29 ltd audio boost,???help

[Tokin]

Save yourself the time and bs modding your rig.
If you want that big radio sound out of your 29 buy one of these and if you need you can make a couple adapter jumpers to use it on any radio you want. Total to your door is under $200 if you pay for the express shipping. Mine was here in a week and is the best addition to my station ive purchased in a long time. You can get it with or without gate control, check out his other sales.
Be sure to follow the set up directions that comes with it as it will save you aggravation.

https://www.ebay.com/itm/142627267024

 

[Tokin]

Try this again, here is some of what you can expect from this eq. Mind you its played thru talk back and an extension speaker but you should get the idea.

 

[1iwilly]

thanks for the info but that's not for me

 

[Shadetree Mechanic]

The hot setup for me is the Cobra 29 with the RM Italy KL203 amplifier that puts out about 150W pep. Astatic 636 MIC, the stock MIC or other mics might need the MIC gain knob turned down to sound good. Always use a second radio on the bench with no antenna and headphones to see how it sounds, I would not run my station without a monitor radio.

This is what I do:

1) AMC mod, change C71 from 220uf to 33uf. This reduces the modulation limiter clamping speed and allows a little overshoot on the peaks. Not enough to sound bad though.

2) MIC Gain, Change R67 from 33 ohm to 10 ohm. This will make the 636 sound like a power MIC. Hold the MIC about 4 inches away from your mouth and talk normal. Might not be needed with other mics.

3) Receive audio, Change C33 and C40 to a 2.2 mfd non polarized electrolytic or two tantalum connected negative to negative to make them non polarized.

4) JP 36 mod, remove JP 36 by the final and replace with an electrolytic capacitor with the - towards the final. Put a 1/2 watt resistor on the other side of the board on the cap leads sticking through. The resistor value determines the dead key. Usually around 150 ohms will give you 1.5 watts dead key which is perfect for driving the KL 203 amp. The capacitor will give you full swing to peak power from any dead key.

I have done several radios this way for myself and some of the locals here. If you just do step 4 with the amp, you will get good results, the other steps are the icing on the cake.
Chris

 

[Tokin]

I have a habit of assuming folks are using mobiles as a base like I am although you never did say. The eq wouldnt work well in a car but on a base it works great.

 

[Handy Andy]

Man I wish I could have consolidated all those posts earlier I did helping others with their 29 or Realistic or even the Uniden - because in all, or nearly every post for them - I've given little bits and pieces to those willing to wade thru the postings to find them...

But I'm not sure of what it is you need, are you looking for something in particular?

Mic audio?

Carrier power/performance?

Receive audio?

In a way, I'm seeing you "want" to make others hear you better - and I feel for ya' man _ I know and have been there (in some ways I still am! LOL!)

Ok, my list may not be your "Taste" but then it's only here because I use the Limiter and all it's shortcomings. It gives me something that I can say - yeah - that's the best I can do for it.

But there are many, many threads out here full of knowledge that you just have to wade thru the "fluff" and finally you crack the shell and find your nuggets...

As far as "Mic mods?" A 29' has been the "Staple" for many-many years and is the flagship of many a CB'er that stands the tests of time and durability - time and time again. It's why there are so many threads out here for it, you just have to absorb (in a literal sense) their ways and means of doing it then sort, sift thru the "chaff" to find their "wheat" and work with it in your own ways.

Each person is unique in this - or how they want to sound - so I can only give you so much - the rest will have to be a give and take from you and the others out here whom may be willing to share their knowledge and experiences with you.

There are also other keywords you can use too - like "Goldfinger mods" and stuff like that.

But in doing those mods, it comes at a price - stability is one, and the potential for losing your patience with your patient. You may overdo one mod and then find the radio squeals or doesn't work right...

Ok, document your work get it like it's virgin - photograph the board top parts side and bottom sides. so - you can see the details - do it well so you can recover if you lose something...that way you can zoom in look for and find your error and correct them before permanent damages are done!

Say - for example - a quick mod for your "Limiter" - locate the following...and your board may differ - that's why it's important for us to know what you're up against...

​

C73 - I change to a 0.01uF (103 disc)
C68 - make a 1uF non-polarized - of if you can't locate one - parallel two 0.22uF (224 Disc) here to raise drive but this parallel comes with quirks...

The Rest? We may need to know your board number so we can help you with the mods - for there are at least 3 different Audio chips with these - TA7222. YD-1022 and the TDA 2003 - we need to know what you're dealing with to help you...

 

[1iwilly]

thanks for the replies the board# kepc-060-f built july-1995

Man I wish I could have consolidated all those posts earlier I did helping others with their 29 or Realistic or even the Uniden - because in all, or nearly every post for them - I've given little bits and pieces to those willing to wade thru the postings to find them...

But I'm not sure of what it is you need, are you looking for something in particular?

Mic audio?

Carrier power/performance?

Receive audio?

In a way, I'm seeing you "want" to make others hear you better - and I feel for ya' man _ I know and have been there (in some ways I still am! LOL!)

Ok, my list may not be your "Taste" but then it's only here because I use the Limiter and all it's shortcomings. It gives me something that I can say - yeah - that's the best I can do for it.

But there are many, many threads out here full of knowledge that you just have to wade thru the "fluff" and finally you crack the shell and find your nuggets...

As far as "Mic mods?" A 29' has been the "Staple" for many-many years and is the flagship of many a CB'er that stands the tests of time and durability - time and time again. It's why there are so many threads out here for it, you just have to absorb (in a literal sense) their ways and means of doing it then sort, sift thru the "chaff" to find their "wheat" and work with it in your own ways.

Each person is unique in this - or how they want to sound - so I can only give you so much - the rest will have to be a give and take from you and the others out here whom may be willing to share their knowledge and experiences with you.

There are also other keywords you can use too - like "Goldfinger mods" and stuff like that.

But in doing those mods, it comes at a price - stability is one, and the potential for losing your patience with your patient. You may overdo one mod and then find the radio squeals or doesn't work right...

Ok, document your work get it like it's virgin - photograph the board top parts side and bottom sides. so - you can see the details - do it well so you can recover if you lose something...that way you can zoom in look for and find your error and correct them before permanent damages are done!

Say - for example - a quick mod for your "Limiter" - locate the following...and your board may differ - that's why it's important for us to know what you're up against...

View attachment 37775​

C73 - I change to a 0.01uF (103 disc)
C68 - make a 1uF non-polarized - of if you can't locate one - parallel two 0.22uF (224 Disc) here to raise drive but this parallel comes with quirks...

The Rest? We may need to know your board number so we can help you with the mods - for there are at least 3 different Audio chips with these - TA7222. YD-1022 and the TDA 2003 - we need to know what you're dealing with to help you...

 

[Handy Andy]

Ok, for starters, this link - I had a heck of a time finding it, but yep, its' there - at least I had to go to BING to re-link to this link - I foudn what Robb was directing you to...to make this story short - it looks like the site was upgraded so the posts initial thread listing was Post # first, - now thie posting # is last.

Here's the example...

The correct link-- Is this
https://www.worldwidedx.com/threads/cobra-29-high-power-mod-with-2sc1969-transistor.31449/

But the link for it in this thread was this...

http://www.worldwidedx.com/radio-radio-related-modifications/31449-cobra-29-high-power-mod-2sc1969-transistor.html Which is a bad link...

So if you can find the starting page, which is @Moleculo taking about it - that can get you started...

For the best results - you need to keeping this simple - work on one section at a time - do just one mod part swap at a time.

Why? Because if you go too far, the radio will squeal like a pig, complaining about the new value and it wants the old value back in it's place right now!

In my experience, work small stuff. you want some "treble" change some of the capacitance but in SPECIFIC areas, not all throughout the radio.

Example...

Change C37 and C68 to 2 - meaning they want to you up it's value to pass more audio power into the next stage...

When you do that, remember that you are ADDING more audio into the next stage, the stage may not like all that extra audio - so if it don't like 2.2uF, settle for say 224 which is a 0.22uF instead.

Does that swap make you sound muddy, there's other work that has to be done, So then revert out that C37 and use a 223 in it's place then go find some other areas - using your schematic - to locate parts of the audio chain they also contain parts suggested in that post listed above...

Not here to rework an otherwise great thread, just trying to point you in a direction that is; you need to work in small steps - you can make big changes with one simple value change - don't want you to be disappointed - challenged? Perhaps, but if you do this right, you won't have to keep going back to make tons of changes every time.,

If you find some poster has some of the better mods, then search for that poster and work with their values.

Good luck in your journey..

 

[Handy Andy]

I showed that photo above for the reason of - Audio "sweetening".

EVERY Cobra 29 uses Capacitance in the Audio and Bias line to the Driver and Final...

Some of the Cobra 29 series use DIFFERENT values than stated on the Schematic.

You will have to be aware of these changes they do - so you have to locate them, dig them out and swap out these for different values to achieve an effect.

There is also the effort of simple swaps, using the same part, but in a different location to help you out, without having to run to a local store or $$$ at eBay - just swap the values in the areas I highlighted. Adding extra capacitance in one area, but lessening in another, using the parts inside the radio itself makes for an efficient method to keep the replacement, retooling and rework to a more manageable level.

 

[Mk121]

Very helpful Andy. Thanks for putting that together.

 

[1iwilly]

ok today i receive 2 HG-1969 the best i can get out of this radio is wide open 8 watts swings forward to almost 9 1/2 on a bird then from 2 watts to 8 1/2 watts now i'm reading to work on the amc side to get a tad more outdio out of it i saw somewhere here about some caps and resistor change for this ???//

 

[9C1Driver]

If that's a Bird 43 your getting it done. Or are you running a Bird 43P ?

 

[1iwilly]

thru rms no peak reading

If that's a Bird 43 your getting it done. Or are you running a Bird 43P ?

 

[Shadetree Mechanic]

Bump for Cobra 29 audio.

 

[Eldorado828]

What a gold mine when digging in the right spot. Gotta love wwdx!