Hifi

[3006]

This may have been posted before am new to hi-fi audio.i have a cobra 29gtl and a galaxy dx959 completely stock then a galaxy dx66v with MOSFET 10 watts swinging 35 not bird.. too poor for that I'm trying g to figure out which radio to use and if I should direct inject or not and as far as amplifiers i have a varmint xl 150 and a messenger m4v 9 pill all 1446 amp advice would be nice too just looking to get started any advice would be appreciated! Thank you in advance

 

[LeapFrog]

You will need the following: 1 - cap between 3uf - 10uf no more than 10uf. 1 - 1/4 mono jack chassis mount. 1 - on/on switch. wire and soldering stuff.

1. Drill and mount the switch and mono jack. 2. Locate and remove C191. 3. Solder + leg of cap in hole closest to middle of radio. 4. Solder A wire from - side of cap to center pin of on/on switch. 5. Solder a wire from one side of the switch to the other hole of C191. 6. Solder a wire from other side of switch to the + side of mono jack. 7. Solder - side of mono jack to board ground (you can solder to a can).

Ok if you are using a mylar style cap it doesn't matter which side of the cap you put to the board but just make sure it goes to the hole of C191 Closest to Middle of Radio. I used a Tantalum cap which has a +/- leg. Ok you will also need away of keying radio either a foot or hand switch or even a stock mic with audio wire unhooked. but these radios a 4 pin mic plugs so they are very easy to make a foot or hand switch. If you need any help with making a foot or hand switch please ask and I will help as much as I can. I will post a new post later with all my foot and hand designs for 4 and 5 pin radios. I hope this will help someone have fun and enjoy!!!

From another forum, maybe that will help you.

Can you solder?
Are your radios NPC or swing modded?
This takes a lot to get setup correctly, I used a DX66V and computer when I tried the experiment.. Works good, I may shoot a video of it. Some would say an oscilloscope is required.

The Cobra 29 would be the most difficult And I don't know about the 959, but the 66v would be direct injected if you apply the quoted information above as it's for older Galaxy / Connex / Ranger radios.

*I would not drill any holes into the radio though.*

 

[LeapFrog]

[photo="medium"]4309[/photo] .
The HeadPhones pictured have a microphone that is used with a p.c. sound card (in lieu of rack gear) to insert audio into the radio, you could use any microphone (use "mic in" or soundcard input) if you don't have a p.c. microphone, you could use an audio file (like an mp3) for testing purposes, I have even broadcasted a youtube videos audio into my dummy load.

I ran wires out the side near the mic jack so I wouldn't have to drill holes.
Both wires were ran through a single ferrite bead pictured (two turns/wraps) because I didn't use mini-coax or anything shielded for the audio wire, it's not that I had problems with interference but I wanted to prevent any from ever happening, it could be based on bad science (no science) and just left out for your experiment. The double ended 3.5mm audio cable connects the computers sound card output directly to the new input jack on the radio.

* I omitted the switch and wired the input jack directly, as It's only one wire to swap if you need to use the factory mic again.

* I use a standard four pin microphone with the mic element removed to key the radio.
A foot pedal would be more ideal.

* Beware of the possibility of an impedance mismatch occurring between the audio source and the radio, some have used a 1:1 audio transformer inline but this will not solve the mismatch as far as I know.

* It's extremely easy to over (or under) drive the radio fom the PC soundcard, finding the proper level of drive would be difficult without an oscillosope.

* A slick set of aviator shades (while not required) would help bring the cool factor up over 9000.

It's still a subject I need to read up on.
Hope this helps you, and as always know your country / locations regulations before transmitting on experimental equipment, I do all my testing on a dummy load and choose to follow the rules and do not use an export radio on the C.B.

Best Regards.
-LeapFrog

 

[3006]

That was all useful information I'm afraid the 66 has been swing modded not certain but more than likely it was bought used I could undo the swing kit and I can solder so it seems fairly straight forward as for the PC sound card I got an older PC with a sound blaster live in would that do the trick

 

[LeapFrog]

SoundBlaster Cards used to be one of the best, i'm sure yours will work fine. (The audio bandwidth may be a little limited compared to newer cards but I don't know)

That was all useful information I'm afraid the 66 has been swing modded not certain but more than likely it was bought used I could undo the swing kit and I can solder so it seems fairly straight forward as for the PC sound card I got an older PC with a sound blaster live in would that do the trick

My DX66V is NPC-RC modded (by me on the 'scope/test bench) it will exceed 100% modulation on the positive peaks while not "flat topping" or "box car'ing" the negatives on the scope, no added diode @ R238 (check this) and the limiters are all intact the main ones hacked out being TR53/TR32 (TR32 not needed after D.I. as it works on the stock mic-amp) check for these & also R249 may have been clipped in your rig). I used one diode(not @ R238), one resistor and a piece of wire for the NPC mod, but that's for a whole 'nother thread and draws controversy.

When you add it all together it makes for a clean, "LOUD" (not distorted but over 100% mod), Hi-Fidelity station. [As long as the drive level is correct]

A "better yet" way of doing this mod is to build a buffer amp circuit to install between the audio source and the radio. Then the setup would be a little more forgiving on the input levels. I turn the soundcard output way down (like 15-20% of max) and use a program called "Dolby Home Theater v4" to add some processing into the mix, with an e.q. settings range from 32Hz to 16kHz, a compression feature ("Volume leveler"), and negative peak clipping mentioned in the promotional video I saw (a "Dialogue enhancer") apparently features abound in this software (for pre-packaged "bloatware" it's simply great) pre-set E.Q. settings are offered, including a "warm" settings that almost sounds like tube emulation.

Better software equals better results if "tuned'' correctly. Some would go as far as burning a linux live dvd (KXStudio), or making a bootable thumbdrive to run Calf Studio Gear plugins with more features than Dolby has. Some would even have a dedicated linux machine with the OS installed on the hard drive to run this free software that is (extremely) capable, you don't need to pay an arm and a leg for ProTools or FL Studio to get great audio anymore. You could run rack gear into the new input, this would remove the need for a p.c. altogether, but a buffer amp may be required depending on what you're using.

To Hifi the same radio for receive you would do a few cap changes and if the factory 455h ceramic filter is in the RX chain (I forget if it is) change it for a Murata 6kHz or even 8kHz wide: I will be using an SDR for my hi-fi receiver as it is not limited to the 10kHz wide channel spacing found on cb/exports, and so I did not worry about doing these capacitor changes.

Goldfinger's HiFi mod for ept3600 series board

Receive:

C36: Change to a 2.2uF, 50 Volt (or better) mylar/polyester film
C38: Remove for more highs
C39. C154, C155: change to 2.2uF 50 volt (or better) Non-polarized electrolytic or mylar/polyester film
C157: Change to a 2.2uF, 16 Volt (or better) tantalum (observe polarity)

Transmit:

C129: Change to a 10uF, 16 Volt (or better) tantalum (observe polarity)
C187, C191: Change to 2.2uF, 50 volt (or better) mylar/polyester film

Best Regards.
-LeapFrog

 

[LeapFrog]

I should mention also If you do decide to drill a hole into the radio, that the audio input jack should remain isolated from the chassis to prevent issues.

 

[3006]

I think I'm gonna do it with the 66 you can't run hi-fi on sideband correct?

 

[dave457]

Sure you can, look up eSSB

 

[JoeDirt]

I think Leapfrog over complicates things. All Galaxy style radios direct inject in the exact location including Connex, Super Star, RCI.....ect The only difference is how they number the capacitor. Easiest way to direct inject is to isolate the PA jack (rf bypass caps and all) or drill a hole. Inject the radio with a 10uf capacitor in the correct location, Use a stock mic to key the radio..... No need to remove the element...... Download Live Professor and free VST plugins. Make a AM demodulater or buy a cheap usb dongle to monitor your transmitted audio. A CB radio isnt ever going to be good enough on the RX. The best radio for HiFi a Cobra 148/2000/grant but its still not perfect on the RX. Also get a scope, if someone talks about hifi and doesn't have a scope kick them in the nuts and ignore that they say unless audio production is there profession. Your also not going to get hifi SSB out of a CB, If you mod your Galaxy SSB will operate as stock. If you dont like direct injection its easily reversible.

 

[RatsoW8]

Or you can just search this forum and save us the misery of explaining it again

 

[LeapFrog]

Also get a scope, if someone talks about hifi and doesn't have a scope kick them in the nuts and ignore that they say unless audio production is there profession.

I am glad I got mine 6 months ago without it I could never npc mod (or anyother) properly. An oscilloscope can save you tons of grief down the road.

 

[Chris Wells]

Is thar A Hi fi mod Cobra 139xlr . Upd858 pll.

 

[LeapFrog]

Hello Chris Wells, welcome to WWDX!

to attempt to answer your question.
Well sure, many a "Hi fi"....
What does "Hi fi" mean to you?

What are you trying to achieve?
If you're looking for capacitors & resistors values to modify for different audio response through the radio, I'm sure a list of locations and values could be found...