Can Someone Help Me Make This Connection??

[Andrew F. Ali]

Hi Team.
I need to connect a low power amplifier (2W) to and Booster amplifier (100W). The speaker outputs from the low power amp must be connected to the inputs of the high power amp. My problem is that the speaker out wires are floating ground that is the -ve wire is independent of chassis ground and the input to the high power amp is Negative Ground-Chassis ground. Is there a safe way to connect these together without leaving the Speaker out -ve wires on the Low amp disconnected which may lead to Output ICs damage due to leaving circuit opened?
Please see the picture attached

[Andrew F. Ali]

Re: Can Someone Help Me Make This Connection??

BUMP....Anything anyone???

[R_J]

Re: Can Someone Help Me Make This Connection??

Is this a car stereo/amp ? if it is you need a floating ground adaptor, basically an isolation transformer for each channel. the left and right channels drive the isolated primaries and the secondaries can have a common ground and drive the amp.

something like this https://www.amazon.com/Scosche-Stere.../dp/B001GQ2QW2

[keeney123]

Re: Can Someone Help Me Make This Connection??

Hi Team.
I need to connect a low power amplifier (2W) to and Booster amplifier (100W). The speaker outputs from the low power amp must be connected to the inputs of the high power amp. My problem is that the speaker out wires are floating ground that is the -ve wire is independent of chassis ground and the input to the high power amp is Negative Ground-Chassis ground. Is there a safe way to connect these together without leaving the Speaker out -ve wires on the Low amp disconnected which may lead to Output ICs damage due to leaving circuit opened?
Please see the picture attached

So what low power amp do you have and do you have a schematic for it?

[stj]

Re: Can Someone Help Me Make This Connection??

what R_J said, i had one once from Radio Shack.
or try to bypass the original amplifier - or is it built into the audio source?

[Andrew F. Ali]

Re: Can Someone Help Me Make This Connection??

Thanks....Yes this is for a car audio set up...the head unit/radio has the floating ground speaker outputs....the equalizer/booster has no RCA inputs...the inputs connect directly to the speaker connections on the radio but the inputs are left and right with a -ve GND connection only.

[budm]

Re: Can Someone Help Me Make This Connection??

So the 2W amp uses Bridged (BTL) output set up so the speaker connection is not reference to GND, if that is the case then you can use a DC blocking cap on the + of the 2W amp to feed the input of the power amp, the GND will be the common GND.
I.E.
https://cdn.badcaps-static.com/pdfs/...f84e4e8597.pdf

[keeney123]

Re: Can Someone Help Me Make This Connection??

So the 2W amp uses Bridged (BTL) output set up so the speaker connection is not reference to GND, if that is the case then you can use a DC blocking cap on the + of the 2W amp to feed the input of the power amp, the GND will be the common GND.
I.E.
https://cdn.badcaps-static.com/pdfs/...f84e4e8597.pdf

There you go, by blocking the DC you eliminate the first stage DC being referenced to ground and yet allow the Signal component to pass to the second stage and the signal will still be amplified by the first stage. Well done BudM.

[Andrew F. Ali]

Re: Can Someone Help Me Make This Connection??

So the 2W amp uses Bridged (BTL) output set up so the speaker connection is not reference to GND, if that is the case then you can use a DC blocking cap on the + of the 2W amp to feed the input of the power amp, the GND will be the common GND.
I.E.
https://cdn.badcaps-static.com/pdfs/...f84e4e8597.pdf

Thanks...I'll do just that...thanks to everyone who chimed in to help.