Re: [time-nuts] FEI-5660 Rubidium Oscillator
On 3/27/2014 8:47 PM, Mark Sims wrote: Granite tends to be rather radioactive (particularly avoid the pink stuff). Apologies before I begin... He who holds the scintillation detector has a gamma ray-son detre. Paranoia strikes deep into your home it will creep There's a man with a Geiger counter over there telling me I ought to beware OK, sorry, crawling back into the stonework. TIC Tic tic ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
On 28/03/14 04:47, Mark Sims wrote: no, No, NO granite! Granite tends to be rather radioactive (particularly avoid the pink stuff). Any audiofool worth his tin ears can't have no stinkin' alpha/beta/gamma particles mucking with his music! In that case you don't want a Rubidium clock in there. Rb-87 has a 48,8 miljard years half-time with beta- emission. Then again, it's about three times the life of universe, so it's not a very strong radioactive source. :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
On 28/03/14 12:33, Bob Camp wrote: Hi Crystals are susceptible to vibration. That’s pretty well documented. They have resonances in the mount structure. They have a 2G tip sensitivity. Audio when it “impacts” an oscillator induces vibration. If your noise source is a rocket engine, then the vibration is “non trivial”. You do indeed see phase noise on the oscillator from audio … The effect is well known and different approaches to reduce impairment of vibration have been presented. One approach have been to mount two crystals as a pair such that they will first-degree cancel each other. Those have been electrically operated in parallel. Another approach have been in mounting, both the direct mounting of the crystal but also mounting of the assembly. For instance, the Ashtech Z-12 has it's 20 MHz OCXO mounted in a vibration-reduced setup, which makes sense since it is a box intended to be carried around in the field and as one intends to collect carrier-phase measurements you want to avoid carrier phase cycle-slips. For other uses such as helicopters, vibration is a big deal, and well, guess what makers of vibration-improved oscillators address as a market. Then we have those that want their oscillators to not be too much affected as it is shot out of a canon. The acceleration kick is 12000 g. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
granite is not only radioactive, but also piezoelectric. Dpn On 03/29/2014 12:48 PM, Magnus Danielson wrote: On 28/03/14 04:47, Mark Sims wrote: no, No, NO granite! Granite tends to be rather radioactive (particularly avoid the pink stuff). Any audiofool worth his tin ears can't have no stinkin' alpha/beta/gamma particles mucking with his music! In that case you don't want a Rubidium clock in there. Rb-87 has a 48,8 miljard years half-time with beta- emission. Then again, it's about three times the life of universe, so it's not a very strong radioactive source. :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
On 30/03/14 00:01, djl wrote: granite is not only radioactive, but also piezoelectric. Ah, granite resontator? :) Will have to try the resonator mode of the granite slab I have in the (kitchen) oven. :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
Hi Crystals are susceptible to vibration. That’s pretty well documented. They have resonances in the mount structure. They have a 2G tip sensitivity. Audio when it “impacts” an oscillator induces vibration. If your noise source is a rocket engine, then the vibration is “non trivial”. You do indeed see phase noise on the oscillator from audio … Bob On Mar 27, 2014, at 11:42 PM, Tom Van Baak t...@leapsecond.com wrote: More seriously, I'm assuming you're advocating rock for the thermal mass and/or mechanical. What about a 100 pound box of sand? Mechanical. I figured a OCXO might be susceptible to microphonics, especially in a recording studio. But if it's down to the level of 1 lsb of the digital sampling, then no worries. Has anyone on the list ever measured this effect, even on a cheap crystal? /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
What about the other side of audio-phoolery: audio FFT? I'm thinking more along the lines of an ARRL FMT. From: Tom Van Baak t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, March 27, 2014 6:10 PM Subject: Re: [time-nuts] FEI-5660 Rubidium Oscillator Recently I happened across an eBay listing for an Antelope Audio Isochrome, a device that apparently packages an SRI-PRS10 rubidium oscillator and distribution amplifier in a box and sells to audiophiles for a price in the Bruce, There have been threads about this on time-nuts every few years. The consensus is that audio companies that use atomic clocks are naive. It makes good marketing, though. Then again, speaking from experience, many of us make the same mistake: first thinking that precise time is the goal, then thinking that precise frequency is what counts, and later thinking that stability is what really matters, and only eventually realizing that all of these metrics are functions of tau, and that tau ranges from MHz/microseconds to years. Phase noise plots along with log-log ADEV plots start to tell the whole story. In the case of digital music, as far as I know, L(f) phase noise in the audio band and ADEV(tau) frequency stability from microseconds to seconds is far more important to the fidelity of digital recording and playback than absolute SI-accurate frequency or long-term timekeeping. Consequently, most atomic frequency standards are actually a poor choice as a sampling reference clock -- because their jitter (short-term noise) is no where near as good as a free-running, undisciplined, high-end OCXO. True, the PRS10 is a better choice than other cheap telecom rubidium's but none of these comes close to the performance of a premium OCXO. For the ultimate audio reference clock you want to avoid Rb, or GPSDO, or Cs for that matter. Instead pick a 1e-12 or 1e-13 stable OCXO, strap it to a 100 pound block of granite, and leave it alone. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
All Rb's have XO's and with the exception of the HP5065C all Rb's influence long term stability only the only exception is the HP which uses a TC below 0.1.sec, and as Corbe demonstrated ADEV is controlled below 1 sec. by the cell. The same can not be said with other Rb's. Bert Kehren In a message dated 3/28/2014 7:33:45 A.M. Eastern Daylight Time, li...@rtty.us writes: Hi Crystals are susceptible to vibration. That’s pretty well documented. They have resonances in the mount structure. They have a 2G tip sensitivity. Audio when it “impacts” an oscillator induces vibration. If your noise source is a rocket engine, then the vibration is “non trivial”. You do indeed see phase noise on the oscillator from audio … Bob On Mar 27, 2014, at 11:42 PM, Tom Van Baak t...@leapsecond.com wrote: More seriously, I'm assuming you're advocating rock for the thermal mass and/or mechanical. What about a 100 pound box of sand? Mechanical. I figured a OCXO might be susceptible to microphonics, especially in a recording studio. But if it's down to the level of 1 lsb of the digital sampling, then no worries. Has anyone on the list ever measured this effect, even on a cheap crystal? /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] FEI-5660 Rubidium Oscillator
Recently I happened across an eBay listing for an Antelope Audio Isochrome, a device that apparently packages an SRI-PRS10 rubidium oscillator and distribution amplifier in a box and sells to audiophiles for a price in the $10K range. For the fun of it I searched eBay for Audio Isochrome and found a number of listings. Clicking on the lowest priced (eBay 271432562792) for $4,500, there is a note that the SRS-10 has been replaced with a FEI-5660 which is said to be a PRS-10 equivalent. Is this the one that has been showing up from surplus cellphone equipment? Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
Aren't those Isochromes lovely? Just the prettiness and the name itself seems to make spending $10K so much more worthwhile:-) The FE-5660 is one of those featured in the FEI 12 page Rubidium Standards brochure that's available online, not much data though and I've never seen a manual, but most of the more recent ex-cellphone units seem to have been the FE-5680s. Some FE5660s, from Tait T801 UHF base station references, became available on the UK surplus market a few years ago and I've always considered them a possible equivalent of the Efratom FRS series, physically and electrically quite similar, but have never considered either to be an equivalernt of the PRS10. They do all share the same case and connector style, as well as pinout, so perhaps made to another common telecom standard at least in that respect, but the PRS10 has a 1PPS conditioning option that neither of the others do and I seem to recall it also has lower phase noise, so I suspect someone is being a bit optimistic. Regards Nigel GM8PZR In a message dated 27/03/2014 17:40:55 GMT Standard Time, brucekar...@aol.com writes: Recently I happened across an eBay listing for an Antelope Audio Isochrome, a device that apparently packages an SRI-PRS10 rubidium oscillator and distribution amplifier in a box and sells to audiophiles for a price in the $10K range. For the fun of it I searched eBay for Audio Isochrome and found a number of listings. Clicking on the lowest priced (eBay 271432562792) for $4,500, there is a note that the SRS-10 has been replaced with a FEI-5660 which is said to be a PRS-10 equivalent. Is this the one that has been showing up from surplus cellphone equipment? Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
Recently I happened across an eBay listing for an Antelope Audio Isochrome, a device that apparently packages an SRI-PRS10 rubidium oscillator and distribution amplifier in a box and sells to audiophiles for a price in the Bruce, There have been threads about this on time-nuts every few years. The consensus is that audio companies that use atomic clocks are naive. It makes good marketing, though. Then again, speaking from experience, many of us make the same mistake: first thinking that precise time is the goal, then thinking that precise frequency is what counts, and later thinking that stability is what really matters, and only eventually realizing that all of these metrics are functions of tau, and that tau ranges from MHz/microseconds to years. Phase noise plots along with log-log ADEV plots start to tell the whole story. In the case of digital music, as far as I know, L(f) phase noise in the audio band and ADEV(tau) frequency stability from microseconds to seconds is far more important to the fidelity of digital recording and playback than absolute SI-accurate frequency or long-term timekeeping. Consequently, most atomic frequency standards are actually a poor choice as a sampling reference clock -- because their jitter (short-term noise) is no where near as good as a free-running, undisciplined, high-end OCXO. True, the PRS10 is a better choice than other cheap telecom rubidium's but none of these comes close to the performance of a premium OCXO. For the ultimate audio reference clock you want to avoid Rb, or GPSDO, or Cs for that matter. Instead pick a 1e-12 or 1e-13 stable OCXO, strap it to a 100 pound block of granite, and leave it alone. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
The audio marketplace is really weird. For many the goals is not sound quality but bragging rights I spent more money then you did. or My ears are so good I can hear if a cable as been swapped end for end. Some even think they can hear the difference between gold and nickel pated AC mains power plugs. There is one good reason for long-term stable frequency reference in audio, it's not in home playback equipment but in recording. You like two one hour recordings that have the same duration to also have EXACTLY the same number of samples. I've seen errors where two recorders where running independently and later when played back using a common clock they got out of sync because one had a very slightly different sample rate. This is no different then in the analog recording world if one tape machine is faster. They fixed this by using multi-track machines up to about 24 audio tracks Rubidium makes some sense because tracks recored weeks apart and/or a continent apart can then be exactly sample per sample in sync. But for home use in playback. It's like gold plated speaker wires, just taking the mark's money. On Thu, Mar 27, 2014 at 4:10 PM, Tom Van Baak t...@leapsecond.com wrote: Recently I happened across an eBay listing for an Antelope Audio Isochrome, a device that apparently packages an SRI-PRS10 rubidium oscillator and distribution amplifier in a box and sells to audiophiles for a price in the Bruce, There have been threads about this on time-nuts every few years. The consensus is that audio companies that use atomic clocks are naive. It makes good marketing, though. Then again, speaking from experience, many of us make the same mistake: first thinking that precise time is the goal, then thinking that precise frequency is what counts, and later thinking that stability is what really matters, and only eventually realizing that all of these metrics are functions of tau, and that tau ranges from MHz/microseconds to years. Phase noise plots along with log-log ADEV plots start to tell the whole story. In the case of digital music, as far as I know, L(f) phase noise in the audio band and ADEV(tau) frequency stability from microseconds to seconds is far more important to the fidelity of digital recording and playback than absolute SI-accurate frequency or long-term timekeeping. Consequently, most atomic frequency standards are actually a poor choice as a sampling reference clock -- because their jitter (short-term noise) is no where near as good as a free-running, undisciplined, high-end OCXO. True, the PRS10 is a better choice than other cheap telecom rubidium's but none of these comes close to the performance of a premium OCXO. For the ultimate audio reference clock you want to avoid Rb, or GPSDO, or Cs for that matter. Instead pick a 1e-12 or 1e-13 stable OCXO, strap it to a 100 pound block of granite, and leave it alone. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
On 3/27/14 4:10 PM, Tom Van Baak wrote: Recently I happened across an eBay listing for an Antelope Audio Isochrome, a device that apparently packages an SRI-PRS10 rubidium oscillator and distribution amplifier in a box and sells to audiophiles for a price in the True, the PRS10 is a better choice than other cheap telecom rubidium's but none of these comes close to the performance of a premium OCXO. For the ultimate audio reference clock you want to avoid Rb, or GPSDO, or Cs for that matter. Instead pick a 1e-12 or 1e-13 stable OCXO, strap it to a 100 pound block of granite, and leave it alone. A precision machined, finely crafted 100 pound block of granite (which isn't all that big.. 1/3 cubic foot or so?) selected from the most acoustically perfect granite by trained audiogranite craftsmen. The relative ratios of feldspar, hornblende and quartz are chosen for each installation according to the type of music and the vital harmonics of the listener. If two different people will be listening (obviously not at the same time, because only one can be at the perfect point between the loudspeakers), you need a mixture of granites. More seriously, I'm assuming you're advocating rock for the thermal mass and/or mechanical. What about a 100 pound box of sand? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FEI-5660 Rubidium Oscillator
More seriously, I'm assuming you're advocating rock for the thermal mass and/or mechanical. What about a 100 pound box of sand? Mechanical. I figured a OCXO might be susceptible to microphonics, especially in a recording studio. But if it's down to the level of 1 lsb of the digital sampling, then no worries. Has anyone on the list ever measured this effect, even on a cheap crystal? /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] FEI-5660 Rubidium Oscillator
no, No, NO granite! Granite tends to be rather radioactive (particularly avoid the pink stuff). Any audiofool worth his tin ears can't have no stinkin' alpha/beta/gamma particles mucking with his music! BTW, before I bought my house, I tested all the granite surfaces with my rather nice scintillator. The real estate agents were rather bemused... but when one bought his own house had me give it the once over... he had read up on the subject.. Oh, and I've never seen a fireplace that didn't tick like a mother... --- A precision machined, finely crafted 100 pound block of granite ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
