Sorry, Richard, you've just shot yourself in the foot ... how are we going to get around the "wonky contacts" between cable and speaker, eh? ...
Frank
JC, would you like to describe YOUR double blind tests?
I've described an alternative to ABX which I call ABC. Is this a form that in your august opinion "works better"? If not, have you any suggestions to improve it.
JC, your letter to the editor is somewhat vague about the test itself. Anyone have a copy of the original article so we can put JC's learned opinion in the correct context?
No problem with that Frank. We just weld the cable to the speaker terminals like JC recommends.
The problem is changing the cables over at the two matched Parasound A21 outputs. JC, what welding rods do you recommend for this?
We could use the A21s to do the welding by shorting the speaker terminals but it's probably less complicated to train our monkey to use a welding torch and angle grinder. I'm open to suggestions.
Last to first, SRS has a really good new phase noise feature in their audio analyzer. Its also way cheaper than most commercial solutions. The sales guy claimed it can measure AES as well as the HF clocks. The floor I saw was in the -165 dB range and possibly below -150 at 1 KHz.
The SRS Rubidium is very good. Long term is better than a good crystal, but short term a free running really good crystal oscillator (Like a Wenzel) is better. And they can be made at audio clock frequencies. Getting ppb from one is well within their capabilities. The really good ones are export controlled so more trouble that they are worth. but cheaper than the SRS clock. You could use both and set the time constants to get the best of everything. Adding a GPSDO would be the final step and not expensive in this situation.
How much pulling on the oscillator do you need for this? Are you syncing to something like video?
Peltier coolers on a crystal is unusual to say the least. The high accuracy low phase noise (essentially very high Q) crystals (SC cut) need to be something like 80C to get stability from them. There is a whole science of double oven controllers for that. They don't pull very far but its probably not needed.
Go for it, Ed Simon! It is refreshing to see an all-out effort made. This was the original principle that the Blowtorch was made. Cover EVERY BASE possible. Accept NO compromise that is made for cost saving or ease in construction. Heck, we only had enough parts to build 50 units, why not? There was no mass production involved where a small cost saving saves millions of dollars. The real EXPENSE of the CTC Blowtorch is in the LABOR of designing, building and testing it.
This morning I thought that I might bring up the TRADE-OFF'S in audio design, that are of course necessary, to meet different cost levels and ease in construction.
For the record, for Parasound, I have 3 models of power amp that I put my name or reputation to. However, Parasound makes many more power amps, some at a similar price to some of my designs, most at a lower price.
The question is: Why buy a more expensive design than the cheapest one that will essentially fit your needs? I am not looking for ad hype here, or listening differences, just hard, cold facts about what the tradeoffs are. (more later)
For the record, for Parasound, I have 3 models of power amp that I put my name or reputation to. However, Parasound makes many more power amps, some at a similar price to some of my designs, most at a lower price.
The question is: Why buy a more expensive design than the cheapest one that will essentially fit your needs? I am not looking for ad hype here, or listening differences, just hard, cold facts about what the tradeoffs are. (more later)
JC, can you tell us a bit more about the testing seeing as Hirata, Quan and Listening were not on the agenda?
Demian,
I plan on picking up the SR1 analyzer very soon.
I have attached a shot of the sweep noise from an eBay $60 rubidium oscillator.
The roadies today use an Apogee Big Ben word clock on their consoles because they notice an improvement.
So we are in agreement that a high quality crystal oscillator is adequate. As the screen shot shows the 200hz sweep noise from a rubidium source may be a problem if not used with a crystal oscillator.
Where we differ is that my system is not just playback. I also have A/Ds and record. Accurate time stamps are very useful in recording. So the full works with GPSDO is useful. I expect the video guys will take a clock from my system.
Now as to crystal temperature. You are right in that crystals have long been designed to work in an oven, so they cut them to work best at an elevated temperature. However if you look at the curves you will see they flatten out at lower temperatures. One issue is how accurately you can control temperature. So my playing around has shown lower jitter at freezing. Due to the properties of the frost formation the temperature is quite uniform and stable. (Moisture in the air is the actual regulation mechanism!)
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John,
The only reason that has ever prompted me to purchase a particular audio component over another less-expensive, ostensibly comparably-performing audio component is the perceived sound of the component in my home music reproduction system. "Better sound" is the only cold, hard fact for the selection of audio gear, IMHO....
In my case, I only purchased my Audio Research D-79B power-amplifier (ARCDB - D-79) to replace my D76A power-amplifier (ARCDB - D-76) because the D-79B significantly raised-the-ante on the sonic performance of the D76A. Yes, these are "oldies, but goodies", but they've held their own in comparison with everything that I've tested in my reference system over the years.
Well, 34, you appear to be on the right track. I once had access for a few months of the AR-D150 tube power amp. It was WONDERFUL with STAX electrostatic phones.
Today, I use STAX electrostatic phones with vacuum tube drive as my reference. I don't design with tubes, but I DO respect their sound quality, and I use their advantages to compare with my solid state efforts. Sometimes I can drive a loudspeaker 'better' than a tube amp, but not STAX phones.
Today, I use STAX electrostatic phones with vacuum tube drive as my reference. I don't design with tubes, but I DO respect their sound quality, and I use their advantages to compare with my solid state efforts. Sometimes I can drive a loudspeaker 'better' than a tube amp, but not STAX phones.
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I'm pleased to see examples of aging of cardboard containers, in neat rows, as a way of improving the contents. At least the audio community learnt one thing from the wine industry ...
Frank
At least one container must have travelled a lot. Gerolsteiner Sprudel
(German mineral water) in a massachusetts-ian swamp!
At freezing the issue then comes from changes in moisture level on the outside of everything that is not hermetically sealed.
John,
I also love to listen with Stax electrostatic ear-speakers (selected pairs of SRX Mk-III's with the SRM1 Mk-II Pro (a FET-based, pure Class-A Stax driver/amplifier)). I had to sift through about 10 pairs of Stax SRX Mk-III's at the stocking dealership in order to locate two pair without a tipped-up high-frequency response.
But, getting back to topic, is there any selection criteria beyond rational, intelligent engineering other than auditioning gear over the long-term in a known reference system? Isn't that component-performance criteria at the core of your design process? After all, isn't engineering defined as, "...the creative application of scientific principles to design or develop structures, machines, apparatus..."
(2) Too bad Radio Shack will no longer honor the warranty on those lifetime guaranteed tubes.
It is a really dumb idea, that's why it is unusual.
To get good stability, you need looow time constants in your envionment,
as it happens when you have high thermal resistance and large thermal
capacity.
Peltiers are just about the opposite. High thermal conductivity, in fact so high
that they mostly work against themselves, and that results in their low
efficiency.
They are close to transparent to environmental transients; only when the
transient has made it to the temperature sensor in the middle, one can
try to regulate it away. But then the harm is already done.
regards, Gerhard
I'll let you know the difference in a few weeks. I am building a few. As the temperature control is a separate unit I can do some of each.
The owner won't have any other, it still comes in glass. Gerolsteiner and Pellegrino both have a large presence here.
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