Cobra 148 gtl dx ss360fm pb010ab wider audio mods tx Rx

[Abikerlad]

When comparing the pb010ab Cobra to the later anytone 5555 etc there is a much fuller sound coming from the anytone, the old pb010 cobra has the bass rolled off compared to the fuller sounding anytone.
I see there are some Hi Fi tx Rx mods for other radios is there any for this?

 

[tecnicoloco]

Not published,but you can try to study what has been done to other radios similar to this,like galaxy,rangers,superstar,etc...

 

[tecnicoloco]

TX ONLY

C150 .22uF/25V to 2.2uF/25V Tantalum

C143 .1uF/25V to 2.2uF/25V Tantalum

C144 2.2uF/25V to 2.2uF/25V Tantalum

C221 .022uF/50V to 2uF/50V Mylar/Plastic Film

C223 .047uF/50V to 2uF/50V Mylar/Plastic Film


Plastic Film Capacitors

Tantalum

 

[Abikerlad]

Thank your for the tx side could you look at the receive side for me please ?

 

[tecnicoloco]

RX Mod

C39 .022uF to .001uF Mylar

C40 .1uF to 1.5uF Mylar

C42 .01 to .1uF Mylar

C181 1uF/50V to 2.2uF/35V Tantalum

C175 .01uF to .001uF Mylar

C167 330uF/10V to 680uF/25V Electrolytic

C173 22uF/16V to 47uF/25V Electrolytic




If you replace the microphone pre-amplifier with a better quality opamp your tx audio will be improve

Replace 4558 with NE5532 op amp

 

[Abikerlad]

RX Mod

C39 .022uF to .001uF Mylar

C40 .1uF to 1.5uF Mylar

C42 .01 to .1uF Mylar

C181 1uF/50V to 2.2uF/35V Tantalum

C175 .01uF to .001uF Mylar

C167 330uF/10V to 680uF/25V Electrolytic

C173 22uF/16V to 47uF/25V Electrolytic




If you replace the microphone pre-amplifier with a better quality opamp your tx audio will be improve

Replace 4558 with NE5532 op amp

Thank you so much did most of the bass ones as don't have all the caps yet but it's transformed it lots.

 

[Abikerlad]

TX ONLY

C150 .22uF/25V to 2.2uF/25V Tantalum

C143 .1uF/25V to 2.2uF/25V Tantalum

C44 2.2uF/25V to 2.2uF/25V Tantalum

C221 .022uF/50V to 2uF/50V Mylar/Plastic Film

C223 .047uF/50V to 2uF/50V Mylar/Plastic Film


Plastic Film Capacitors

Tantalum

On the tx side are you sure about c44 it's a 10uf electrolytic stock?

 

[Captain Kilowatt]

On the tx side are you sure about c44 it's a 10uf electrolytic stock?

It was a typo above. It has been corrected to read C-144.

 

[Abikerlad]

I am still hearing lots of bass roll off is there any place I could take a low lovel line out before it goes through the audio amp? Also a way to tap into the mic input bypassing any restrictions that are robbing the low end sound.
As mentioned here on this other radio.
http://www.mauldroppers.com/showthread.php?16572-Super-Wide-amp-flat-148-2000-Grant-receive

 

[Abikerlad]

I am still hearing lots of bass roll off is there any place I could take a low lovel line out before it goes through the audio amp? Also a way to tap into the mic input bypassing any restrictions that are robbing the low end sound.
As mentioned here on this other radio.
http://www.mauldroppers.com/showthread.php?16572-Super-Wide-amp-flat-148-2000-Grant-receive

Infact the bass roll off seems the most on Fm receive

 

[tecnicoloco]

I am still hearing lots of bass roll off is there any place I could take a low lovel line out before it goes through the audio amp? Also a way to tap into the mic input bypassing any restrictions that are robbing the low end sound.
As mentioned here on this other radio.
http://www.mauldroppers.com/showthread.php?16572-Super-Wide-amp-flat-148-2000-Grant-receive

Use a 2uF Mylar 100V Capacitor to tap Line Level to R290 and R291 juntion lifting C223 for TX on AM only

For SSB TX Only lift C143 and tap Line Level to Pin 1 of IC3 using a 4.7uF/25V Tantalum Polarized Capacitor(Observe Polarity) + side goes to Pin 1,- side goes to Line Level Input


Do you have a wide receiver? or how do you measure your TX audio bandwidth?

 

[Abikerlad]

Use a 2uF Mylar 100V Capacitor to tap Line Level to R290 and R291 juntion lifting C223 for TX on AM only

For SSB TX Only lift C143 and tap Line Level to Pin 1 of IC3 using a 4.7uF/25V Tantalum Polarized Capacitor(Observe Polarity) + side goes to Pin 1,- side goes to Line Level Input


Do you have a wide receiver? or how do you measure your TX audio bandwidth?

I have an sdr I can see the tx bandwith it's 5k with teardrop astatic, will try with audio gear later when I make up a lead to tx and feed audio in.

 

[tecnicoloco]

I have an sdr I can see the tx bandwith it's 5k with teardrop astatic, will try with audio gear later when I make up a lead to tx and feed audio in.

no wonder,those microphones roll off at 250Hz

use a modified D-104 Lollypop with a Fet

https://sites.google.com/site/grinchradio/cobra-and-johnson-extreme-audio-mods/d104mods/the-circuit