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speaker for 37-665x
06-28-2017, 11:59 PM
I am the proud new owner of a 37-665x that is missing its speaker.
The speaker is listed as H26, 36-1238. Is the speaker for a 40-195 a suitable replacement? Thanks, Marko
06-29-2017, 12:24 AM
Probably not the best match, the plate current and impedance of the 41's vs the 6F6's is a bit different. The FC is abt 1/2 of the resistance. The overall current is going to be a little higher on the '665.
When my pals were reading comic books I was down in the basement in my dad's workshop. Perusing his Sam's Photofoacts Vol 1-50 admiring the old set and trying to figure out what all those squiggly meant. Circa 1966 Now I think I've got! Terry
06-30-2017, 04:23 PM
Okay, point well taken.
While studying this, I see that 41's pp want to see 12k and 6F6's pp want to see 10k. Hmmm, Is that a significant difference? The field coil, okay, yes that is major. I have located a couple of speakers with approximately 600 ohm field coils, while the radio was designed for a 460 ohm field coil. How much difference would that make? Would paralleling a suitable resistor with the field coil be an acceptable solution? Please take me to school on this. I am trying to learn. Thanks, Mark
06-30-2017, 09:20 PM
From my vantage point the 41's (6K6's) are going to be abt 16K end to end. 42's are abt 10K. This is from the 1940 RCA tube manual. Plate current is going to be abt 50ma for the 41's and almost 80ma for the 42's. Methinks the opt is going to be a little wimpy for the job.
The FC presents a couple of issues too. It needs to be rated enough current to handle all the circuits in the set, abt 100ma. So even though the resistance is good it has to be able to pass that amount of current w/o overheating. This means that the replacement spkr will need to come from a set that has 7 or 8 tubes w/pp output. When my pals were reading comic books I was down in the basement in my dad's workshop. Perusing his Sam's Photofoacts Vol 1-50 admiring the old set and trying to figure out what all those squiggly meant. Circa 1966 Now I think I've got! Terry
07-09-2017, 12:18 PM
Okay, I found an Atwater Kent speaker with 550 ohm field coil and OP transformer for 2A5 pp.
Both sets have the same tube count. Does this look like a close match? 2A5 and 6F6 are the same except for heaters?
07-09-2017, 12:45 PM
>Does this look like a close match?
Much better than the other one. >2A5 and 6F6 are the same except for heaters? Yes the 47, 2A5, 42, and 6F6 are all abt the same in terms of plate load resistance. The exception is when the tube is wired as a triode, plate and screen grid strapped together. Philco did this on a number of older High Fidelity sets like the 38-116, 116B, 200X, 18, and some others. When configured like this the plate load is much lower around 3K per tube. When my pals were reading comic books I was down in the basement in my dad's workshop. Perusing his Sam's Photofoacts Vol 1-50 admiring the old set and trying to figure out what all those squiggly meant. Circa 1966 Now I think I've got! Terry
07-09-2017, 01:05 PM
Your welcome. Was just sitting around doin' nothin'. I'm a wealth of useless information.
Still a ham?? de N3GTE When my pals were reading comic books I was down in the basement in my dad's workshop. Perusing his Sam's Photofoacts Vol 1-50 admiring the old set and trying to figure out what all those squiggly meant. Circa 1966 Now I think I've got! Terry
07-09-2017, 01:31 PM
No, my ticket expired years ago. It was my intention to keep my novice call forever but after I let it lapse I was not able to contact anyone to retest.
07-09-2017, 01:40 PM
Terry, your information is not useless...its timeless...we'll always need it!
07-09-2017, 02:46 PM
Don't think they issue Novice tickets any more. Of you have a current one it can be renewed but you can't get a new one. Don't know if they still issue 2x3 calls as those used to be relegated to Novices. With the Tech license being the entry level those carry the 1x3 calls.
Anyway if you had a burning desire to have another go at it you could probably get your old call as a vanity call as a Tech and no code any more.. Around here testing was done a lot of time a hamfest or club meetings. Bands are not so hot these days do to the solar cycle. When my pals were reading comic books I was down in the basement in my dad's workshop. Perusing his Sam's Photofoacts Vol 1-50 admiring the old set and trying to figure out what all those squiggly meant. Circa 1966 Now I think I've got! Terry
07-09-2017, 02:58 PM
I didn't have no code tech. From what I remember it was called tech plus or something.
When I first started ham radio we were in a sunspot cycle. Now we are in another one? Then it has been about 22 years.
07-09-2017, 03:07 PM
Yeah just creeping out of the bottom. Another 4-5yrs and things will be hot gain. There are periodic openings but generally thing are pretty flat. I was a VE back when the no code tech came out. Think that was abt '96 or so. A few yrs later all code exams were dropped down to 5wpm. And then code was dropped all together.
When my pals were reading comic books I was down in the basement in my dad's workshop. Perusing his Sam's Photofoacts Vol 1-50 admiring the old set and trying to figure out what all those squiggly meant. Circa 1966 Now I think I've got! Terry
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