Replacement amplifier..

[NickW]

We've owned our 2008 new shape Alphard for >1yr now and have a done a few good trips to the Alps with incident. We upgraded the stereo/satnav etc to a touch screen at the start of this year and its worked very well. However, about 1 month ago, when playing music quite loud, there was some crackling and then the sound almost disappeared. It came back briefly, and then went again and hasn't come back since. The front speakers do play, but only at a low volume even when turned up to the max. We have the 18 speaker system and the other speakers appear not to be playing but in fact are playing but very very quietly. We took the car to one car audio specialist who just didn't want to know. We then took it back to the chap that installed the touch screen and he checked fuses etc and says it's probably the amplifier. A quick ebay search results in several Alphard amplifiers for sale, which suggests they frequently fail. What I'm in need of is a specialist that has tested and then replaced an Alphard amplifier before. Any thoughts? Many thanks,..   

[Rojie]

On 12/1/2023 at 4:50 PM, NickW said:

We've owned our 2008 new shape Alphard for >1yr now and have a done a few good trips to the Alps with incident. We upgraded the stereo/satnav etc to a touch screen at the start of this year and its worked very well. However, about 1 month ago, when playing music quite loud, there was some crackling and then the sound almost disappeared. It came back briefly, and then went again and hasn't come back since. The front speakers do play, but only at a low volume even when turned up to the max. We have the 18 speaker system and the other speakers appear not to be playing but in fact are playing but very very quietly. We took the car to one car audio specialist who just didn't want to know. We then took it back to the chap that installed the touch screen and he checked fuses etc and says it's probably the amplifier. A quick ebay search results in several Alphard amplifiers for sale, which suggests they frequently fail. What I'm in need of is a specialist that has tested and then replaced an Alphard amplifier before. Any thoughts? Many thanks,..   

 

Hello Nick,

 

Welcome to the Forum.

 

I don't agree with your assumption that they 'frequently fail'.

 

I feel quite certain I haven't read about any failing in this forum.

I have read about many being replaced, but that is quite different as many wish to upgrade the head unit facilities / functions.

 

As a retired Electronics Engineer I can assure you running any amplifier at, or near, full volume is just asking for trouble.

There are a very few amplifiers or loudspeakers that can withstand that treatment.

 

Most audio amplifiers will generate increasing levels of distortion (crackling) as maximum power / volume is approached.

That distortion frequently destroys speakers.

 

My advice ?

 

Before spending 'many pennies' on a 'new' multi-channel amplifier I would have the speakers checked first.

If all channels are effected equally you may have a preamplifier problem, i.e. the head unit.

 

Try not to jump too quickly to conclusions; you will need a logical approach to resolve this without spending unnecessarily.

 

Good Luck, I hope it goes well for you.

[Chris.ac]

With the 18 speaker system, there will be a MOST adaptor box connected to the headunit.

I would be more suspicious that that has failed before the 480Watt Toyota amplifier.

 

You have checked both amp fuses in engine bay? 18 speaker system has 2.

Edited January 3 by Chris.ac

[NickW]

Yes, the fuses have been checked by the chap that installed the flat screen. Where is the MOST adapter box located? As the amp is under the passenger seat, most audio repair folk just don't want to know.. Thanks, Nick 

[threepot]

I would agree with chris....

Take the head unit out and look at the little brown box... or it might be a metal box.

It'll just be loose behind the head unit.

 

I'd be tempted to plug the original Toyota head unit back in to make sure it all works on that.