I have that folly already behind me. Built a Peltier unit to cool wafers for
characterization and decided to test one of my better oscillators on it.
A E5052B signal source analyzer or a hp53310A modulation domain analyzer
are cruel eye openers.
Gerhard
For audio and video production very accurate time coding is quite useful. That requires long term accuracy. For audio it is the jitter. Currently I am below 1 ns according to the limited instrumentation I have.
Yes the other issue is the WOW factor. I once had someone design an arena system and specify a $300 mixer. Yes it would have worked, but folks looking in the window at the control room would not have been impressed.
May-be the most important. Unless you have succeeded to make your place a reputation of "magic room".
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And they come in qualities ranging from Platinum to lead. . . Like audio a lot of the performance comes from design and execution. The components aren't too expensive, but getting the performance is a lot of work and experience.
For bling the SRS box is a good start. I would look closely at this alternative if a GPS antenna can be managed: Model 1083B GPS Satellite-Controlled Frequency Standard - Precision Time Clock Series It has a 10 MHz Wenzel oscillator disciplined by GPS with a neat display on the front. You can also use it for time and timing probably to well less than 1 uS absolute (for time code sync.). Get the battery backup version.
I would transformer isolate the incoming clock just to reduce the noise coupling between the chassis.
Measuring jitter in a system becomes a complex issue but the most straightforward way is in the final output since the DAC will either hide or accentuate the jitter components and its really what matters. Its easier to measure at the output that looking at the internal stages.
Nah, not enough bling...
Now you mention the transformer, after I have finished the layout! Fortunately it hasn't gone out yet...
Jitter is worse in recording than play back. As long as I get it to where I can't measure it, that will have to do. Listening tests in a stadium are a bit limited by noise!
Now you mention the transformer, after I have finished the layout! Fortunately it hasn't gone out yet...
Jitter is worse in recording than play back. As long as I get it to where I can't measure it, that will have to do. Listening tests in a stadium are a bit limited by noise!
Well, after John's excellent tips I delved into the "micro-detail" world of contacts, and can now toss around good phrases like asperities, fritting, a-spots and dry circuits with the best of them ... perhaps ... 
It's a nightmare world, at times one marvels that things can work as well as they do. It confirms that my choice years ago to go for broke, and hardwire everthing was a good move, at the very least.
That said, if using relays in audio work, so far the best choice seems to be to use hermetically sealed units, AuAg10 contacts, with a very strong wiping action. Do others concur, and if so which is the best brand and series?
Frank
It's a nightmare world, at times one marvels that things can work as well as they do. It confirms that my choice years ago to go for broke, and hardwire everthing was a good move, at the very least.
That said, if using relays in audio work, so far the best choice seems to be to use hermetically sealed units, AuAg10 contacts, with a very strong wiping action. Do others concur, and if so which is the best brand and series?
Frank
Here is some bling: MHM 2010 Perhaps a little overkill.
I would use the Scientific Conversions shielded transformers to keep the isolation high. They seem to work pretty well. Or there are some nice transformers at Minicircuits, cheaper as well.
You are right to make sure your source is pretty clean. You are distributing word clock and the ADC's all lock internal oscillators to that clock. The jitter is dominated by the internal clocks but if the word clock is not clean the PLL will be very busy, not good. Maybe just looking at the PLL control in an ADC box will yield a lot of insight into the clocks.
Yes, that's the interesting thing ... why is there this apparent discrepancy? IMO, there are three aspects: firstly, the quality of the many connectors in the recording arena are of pretty good quality in of themselves, none of this RCA rubbish would be allowed, because the engineers doing their job want their gear to work reasonably well, over a reasonable period of time; secondly, the contact areas of the many connections in the studio are constantly being disturbed, things are plugged and unplugged, switched continually, and if there was the slightest suspicion of a dodgy connection the engineer would reseat every possible offender; and thirdly, IME, the replay side of things is far more critical, I can't speak with good technical knowlege as to why, but if the gear is only concerned with recording voltages, rather than delivering power to speakers then the problem is much less ..
Edit: the problem is also compounded in the consumer's room because he has to deal with two levels of distortion: that of the recording operation, and then the intermodulation of that with the, very different in style, distortion of the replay side of things. If you make the latter "perfect" then chances are much better that a person can subjectively handle the recording distortion without discomfort.
Frank
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It is not absolutely true, fas42. Most of the equipments are wired in the patch bay and don't move until they fail or are changed for something else.
We care of contacts when we have a noise's problem (it happens often in the patch bay, switches in the mixing desks, Penny and Giles potentiometers). And it is boring. Always a bomb of special cleaning oil near us.
We live in a real world, no time to fight against phantoms.
About relays for speakers, i use the same relay for protection and silent power on/off of my amplifier since 30 years with no problem. At home, I can listen to music each time i want. I'm just bored with the deterioration of my sources (vinyls, CDs, tapes), the foam suspension of my boomers i was obliged to change last summer, that kind of things. One time a year or two, i use to clean the contacts of my plugs, that's all.
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Care to share?
And I get bored, nay, irritated, listening to difficult recordings through dirty contacts. I don't say "That's a bad recording!!", I say, "Hello, system's got a problem!". I find the mongrel of a thing, and then fix it.
That way, I get to listen to a lot of music, and enjoy it all ...
Frank
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