening to a conserve, a technical playback and not the real life stuff.
Most prominent is the playback of voices that suffers.
Is it a colorful 3-dimensional person singing or a grayscale printout?
Now ESLs microdynamics and distortion levels are so far superior to dynamic speakers, that they can present such effects while most any dynamic speaker I know of is far less sensitive, equalizing amplifier differences to close to not recognizeable.
jauu
Calvin
I'm not much better with effectively an 11' cube as a living room. And also a great fan of early music. I can very much recommend this box set Various, Johann Sebastian Bach, Christopher Hogwood, Philip Pickett - L'Oiseau-Lyre - The Baroque Era [50 CD][Limited Edition] - Amazon.com Music I used to collect them on vinyl (and anything else Hogwood/AAM) but couldn't resist this.
And happy to be shot down, but IMHO a quintet (if you like that sort of music) is very good for testing certain aspects of good performance in a system.
Possible, sure- but with those high efficiency speakers, isn't 1W already pretty darn loud? What were the actual drive levels on the EL34 amp with your speakers? (I confess that this is not an area I play in- I have those stodgy low distortion high power amps that drive speakers of moderate efficiency)
edit: so the amp here is a low tech Aural Exciter?
I am amateur in electronics, so I am not 100% sure about anything but this is verbatim quote for Denon amp (in Japanese English):
Non feedback 0dB amplifier - Input signals are unidirectionally amplified so that dynamic distortion causing problems such as time lag, etc. are completely eliminated. Frequency distortion includes mainly static distortion, which occurs at power transistors. This static distortion is completely eliminated by a direct distortion servo circuit. Harmonic sounds from the program source are clearly reproduced.
End of quote
If I understand correctly there is some kind of servo around output transistors and that's probably what opamp is used for.
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