2. amps-preamps
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Am I damaging my Preamp?

All:

I have an analog preamp (Audio Refinement Pre5), and 3 sources (DVD player, Computer, and outboard DD decoder).

The DVD player is fixed output
The computer soundcard is variable (ie. volume control)
The decoder is also variable (ie. volume control)

I have the DVD player into the preamp, and it sounds great.

I have the two variable output devices hooked into the amp. The problem is that they sound a little thin, this way. However, when I pass them through the preamp, they sound warm and nice! Much preferred.

My question is, am I doing damage to the sensitive inputs of the preamp by doing this? I've been told to not ever plug a variable output into your preamp inputs: you’ll kill the pre by overloading it’s sensitive preamp inputs. Is it safe to do this if I keep the volume low on the source, and just use the pre-amp volume to listen to my music?

What I described above is really no different then the millions of people out there with their iPods and MP3 players, each with their own volume control for their headphones. But they basically go through the same thing I described, when they take their mini-headphone jack and output it to the input of their own receiver via L/R RCAs. Double-volume and all.

Thanks for any help!

Jason
jfiluk
4 responses Add your response
ghostrider45
449 posts
 
I can't imagine how you'd damage a line level input by feeding it a line level signal, even though it might be relatively high level. The worst that could happen is you'd overload the input, resulting in obvious distortion but no damage.

Since you say it sounds good, continue on without fear.
sean
6,231 posts
 
Simply adjust the output levels on the variable devices so that they provide you with the same listening level as the fixed DVD player does. If the variables have to be turned all the way up, that's fine. That just means that the variables are putting out a standard line level signal when they are wide open and allow you to attenuate it as needed. Some variables may be a tad hotter than line level, hence the ability to attenuate as needed. Either way, your preamp should be able to cope with a slightly "hotter" input signal so long as they aren't WAY above 2 volts. Sean
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jfiluk OP
8 posts
 
I'm worried that I might overload and destroy the input devices (transistors, caps, chips) and potentially the pc board itself (which would mean you’re totally screwed). You know that silicon burning smell… but you guys are probably right -- it will sound like krap before this happens.
sean
6,231 posts
 
Believe me, typical phenolic PC boards don't burn all that easily. You would have to have a pretty sizable amount of sustained heat in order to do something like that. Even if that were to happen ANY circuit board can be repaired. That is, unless it is a molten chunk of refuse.

Other than that, just start out very low on the output level and gradually bring it up. When you can reach a good level with the preamp level where it would normally be, you'll be fine. Sean
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