Globe Champ

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K9ACT:
My new station since the fire is a Globe Champ, generously donated by K9WEK.  Works like a champ but some folks are just never satisfied.

The manual specifies an audio bandwidth of 3.5 kc and I presume there would be some mods out there to broaden it a bit but can't find any searching this site.

I have seen suggestions of replacing the Coupleats with caps but nothing very specific.

Anyone have any experience on this?

Thanks,

Jack

Opcom:
no experience on that unit but if following the articles and stuff that others have done is not satisfactory then you can tune it up into a dummy load and give it a constant amplitude swept frequency audio signal and find the restrictions part by part and stage by stage. Then you will know for certain what to change.

3.5KC is pretty good. Maybe a so called '75us pre-emphasis' filter would get good results with it as-is. -if what you want is extra intelligibility in bad receiving conditions.

WD5JKO:

Jack,

   I once brought back from the dead a Champ. The Ax9909 finals were gassy, and the 809 modulators were flat. In the pre internet days, finding tubes like that was a lot harder, so I went to the junk box. Had a nice pair of Eimac 4-65's, and some 808's. The conversion was a long story, but worked out quite well. I recall the audio driver, a 6AQ5 was the bottleneck in modulation capability. Switching to an Octal socket gives more choices (like an el-34). Perhaps para-feed the driver transformer, and add some negative feedback.

Jim
Wd5JKO

Jim, W5JO:
See if this works for you

nq5t:
Getting rid of the couplets is a must.

My affinity for the Globe Champion goes back to my mis-spent teenage years when I had a 350 and used it throughout high school.  Bought a 300 in the mid-90's, restored it,  and ran it off and on until a couple of years ago, when I parted with it prior to a cross country move.

If I can ever find my audio mods (lab books are somewhere, still in some box .. somewhere) I'll send them to you.  I did install some negative feedback.  All in all, it played well, and according to reports sounded good.  I usually drove it from an audio chain through the phone patch input. 

Don't know if you have a 300, 300A, or 350.  In any case, the 300 did NOT have cooling fans on the AX9909s.  That proved to be deadly to the tube seals at the base, which shortened their lives considerably.  The 300A did have cooling, and that is likely the only substantive change from the 300.  So if you have a 300, you need to add cooling.  I installed two DC fans in the final shield, blowing at the tube bases, and never had a tube failure.  When I finally sold it, it still had the original tubes (plus 2-3 sets of new AX9909/6083 tubes I'd acquired over the years just in case). 

It's a nice radio …

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