I am about to reveal one of the great secrets of really cheap test methods. Just use an FM tuner set to the frequency or even a harmonic of your clock! If you want to get fancy use an audio spectrum analyzer on the output.
I have tried that with a fancy modulation analyzer. Either its not sensitive enough or my crystal oscillators are much lower noise than the noise floor of the analyzer (Boonton 82AD hot-rodded with low noise opamps). I think the limit is the PLL oscillator in any of these types of tricks. We are looking at levels as low as -170 dBc. Also doesn't work with generic spectrum analyzers since this is all about close in phase noise. It may work for finding a bad crystal oscillator. . .
Thanks, for the info. I had better luck on a high harmonic and the results even to the ear were quite informative. Of course it was an old fashioned non PLL tuner!
I'll try the harmonic trick. it may magnify the modulation so there is more to see. The analyzer has a 1 MHz IF so I need a LO that is 1 MHz from the crystal. This should be interesting. I'll try a low PN synthesizer for the local oscillator and see what I get. if I didn't have this stuff the double balanced mixer and good reference oscillator would still be the cheap solution. Good tuners still get a good price.
For an FM tuner the target frequencies to look at are:
44.1 chain- 90.3168 MHz
48 chain- 98.304 MHz
The analog tuned tuner can be dialed in directly but a digital tuner will be complaining since the 44.1 chain ends up 16 KHz off of the center. Most fm tuners have an afc (similar to a PLL) which will limit the low frequency sensitivity. It will be interesting to see what comes out. A new use for an old technology.
For an FM tuner the target frequencies to look at are:
44.1 chain- 90.3168 MHz
48 chain- 98.304 MHz
The analog tuned tuner can be dialed in directly but a digital tuner will be complaining since the 44.1 chain ends up 16 KHz off of the center. Most fm tuners have an afc (similar to a PLL) which will limit the low frequency sensitivity. It will be interesting to see what comes out. A new use for an old technology.
Source resistance should be taken into consideration since AD797 is optimize for low noise performance if the source resistance is kept less than 1 kΩ else other amplifiers should be used.
This may be of interest to all :
TI to acquire National Semiconductor ? What this means for customers
TI to acquire National Semiconductor ? What this means for customers
The output of the DBM is around 50 Ohms. It should be low pass filtered so the RF is suppressed, 100 KHz perhaps. The AD797 it almost ideal and easy to use.
A reasonable question. The standard is input on the left and output on the right. This follows that. Common on the bottom Power on the top. (Those with power always seem to end up on top!)
Thing to keep in mind is that Eurotten retail prices are the US figures (minimum), but in Euros instead of Dollars.
$20K turns €20K (if you're lucky), half priced for a mint late production item incl. phono stage isn't that bad. (the tacky color is, yikes
)I'm still trying to track down a semi-used KX-R in Eugh dress code at a jolly buck figure.
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The CTC preamp that is being sold in Europe does NOT have a phono stage. Only a phono input designation that is another line level input. Joachim can you confirm this? It appears to be the one from our guy in Hamburg. He is asking what he paid for it, from me, several years ago.
Collectors Items ?....
Hi John, what are the approximate production quantities of your different products, for interest's sake ?.
Regards, Eric.
That sounds like a recommendation in itself....how many other electronic items in modern life retain their original price ?.
Hi John, what are the approximate production quantities of your different products, for interest's sake ?.
Regards, Eric.
That's a genious circuit, hiding the base behind a collector/emitter to keep unwanted spurious signals to enter! No admittance of audio or noice makes the sleep better.
But why are there two serial coupled diodes? As I remember, it takes four to make a bridge..
But why are there two serial coupled diodes? As I remember, it takes four to make a bridge..
Whatayaknow, number 40 is a Phoney.
(makes me wonder how much you would charge for a phono silicon transplant ?)
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Whatayaknow, number 40 is a Phoney.
(makes me wonder how much you would charge for a phono silicon transplant ?)
Another 5K +?
JC might know - current interest in used Blowtorch
Recently I saw one Vendetta Research SCP2 going for 2.5K in Audiogon
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