[AMRadio] FS: restored Gonset G-76


Brett gazdzinski brett.gazdzinski at verizonbusiness.com
Thu Feb 9 22:21:54 EST 2006


I guess I have different expectations then most here.
I would say its not possible to have the G76 sound good 
on receive or transmit, what with the design and parts
they used.
You have a 470pf (yes, that pico)coupling cap between the 1st and 
second stage microphone amplifier, and they inject the 
receive audio in there also, and that uses another 470pf (yes pico)
coupling cap, with a .001 to ground.

How can anyone get nice lows with a 470pf coupling cap, or highs
with a .001 to ground. I would think a good telephone would have
a better frequency response.

We wont even get into the modulator grid driver/audio output 
transformer, which makes the dx100 driver transformer look massive.
As an audio output transformer, it looks like it would be good for
about 1/4 watt output.

The mike input amp has a 470K resistor to ground, no way you
are getting any lows at all there....needs to be like 5 meg 
for lows with a D104.

I did some playing around with it tonight, and found two problems,
a bad 12ax7 mike amp, and also found the modulation gets better with 
much more grid drive.

I have some changes to do in the mike amp stage, but it sounds
back to its old self as long as the output power is below 60 watts.

The audio waveform looks ok up to 100% mod at 60 watts, any more
and it starts looking funky, I did not look into the driver tube
and its circuit yet, or the clamp tube screen circuit in the RF output.

Brett
N2DTS

 

> 
> Hi Guys,
> 
> I have been following this thread and I also agree with Charlie.
> My G76 gets great audio reports as it is. I am using a D-104 and have 
> very good audio reports. I am currently listening to a group on the 
> East Coast using a a 5" Motorola Micor speaker and it sounds great.  
> Power out is around 70 - 75 watts into a sloper. I use it to 
> check into 
> the Midwest Classic Radio net on Saturday morning on 3885, the DX-60 
> net on Sunday morning on 3880, on Tuesday the Southeast AM 
> Radio net on 
> 3885, and the First Wednesday CCA AM net on 3880. Believe me if it 
> sounded BAD I would get chastized on the CCA net since I am the 
> coordinator of the event. (defense if needed) My 32V-3 is under going 
> major surgery and some day when I am retired it will get finished. We 
> encourage the use of anything on the CCA net that runs AM and I am 
> living proof that we abide by that.
> 
> Anyone out there using a G-76 mobile?  I have the mobile supply and 
> would like to give it a try.
> 
> 73 Larry WA9VRH
> 
> 
> 
> On Thursday, February 9, 2006, at 06:44  PM, k0ng at inebraska.com wrote:
> 
> >
> > Jim:  I agree with all of your comments as my G76 works well as is.
> >       Not that anything cant be improved but....if it aint broke ..
> >       Maybe in this case, there is a problem ??
> >
> > Regards to all,  Charlie,   K0NG .
> >
> >
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