Al, can you please clarify where in the frequency spectrum slew rate vs rise time is relevant? My understanding is that for the most part sonically, slew rate correlates to bass performance and rise time to treble. This is what I've been told by the tech who's worked on some of my amps.
Also, that slew rates past a certain level become irrelevant like DF. Rise times lower than 2u sec. are about where the source material becomes the limiting factor.
Does musicality suffer when these thresholds are breached in an effort which may typically result only in marketing strategy? |
Thank you Al, but look who my tech is talking to. I need simple. All my amps are in that optimal range you suggest but I can attest to your suspicion that low noise floor plays a key role in realistic sound stage and what sets amps apart from one another with otherwise similar specs. |
I think it would be useful to get a subjective description of just what the attributes of a 'fast' amp are sonically. What does speed sound like in an amp in comparison to mediocrity? Anyone? |
Can you give an example of an amp that is outstanding in this regard? |
Zd, I would think the opposite is the case in fact. Deliberately not designing true to life character seems to be the gimmick among tube amp designers especially. Just because of the well known quirky expectations of their market base. From what I gather, tubes sounding closer to ss is more trendy than vise versa. If the sound is 'balanced' as you say, it will display serious speed and attack...like reality does. If that's not what you want, it's okay to be honest and not obfuscate or try to reinvent the English language.
Btw, a soa amp will always display serious speed and attack. |
Zd, I do own a few amps. You clearly favor tubes so I responded commensurate with your bent. Not everyone considers your subjective view as reality btw. I'm perfectly happy with your answer. I just think it's bullshit, that's all. I expected as much.
Oh, I've never read or bothered with one of those mags. |
Okay, well thank you for showing me the error of my ways. From now on I'll try and do my best to not actually respond to your rants. Have you forgotten that I'm never wrong? Perhaps if you go back and read a past post or two you'll come finally to the realization that I've made it abundantly clear. |
Al, as you and Ralph are obviously the two most technically knowledgeable, I think it most appropriate for the two of you to also define/describe amplifier 'speed' from a subjective/sonic perspective. As yet, no one has given a description of what a 'fast' amp sounds like in comparison to something unremarkable. This goes to the op in reference to it's effect on the music. I'd like to hear references beyond HF transient performance/attack and bottom end definition. Grooming is necessary in this hobby just because of it's inherent limitations. The moon is too far away. |
Thank you Al. I thought there is always going to be a direct causal effect of actual amp speed and subjective/sonic speed. That's very interesting. I understand the obvious descriptors of a really good amp but there's another effect/indicator of subjective speed which is observable. It may be that I have a too limited perspective on what transient performance is. The things I'm referring to are effects of ambiance being injected where you can hear it's instantaneous up front presence less subtly than the engineer may have intended probably expecting it not to be noticeable, and maybe with a sparkling almost grainy effect. As if you can hear that sound being constructed. Also for example a string being stretched or when they are sliding up or down the neck of the instrument, or soft consonants like the word 'you' for example where after the initial attack the remainder of the tone is so consistently immediate as to convey the same sense of speed as the transient. Or the precisely contained decay of a kick drum where you can hear reverberations clearly/sharply. Or even a trombone doing it's thing with a sense of strength and immediacy that denotes speed. I have a pair of Meridian 105s that are uncanny in their ability to convey this sense of speed. I also have a pair of the famed LOW TIM LSR&D Superamp monos designed by the late Dr. Marshall Leach of Georgia Tech. Although they both display equally competent transient performance, the Meridians have that sense of immediacy that raises them a notch above. I also have a GAS500 that has this sense of immediacy but not quite as fast in transient performance.
If the relationship between technical parameters and subjective perception is indirect or vague, then how does someone set out to design a 'subjectively fast' amp? Is it just a crap shoot? Technically, what descriptors must an amp possess in order to facilitate subjective speed? Isn't this the goal?
I do recognize those here with knowledge and pay attention to their conversations. But it's you and Ralph who seem to stand out among the others for me. |
I agree and the opposite is also true ime. Those Meridian 105s will fool you into perceiving a faster than normal pace. |
But there's another question that hasn't come up and that's 'how much of an influence does a pre amp have in perceived speed'? |
I am absolutely amazed to find this out Al. So it's more or less a matter of alchemy? Like an unguarded secret by someone successful in coming up with the right recipe but in the end not being able to put their finger on just what makes or breaks the design. So a great mind with knowledge and experience still must exercise some trial and error in designing a circuit. Like art. I've heard it said you're not an artist til someone else says you are. I think there's some merit in that saying. |
I get that Ralph. But even the alchemists were careful not to make the same mistake after an explosion. I don't know why I thought it was basically cut and dried. I don't have two amps that sound the same, even among identical examples. I guess I just think it should be entirely straight forward as to how to achieve a pre-conceived sonic result. I thought the differences are borne entirely of preference and not ability. IOW, lots of designers need conceptual adjustment. I suppose it's yes and no/know. |
I would have to agree. However no conditioning here except for dedicated lines. But not sure how noise floor plays into this. I have no poor examples to compare but the ones with the lowest noise floor have seemingly infinite depth. |
Psag, agreed. However you can hear it and recognize you're hearing it in comparison. |
