president madison vs uniden madison

[Needle Bender]

Based on my experiences with both boards, and having both the President (D858 AM/SSB board) and the Uniden Washington (MB8719 single AM conversion board) along with the Cobra 2000 GTL (MB8719 dual AM conversion board), I prefer the D858 chassis for sensitivity, as both my President Washington and Teaberry Stalker II can RX a signal down to .32uV (.32 microvolts). Both the MB8719 boards drop RX at about 3uV (3 microvolts).

However, provided that you do not do the NB/ANL mod for the D858 chassis, the MB8719 boards do have better NB/ANL filtering.

For me, at least where I live adjacent channel rejection on the D858's and the MB8719's are very close, not enough of a difference for me to choose one over the other. I don't have any issues with my D858 boards being muffled in any mode.

It's really just a matter of preference. You go with what you like.


~Cheers~

maybe my 858 noise blankers needed the mod if it stops images from happening from strong signal mixing. whats the mod?

and i found the specs on a 148gtl that show .25microvolts sensitivity for ssb. i know its tremendously sensitive, i can hear things on it that my icom and yaesu dont. if yours tests down to only 3 microvolts ssb then you have a dead if stage or need an alignment

 

[ExitThirteen]

Change R43, it'll be a 680-720k resistor to a 1 meg ohm. That helps the ANL/NB filter a little better without really dropping RX sensitivity.

Best I've ever seen a MB8719 board do with a full RX alignment is about .76 uV (.76 microvolts). Most MB8719's I've done alignments on start dropping RX at about 2-3 uV. The lowest that my signal generator goes to is .32 uV. Keep in mind that the 2SC1730 that is used in the 1st stage on the D858 boards is a little bit better device than the 2SC1674's that are used in the MB8719 boards.

Again, it's mainly just personal preference. And I'm saying all this based on my personal experiences and testing equipment. There will always be variables. Carry on!


~Cheers~

 

[zebbman]

well i purchased the radio...just gotta go pick it up...ill post when i can run them side by side. thanks for the input on this subject

 

[zebbman]

well after a couple days of comparing i must say the 858 is better on both am and ssb. now im not talking major difference but it is enough to be noticed. the 858 is quieter and has a more natural tone. now it can be that the 858 is bone stock and the 8719 is modified. i know that can affect performance. going in for a complete tune today. this is a pretty early model so it will probably get completely re capped and aligned and be put in place of the 8719. been sitting in its original box for 20+ years..only thing not working are the meters but ill see if i cant bring them back. should be good for another 25 years..thanks for the input and if anyone has a madison they dont want ill buy today...as long as its in good condition

 

[Retro CB Guy]

Based on my experiences with both boards, and having both the President (D858 AM/SSB board) and the Uniden Washington (MB8719 single AM conversion board) along with the Cobra 2000 GTL (MB8719 dual AM conversion board), I prefer the D858 chassis for sensitivity, as both my President Washington and Teaberry Stalker II can RX a signal down to .32uV (.32 microvolts). Both the MB8719 boards drop RX at about 3uV (3 microvolts).

However, provided that you do not do the NB/ANL mod for the D858 chassis, the MB8719 boards do have better NB/ANL filtering.

For me, at least where I live adjacent channel rejection on the D858's and the MB8719's are very close, not enough of a difference for me to choose one over the other. I don't have any issues with my D858 boards being muffled in any mode.

It's really just a matter of preference. You go with what you like.


~Cheers~

Interesting cos I'm considering getting a Madison and got some same questions...

 

[ExitThirteen]

Update:

With the Schottky diode mod, and a 2SC1730L transistor, the MB8719 board does the exact same as the D858 board in RX sensitivity, at almost the exact same noise floor.


~Cheers~

 

[Klondike Mike]

Change R43, it'll be a 680-720k resistor to a 1 meg ohm. That helps the ANL/NB filter a little better without really dropping RX sensitivity.

What are your thoughts/findings on this mod; uPD858 chassis: Sensitivity enhancing by change the output impedance on L4 ?

 

[Stellasarat]

can anyone tell me if the receive is any different on the 858 pll president than it is on the 8719. im only concerned with the receive portion. i have a nice opportunity to pick up the old president but if it receives like the washington i dont want it...thanks

I've never heard or talked on the Madison with the 858 but my uniden 8719 i

can anyone tell me if the receive is any different on the 858 pll president thn the 8719. im only concerned with the receive portion. i have a nice opportunity to pick up the old president but if it receives like the washington i dont want it...thanks

I've never heard or talked on the Madison with the 858 in it, but I can say that my uniden Madison 8719 hears very nicely for a stock CB radid(AM/SSB). When I say stock the audio and receive sections have never been touched. I'm sure you'd be satisfied with either as I've read Meany articles praising both. My back up uniden Washington isn't as quiet as my Madison.

 

[Stellasarat]

What are your thoughts/findings on this mod; uPD858 chassis: Sensitivity enhancing by change the output impedance on L4 ?

Thanks for sharing, KM. Great video and an excellent mod.

 

[Crawdad7]

In all of this thread can someone enlighten me how I can tell the difference between a Madison 8719 & a Madison 858. Please advise. Thank You

 

[Klondike Mike]

I describe the visual differences in my electrolytic capacitor kit listing. See link below;

https://klondikemikescapkits.com/pr...stalker-xx-pc411ad-electrolytic-capacitor-kit

 

[Crawdad7]

I describe the visual differences in my electrolytic capacitor kit listing. See link below;

https://klondikemikescapkits.com/pr...stalker-xx-pc411ad-electrolytic-capacitor-kit

Thank You much! Now if I could just find a First/Second Generation President Madison w///D858 to purchase!

 

[Crawdad7]

I describe the visual differences in my electrolytic capacitor kit listing. See link below;

https://klondikemikescapkits.com/pr...stalker-xx-pc411ad-electrolytic-capacitor-kit

So I found a nice first generation Madison, very very clean, working & on frequency.
I've been advised to do "Total re-cap for starters, Replace the crystals and the relay, Replace the AM Regulator with a newer better part, & Upgrade the power supply with newer better transistors and regulators. For starters"

I found your caps Mike. Thank You Any references where to get the rest of high quality parts?

 

[midnight special]

In all of this thread can someone enlighten me how I can tell the difference between a Madison 8719 & a Madison 858. Please advise. Thank You

Uniden & President Washington Madison Grant and the Transition from one to the other

 

[Holydvr]

Last 858 relays I found were on fleabay I do believe.