Upgrade stock amp along with speakers?

[Rtlane]

I have a 1989 GMC Sierra with tape deck and equalizer. I’m assuming I also have an amp with this unit? If so, can I upgrade the stock amp along with my stock 4x6 speakers or is it even necessary to upgrade amp? I might eventually add a amp and small sub, but not yet. I want to keep the the head unit stock because i want to retain the look.

 

[Nad_Yvalhosert]

No such thing as a factory amplifier in 1989

 

[DerekTheGreat]

Well, it does have an amplifier but it's part of the brainbox (CDM) which controls the other stuff such as the clock. You'll find that above and to the right of the gas pedal. Something like three 7mm bolts hold it in place.

As for an upgrade? Check this thread out started by AK49BL: https://www.gmt400.com/threads/88-94-factory-stereo-info.48716/

There's a lot of good info in there along with photos to help identify which units to hunt for. Essentially, if you want to keep the stock set up you'll need to hunt for a CDM from another equalizer equipped unit with the upgraded cooling fins. Pull that unit, cross reference it with AK49BL's list to check it's the right one and install in your truck. That's what I did and have found it adds a bit more oomph as well as ability to drive lower impedance speakers- the display doesn't dim nearly as much as the old CDM I had (My truck is also an '89). As for speakers? I highly recommend Infinity Kappa 64CX 4x6 plate speakers: https://www.infinityspeakers.com/ka...r=Black-USA-Current&cgid=kappa-series#start=1

You can find them cheaper elsewhere, but that's got accurate factory specs, one of the most important being sensitivity. At 94dB (1w/1m), that's the lowest I would go with a factory set-up. It'll be louder than you remember and will actually sound much, much better.

 

[Rtlane]

Well, it does have an amplifier but it's part of the brainbox (CDM) which controls the other stuff such as the clock. You'll find that above and to the right of the gas pedal. Something like three 7mm bolts hold it in place.

As for an upgrade? Check this thread out started by AK49BL: https://www.gmt400.com/threads/88-94-factory-stereo-info.48716/

There's a lot of good info in there along with photos to help identify which units to hunt for. Essentially, if you want to keep the stock set up you'll need to hunt for a CDM from another equalizer equipped unit with the upgraded cooling fins. Pull that unit, cross reference it with AK49BL's list to check it's the right one and install in your truck. That's what I did and have found it adds a bit more oomph as well as ability to drive lower impedance speakers- the display doesn't dim nearly as much as the old CDM I had (My truck is also an '89). As for speakers? I highly recommend Infinity Kappa 64CX 4x6 plate speakers: https://www.infinityspeakers.com/kappa-series/KAPPA+64CFX_.html?dwvar_KAPPA 64CFX___color=Black-USA-Current&cgid=kappa-series#start=1

You can find them cheaper elsewhere, but that's got accurate factory specs, one of the most important being sensitivity. At 94dB (1w/1m), that's the lowest I would go with a factory set-up. It'll be louder than you remember and will actually sound much, much better.

Thank you for the info. My cdm is 16072780. I’ll start looking for the better ones and also look into those speakers. I see everyone recommends them quite often. Do you happen to know how may extra watts the other CDM’s are pushing versus mine?

 

[DerekTheGreat]

No, not exactly. Not sure if AK measured the output of them or not either. It's probably something trivial like an extra five or ten. I think the big thing is they can supply more current than the older ones. With audio watts, it's the land of diminishing returns. So if you start with say 10 watts and take yourself to 100, you are not going to end up with a system that is ten times louder. That's why sensitivity is so important. When you dissect the test, xx dB @ 1 watt/1 meter away, it takes a second to see that only 1 watt gives you whatever volume that particular speaker was rated at. In the case of the Infinities, it's 94. But, juicing them with say 50 watts may only increase their output to like 100 or 98 dB. So a lot of people (especially in the home audio world) spend big bux on big watt amplifiers to drive their inefficient speakers in search of higher SPL's. Money better spent would have taken them over to the folks at Klipsch who offer several products that are rated in excess of 100 dB @ 1w/1m.

 

[HeavyAsAChevy]

Also some other speakers to check out arehttps://www.crutchfield.com/p_20647KSC46/Kicker-47KSC4604.html
Put them in mine and they work amazing. If you order them from crutch field you can get the plugs for the factory harnesses for free as well. Idk if others do that. I’ve only ordered from them once.

 

[DerekTheGreat]

I wouldn't recommend those, 88 dB sensitivity. That would be real pooey with the stock amp.

 

[BaySHO_510]

You can also use a quality line output converter to create a rca connection from the factory speaker wires.
At that point you'd have more options for amp / speaker / sub combinations & wouldn't have to rely on 30 year old equipment to power your speakers, you're just tapping into the audio signal. You can spend as low as $12 or a few hundred depending on fancy you want to get.

Rockford Fosgate RF-HLC4

4-channel line output converter

www.crutchfield.com