Help needed. Setting up av processor and 2 channel amp with no AV Bypass. Input trim/volume levels

Timmy C

Distinguished Member
Just set up my old av processor to use in conjunction with my Arcam 2 channel amp as I was missing having rear speakers. I've always used amps with HT bypass in the past but this particular amp doesn't have that option and as I'm using a processor and not an av receiver, a speakers switch isn't an option.

So I have set it up as you would expect. Processor out to one of the inputs on the Arcam, set the Arcam volume to a reasonable level and then level matched the speakers using the processor. All seems ok to a point.

However, the Arcam has an option to select input trim for each input. The choices being 1v, 2v or 4v. It is set to 2v by default but suggests changing to 1v for sources with low output levels and 4v for those with very high output levels. Now given I will be using the processor volume control on this input, I assume that means the input level is variable and perhaps low or am I completely barking up the wrong tree?


While I have plenty of experience setting this kind of thing up, I have no idea what goes on inside them so please go easy with any explanation of how this input trim works. Thanks in advance.
 
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Timmy C

Distinguished Member
Brief experimenting suggests I get the same result from three different methods...

1. L/R set up levels boosted a lot on the Lexicon with Arcam volume fixed at 60. I think I found the Lexicon master volume also needed to be set unusually high for a decent volume with this method.

2. L/R levels lower on the the Lexicon, Arcam fixed at 60 and Arcam input trim setting changed from 2V(default) to 1v.

3. L/R levels lower on Lexicon but with Arcam main volume up to 70 with input trim back on the default 2v setting. ( I hoped to avoid this method in case anyone accidentally switched inputs with volume at that level.)

So all these methods appear to make things sound similar after a brief test but are they all doing the same thing internally? Am I potentially gaining or losing anything depending on which method I use?
 
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