SY, I design for low distortion, BUT not with heroic amounts of negative feedback to get me there. I am suspicious of global negative feedback, especially when it tends to lower the open loop response. I ALWAYS look out for odd order harmonics, but below -110 dB, then perhaps they are not so important.
There is more to audio sound quality that steady state distortion. That is my opinion and experience.
For balance, the Halcro preamp got a bad review in 'Hi Fi News' years ago. Something about the digital power supply effecting the rest of the equipment in a bad way.
There is more to audio sound quality that steady state distortion. That is my opinion and experience.
For balance, the Halcro preamp got a bad review in 'Hi Fi News' years ago. Something about the digital power supply effecting the rest of the equipment in a bad way.
Exactly. Unfortunately, this is in the "devil's in the details" area, in my experience. When I get to this point the slightest variation from optimum causes the subjective quality to plummet, it's a very fine balancing act. One of the reasons is that when the SQ is spot on then you can wind up the volume as far as you like with no problems, this is in the territory of being able to go outside the house and the music inside still sounds completely realistic. But, at these volumes the slightest audible deficiency sounds horrendous, it is instantly unlistenable to ...
Very much, razor's edge territory ...
Frank
A hypoth that a super low THD+N in a power amp listening contest would NOt mean that only THD+N was the reason for a win. Or, sole reason. PSRR, PS noise, regulation of the PS under those load conditions, CMRR, peak current into various load Z, output Z et al are needed to get an over-all evaluation of the total parameters that lead to the decision. AND, how the total harmonic structure combined in That system being used in the listening test. -RNM
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Perhaps all that ties into the (according to John) super high levels of "global" feedback. The THD performance is just part of the picture, the result of excellent engineering, not a specific desideratum in and of itself. It performs well because the designer knew what he was doing and didn't reflexively dismiss using good engineering practice because of being stuck in 1968 thinking.
The "listening contest" performance has very little- or perhaps nothing- to do with actual listening, but clearly the designer knew how to make something that looks and feels impressive as well.
The "listening contest" performance has very little- or perhaps nothing- to do with actual listening, but clearly the designer knew how to make something that looks and feels impressive as well.
I find that a middle of the road design philosophy works best with Parasound. That is: A good balanced topology (if possible) running as hot as is prudent, even if it requires extra heat sinks, however, not truly all Class A, with power amps, but in A-B with as much current as possible in the output devices, without overheating the heatsink. Everything else all the way back to the input runs in truly Class A in operation. This is because I want to minimize any higher order nonlinearities, as much as possible, open loop. Class A in the driver circuits is important in this quest. For my preamps, ALL Class A, including the output. NO, Class AB, or Class B. My preamps run relatively hot, if I can make it that way. Works for me, gives me Class A reviews and appreciation for my efforts by serious listeners.
Feedback is an added 'compromise'. IF I could, I would use less negative feedback, but the distortion numbers start to rise, and look bad, on paper. Only Ayre, at this time, to my knowledge, does it in a more ideal way, BUT their distortion specs are necessarily worse. However their sonic success, often, is better than mine.
Feedback is an added 'compromise'. IF I could, I would use less negative feedback, but the distortion numbers start to rise, and look bad, on paper. Only Ayre, at this time, to my knowledge, does it in a more ideal way, BUT their distortion specs are necessarily worse. However their sonic success, often, is better than mine.
"The REF5 is only the second Reference preamplifier to have its main board laid out horizontally, after the REF Phono2, with its transformers off the board and mounted on the sides of the chassis. The new audio circuit is fully balanced, pure Class-A triode, with zero feedback. The tube complement includes four 6H30s in the analog stage, with a 6550 and a 6H30 in the power supply. Massive energy storage, the most of any Reference preamplifier, provides tremendous dynamic capability. Total gain is 12dB via the balanced outputs and 6dB via the single-ended outputs."
Audio Research REFERENCE 5 Vacuum Tube Line-Stage Preamplifier
But tubes don't count!
Audio Research REFERENCE 5 Vacuum Tube Line-Stage Preamplifier
But tubes don't count!
Well, 6H30s can be pretty quiet, especially if one is weighting things to reduce low frequency noise contributions, running at modest gains, and not making anything worse otherwise. And running balanced at once reduces even order distortions to the extent devices are matched."The REF5 is only the second Reference preamplifier to have its main board laid out horizontally, after the REF Phono2, with its transformers off the board and mounted on the sides of the chassis. The new audio circuit is fully balanced, pure Class-A triode, with zero feedback. The tube complement includes four 6H30s in the analog stage, with a 6550 and a 6H30 in the power supply. Massive energy storage, the most of any Reference preamplifier, provides tremendous dynamic capability. Total gain is 12dB via the balanced outputs and 6dB via the single-ended outputs."
Audio Research REFERENCE 5 Vacuum Tube Line-Stage Preamplifier
But tubes don't count!
Massive energy storage in the power supply. That would be one to be able to discriminate aurally. Or not
I was doing some surfing of YouTube, to find an example of what the end goal is in audio, and this is the best sample I found so far, by Kenrick Sound: Manfrotto FIG RIG 595B test video - REY AUDIO RM-7V in KENRICK SOUND showroom - YouTube. This is worth watching through to the end, to see how the sound fills the room even when the recorder is completely unaligned, in the extreme sense, to the sweet spot.
This is a group of people who "get it", who understand what's possible, which is why they keep moving the video POV throughout the shoot -- apart from demo'ing the steadycam ...
Frank
This is a group of people who "get it", who understand what's possible, which is why they keep moving the video POV throughout the shoot -- apart from demo'ing the steadycam ...
Frank
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This is what I usually tell my customers when they start asking similar questions - when you go dining to the 5-star restaurant you don't expect to be charged basic prices for the raw "materials" (water, salt, meat, vegetables etc.). Why should it be different in audio?
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