Past a minimum point, they don't make any difference. You sure won't hear anything unless something is wrong. Measurements will clearly show this long before you can hear it.
It's really hard to improve on a crystal oscillator in this application. You can make better ones, and the test equipment in my lab uses better oscillators than mostly discussed - so I don't comment much.
So, unless the actual oscillator / DSP circuit is messed up, anything beyond a simple crystal oscillator is a bit of a waste of money. If you think you can hear a difference - great! It's your mind playing tricks on you.
So you know, I learned how to service CD players when they first came out and have worked on them continuously since. My bench frequency reference is a real GPS timing receiver locked to the GPS system and distributes that reference to the instruments that use it through a real distribution amplifier deigned for that purpose by Hewlett Packard. Most of my equipment is manufactured by HP / Agilent / Keysight. I also have an HP 5372A which is a "Frequency and Time Interval Analyzer". It's a $30 K piece of test equipment that analyses oscillators and the resultant frequency outputs from CD DSP chips.
Having said all that, I have no problem with people striving for perfection within reasonable limits. Another point. Noise and hash down far enough doesn't really matter to timing, which is what we are talking about here. Everything has reasonable limits, so don't get blinded by things that don't matter. Jitter is different than low level hash and noise. The real trick is to know what is important so you don't waste effort on things that do not matter.
-Chris
It's really hard to improve on a crystal oscillator in this application. You can make better ones, and the test equipment in my lab uses better oscillators than mostly discussed - so I don't comment much.
So, unless the actual oscillator / DSP circuit is messed up, anything beyond a simple crystal oscillator is a bit of a waste of money. If you think you can hear a difference - great! It's your mind playing tricks on you.
So you know, I learned how to service CD players when they first came out and have worked on them continuously since. My bench frequency reference is a real GPS timing receiver locked to the GPS system and distributes that reference to the instruments that use it through a real distribution amplifier deigned for that purpose by Hewlett Packard. Most of my equipment is manufactured by HP / Agilent / Keysight. I also have an HP 5372A which is a "Frequency and Time Interval Analyzer". It's a $30 K piece of test equipment that analyses oscillators and the resultant frequency outputs from CD DSP chips.
Having said all that, I have no problem with people striving for perfection within reasonable limits. Another point. Noise and hash down far enough doesn't really matter to timing, which is what we are talking about here. Everything has reasonable limits, so don't get blinded by things that don't matter. Jitter is different than low level hash and noise. The real trick is to know what is important so you don't waste effort on things that do not matter.
-Chris
Funny, I'm using the same kind of setup, only that I am using passive distribution (1:8 50ohm resistive power divider) since the 10MHz output is very hot (some 10Vpp). My GPSDO is a Symmetricom TymServe 2100 (a Stratum 1 time server and reference), fitted with a new Trimble receiver to work around a known issue in the original equipment firmware.
No issues with you Chris, I recall we had some interesting discussions about speakers design (something I am not even at a beginner level, but certainly interested in, since I strongly believe that's one place where the audio experience could really be improved).
When I was looking for a GPS antenna, I got a deal for a box of brand new 10 pcs. at $5 a pop. I still have 9 of them, so 6-7 pcs are up for grabs, for free or, worst case, shipping cost. To me, they are only collecting dust and taking shelf space.
Hi Doede,
Yes it is SC-cut.
Nice to read the test on your blog and looking forward to the next episode with the stuff from Edward (who is a nice guy by the way that sent me a choke years ago that is still doing it’s magic in the PS of my dddac)
And I will try the tip of diyiggy when you sent me the crystek back
Wise words Chris. My ignore list is only one, but makes reading of the forum much more pleasurable.
Hi syn08,
Yes, we had a good conversation as I recall. Feel free to PM me, email or call.
Did you get timing antennas? If so, I'll pay you for a spare. How much gain did they have if you recall. Don't go searching.
Still building up my lab. Do you do HF work? I just got a Gigatronics 6100 generator. It was supposed to go way lower in frequency, but doesn't. Therefore of no use to me. It goes from 2 GHz to 6 GHz and seems to be in good condition. Display is bright and clear. Ideally I would like something like an HP 8656B that goes higher in frequency, or a good stereo FM generator. The only thing I can do is cover one GPS band. I was hoping to cover my normal work and also the GPS bands.
-Chris
Yes, we had a good conversation as I recall. Feel free to PM me, email or call.
Did you get timing antennas? If so, I'll pay you for a spare. How much gain did they have if you recall. Don't go searching.
Still building up my lab. Do you do HF work? I just got a Gigatronics 6100 generator. It was supposed to go way lower in frequency, but doesn't. Therefore of no use to me. It goes from 2 GHz to 6 GHz and seems to be in good condition. Display is bright and clear. Ideally I would like something like an HP 8656B that goes higher in frequency, or a good stereo FM generator. The only thing I can do is cover one GPS band. I was hoping to cover my normal work and also the GPS bands.
-Chris
Chris, I have everything one could only hope, VNA, Spectrum analyzer, frequency counters, calibration kits, scopes etc... up to 40GHz. High frequency VNAs are Wiltron (I have two 360B units, one up to 20GHz, one up to 40GHz, both with digitally synthesized generators), Scalar network analyzer is also Wiltron 56147A with a whole set of detectors and bridges, Spectrum analyzer is Agilent 8563A (up to 26GHz, fitted with a color LCD display), frequency counter is Agilent 5352B (40GHz), scope is a Tek 11801C with sampling heads up to 40GHz, lower frequencies VNAs are 8702B (with 6GHz test set), Advantest R3131 Spectrum analyzer (3GHz), Racal Dana frequency counter, etc...
With the board houses in China doing impedance controlled PCBs for almost free, I find lately the black magic of microwave design much more entertaining compared with linear audio stuff.
Sorry, I have no idea if they are timing antennas, they are of the dome type, about 5 inch in diameter, for outdoor use, and as far as I recall they are of L-Com brand.
With the board houses in China doing impedance controlled PCBs for almost free, I find lately the black magic of microwave design much more entertaining compared with linear audio stuff.
Sorry, I have no idea if they are timing antennas, they are of the dome type, about 5 inch in diameter, for outdoor use, and as far as I recall they are of L-Com brand.
Last edited:
Hi Sligolad,
Upgrading CD players is what I do for a living - partially. I am very careful about how I spend people's money, and I both measure and listen to the result of my work. I'm listening to an upgraded Denon DCD-2560 as I type, I have better units upstairs.
I know exactly what I am not missing - having tried most "upgrades" before. I have fed very clean instrument grade clock signals into CD player before, more than once. I've done things most of you will never be able to do. I have also had other people listen to the changes without telling them what I did. Their observations form part of my opinion, so I am very careful about what I say. These people know me well enough to listen carefully, and some times I throw stock units in for tests. They now report exactly what they can detect, and we compare machines between modified and unmodified.
We happen to be talking about one of my interests and one thing I do for a living. I am on very solid ground here. In fact, I just bought another expensive CD player for myself today. I will modify it properly, and sell another off. I do put my money where my mouth is - every day. Do you? Do you know, or just think you know? Can you actually prove something beyond just listening? Structured listening tests at least?
Speaking from experience, it is too easy to believe doing something is an improvement. When that improvement cost any reasonable sum of money, people will hear a positive difference even when there is none. Listening tests with others, and instrumentation keeps me honest.
-Chris
Upgrading CD players is what I do for a living - partially. I am very careful about how I spend people's money, and I both measure and listen to the result of my work. I'm listening to an upgraded Denon DCD-2560 as I type, I have better units upstairs.
I know exactly what I am not missing - having tried most "upgrades" before. I have fed very clean instrument grade clock signals into CD player before, more than once. I've done things most of you will never be able to do. I have also had other people listen to the changes without telling them what I did. Their observations form part of my opinion, so I am very careful about what I say. These people know me well enough to listen carefully, and some times I throw stock units in for tests. They now report exactly what they can detect, and we compare machines between modified and unmodified.
We happen to be talking about one of my interests and one thing I do for a living. I am on very solid ground here. In fact, I just bought another expensive CD player for myself today. I will modify it properly, and sell another off. I do put my money where my mouth is - every day. Do you? Do you know, or just think you know? Can you actually prove something beyond just listening? Structured listening tests at least?
Speaking from experience, it is too easy to believe doing something is an improvement. When that improvement cost any reasonable sum of money, people will hear a positive difference even when there is none. Listening tests with others, and instrumentation keeps me honest.
-Chris
Hi syn08,
I have a 360 here I won't use. Want a parts unit? I never did have any probes.
I'll take an antenna then. It is probably a timing antenna - being used for outdoor mounting. Positioning antennas or designed mostly to be mobile.
I'm scraping at the low end of noise floors and other margins. So it is interesting for me. That and repairing the stuff and seeing how far I can improve the odd piece. As you can guess, I like to see how much I can get out of a tuner.
Edit:
Just got a Tek 7104 mainframe, 1 GHz. Needs power supply work, but it does work. I also got a 7854 mainframe I would like to fix. The timing plug-in card connectors are both destroyed and I want to fix that one.
_Chris
I have a 360 here I won't use. Want a parts unit? I never did have any probes.
I'll take an antenna then. It is probably a timing antenna - being used for outdoor mounting. Positioning antennas or designed mostly to be mobile.
I'm scraping at the low end of noise floors and other margins. So it is interesting for me. That and repairing the stuff and seeing how far I can improve the odd piece. As you can guess, I like to see how much I can get out of a tuner.
Edit:
Just got a Tek 7104 mainframe, 1 GHz. Needs power supply work, but it does work. I also got a 7854 mainframe I would like to fix. The timing plug-in card connectors are both destroyed and I want to fix that one.
_Chris
I'm interested in the 360B only if you have the original software floppy disk, and the floppy has the Time Domain Option marked on it. This is a software option which is difficult to crack (is on my very log list of TODO things). One of my 360Bs came without the original floppy (to be more precise, I had to pull the floppy from the unit using a pair of pliers) and the transplanted software floppy lacks the time domain functionality (even if the required DSP hardware is installed).
Sorry, I checked and the antennas are not L-Com, but of the MobileMark brand, SMW-308-3HA3HA2HC-WHT-180 see the attached datasheet. They are sealed in the original plastic bags, with some documentation included. If still interested, you have 2 free pcs. set aside in case I find somebody else interested.
Sorry, I checked and the antennas are not L-Com, but of the MobileMark brand, SMW-308-3HA3HA2HC-WHT-180 see the attached datasheet. They are sealed in the original plastic bags, with some documentation included. If still interested, you have 2 free pcs. set aside in case I find somebody else interested.
Attachments
Hi TNT,
Just an aside.
Hi syn08,
Those are certainly position type antennas, no use to me - but thanks for the offer. I don't know what my 360 is, but it is yours for the taking if you want it. I am simply never going to use it and it may well have parts you may need in the future. Giving it to you frees up some needed shelf space. I can put the Gigatronics there instead.
-Chris
Just an aside.
Hi syn08,
Those are certainly position type antennas, no use to me - but thanks for the offer. I don't know what my 360 is, but it is yours for the taking if you want it. I am simply never going to use it and it may well have parts you may need in the future. Giving it to you frees up some needed shelf space. I can put the Gigatronics there instead.
-Chris
- Status
- Not open for further replies.