While many here can not figure out why, we still 'trudge on' on a daily basis to make better audio electronics, both analog and digital. What one group of us is working on most, is reducing power supply noise and interference. Kind of like making the equivalent of a perfect battery. How can this matter much?
Subjectively, we have found it to be very important. The CTC Blowtorch that this thread is based on, used 3 passive components and 3 active stages before the DC met the amplifying circuitry.
We are finding the same effort, when used with digital, can be at least as important.
I think that we have to look at the power supply as being an input port, somewhat similar to the inputs, and while often considered an unlikely contributer, but at higher frequencies, especially in this time and age, with switching supplies, etc, the power supply rejection is just not that good to keep it out, in every audible way. Perhaps a meter would have a problem measuring it, but the ear can certainly hear an A-B difference.
Many here have probably seen examples where audio engineers have just given up trying to make a 'perfect' power supply and switched to gell cells, (lead acid batteries), or a string of D cells. If you try this, you might be surprised how good it works, but also what a hassle it is to keep the batteries in operating condition.
It is better if we can use some sort of AC-DC conversion, without compromising the audio quality. That is the quest.
Subjectively, we have found it to be very important. The CTC Blowtorch that this thread is based on, used 3 passive components and 3 active stages before the DC met the amplifying circuitry.
We are finding the same effort, when used with digital, can be at least as important.
I think that we have to look at the power supply as being an input port, somewhat similar to the inputs, and while often considered an unlikely contributer, but at higher frequencies, especially in this time and age, with switching supplies, etc, the power supply rejection is just not that good to keep it out, in every audible way. Perhaps a meter would have a problem measuring it, but the ear can certainly hear an A-B difference.
Many here have probably seen examples where audio engineers have just given up trying to make a 'perfect' power supply and switched to gell cells, (lead acid batteries), or a string of D cells. If you try this, you might be surprised how good it works, but also what a hassle it is to keep the batteries in operating condition.
It is better if we can use some sort of AC-DC conversion, without compromising the audio quality. That is the quest.
john curl said:
I, of course, agree with you about the importance of eliminating noise. I've found even the highest quality audio gear can be susceptible to noise from the power line. The amplifier that hurt my ears measures very well and has excellent noise performance.
Months ago, I was hooking up our main speakers differently - using two amps in a vertical bi-amp configuration - so we could use an external crossover to a subwoofer and not have it go through the mids/tweets.
Anyway, I hooked them up and gave a listen and right ear started hurting. I wasn't sure which amp was the one I just added since they are identical, and they were both hooked up to a PS Audio power line conditioner.
I let the amps warm up and let them alone to let my ear calm down. This type of hurt makes your ears more sensitive to other everyday sounds, and I had to just it easy for awhile. I waited a day and then gave a listen. Again my right ear came away hurt again and my left was hurting slightly. I was kind of upset given the past experience with the amps, and the fact that I was using a power line conditioner.
So, I went looking for a problem, and I found the right amp had a cheater plug on it. I didn't know why that would have any affect ... just guesses, but I took off the cheater plug. As I remember I didn't listen for a day or two to let my ears get feeling better.
The next time I listened, all was good and it sounded as it should. They sounded really good. The amps had very good specs and reviews, and I can heard no noise from the speakers.
I've even talked with some else who had the same problem with a quality amp.
I think the noise spectrum is really important. The LP has a lot of low frequency noise but decreases with increasing frequency, whereas CD has a flat noise spectrum.
Flat, white noise is a lot harder for the ears to filter out. People with decreased sound tolerance find wide band noise difficult to tolerate sometimes, and it hurts their ears at any level. At the same time working with wide band noise is helpful. They use a pink noise or a special wide band noise that's easier on the ears then white noise, to treat people with decreased sound tolerance.
The Bybee Music Rails do what they are supposed to do, and they go right down to very low frequencies. About 40 dB is possible (and measurable) with a relatively noisy supply that needs filtering. IF your supply is already VERY quiet, then they might not help too much, but many standard lab supplies, for example, can be improved. In fact, I am going to add them into my test set-up. Power supply hum residual reduction is amazing!
Those look nice. I would be tempted to try those in our amps ... the trick would be to convince my dad to even let me touch them.
Couldn't agree more John - it has been a mantra of mine for a while now that PS in digital has a huge part to play in the overall sound. I have focused on using battery power & removing the inconvenience factor. The improvements that are immediately apparent with battery power might not be currently measurable but the Nordost/Acuity paper seems to throw a chink of light on this issue & hopefully will prove not to be just marketing blurb? You have probably seen this paper already referenced in the Bybee thread
Every idea and even the air bearings themselves were stolen directly from the VersaDynamics turntables designed by John Bicht.
It is rare for a copy to better the original...
You would prefer a Diamond Rio to an iPod Touch?
I know where you can get a Versa Dynamics very reasonably, you just need to make it work.
John Bicht was a real pioneer.
Those big ones were built for a specific purpose and the application requirements were much different from what the Versa Dynamics could do. I built an air bearing turntable in the late 70's (not using the blockhead bearing). Andy notwithstanding, I would not use a blockhead air bearing in a consumer product because they are difficult to maintain and too easily damaged.
I believe its "Bict". The times I met him I did not ask, somehow it was not necessary.
I never saw a Diamond Rio. My son has an iPod Touch and I hate the damned thing. Give me a Sansa Clip+ any day of the week. I can connect it to any computer and move songs around without being forced to use one piece of bloatware that restricts your choices and is constantly trying to sell you junk you don't want. The Sansa sounds far better. It is cheaper, simpler and accepts 32 GB SD memory cards so I can keep multiple libraries on different cards.
I had a Versa Model 1.1. I loved it and hated it. It sounded insanely great. It would have been even better if I had gone in and re-engineered the control box to get rid of the RFI emitting microprocessor. Too complex a solution for a really simple problem.
But in the end I just got tired of three boxes, fifty feet of hoses, compressors so loud I had to put them in closets, and the teflon platter mat that clung to your records in dry climates. Now we import the Bauer dps because that is exactly the turntable that I want to own. Simple, elegant, indestructible, beautiful, versatile, and (relatively!) reasonably priced.
John worked for a long time with the bearing manufacturer to get it perfected for use with a turntable. He unfortunately had no idea of how to run a business. He should have been charging double the price he was. When it went under he was very bitter about it.
Then Andy came in and scooped up all of the bearings that John had ordered and never paid for. That is probably the real reason that there is no more Rockport turntable -- Andy ran out of John's bearings.
You are right that those four were special beasts. Holy cow! Not just 78 rpm, but reverse as well!
As far as the bearings went, John was adamant that they were tough as nails. He said that you could just turn the pump off and run the arm back and forth across the shaft to clean any dirt off. If I would suggest some gentler way to clean the shaft, he would get crank and start yelling at me to do it "the right way"...
Cars, turntables, espresso bean grinders, and even a bad temper.
My kind of guy.
John Bicht design history
My kind of guy.
John Bicht design history
VersaDynamics versus Rockport
By the way, the original VD turntable was called the Model 2. This had an air-bearing tonearm, an air bearing platter, and a vacuum hold-down. It sold for around $15,000 give or take a thousand or two -- depending on options and how good my memory is.
He called it the Model 2 because he had always planned on introducing a simplified version for less money. About the only thing simpler was that the platter's air bearing was replaced with a zero-clearance design that borrowed from Bill Firebaugh's Well-Tempered but did not break any of the patents. It sold for about $11,000, give or take a few grand.
Just to give you an idea of how underpriced these products were, the Rockport was introduced at something like $40,000, rising up to nearly double that as he added a complex self-leveling stand. And the Rockport was only sold factory-direct.
John was scornful of the Rockports and could cite a dozen design flaws. Both were good, but in the opinion of those who heard both, the Versa was superior.
To the best of my knowledge, the only other turntable in the world with a zero-clearance platter bearing is the Bauer dps. Once you hear one, it is hard to go back. It provides the pitch stability of a CD -- something unique among turntables. Each of the three designers achieved their goal in slightly different ways -- each equally ingenious.
By the way, the original VD turntable was called the Model 2. This had an air-bearing tonearm, an air bearing platter, and a vacuum hold-down. It sold for around $15,000 give or take a thousand or two -- depending on options and how good my memory is.
He called it the Model 2 because he had always planned on introducing a simplified version for less money. About the only thing simpler was that the platter's air bearing was replaced with a zero-clearance design that borrowed from Bill Firebaugh's Well-Tempered but did not break any of the patents. It sold for about $11,000, give or take a few grand.
Just to give you an idea of how underpriced these products were, the Rockport was introduced at something like $40,000, rising up to nearly double that as he added a complex self-leveling stand. And the Rockport was only sold factory-direct.
John was scornful of the Rockports and could cite a dozen design flaws. Both were good, but in the opinion of those who heard both, the Versa was superior.
To the best of my knowledge, the only other turntable in the world with a zero-clearance platter bearing is the Bauer dps. Once you hear one, it is hard to go back. It provides the pitch stability of a CD -- something unique among turntables. Each of the three designers achieved their goal in slightly different ways -- each equally ingenious.
Charles Hansen said:
I just bought an iPod Touch and I love it. I don't expect high end sound but it sounds very good with my Radio Shack Titanium Pro 35A headphones with inline volume control, only about $35.00 as I remember. I'd bet the Touch would not sound so great on my AKGs 701s though since they aren't too forgiving, though I may try it.
The Touch does a whole lot and is fun to use, though I'm sure other players have better fidelity. I'm selling it as soon as the new iPhone comes out.
Phase noise measurement from tuners
Someone here mentioned using a tuner (things scroll so fast its easy to lose the details). The idea is to look at the harmonic which will multiply the phase noise proportionally. I finally tried it. I pulled out an old Yamaha tuner I have and tried it against two oscillators, a generic crystal type at 24.576 MHz and a Wenzel 10 Mhz. To my amazement there was a significant difference with the Wenzel having 20 dB less noise on the audio output which is consistent (except it probably is a even bigger difference in reality). Now the real work starts in verifying this is not just me getting some detail upside down.
If I can get repeatable results this would be much easier than a phase noise analyzer, and would be much easier to use since you don't need to connect it with sma connectors to a source with a specific level out. I doubt the noise floor is as low as the sources but it may be low enough to see real differences.
Unfortunately the good tuners for this have really jumped in price.
Someone here mentioned using a tuner (things scroll so fast its easy to lose the details). The idea is to look at the harmonic which will multiply the phase noise proportionally. I finally tried it. I pulled out an old Yamaha tuner I have and tried it against two oscillators, a generic crystal type at 24.576 MHz and a Wenzel 10 Mhz. To my amazement there was a significant difference with the Wenzel having 20 dB less noise on the audio output which is consistent (except it probably is a even bigger difference in reality). Now the real work starts in verifying this is not just me getting some detail upside down.
If I can get repeatable results this would be much easier than a phase noise analyzer, and would be much easier to use since you don't need to connect it with sma connectors to a source with a specific level out. I doubt the noise floor is as low as the sources but it may be low enough to see real differences.
Unfortunately the good tuners for this have really jumped in price.
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