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Kellogg Red Bar

Started by Ed Morris, June 11, 2017, 11:42:03 AM

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Ed Morris

Interesting.  Apparently the 6 ohm difference must not be a significant factor.  Tomorrow I will take a look at the capacitors.
Ed

unbeldi

#16
Quote from: Ed Morris on June 11, 2017, 06:45:30 PM
Interesting.  Apparently the 6 ohm difference must not be a significant factor.  Tomorrow I will take a look at the capacitors.

I doubt that the difference effects volume much, because a noticeable enhancement in volume requires a doubling of acoustic power output, because of the logarithmic response of human hearing.  We are only considering here ~13% resistance difference.

But in any case, I find the discrepancy in resistance markings notable. Perhaps the specs were changed at a certain time.  We need to collect and record more observations.

Ed Morris

#17
The capacitors tested out of spec, so I replaced them.  You can see how I did that in this thread I posted in the Troubleshooting and Repair subforum:

http://www.classicrotaryphones.com/forum/index.php?topic=18321.0

After replacing the caps, the audio quality improved considerably.  The sound was nice and crisp, no fuzziness, but the volume was still somewhat lower compared to a couple other phones.  I sent a 1000Hz tone at -16.0 dB to the Kellogg, an AE40, and a WE2500.  The Kellogg was still somewhat lower than the AE40, and the WE2500 way better than both.

In a real world test, my wife on her cellphone, and me with the Kellogg, I could hear her plainly and she noted an improvement on her end over the call I made before installing new capacitors.

So, I am back to wondering if maybe the receiver element might be flaky, even though the resistance looks OK.   
Ed

KaiserFrazer67

#18
Hi Ed,

It's my understanding that the quality of the Kellogg Redbar receivers and transmitters was never up there with their WE and AE counterparts.

I experienced trouble with my Redbar's transmitter a while ago, as did another member.  For reference, here is the post pertaining to that: http://www.classicrotaryphones.com/forum/index.php?topic=17028.0  I come in about mid-way through the post.

Granted, your problems seem to be with the receiver unit, but I thought sharing the above post with you might still be helpful in some ways.
-Tom from Oakfield, Wisconsin --  My CO CLLI & switch: OKFDWIXADS0--GTD-5 EAX

"Problems are merely opportunities in workclothes." -Henry J. Kaiser

Ed Morris

Tom, thanks for that link.  That is quite helpful.  It may well be that my handset is actually working as well as expected given its age.
Ed

mentalstampede

For what it's worth, in my limited expereince Redbars have noticeably quieter receivers and subjectively poorer transmitters than any of their contemporaries.
My name is Kenn, and I like telephones.

"Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something." --Robert Heinlein

Ed Morris

#21
The audio quality issues with my Kellogg 1000 are definitely handset related.  As an experiment, I attached a WE G1 handset to the Kellogg in place of the Kellogg 47-C handset, and what a world of difference!  Both transmission and reception vastly improved, on par with a good WE 302, I think.

So if keeping the phone 100% internally original isn't an issue, then modifying the Kellogg handset to use WE elements will make a substantial improvement on both ends.  If I can find an orphaned Kellogg 1000 handset, I might try retro-fitting WE elements.  But I would keep the handset that came with the phone original.
Ed

HarrySmith

I would try putting WE elements in the original Kellogg handset. Hook up temporarily first as a test. If they sound is greatly improved it should not be too difficult to find a way to mount them.
Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"

LarryInMichigan

I bought a very dirty and neglected metal Kellogg 1000 yesterday at the flea market.  It has an 89-A transmitter marked 42Ω.  The interesting thing is that the connector on the back with the wide tab goes to the wrong side of the handset transmitter cup when the transmitter is inserted so it misses the contact in the handset.  The pictures in this thread look like the same problem would occur.  What am I missing?

Larry


RB

Hi Larry.
If that's a Kellogg handset, it is configured for a different transmitter.
Yours does not look like mine. at all...
I suspect your handset would need a mod, or the correct transmitter for your handset configuration.
Look at the mounts inside the cup.
can you reposition them?

LarryInMichigan

Quote from: RB on June 17, 2019, 11:32:00 AM
Hi Larry.
If that's a Kellogg handset, it is configured for a different transmitter.
Yours does not look like mine. at all...
I suspect your handset would need a mod, or the correct transmitter for your handset configuration.
Look at the mounts inside the cup.
can you reposition them?

As far as I can see, the transmitter cup on this handset is configured the same way as all my other Kellogg handsets and the one pictured in this thread.  The wider groove is on the end near where the cord exits.  Looking at the handset with that end at the bottom, the connector in the handset is on the left, but when this transmitter is inserted, its connector will be on the right side.

Larry

rdelius

That is a Rec capsule, not a transmitter capsule. It will not fit or work  in the transmitter cavity

LarryInMichigan

Apparently, I was missing something.  The capsules had been swapped.  No wonder the phone didn't work.

Thank You

Larry

Jack Ryan

I attempted to say that that was a receiver element but I wasn't quick enough.

There are several Masterphone handsets and the Masterphone 1000 that is the subject of this thread has the wrong one. The Masterphones 700, 900 and 1000 all seem to have had their own handset and the last version, the Masterphone 1000 handset (47-C I think) is a slightly different shape - the handle has pointy ears a bit like a WE F handset.

Regards
Jack


19and41

Nice phone, good work!
"Any sufficiently advanced technology is indistinguishable from magic."
— Arthur C. Clarke