Non Bose stereo with Bose speakers
#11
09-04-2008, 08:15 PM
RE: Non Bose stereo with Bose speakers
Hey i have a c4 and i am also replacing the head unit. i found a wiring harness adapter that has the same plugs as the reciever that comes stock in the corvette (GMDA). i was wondering if i remove the reciever and wire this plug to the new head unit and everything that was plugged into the stock reciever should plug into the harness adapter to the head unit, am i correct in this? if not how do i wire this up. also i read something about inline gain adjusters so you dont blow out your speakers. thanks
#12
09-26-2008, 09:51 PM
RE: Non Bose stereo with Bose speakers
I totally missed this request. I do not frequent the boards that much because work keeps me very occupied. I am looking for a diagram / schematic, that I made, and I will post it ASAP.
The adapter parts can be purchased from Radio Shack or similar parts source. They are very common parts. The transformers are from "ground loop" isolators. Radio Shack has a two-channel ground loop isolator, which actuallyuses fairly decent transformers. What I mean by this is that they have good bandwidth, which means the adapter will not limit the sound quality of your system. (In theory anything in between your head unit and amplifiers will affect sound quality, but in this case 99% of us will not hear it) You will need two ground loop isolators because you need to make a four-channel adapter for the C4 Bose interface.
The ground loop isolators are usually packaged in plastic or metal cylindrical enclosures. They are fairly easy to get open. After you open the enclosure, unsolder the transformers and RCA wires from the small circuit board. All you need are the transformers and RCA wires. You can discard the rest. A small plastic enclosure will also need to be purcahsed from Radio Shack in order to place the transformers and capacitors inside to make a nice adapter. The only part that is tricky is wiring ALL the transformers the same way. If the transformers are not wired in the correct manner, some of your channels may be "out of phase" with one another. Phase is a relative term and as long as everything is "in phase" this is all that matters. (I am certain that some people would disagree, but for the purpose of this adapter we will not go there)
Theory of Operation
The transformers provide isolation from any dc-offset (from the head unit) and also prevent thumps / pops from being injected into the system. The capacitorsblock the dc-offset from the Bose amplifier input circuitry and provide an AC signal path. The 20k resistors provide a return path to ground for proper operation. A small voltage is present on the negative side of the capacitor due to the dc-offset coming from the Bose amp and the 20k resistors "bleed" it to ground.
I have made two of these adapters and both have worked great. I installed one in my '92 and one in a buddy's '96.
CG
The adapter parts can be purchased from Radio Shack or similar parts source. They are very common parts. The transformers are from "ground loop" isolators. Radio Shack has a two-channel ground loop isolator, which actuallyuses fairly decent transformers. What I mean by this is that they have good bandwidth, which means the adapter will not limit the sound quality of your system. (In theory anything in between your head unit and amplifiers will affect sound quality, but in this case 99% of us will not hear it) You will need two ground loop isolators because you need to make a four-channel adapter for the C4 Bose interface.
The ground loop isolators are usually packaged in plastic or metal cylindrical enclosures. They are fairly easy to get open. After you open the enclosure, unsolder the transformers and RCA wires from the small circuit board. All you need are the transformers and RCA wires. You can discard the rest. A small plastic enclosure will also need to be purcahsed from Radio Shack in order to place the transformers and capacitors inside to make a nice adapter. The only part that is tricky is wiring ALL the transformers the same way. If the transformers are not wired in the correct manner, some of your channels may be "out of phase" with one another. Phase is a relative term and as long as everything is "in phase" this is all that matters. (I am certain that some people would disagree, but for the purpose of this adapter we will not go there)
Theory of Operation
The transformers provide isolation from any dc-offset (from the head unit) and also prevent thumps / pops from being injected into the system. The capacitorsblock the dc-offset from the Bose amplifier input circuitry and provide an AC signal path. The 20k resistors provide a return path to ground for proper operation. A small voltage is present on the negative side of the capacitor due to the dc-offset coming from the Bose amp and the 20k resistors "bleed" it to ground.
I have made two of these adapters and both have worked great. I installed one in my '92 and one in a buddy's '96.
CG
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