President madison lack of highs in tx audio

[Abikerlad]

Hi I have a madison to mod uk EPROM, but have noticed its got very bassy audio hardly any highs, giving this radio the impression it sounds quiet on air.
Does anyone know of any so called hi Fi mods for this ? I feel like we have capacitor to ground in place on the audio path so where rolling of things too much.
Madison with silver eagle mic.
Not a great match.
Thanks all.

 

[Robb]

858 or 8719 PLL Madison?

 

[Abikerlad]

I will look and find out .

 

[RatsoW8]

It's your voice.

 

[Mudfoot]

Let's hear a recording of your voice.

I have a very deep voice. My radio pals say I sound good on any mic I use. Every time I talk to a baby or a toddler they usually freeze in their tracks for a few seconds then start screaming.

I think I'm one octave up from Barry White.

 

[Lil'Yeshua]

Here's your fix
D-104 Microphone amplifier / Equalizer for Ham Radio - YouTube

 

[bob85]

the madison is usually bass heavy of fm mode only, years ago i used to swap a couple of caps on the fm board to reduce bass and add a bit of trebble.

 

[Lil'Yeshua]

The YouTube link I posted shows a home built amp section for a D104 mic that you can set it either bassy or trebly and has an impedance matcher built into it as well. If I had a D104,that's the mod I would do. Also the guy shows how he uses a O- scope and something else to set it.

 

[Robb]

Abikerlad:
The following is the 'Goldfinger' Audio mod found on the 'DeepSouthRadioForum'. You might want to compare the schematic of the Cobra 148/2000/Grant XL to your Madison. Provided that it is a 8719 PLL chip, it should be similar or the same as a Madison with the same PLL. Look at the Balanced Modulator and receiver parts of those schematics.

I used this mod on an old Uniden/President Grant mobile radio and it worked very well. The schematic was different from the Cobra 148/2000/Grant XL; but all of the same parts were there and just had different numbers. Don't do this if you aren't handy with a soldering iron or can fix the radio if you have to. Take accurate notes so that you have a trail of breadcrumbs to follow if you get lost or screw up. Or just try the cap changes for the higher tones; that means only a few cap changes. But do it all at your own risk!

Did you try using a 2-way external speaker from an old computer sound system - first? They usually have the correct plug you need on them as well.
That works wonders on many radios too . . .

Cobra 148/2000/Grant XL

TX

C46 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
C101 Change to 1.5uf tantalum 16 to 50 volt
C102 Change to a 910pf ceramic disc
C104 Change to 2.2uf tantalum 16 to 50 volt
C108 Change to 1uf to 2.2 uf tantalum 16 to 50 volt
I found that if you have a very deep voice start with 1uf on C108
and work up if need be.
If you need more highs on tx Change C 105 to .001 to .0001uf mylar/polyester film The smaller you go the more highs you get.

RX

C71 Change to 1uf mylar/polyester film or non-polarized electrolytic
C75 Change to .001 to .0001uf this will give you more highs on rx
optional
C76 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
C182 Change to .001 to .0001 for more highs on rx and tx
optional
C183 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
C187 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
With C75 and C182 you can start with no Change to them, then if you feel you want more highs then change them out

 

[Abikerlad]

Abikerlad:
The following is the 'Goldfinger' Audio mod found on the 'DeepSouthRadioForum'. You might want to compare the schematic of the Cobra 148/2000/Grant XL to your Madison. Provided that it is a 8719 PLL chip, it should be similar or the same as a Madison with the same PLL. Look at the Balanced Modulator and receiver parts of those schematics.

I used this mod on an old Uniden/President Grant mobile radio and it worked very well. The schematic was different from the Cobra 148/2000/Grant XL; but all of the same parts were there and just had different numbers. Don't do this if you aren't handy with a soldering iron or can fix the radio if you have to. Take accurate notes so that you have a trail of breadcrumbs to follow if you get lost or screw up. Or just try the cap changes for the higher tones; that means only a few cap changes. But do it all at your own risk!

Did you try using a 2-way external speaker from an old computer sound system - first? They usually have the correct plug you need on them as well.
That works wonders on many radios too . . .

Cobra 148/2000/Grant XL

TX

C46 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
C101 Change to 1.5uf tantalum 16 to 50 volt
C102 Change to a 910pf ceramic disc
C104 Change to 2.2uf tantalum 16 to 50 volt
C108 Change to 1uf to 2.2 uf tantalum 16 to 50 volt
I found that if you have a very deep voice start with 1uf on C108
and work up if need be.
If you need more highs on tx Change C 105 to .001 to .0001uf mylar/polyester film The smaller you go the more highs you get.

RX

C71 Change to 1uf mylar/polyester film or non-polarized electrolytic
C75 Change to .001 to .0001uf this will give you more highs on rx
optional
C76 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
C182 Change to .001 to .0001 for more highs on rx and tx
optional
C183 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
C187 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
With C75 and C182 you can start with no Change to them, then if you feel you want more highs then change them out

Thanks this is what I am looking for, I know the owner so I know his voice from his other radios, just this was sounding awful distorted when trying to get any volume due to muddy mid bass content.