No, we laid claim to PRAT!
(aside, my current phono stage is an ebay impulse buy DPA 50S I got for £30 sans PSU. After I got it up and running I looked at the reviews of the time and found that all the flat earthers had written it off as lacking PRAT. I took this as a big plus as this indicated to be that it was likely to be neutral. I also approve of any startup who, in the early 90s decided to design their own thick film hybrid opamp. lunacy, and of course they went bust.)
Nice rhetorical remark, even if somewhat provocative...
I guess it was this review of a Macro Reference amp in 1992, put on line in 2008 Crown Macro Reference power amplifier | Stereophile.com ?
I absolutely don't agree with the listening experience with the low frequency department.
Idem for my friend who is a long time user of different amping techniques whether expensive or not, whether transistor-based or valve-based including hi power and mid power amps of reputable brands. We use large bass speaker systems and there is also lots of definition, clarity etc. in addition to the said bass impact which is everything (dry, articulate and punchy) but overwhelming or fat (is that what "gobs" means ?). I guess it may also be a matter of taste and listening culture.
Others had the following experience with SR amps:
Crown Studio Reference One Amplifiers reviews - Audioreview.com
and for an authorised opinion (read: commercial magazine review, "what else"), I guess this one would be it StereoTimes -- Crown K2 Amplifier and Studio Reference 1 Amplifier
I did see the 1992 review before deciding to buy an SR 1. Then after I had spent a few weeks with a first aquisition, I just decided to buy two more (no, I have none for sale...). Does it matter for the present thread ? I guess not.
Maybe.
This being said,
a) good slew rate is not a characteristic of the SR1/Macro Ref: slew rate is "just" around 20 to 30 v/uS. We're average here, and far from the 650 V/uS of certain Spectral Audio amps.
b) "quick psu current delivery"; "heaps of caps" : hmmm; maybe it is quick indeed but not for reasons of loads of caps; see earlier posts. The SR 1 has just 2 caps of 6800 uF loading lines of approx. 100 VDC or so.
c) the transformer is relatively big, but not immensly big. I had power supplies with a larger margin between VA capability and nominal amp power. I wouldn't say this (alone) explains it on this amp.
Yes, I agree in principle.
But:
The power is useful on two occasions that I'm confronted with (in home audio):
a) If it gets *really* loud on certain days, to the extent that I reach maybe 25%-30% of power capacity, it still sounds clean and undistorted even on very heavy bass (reggae, electronic music) and I sometimes just continue to turn it up. Endless undistorted and still "slaming" sound up into the "red led zone".
b) on uncompressed music, i.e. recorded with a large dynamic range of very low to very high sound level (as in reality), the extra power is a must to experience music at life-like sound levels. I have experienced large choirs of 60-80 singers, live at 3-10 meters. It's a physical experience which can be reproduced at home, provided power is available. Those interested in trying may wish to aquire for instance Schubert's "Songs for Male Chorus" (on Telarc)
An interesting series of remarks here, including the hypothesis that it's a combination of factors that could explain any particular sound of the amp(s) concerned. As so often in life, there is no one unique factor to be optimized in order to maximize benefits.
I like the idea that what matters is what lies behind the high DF. Can you elaborate on "enough beta in the output followers (double EF need not apply)" for those like me who are not an electronician.
Ohhh.
This thread was just moved elsewhere (the Lounge), out of reach and sight of those interested in amplifier technique. A warning signal that this debate is of no interest to the larger number and that it is undesirable ?
Can't see which rules apply here, but OK. Before it is completely banned, I just want to mention that I got this evening pm from someone who has worked for a decade in the pro-audio and who has been an audio hobbyist for much longer. In his opinion based on experience over those years, there is a correlation between the particular slam of the mentioned amps and the (abnormally) high damping factor.
This thread was just moved elsewhere (the Lounge), out of reach and sight of those interested in amplifier technique. A warning signal that this debate is of no interest to the larger number and that it is undesirable ?
Can't see which rules apply here, but OK. Before it is completely banned, I just want to mention that I got this evening pm from someone who has worked for a decade in the pro-audio and who has been an audio hobbyist for much longer. In his opinion based on experience over those years, there is a correlation between the particular slam of the mentioned amps and the (abnormally) high damping factor.
My hypothesis is that the DF is merely a by-product.
What we're looking at here is the very very high loop feedback - two loops in the case of the MacroRef, and I have not seen the StudioRef, but would guess it is the same. One in the MacroTechs, but still a very high DF, like 10,000 iirc.
I'm not saying that they have "slam" at all. Of that I am not convinced.
But they do have oodles of power and reasonably high current capability too. Work well into weird loads.
If an amp will not handle complex passages effortlessly, I am not interested. It's one of the first "tests" I listen to/for.
Ymmv.
What we're looking at here is the very very high loop feedback - two loops in the case of the MacroRef, and I have not seen the StudioRef, but would guess it is the same. One in the MacroTechs, but still a very high DF, like 10,000 iirc.
I'm not saying that they have "slam" at all. Of that I am not convinced.
But they do have oodles of power and reasonably high current capability too. Work well into weird loads.
If an amp will not handle complex passages effortlessly, I am not interested. It's one of the first "tests" I listen to/for.
Ymmv.
1) This has been a very interesting thread. Discussion has been civil (compared to many other threads) and the topic is certainly SS amplifier related. Makes no sense to me why it should be moved, was it a mistake possibly? MODS, might this be moved back to SS?
2) To the OP, I used to work in sound reinforcement. And when not mixing live sound, have spent tons of time listening to live sound in various venues. I know exactly what you are referring to as regards the Crown Macro Tech's handling of low frequency information. No other amp, IMO, is as clean and effortless. I am not sure that using the term "slam" is helping your case though, lol
3) What about the theory put forth on page 2 asserting that fully regulated supplies are the significant factor? Do the Macro Techs indeed have fully regulated supplies? If so, this seems a reasonable theory to me and I am wondering why it has not received much comment or follow-up discussion:
2) To the OP, I used to work in sound reinforcement. And when not mixing live sound, have spent tons of time listening to live sound in various venues. I know exactly what you are referring to as regards the Crown Macro Tech's handling of low frequency information. No other amp, IMO, is as clean and effortless. I am not sure that using the term "slam" is helping your case though, lol
3) What about the theory put forth on page 2 asserting that fully regulated supplies are the significant factor? Do the Macro Techs indeed have fully regulated supplies? If so, this seems a reasonable theory to me and I am wondering why it has not received much comment or follow-up discussion:
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Absolutely not regulated supplies.
It's a sliding bridge with very high feedback.
Fair number of output devices (fan cooling for the MacroTechs).
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It's a sliding bridge with very high feedback.
Fair number of output devices (fan cooling for the MacroTechs).
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Here is another pm I received from a guy called Mitch (with his permission):
"Referencing the Crown link I sent to you (note: http://www.crownaudio.com/media/pdf/...ing_factor.pdf )
I think says it all - would be good to post that.
If you look at the various Crown patents like: Patent US5015969 - Amplifier control system - Google Patents One can see they do a great job of all sorts of amp monitoring, protection, etc., but nothing like the Crown link on damping factor, where it basically states the reason is "High damping factor equals tight bass". How they are achieving the high DF is certainly open to question.
As mentioned before, I know of no other amp that measure that high of damping factor. Another anecdote, I was part of a studio/control room build with Chips Davis Chips Davis Designs - Acoustical Consultants & Studio Design where there was debate about this very point. We switched in and out a variety of amps in the control room driving a set of Urei Time Aligns (813C with the JBL drivers) in a blind listening test. Meaning the technicians were switching in/out the amps with us (5 people if I recall right) were sitting in the control room listening to Peter Gabriel's Security CD-ROM because of it's bass and drums slam with huge dynamic range. We had no visual clue to which amp we were listening to. While the top end's of the amps varied a little bit, it was the bottom end where it was no contest. Everyone within a sort period of time guessed every time the Crown.
Chips used a TEF acoustical analysis computer back then to measure the decay of the control room and it was quite a measurable difference in the bottom end decay, with the Crown easily having the least amount of decay, which confirmed what we were hearing. Unfortunately, that was many years ago and I don't have the data files. But that was the end for me guessing which amp has the best "slam" and again, I think Crown said it best in the paper: High damping factor equals tight bass. "How" they achieve that, whether through high negative feedback or... is likely to remain a mystery 🙂"
"Referencing the Crown link I sent to you (note: http://www.crownaudio.com/media/pdf/...ing_factor.pdf )
I think says it all - would be good to post that.
If you look at the various Crown patents like: Patent US5015969 - Amplifier control system - Google Patents One can see they do a great job of all sorts of amp monitoring, protection, etc., but nothing like the Crown link on damping factor, where it basically states the reason is "High damping factor equals tight bass". How they are achieving the high DF is certainly open to question.
As mentioned before, I know of no other amp that measure that high of damping factor. Another anecdote, I was part of a studio/control room build with Chips Davis Chips Davis Designs - Acoustical Consultants & Studio Design where there was debate about this very point. We switched in and out a variety of amps in the control room driving a set of Urei Time Aligns (813C with the JBL drivers) in a blind listening test. Meaning the technicians were switching in/out the amps with us (5 people if I recall right) were sitting in the control room listening to Peter Gabriel's Security CD-ROM because of it's bass and drums slam with huge dynamic range. We had no visual clue to which amp we were listening to. While the top end's of the amps varied a little bit, it was the bottom end where it was no contest. Everyone within a sort period of time guessed every time the Crown.
Chips used a TEF acoustical analysis computer back then to measure the decay of the control room and it was quite a measurable difference in the bottom end decay, with the Crown easily having the least amount of decay, which confirmed what we were hearing. Unfortunately, that was many years ago and I don't have the data files. But that was the end for me guessing which amp has the best "slam" and again, I think Crown said it best in the paper: High damping factor equals tight bass. "How" they achieve that, whether through high negative feedback or... is likely to remain a mystery 🙂"
OK, seems that we are progressively getting a hint that the power supply philosophy contributes little or not to the sound characteristic: no regulation to avoid a phenomenon of saging on peak power demands etc., no significant amount of capacitance, transformer is not monstruously big etc.
but DF can go down with the addition of Zobel network at the output, DF can be very high at LF but drops at HF..
Using the drum sound in that album to differentiate is a giveaway that the Crown's were superior in their ability to reject voltage rail modulation interfering with the functioning of the amplifying circuitry - IOW, real, rather than theoretical PSRR. It may be that a combination of techniques were used, but the designers had fine-tuned their approach so that the combination of circuit parameters were truly effective in making the core circuitry reject the rail noise - they didn't use any "magic" sauce, but knew what they were after, and tweaked until they achieved their goal ...
Said because I've used those parts of that album many, many times for assessment - and noting how very expensive, "high end" systems usually are just nowhere in the hunt ...
I like them on the bass, I use them myself for that reason.
I'd expect that they'd not be my choice in the lower mids or in the highs for "discriminating home use".
If I did not need to cart them around, I'd be fine using them for a fixed PA/SR install.
I've not looked at the schematics for a number of years (although I think I have them on this drive?) but recalling the layout, it's my guess that some of the HF sound could be laid off on various things that are higher order concerns than circuit design - like some parts, parts ratings (like resistor wattage), connectors (if you think they matter), wire routing. Also I'm not sure where the noise floor sits on this amp, or if that matters. Another way of saying this, is that perhaps, maybe the same amp circuit "optimized" might be more to some listeners liking in terms of the way the highs are presented, etc...
Otoh, there are some speakers that definitely do NOT benefit from a high DF amp in terms of the bass response's subjective presentation.
Ymmv, and according to some I am always right, never make a mistake, and have nothing bad or good to say about "rule 12" whatever that is... 😀
_-_-
I'd expect that they'd not be my choice in the lower mids or in the highs for "discriminating home use".
If I did not need to cart them around, I'd be fine using them for a fixed PA/SR install.
I've not looked at the schematics for a number of years (although I think I have them on this drive?) but recalling the layout, it's my guess that some of the HF sound could be laid off on various things that are higher order concerns than circuit design - like some parts, parts ratings (like resistor wattage), connectors (if you think they matter), wire routing. Also I'm not sure where the noise floor sits on this amp, or if that matters. Another way of saying this, is that perhaps, maybe the same amp circuit "optimized" might be more to some listeners liking in terms of the way the highs are presented, etc...
Otoh, there are some speakers that definitely do NOT benefit from a high DF amp in terms of the bass response's subjective presentation.
Ymmv, and according to some I am always right, never make a mistake, and have nothing bad or good to say about "rule 12" whatever that is... 😀
_-_-
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