Any ideas on this one???

Dagwood · 2nd February 2011, 03:23 AM

Hi all,

I've searched the web for over an hour and cannot find any details on this valve

Print reads,

STC
290
4013
AUG - 60

Any ideas???

Thanks

STC, 1.JPG

STC, 2.JPG

HollowState · 2nd February 2011, 03:31 AM

It isn't a tube. It's a crystal and it looks like it might be bad. the connection looks broken off. Maybe just the picture?

Dagwood · 2nd February 2011, 03:38 AM

Thanks for that any more info ???

Seems tobe intact to me, have attached another pic

Thanks

HollowState · 03:49 AM

Ok, now it looks better. Probably quartz. No telling what the frequency is by those numbers though. By the thickness of it I'd guess it was fairly low. Maybe 100K or so. (?) You'd have to hook it up with something like a one transistor Pierce oscillator and measure the frequency.

Dagwood · 2nd February 2011, 03:59 AM

Thanks Hollowstate

Will put that one away for a rainy day.

Thanks again.

Wavebourn · 2nd February 2011, 04:14 AM

Most probably it is not quartz, it is a salt crystal resonator, that's why it is in sealed envelope. But may be it is a quartz. 290 KHz?

rotaspec · 2nd February 2011, 04:35 AM

And you have to ask yourself how did the guy get his hand in there to write the "699" on the mica?

Gary

tomchr · 2nd February 2011, 06:07 PM

One thing I've come to appreciate about tubes is that you can tell the pinout by looking through the glass at the internal connections...

I'd run an impedance sweep. Ground one side of the XTAL and hook up the other side through a resistor (10 kOhm would be my starting point) to a function generator. Then measure the voltage across the XTAL as you sweep the frequency. You should hit minimum voltage at the series resonance and maximum voltage at the parallel resonance.

~Tom

2nd February 2011, 03:23 AM	#1
Dagwood diyAudio Member Join Date: Feb 2010 Location: North of Auckland	Any ideas on this one??? Hi all, I've searched the web for over an hour and cannot find any details on this valve Print reads, STC 290 4013 AUG - 60 Any ideas??? Thanks STC, 1.JPG STC, 2.JPG __________________ If you keep digging in the garden of failure you will eventually find success

2nd February 2011, 03:31 AM	#2
HollowState diyAudio Member Join Date: Aug 2006 Location: Taxland, New Jersey	It isn't a tube. It's a crystal and it looks like it might be bad. the connection looks broken off. Maybe just the picture? __________________ "The supercomputer is technologically impossible. It would take all of the water that flows over Niagara Falls to cool the heat generated by the number of vacuum tubes required." ~ Professor of Electrical Engineering, New York University

2nd February 2011, 03:44 AM	#4
HollowState diyAudio Member Join Date: Aug 2006 Location: Taxland, New Jersey	Ok, now it looks better. Probably quartz. No telling what the frequency is by those numbers though. By the thickness of it I'd guess it was fairly low. Maybe 100K or so. (?) You'd have to hook it up with something like a one transistor Pierce oscillator and measure the frequency. __________________ "The supercomputer is technologically impossible. It would take all of the water that flows over Niagara Falls to cool the heat generated by the number of vacuum tubes required." ~ Professor of Electrical Engineering, New York University Last edited by HollowState; 2nd February 2011 at 03:49 AM.

2nd February 2011, 03:59 AM	#5
Dagwood diyAudio Member Join Date: Feb 2010 Location: North of Auckland	Thanks Hollowstate Will put that one away for a rainy day. Thanks again. __________________ If you keep digging in the garden of failure you will eventually find success

2nd February 2011, 04:14 AM	#6
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	Most probably it is not quartz, it is a salt crystal resonator, that's why it is in sealed envelope. But may be it is a quartz. 290 KHz? __________________ If I disappear suddenly, that means I finally created a time machine and pushed wrong button that brought me to Stalin's Russia. In any experiment any result is the result. Even if it is negative.


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2nd February 2011, 04:35 AM	#7
rotaspec diyAudio Member Join Date: Nov 2007	And you have to ask yourself how did the guy get his hand in there to write the "699" on the mica? Gary

2nd February 2011, 06:07 PM	#8
tomchr diyAudio Member Join Date: Feb 2009 Location: Greater Seattle Area	One thing I've come to appreciate about tubes is that you can tell the pinout by looking through the glass at the internal connections... I'd run an impedance sweep. Ground one side of the XTAL and hook up the other side through a resistor (10 kOhm would be my starting point) to a function generator. Then measure the voltage across the XTAL as you sweep the frequency. You should hit minimum voltage at the series resonance and maximum voltage at the parallel resonance. ~Tom

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