Engineering is about tradeoffs. If you don't make compromises somewhere, you could wind up with an amplifier that costs a million dollars or even more. The engineer's art is to decide where those tradeoffs have the least impact on what is of benefit to those who use the product of their designs. Not all products are created alike because not all engineers are alike.
Good on ya! I wish you similar success for the following 8 years.
Not so much in audio other than the profitable manufacture of power cords and filters, which is a byproduct of the real interest in these devices for medical application. While my cabling and capacitor choice and voicing is used in some successful audiophile conditioners, NDAs prevent further disclosure.
Yes, I do modify my own audio equipment, primarily in the power supplies where ac filtering properly belongs. As to other equipment, I really make an effort not to 'teach my gran to suck eggs'. I get my kit from folks who I believe do it right.
I honestly don't think we're really that far apart. I do the objective measures prior to any subjective evaluations. The bulk of audio equipment makes poor choices in power filter and supply implementation. I can only assume the incremental cost of grounded shield in a toroidal transformer (or a 'flatpack' transformer), or even snubbing their secondaries is too dear for the accountants, as are the costs of the appropriate inductive and capacitive elements for proper power conditioning. But those comments apply equally to the medical instrument industry. Other than complying with leakage requirements, the efficacy to their efforts are no better than that of the audio industry.
In truth, MONO was higher quality sonically than stereo, when you had a choice between vinyl records, AND the main source was a single individual, singing. I have examples, even today, that prove this. Stereo records cost $1 more than Mono records 45 years ago in Berkeley, where I live today, and this is probably why some record makers pushed it so hard, much like SACD, today. With stereo headphones, Stereo records sounded better, because they were more dimensional, even with the sonic degradation.
As time passed, there became little, to no real sonic difference between Stereo and Mono, and Mono records were dropped for commercial reasons. This was mostly due to improvements of disc recording and phono reproduction, not some vast conspiracy.
When it comes to switches used in A-B tests, it is important to AVOID mercury wetted switches, because they have been shown in blind tests to change the sound, usually making everything sound the same. Silver on Silver military grade rotary switches, such as Shallco, are highly recommended. This is what Dave Wilson, Peter Moncrief, and I use, and have for many years. They really work well for this application.
As time passed, there became little, to no real sonic difference between Stereo and Mono, and Mono records were dropped for commercial reasons. This was mostly due to improvements of disc recording and phono reproduction, not some vast conspiracy.
When it comes to switches used in A-B tests, it is important to AVOID mercury wetted switches, because they have been shown in blind tests to change the sound, usually making everything sound the same. Silver on Silver military grade rotary switches, such as Shallco, are highly recommended. This is what Dave Wilson, Peter Moncrief, and I use, and have for many years. They really work well for this application.
I agree with you John; if only because it's easier to make as good tracking mono cart than a stereo one.
Anyway, I thought that Youtube video had a gem in it too: It always amazes me a great deal when people on the one hand fully accept that 'what I hear is what I hear', and absolutely refuse to entertain the possibility that their perception is at odds with reality. While on the other hand their perception fools them again and again, big time, every time they listen to stereo.
jan didden
Apparently, and at 60 hertz also I bet. So how loud would 18ua into a 33k ohm input impedance power amplifier input be? Given the amplifier voltage gain of 22 and an 8 ohm loudspeaker with a sensitivity of 92 db/w @ 1 meter, down by 6 db at 60 hertz and from a listening distance of 12 feet.
Well, I can see the relevance of that calculation if you connect your input in series with that current and the current doesn't vary when shunted. But you'd have to work pretty hard to do that; it would take a perverse grounding scheme to run 18uA from the power transformer primary leakage through the unshunted amplifier input impedance, much less maintain that current into a low impedance like 33k.
That's not to say that there couldn't be a difference, it's just that I don't think this is a good plausibility argument.
Sy,
That was part one of the question. Part 2 is given the output preamplifier has an impedance at 60hz of 100 ohms (all resistive for calculation purposes) and the safety ground is allowed to be 3 ohms now what level would you have?
But it would be nice to see who can do the basic arithmetic.
ES
I wrote this up, and put it in a series of LTE's into 'The Audio Amateur' around 1980. Please don't waste your time, SY, it was not PEER APPROVED by a PhD, just an answer to Liptshitz et al, as to why the Spiegel box didn't work right.
I was surprised too, Dick Marsh, Karen Richardson, Peter Moncreiff and I, all heard the difference in an A-B test at Peter's at that time.
I was surprised too, Dick Marsh, Karen Richardson, Peter Moncreiff and I, all heard the difference in an A-B test at Peter's at that time.
OK, so there wasn't any sort of controlled blind test. Just assertion. I have copies of those Letters.
It doesn't take a PhD to figure out how to do and document a decent listening test. I understand that this isn't your business, you're designing Rolexes and have to justify them in a world of atomic clocks.
It doesn't take a PhD to figure out how to do and document a decent listening test. I understand that this isn't your business, you're designing Rolexes and have to justify them in a world of atomic clocks.
Yes, SY, I would have given up, long ago, if I was FORCED to do a double blind test to prove that an ABX box didn't work and that EVERY IMPROVEMENT that I have found over the 3 decades since was not real, BECAUSE it was not compared in a peer reviewed double blind test. WOW! What a concept! 'I am deaf to differences, except those approved by Lipshitz et al.' Now remember everyone:
It is all:" 'delusion,' 'hallucination,' 'group hallucination,' 'mass hallucination,' 'mere coincidence,' 'sheer coincidence,' or 'sloppy research'. (p151, PR)
Did I miss anything?
It is all:" 'delusion,' 'hallucination,' 'group hallucination,' 'mass hallucination,' 'mere coincidence,' 'sheer coincidence,' or 'sloppy research'. (p151, PR)
Did I miss anything?
Yes. Doing a controlled listening test even once to try to validate something you think you heard. "Every time" is a bit much to ask for.
Yes. Doing a controlled listening test even once to try to validate something you think you heard. "Every time" is a bit much to ask for.
Sy,
Couple of points since you made me have to think and the strain was painful.
The 18ua current was measured with a current meter which is close to a short circuit so the AC line should be able to put all of it into a 33k resistor if the wiring would permit it.
Second, a mercury relay uses mercury as a renewable contact so that arcing doesn't wear out the contact. After the initial "make" it is the base contact material that maintains the current flow. Of course this is not the magic silver John uses and so does not sound as good. However a local company used to put in a lot of school auditorium sound systems (As bad a thing I can call anyone with out violating forum rules) using two mixers, one a large console and the other a small mixer for use without an operator. They used a relay to switch between the line level output of the two mixers. Of course they used power relays and so no listening panel was required to determine when the system just died. The normally closed side of the relays would just not want to start conducting after a bit of age set in. Flipping the relay a few times would provide a temporary fix, but a bad design is a bad design. The folks who brought us the telephone also were picky about relays, to the point they made their own down to the contact alloy.
Third point there really are bad audio switches so if you are not careful you can get bad data, just look at my noisy graph of yesterday.
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For example, the "McGurk effect"
YouTube - The McGurk Effect - Horizon Is Seeing Believing?
Cheers.
ZAP
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