unable to adjust the volume after replacing my RX330 factory amplifier

[gneth]

I've recently replaced my 05 Lexus RX330 factory Pioneer amplifier with a macrom 4150 while retaining the orginal head unit. The sound produced by the amplifier was terrific but I was unable to adjust the volume up or down. I really hope that anyone could give me some advise on that? Thanks!

[psk]

I have a 2007 Camry Hybrid so I'm not sure if it is the same issue, but I believe there is some sort of two way communication between the head unit and the amp that controls volume among other things.

The installer and I came across this problem in doing my install of a new amp as well. There is not an easy solution to this. Hopefully you didn't throw away your amp b/c you will need it or replace your head unit as well.

I am getting an Audio Control LC8 to solve this problem and other problems (no single full range single to send to my amp - so need summing feature of LC8).

[gneth]

I thought so. In fact, I'm suspecting the AVC-LAN protocol Toyota implemented between the head unit and stock amplifier for two way communication.

Anyway, the sad thing is my stock amplifier is damaged. So, could you give me more details about the audio control LC8 you mentioned. How does it work with the factory head unit?

Thanks.

[psk]

If your factory amp is messed up you are in trouble b/c I don't beleive you can overcome the volume problem. However I am not an expert, I am just someone that is in the middle of an install and came across the same problem.

My solution was to KEEP the amp and then run the output of the amp to the LC8 which sums the signals and down converts it to the signal level (like a line converter would), which I can then send to a 'good' amp and then to the speakers. So I had to keep the existing amp in the signal chain.

At this point I am assuming you will have to replace the head unit or get another amp - again I am not an expert.

I'm sure there may be other models like the LC8 that do this but my installer choose this one. The purpose of the LC8 or similar product is to sum the signals and convert the signal from the speaker level signal to a signal level to input to an amp. The reason I needed to sum the signal is that the output of the factory amp had outputs for a front tweeter and front woofer and I was in essence sending the signal from these two separate signals to one speaker (really a 2 piece componant but from a signal view it was one signal) so I did not have a full range signal to send to the good amp that was full range ergo the summing function on the LC8.

[TS Support]

Originally Posted by gneth

I've recently replaced my 05 Lexus RX330 factory Pioneer amplifier with a macrom 4150 while retaining the orginal head unit. The sound produced by the amplifier was terrific but I was unable to adjust the volume up or down. I really hope that anyone could give me some advise on that? Thanks!

The '04 and newer RX330 utilizes an AVC-LAN (Audio Visual Communication-
Local Area Network) multiplex communication between the head unit and amplifier. You can't bypass the factory amp without running into these types of issues.