New old toy - tube phono preamp

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Behind The Curtain
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Just got this little Calrad new in the box tube preamp. Now I can reverse engineer it to make my own stereo version. Not bad for $25.
 
I have some military potted transformers that would be perfect for a stereo preamp. Lets do some horse trading! You engineer and I will scout out some parts.
 
cool maybe we can work on it at the next bottlehead meet at my house.
 
By the way that metal tube in definatly a replacement as they had not been made for years when Calrad started into business. Also the original tube would have been made in Japan just like the preamp.
 
looks a lot like this GE version
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3020640868&category=14974

i-1.JPG
 
I would have guessed 6SC7 - it's the only dual triode that came in a metal version (Ok, there's the 6N7 too...) - and as far as being out of production - that didn't bother them when there were millions of NEW war surpus tubes around. And it saved the cost of a shield too...
 
Tom,

OK so the 6SC7 gives you a spare triode to use as a cathode follower for the output run, but presumably you are gonna use this next to your control amplifier so that isn't really necessary. A pentode is better for getting the gain needed for a mag phono input.

Rob
 
I have seen these before and do not recall ever seeing a metal tube. It could be a 6J5 which is a single triode. It came in metal too.
 
Originally posted by Rob
What tube is that Wards, a 6SJ7?
Rob

Close but no C-Gar, It is a 6SC7, so Tom is the winner of a bag of pure ionized aligned air.
 
Metal tubes were being made, at least in some tube types, at least until the mid 70's, possibly to the early 80's by G.E. The later models have a warning on the tube that Pin 1 is connected to the metal shell (in case pin 1 in the equipment is used as an HV tie point.) Metal tubes are still on the current production list in the 1974 GE tube manual.
 
Here is the Lafayette mono version, purchased in their
Scarsdale NY store in 1970 for $5.95. Also shown is the GE unit and another removed from a console set that got its power from the radio/phono chassis to which it was connected. GE also sold a version that got its power from external equipment.
 
I have never seen one but I do own some Calrad gear and it is pretty good stuff. This is not listed in Sam's so it might have been sold in Music stores and so considered pro gear.
 
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