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EiMac & Penta Tubes	Reply
by MOBILE17 on March 3, 2003	Mail this to a friend!
I recently aquired three tubes from my Grandfather. I was wondering if any one has any information on this type of product. The first tubes are Penta Lab. PL-254W, 4 prong base, blown glass about 6 inches long. I have two of these. The other is an EiMac 250TH, 4 prong base, blown glass, about 11 inches in length. Any information you may have would be of great help. Thanks, KG6JFN

RE: EiMac & Penta Tubes	Reply
by K0BG on March 4, 2003	Mail this to a friend!
You're going to need a VERY old tube book on these! The 250 was used a lot during the 50s as both drivers and finals. The first one you listed I've not heard of. If you can find a circa 50s Handbook, these types should be listed. Alan, KØBG

RE: EiMac & Penta Tubes	Reply
by WB2WIK on March 4, 2003	Mail this to a friend!
These sure are old, and would be of more value to an "old tube collector" than for any construction project. There are several collectors out there, and many are hams. One who comes to mind is Sherman, W2FLA. On his website http://www.w2fla.com he shows his "big old tube" collection and does state that he'd like to buy more like those. WB2WIK/6

RE: EiMac & Penta Tubes	Reply
by WB5WPA on July 12, 2004	Mail this to a friend!
Wow ... you've got some possibly new (NIB/NOS?) 254W tubes? I've got an old Motorola Base Station circa 1959 (there is a date stamp inside the cabinet) that uses a pair of those in the final amplifier in push-pull configuration - it used to do around 330 Watts output if pushed a little on Six Meters, but the last time I checked it would only do about 200 Watts out with 50 Watts drive! (It used to do 250 Watts out with only 15 watts drive!) Would you be willing to part with them - or trade for a known soft pair (if all you wanted were some 'display' models)? Jim WB5WPA (good on QRZ.com) PS. I used to work for 'ol Sherm (W2FLA) in the 'ham' or "Communications Department" - back when he was a PLM (Product Line Manager) at Heathkit in the late 70's ...

1953 Motorola Amp	Reply
by KB8FLY on February 21, 2007	Mail this to a friend!
Hi Jim, I just came into a 1953 model FSTR520BR(FW)1ASP2. Amazing there's any information out there at all,it's hard to get!! Mine has been 'crystalled for 52.525 FM. Still has the exciter and receiver decks. Some have recommended ditching them. I'm not ready to do that just yet. +I'm doing what I can with the exciter (good, operational!- S reports high and modulation good!) and the receiver (wide FM may be a problem, don't know for sure yet for intended FM simplex op.) is coming along. It may be possible to recrystal IF for narrow band, others say not necessary. I'd like to dialog with you if you would be so kind as to reply. I'm looking for any documentation on receiver peaking, exciter doc's, anything you might be able to share. I haven't been able to notice any balls of mercury in my HV gas diodes. How long do you recommend I let them 'warm up'. I'm getting all kinds of power out of it. Unreal, and yes, I'm being hypercareful. My first Tube Amp, a real BEAST! The 254's look mighty 'perty don't they? Thank you for your time, 73, Rod.

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