My Factory AM Radio is now mp3 Compatible! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Frizzle Fry · 03-01-2007, 07:48 PM

I’m the type that likes the look of a stock dash and radio but wants a modern sound system. A few weeks ago I bought a Rockford Fosgate Omnifi mp3 player. It’s basically a 20gig hard drive based system (easily upgradeable to 120gig) that allows you to transfer mp3s from your computer to your car via USB or optional wireless (which I have).

I had planned to run it stand-alone directly to my cross-over/amps, but I soon found out that it has no built in pre-amp, so no volume control. My existing 10+ year old CD player had no audio inputs either (the way the Omnifi was designed to be installed). I looked at the USA-1thru6 options, but didn’t really want a new deck.

I decided that all really needed to run this thing stand-alone was some sort of volume control capability and power antenna signal. So I did a little google’ing and found info on in-line RCA volume control. A trip to Radio Shack and I was ready to do a little radio surgery.

I picked up some 0-10k ohm potentiometers and surface-mountable RCA jacks. I later discovered that 0-10k was insufficient and went to 0-1M ohm. The 0-10k pots only adjusted volume from 100% down to about 90%. The 0-1M pots adjust volume from 100% down to about 5% (plenty low). A further improvement may be possible using this configuration. My setup works just fine, though it does get a little touchy/sensitive near full volume, meaning a little adjustment goes a long way in volume. But it's not enough to be an issue.

When you remove the covers from the radio you can see there is plenty of room to do this. Just take out a few components behind the volume knob. I didn’t use nor did I plan to use the radio as an actual AM radio.

The existing volume/tone knob has two pots (two are required for stereo volume control) so at first glance I thought this was going to be easier than expected. But they are not matched and are the wrong specs for the job. But the amazing thing is that the annulus (resistive disc - more info here), is nearly identical in size/shape from stock to new. A little clearancing on the new ones and they fit perfectly.

Frizzle Fry · 03-01-2007, 07:54 PM

Now, the other thing I learned is that the stock sweepers don’t work very well with the new annuluses. They look like they will but when I tested them in this configuration there were open spots in the volume range. So, tried gluing the new sweepers onto the stock sweeper discs. That seemed to work ok, but when I went to the 1M pots I decided to use the new sweepers AND their plastic discs. I did this because the centering of the sweeper on the annulus and shaft is critical. I just drilled holes in the center of the black plastic sweeper discs to fit them over the shafts.

Frizzle Fry · 03-01-2007, 08:01 PM

Drilled holes and mounted the RCA jacks. I would move them forward or to the bottom of the deck if I had it to do over because they are pretty close to the wiper motor as is.

Another great thing about the stock pot housing is that it has a built in switch. This was the main reason I chose to stick with the stock pot housing instead of trying to find a compatible dual-gang pot. I wired the switch up to the existing power jack in the back of the radio. So two of the spades in that jack are now used for power antenna (on/off signal to the crossover, amps, and mp3 player), and the other spade is now connected to the internal light. I later wired the radio light to the dash light circuit so it will be on/off/dim with those. You could wire it to the knob switch if you want it to switch on/off with your system, but I like the back lighting on and dimmable even when the system is off.

**SactoJim** · 03-01-2007, 08:06 PM

Holy Crap....what are you..a rocket scientist!

That's impressive and a little (way) beyond me!

oj70chevy · 03-02-2007, 10:11 AM

Quote:

Originally Posted by SactoJim

Holy Crap....what are you..a rocket scientist!

That's impressive and a little (way) beyond me!

that is awsome. I see this going to the FAQ!

Frizzle Fry · 03-01-2007, 08:13 PM

I left the tuning mechanism alone so the kids can sill push the preset buttons and watch the needle move all day long. But you could build a balance/fader knob on that side if you wanted using the same technique and simply wiring one pot inversely as is also explained here.

I installed a new bulb while I was in there (also put all new bulbs in the rest of the dash).

This set-up would work for any audio device that is designed to be run through AUX inputs in a deck and has its own control interface.

Here it is installed. The faceplate is pretty thin and could be mounted anywhere, but it's going here for now (hot glued on so it's easily reversible).

Next install; my new covered fiberglass kick panels thanks to this FAQ

67arch · 03-01-2007, 08:23 PM

Nice post!! That is exactly what I would like to do.

**jaros44sr** · 03-01-2007, 08:28 PM

I'm alittle old, well make that a lot old, but what is mp3. Your work is impressive even tho I don't know what you said. I'll have to go back and reread it. That is awesome to see it look stock. Congrats on your success... J.

sdkid · 03-01-2007, 08:26 PM

That is so cool. I'm not sure I'm that smart for this though. It also needs to be moved to the FAQ forum.

jimmydean · 03-01-2007, 08:53 PM

Nice work indeed!

I was going to get the OmniFi setup until I saw the limitations and the price. One thing let to another and I am now planning a system around a Mac Mini. I will do it in stages, I still need to modify the dash to accommodate the screen,

**special-K** · 03-01-2007, 08:59 PM

You`re a frickin`genius Frizzle Fry.Shoot me your address.I`m sending 1/2 dozen radios your way.

That`s great!

Frizzle Fry · 03-01-2007, 10:35 PM

Thanks guys. The basic idea was pretty simple, but making it work the way I wanted it to using some of the factory parts took a little trial and error. Now that it's all figured out it would be cake to do again. I just wired up the radio back light today so I went outside a few minutes ago to check it out after sun down and it looks great

I think I'll move the Omnifi face-plate somewhere else in the future and put the ashtray back, but for now this works.

You could run a stand-alone CD changer or HD-Radio unit this way too.

Here's a link for jaros http://en.wikipedia.org/wiki/Mp3

cdowns · 03-01-2007, 10:46 PM

will it play 8-tracks??

**jaros44sr** · 03-02-2007, 07:36 AM

Quote:

Originally Posted by Frizzle Fry

Thanks guys. The basic idea was pretty simple,

Here's a link for jaros http://en.wikipedia.org/wiki/Mp3

Thanks Fry, but that was way to much info. Are you saying it plays CD's? Your work is way too cooool! Wish I knew what you were talking about.... J.

kieth · 07-10-2011, 12:11 PM

Quote:

Originally Posted by Frizzle Fry

Thanks guys. The basic idea was pretty simple, but making it work the way I wanted it to using some of the factory parts took a little trial and error. Now that it's all figured out it would be cake to do again. I just wired up the radio back light today so I went outside a few minutes ago to check it out after sun down and it looks great

I think I'll move the Omnifi face-plate somewhere else in the future and put the ashtray back, but for now this works.

You could run a stand-alone CD changer or HD-Radio unit this way too.

Here's a link for jaros http://en.wikipedia.org/wiki/Mp3

I am using a Garmin Nuvi 765T with a ram cradle bracket attached to a old 66 gmc ash tray face. This gpa has a MP3 player built in and volume control. I am doing to add a 4 channel base amp and a mono rear sub woofer. This keeps the cost down and If I want the dash to look original I just take out the gps and put the painted original ash tray back in its place.

ps the cord will not show like it does in the picture.

As you will see in the picture it is just temporarily mounted but will be functional in a few weeks.

Kieth

http://kieth.smugmug.com/Trucks/66-G...2_FCsG9GR-A-LB

flatheadnut0 · 03-01-2007, 11:22 PM

That's the coolest thing I ever saw. How the hell did you come up with that?

IvelDesigns · 03-02-2007, 12:22 AM

that's awesome.

724x4a/cchevy · 03-02-2007, 12:25 AM

holy crap man!! this is awsome!!

Draggn66 · 03-02-2007, 02:13 AM

**Yukon Jack** · 03-02-2007, 10:20 AM

Incredible . . . just incredible. You could surely make some money marketing these conversions!

LUV2XCLR8 · 03-04-2007, 09:30 AM

Quote:

Originally Posted by Yukon Jack

Incredible . . . just incredible. You could surely make some money marketing these conversions!

I want one now

gmc1969custom · 03-02-2007, 05:03 PM

Very, Very Impressive!!!!

Orange · 03-02-2007, 05:15 PM

Very impressive. I have a factory AM radio. I may do something with it someday.

DLB

PanelDeland · 03-02-2007, 05:17 PM

Frizzle,you do realize this is a great mod but probably only a few on here are 'lectronically literate.This is a great write up and pics for a FAQ,maybe it should be used as a template for them.You should look at posting it on an audio forum or maybe selling it to them as a mod from stockers.

BTW my TV wont work do you do house calls.

grant's72 · 03-02-2007, 05:37 PM

could I plug a i-pod in to that and have it work

03-01-2007, 07:48 PM	#1
Frizzle Fry Registered User Join Date: Aug 2005 Location: Hillsboro Oregon Posts: 6,449	My Factory AM Radio is now mp3 Compatible! I’m the type that likes the look of a stock dash and radio but wants a modern sound system. A few weeks ago I bought a Rockford Fosgate Omnifi mp3 player. It’s basically a 20gig hard drive based system (easily upgradeable to 120gig) that allows you to transfer mp3s from your computer to your car via USB or optional wireless (which I have). I had planned to run it stand-alone directly to my cross-over/amps, but I soon found out that it has no built in pre-amp, so no volume control. My existing 10+ year old CD player had no audio inputs either (the way the Omnifi was designed to be installed). I looked at the USA-1thru6 options, but didn’t really want a new deck. I decided that all really needed to run this thing stand-alone was some sort of volume control capability and power antenna signal. So I did a little google’ing and found info on in-line RCA volume control. A trip to Radio Shack and I was ready to do a little radio surgery. I picked up some 0-10k ohm potentiometers and surface-mountable RCA jacks. I later discovered that 0-10k was insufficient and went to 0-1M ohm. The 0-10k pots only adjusted volume from 100% down to about 90%. The 0-1M pots adjust volume from 100% down to about 5% (plenty low). A further improvement may be possible using this configuration. My setup works just fine, though it does get a little touchy/sensitive near full volume, meaning a little adjustment goes a long way in volume. But it's not enough to be an issue. When you remove the covers from the radio you can see there is plenty of room to do this. Just take out a few components behind the volume knob. I didn’t use nor did I plan to use the radio as an actual AM radio. The existing volume/tone knob has two pots (two are required for stereo volume control) so at first glance I thought this was going to be easier than expected. But they are not matched and are the wrong specs for the job. But the amazing thing is that the annulus (resistive disc - more info here), is nearly identical in size/shape from stock to new. A little clearancing on the new ones and they fit perfectly.

03-01-2007, 07:54 PM	#2
Frizzle Fry Registered User Join Date: Aug 2005 Location: Hillsboro Oregon Posts: 6,449	Re: My Factory AM Radio is now mp3 Compatible! Now, the other thing I learned is that the stock sweepers don’t work very well with the new annuluses. They look like they will but when I tested them in this configuration there were open spots in the volume range. So, tried gluing the new sweepers onto the stock sweeper discs. That seemed to work ok, but when I went to the 1M pots I decided to use the new sweepers AND their plastic discs. I did this because the centering of the sweeper on the annulus and shaft is critical. I just drilled holes in the center of the black plastic sweeper discs to fit them over the shafts.

03-01-2007, 08:01 PM	#3
Frizzle Fry Registered User Join Date: Aug 2005 Location: Hillsboro Oregon Posts: 6,449	Re: My Factory AM Radio is now mp3 Compatible! Drilled holes and mounted the RCA jacks. I would move them forward or to the bottom of the deck if I had it to do over because they are pretty close to the wiper motor as is. Another great thing about the stock pot housing is that it has a built in switch. This was the main reason I chose to stick with the stock pot housing instead of trying to find a compatible dual-gang pot. I wired the switch up to the existing power jack in the back of the radio. So two of the spades in that jack are now used for power antenna (on/off signal to the crossover, amps, and mp3 player), and the other spade is now connected to the internal light. I later wired the radio light to the dash light circuit so it will be on/off/dim with those. You could wire it to the knob switch if you want it to switch on/off with your system, but I like the back lighting on and dimmable even when the system is off.

03-01-2007, 08:06 PM	#4
SactoJim Registered User Join Date: Oct 2005 Location: Sacramento, CA Posts: 1,970	Re: My Factory AM Radio is now mp3 Compatible! Holy Crap....what are you..a rocket scientist! That's impressive and a little (way) beyond me! __________________ 72 Cheyenne SWB Fleet Nut & bolt frame off in progress...99.9999% - supercharged 383 - 4 wheel discs - relocated fuel tank - My Build Thread

03-01-2007, 08:13 PM	#6
Frizzle Fry Registered User Join Date: Aug 2005 Location: Hillsboro Oregon Posts: 6,449	Re: My Factory AM Radio is now mp3 Compatible! I left the tuning mechanism alone so the kids can sill push the preset buttons and watch the needle move all day long. But you could build a balance/fader knob on that side if you wanted using the same technique and simply wiring one pot inversely as is also explained here. I installed a new bulb while I was in there (also put all new bulbs in the rest of the dash). This set-up would work for any audio device that is designed to be run through AUX inputs in a deck and has its own control interface. Here it is installed. The faceplate is pretty thin and could be mounted anywhere, but it's going here for now (hot glued on so it's easily reversible). Next install; my new covered fiberglass kick panels thanks to this FAQ

03-01-2007, 08:23 PM	#7
67arch WTB:Patience and Talent Join Date: Sep 2006 Location: Oklahoma Posts: 119	Re: My Factory AM Radio is now mp3 Compatible! Nice post!! That is exactly what I would like to do. __________________ 69 shortwide

03-01-2007, 08:28 PM	#8
jaros44sr Senior Member Join Date: May 2006 Location: Philadelphia, Pa. 19454 Posts: 9,714	Re: My Factory AM Radio is now mp3 Compatible! I'm alittle old, well make that a lot old, but what is mp3. Your work is impressive even tho I don't know what you said. I'll have to go back and reread it. That is awesome to see it look stock. Congrats on your success... J. __________________ Semper Fi...Uncle Sam, you da man All parts offered to help are free, unless otherwise noted Dont try this stuff in my build thread, unless you have 55 years of mechanical OTJ training SAFETY FIRST AS usual, off topic They say your mind goes second, can't remember the first Jim

03-01-2007, 08:26 PM	#9
sdkid Registered User Join Date: Sep 2004 Location: Pierre SD Posts: 1,533	Re: My Factory AM Radio is now mp3 Compatible! That is so cool. I'm not sure I'm that smart for this though. It also needs to be moved to the FAQ forum. __________________ I think the world needs a drink... Help somebody...If you can....VanZant We're not wrong, we're not sorry, and its probably gonna happen again. That's the truth about men. Tracy Byrd Member# 13924 '70 c10, 350/350 '68 c10 250/4spd '68 c10 no eng/trans fac ps/pb/ac/at (future father/sons project) '48 Chevy Loadmaster

03-01-2007, 08:53 PM	#10
jimmydean Registered User Join Date: May 2005 Location: Beaverton, OR Posts: 3,728	Re: My Factory AM Radio is now mp3 Compatible! Nice work indeed! I was going to get the OmniFi setup until I saw the limitations and the price. One thing let to another and I am now planning a system around a Mac Mini. I will do it in stages, I still need to modify the dash to accommodate the screen, __________________ New Project: 1966 LWB C20 Plans: 1/2 ton conversion Dropmember front Dropmember rear Corvette discs Restored raised bed http://67-72chevytrucks.com/vboard/s....php?p=4295210

03-01-2007, 08:59 PM	#11
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: My Factory AM Radio is now mp3 Compatible! You`re a frickin`genius Frizzle Fry.Shoot me your address.I`m sending 1/2 dozen radios your way. That`s great! __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

03-01-2007, 10:35 PM	#12
Frizzle Fry Registered User Join Date: Aug 2005 Location: Hillsboro Oregon Posts: 6,449	Re: My Factory AM Radio is now mp3 Compatible! Thanks guys. The basic idea was pretty simple, but making it work the way I wanted it to using some of the factory parts took a little trial and error. Now that it's all figured out it would be cake to do again. I just wired up the radio back light today so I went outside a few minutes ago to check it out after sun down and it looks great I think I'll move the Omnifi face-plate somewhere else in the future and put the ashtray back, but for now this works. You could run a stand-alone CD changer or HD-Radio unit this way too. Here's a link for jaros http://en.wikipedia.org/wiki/Mp3

03-01-2007, 10:46 PM	#13
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: My Factory AM Radio is now mp3 Compatible! will it play 8-tracks?? __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

03-01-2007, 11:22 PM	#16
flatheadnut0 New Member Join Date: Feb 2007 Location: nebraska Posts: 18	Re: My Factory AM Radio is now mp3 Compatible! That's the coolest thing I ever saw. How the hell did you come up with that?

03-02-2007, 12:22 AM	#17
IvelDesigns Commander Taco Bello Join Date: Sep 2006 Location: Des Moines, Iowa Posts: 2,232	Re: My Factory AM Radio is now mp3 Compatible! that's awesome. __________________ Bagged '50 3600 - Bumper punchin' road kill since 2009... Bagged '69 C10 Longbed - Bumper punchin' road kill since 2007...

03-02-2007, 12:25 AM	#18
724x4a/cchevy Self-proclaimed LED man Join Date: Nov 2003 Location: Harrisburg, Missouri Posts: 1,021	Re: My Factory AM Radio is now mp3 Compatible! holy crap man!! this is awsome!! __________________ My LED Website My Photobucket Album of LED's Ask me about hand-made custom L.E.D brake and reverse lights. <- LINK I also do LED: -Third Brake/Cargo -Brake (truck and burb) -Reverse (truck and burb) -67-68 Front Turn Signals -69-70 Front Turn Signals -71-72 Front Turn Signals -GMC Front Turn Signals I can also do custom lights for other vehicles....i did a set for a AMC Gremlin once Norwood Survivor



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03-02-2007, 02:13 AM	#19
Draggn66 Wrenchin & Sandin!!! Join Date: Aug 2006 Location: Joliet, IL. Posts: 523	Re: My Factory AM Radio is now mp3 Compatible! __________________ Randy Shorewood, IL. My Favorite eBay Searches My Driver Restore Thread 1971 C10 Longbed 2005 Silverado Shortbed 2005 FXDWG

03-02-2007, 10:20 AM	#20
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	Re: My Factory AM Radio is now mp3 Compatible! Incredible . . . just incredible. You could surely make some money marketing these conversions! __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

03-02-2007, 05:03 PM	#22
gmc1969custom Registered User Join Date: Jan 2007 Location: Canton, TX Posts: 211	Re: My Factory AM Radio is now mp3 Compatible! Very, Very Impressive!!!! __________________ 1969 Custom w/Turquoise Interior. 75k miles, 350 V8, THM400 (Almost) All Original

03-02-2007, 05:15 PM	#23
Orange Licensed to Thrill! Join Date: Apr 2006 Location: Northwest, GA Posts: 1,673	Re: My Factory AM Radio is now mp3 Compatible! Very impressive. I have a factory AM radio. I may do something with it someday. DLB __________________ 1971 GMC.Lowered. Overdrive. Orange. Krue's excellent FAQ Index.

03-02-2007, 05:17 PM	#24
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: My Factory AM Radio is now mp3 Compatible! Frizzle,you do realize this is a great mod but probably only a few on here are 'lectronically literate.This is a great write up and pics for a FAQ,maybe it should be used as a template for them.You should look at posting it on an audio forum or maybe selling it to them as a mod from stockers. BTW my TV wont work do you do house calls. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

03-02-2007, 05:37 PM	#25
grant's72 Registered User Join Date: Sep 2006 Location: iowa Posts: 33	Re: My Factory AM Radio is now mp3 Compatible! could I plug a i-pod in to that and have it work

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