Adding Bluetooth, an amp and subwoofer to OE Delco 2700 ETR radio

[1975Jimmy]

About two years ago, I installed a Delco 2700 ETR radio and connected a few speakers to it, but wasn't ever happy with how it sounded and being a 20+ year old radio, it didn't have an aux input or Bluetooth. That said, I refuse the to hack up my dashboard and I really like the OE look of the Delco radio over the RetroSound and Classic Auto Sound options. So, first, I addressed adding Bluetooth to the Delco radio. To do that, I purchased an In-line FM modulator for a CD changer with an on/off switch. Switched off, it used the Antenna, switched on, it cuts off the antenna and takes music from the connected input. Instead of connecting a cd changer, I wired up a 12volt Bluetooth module and connected it to the FM modulator. Voila, I now have Bluetooth music! For sound, my friends at Clarion hooked me up with some great new speakers, a mini amplifier and a 12" subwoofer to boost the audio quality of that 80's factory Delco radio. I used custom kick panels in the front to mount the 6 1/2 inch coaxial speakers. I also cut holes out of the custom rear interior quarters to mount the 6x9s. The sub is in the back and is removable when I need extra room or want to hit the trails. All of The new speakers are powered by a Clarion 5-channel mini amplifier. Now, the cool thing about this amplifier, other than it's ridiculously small size, is that it uses either RCA inputs, or uses high-level speaker inputs. Since the 2700 ETR doesn't have RCA outputs, I wired it using the high-level inputs. The hardest part about installing an audio system is trying to keep all of the components concealed. After racking our brains as to where to mount the amplifier so that it got good airflow and was easily accessible, we came up with a pretty unique solution that keeps the amp hidden, easily accessible and out of the way - under the tilt up passenger seat. What do you guys think? Check out the photos below.

 

[bigjimmy82]

Any sound quality issues using the high level inputs? Looks fantastic.

 

[brans87]

Clean I like. Just sub is in plain view.

I will try to get a pic of how my JL is mounted out of site and mind to most. Course all my stereo was free but wiring.

 

[1975Jimmy]

Any sound quality issues using the high level inputs? Looks fantastic.

It's not perfect, but it's 95%. Right now I'm chasing a noise issue that is causing some minor static when I go over bumps. But otherwise, it works awesome!

 

[1975Jimmy]

Clean I like. Just sub is in plain view.

I will try to get a pic of how my JL is mounted out of site and mind to most. Course all my stereo was free but wiring.

Hidden sub, I like how that sounds. What size is your sub?

 

[Blue85]

Why not get an electronics guy to open up the head unit and add a line-in? I've done this to several stockers over the years. The 30Hz-15kHz range of the FM isn't terrible, but the dynamic range doesn't compare to a direct amplifer connection. You've already got everything else set up for good sound. I don't know, a lot of guys swear some of these modulators sound really good.

 

[rampage]

Why not get an electronics guy to open up the head unit and add a line-in? I've done this to several stockers over the years. The 30Hz-15kHz range of the FM isn't terrible, but the dynamic range doesn't compare to a direct amplifer connection. You've already got everything else set up for good sound. I don't know, a lot of guys swear some of these modulators sound really good.

That's what I did to the radio in my Blazer 20 yrs ago to add a portable CD player. Just connect two wires to a cheap speaker, one to ground and the other to use as a probe. There are two ICs on the printed circuit board (one for each channel) that you need to locate where the volume faint volume doesn't change when you adjust the volume knob. Those two lines will be your pre-in. Break the circuit at that point and wire it to one side of a DPDT switch. Other side of switch goes to your aux input. Very clean signal and no one will notice a small switch on the faceplate.

 

[diesel4me]

I'd keep close tabs on the amplifier's temperature--some of them get quite warm in use--one I have in my van gets hot enough to burn your hand after you run the radio at high volume for awhile if you touch the heat sinks..

I mounted it under the metal seat pedestal and had to add a computer fan next to it to keep it from tripping the thermal overload on hot summer days..

It might be wise to put a sheet of metal between the seat springs and the amp,to help dissapate any heat..that stuffing under the seat springs ignites easily and burns hot...

 

[1975Jimmy]

I'd keep close tabs on the amplifier's temperature--some of them get quite warm in use--one I have in my van gets hot enough to burn your hand after you run the radio at high volume for awhile if you touch the heat sinks..

I mounted it under the metal seat pedestal and had to add a computer fan next to it to keep it from tripping the thermal overload on hot summer days..

It might be wise to put a sheet of metal between the seat springs and the amp,to help dissapate any heat..that stuffing under the seat springs ignites easily and burns hot...

I hear ya on that. I've had some older amps running at max capacity that were the same way. Not a bad idea to add some extra insurance between the amp and seat foam. I think i'll go pick up a sheet of aluminum to do that. The cool thing about these mini Clarion amps though is that they actually don't get all the hot. They're a very efficient Class-D design, and even at max volume, i'm maybe only pushing the amp to 50%. I went for a 30 minute drive with the seat folded forward with the radio cranking just to do some torture testing, as I was driving i kept reaching over to feel the amp's temp, and it never got past warm.

 

[diesel4me]

My amp is an old Mofset "American Hi-Fi" flea market special that is rated around 180 watts RMS,but the box says "1000 watts"...

I bet I could light a cigarette off it after I blast some Sabbath or Zeppelin for awhile !..

Today's amps probably are much more efficient and do run cooler--mine is probably 15 to 20 years old now...

I had one identical to it let the magic smoke out of the output transistors one night when I was listening to CCR cranked up loud..--good thing I was using it in my garage,mounted to a board on the wall--it would have set a vehicle on fire probably....

 

[dyeager535]

I like it.

I started down the road to see if I could use an external input (MP3 player) to automatically switch it from radio to "cassette" but I didn't go much further with it. Still a project for the future.

Not sure if this schematic a guy drew up will help or not, if you wanted to get more into the radio:
http://www.badcaps.net/forum/showpost.php?s=5e58a233e1d020e18ca9e1323ab06411&p=291683&postcount=5

I'd definitely like to see that change come automatically. Being able to automate/incorporate bluetooth would be nice as well.

 

[Chevy305]

Just get one of these:

 

[dyeager535]

Doesn't work when the tape deck breaks, as mine has and they all will. And with the new phones being bluetooth, and having all my music, eliminating the cord would be nice.

 

[rampage]

I haven't used this but it's much better than an FM transmitter. No signal drift and I would imagine can drown out almost any weak radio station. It simply plugs in between the antenna and antenna input on the back of any car radio. Then you can plug a Bluetooth adapter to the audio input or for best quality plug directly into the aux input.
www.amazon.com/dp/B002U5XPBE/ref=cm_sw_r_sms_c_api_PAfmzbTEZ0DHT

 

[1975Jimmy]

I haven't used this but it's much better than an FM transmitter. No signal drift and I would imagine can drown out almost any weak radio station. It simply plugs in between the antenna and antenna input on the back of any car radio. Then you can plug a Bluetooth adapter to the audio input or for best quality plug directly into the aux input.
www.amazon.com/dp/B002U5XPBE/ref=cm_sw_r_sms_c_api_PAfmzbTEZ0DHT

This is exactly the kind of device I used. They work very well.

 

[AbramJ]

This is exactly the kind of device I used. They work very well.

That is good to hear, that is what I planned on doing.

 

[dyeager535]

I haven't used this but it's much better than an FM transmitter. No signal drift and I would imagine can drown out almost any weak radio station. It simply plugs in between the antenna and antenna input on the back of any car radio. Then you can plug a Bluetooth adapter to the audio input or for best quality plug directly into the aux input.
www.amazon.com/dp/B002U5XPBE/ref=cm_sw_r_sms_c_api_PAfmzbTEZ0DHT

Wish I had enough money to pay people to execute my crazy ideas.

I'd like to see a microswitch added to the cassette eject button (internal of the radio) that would turn a bluetooth adapter on and switch the feed from radio to "cassette" when eject button was pressed, cassette feed now being the bluetooth.

 

[Blue85]

I had one radio set up like this. The tape deck preamp was on the tape mech, so I intercepted the audio between there and the main board, wired to a switched jack outside the unit. The bluetooth receiver was on a switched ignition source routed to this new line in. I had one of those old tape adapters pictured above, but with the cord removed. Whenever it was in, the bluetooth input was active and I just ejected it to have FM radio. I also had one where I cut the FM audio traces on the main board and wired to an 1/8" switched jack mounted remotely. These kind of cheap/free mods are good for short-term solutions when you have better things to spend time/money on than doing a whole sound system.

But I suppose you're talking about killing tape function and using the button as a bluetooth changeover. You just need a relay and a latch circuit.

 

[1975Jimmy]

I had one radio set up like this. The tape deck preamp was on the tape mech, so I intercepted the audio between there and the main board, wired to a switched jack outside the unit. The bluetooth receiver was on a switched ignition source routed to this new line in. I had one of those old tape adapters pictured above, but with the cord removed. Whenever it was in, the bluetooth input was active and I just ejected it to have FM radio. I also had one where I cut the FM audio traces on the main board and wired to an 1/8" switched jack mounted remotely. These kind of cheap/free mods are good for short-term solutions when you have better things to spend time/money on than doing a whole sound system.

But I suppose you're talking about killing tape function and using the button as a bluetooth changeover. You just need a relay and a latch circuit.

It does look possible in the schematic below. You definitely don't need tape functionality this day in age...

 

[dyeager535]

But I suppose you're talking about killing tape function and using the button as a bluetooth changeover. You just need a relay and a latch circuit.

Actually there wouldn't be anything particularly wrong with using a tape as you mention. That would certainly be easier than retrofitting a switch and relay.

No added switches necessary except the bluetooth, and that could be wired to just come on when the key is on if the simplest method would work for someone. But with a phones bluetooth configured to connect automatically for most people I assume, it would make a bit more sense to switch the bluetooth receiver on when needed.

Now if there was a way to get the bluetooth receiver to trigger the cassette short, that would be even better. Phone rings or music is playing, radio cuts out and automatically switches to phone. The same way modern cars are setup.