# Tuning old amp



## toucansam (Aug 7, 2020)

Got an older Alpine from the 90s, MRV-F300.

The head unit I am considering has 4v out on the RCAs. 

I've seen modern amps with input level controls, to detect and eliminate clipping coming from the head unit.

Since my old amp doesn't have such input controls, how can I properly tune the signal coming out of the source and into the amp?


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## sqshoestring (Jun 19, 2007)

Play a sine and scope it, you will see the clipping when it starts. I'm not sure how an amp can eliminate clipping it would have to make its own source signal, but what do I know.

If your head clips its not that good, and if it clips you just have to not use that clipped louder signal. So you end up only running the HU to 80% or whatever safe level it can provide without clipping and set your gains around that, and hope some jerk does not drive your car and crank it way up.

In the old days we didn't have scopes, you just turn the amp gains way down and HU way up and listen for clipping. You can figure where it needs to be for a safe zone without clipping.


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## toucansam (Aug 7, 2020)

I don't have an o-scope.

Back in the day, yeah, we tuned by ear. I'm told there are better methods these days, and that tuning by ear can still lead to clipping and distortion, essentially unheard. 

Just trying to get the most out of an older amp, and don't want to damage any components.


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## MikeMcChiken (Dec 23, 2020)

We used to run a deck and Sanyo PA6100's . They had no gain . We had gains on eq's if we installed them but a lot of amps in the 80's just didnt have them . We didnt care . The amps were designed for the equipment in its time and worked fine . Many decks back then put out 4-5volts on the preamps . Nowadays you see head units that only put out a couple volts and have to search for the good ones . Kenwood , Sony , Pioneer and Alpine all have decks with 4-5 volts preamps . If you noticed some time in the 2000's the recording volume on CD's changed . Our recording levels were much lower in the 80's and 90's . Now they are higher and output voltages are lower . Maybe that has to do with what we are talking about . Why the industry changed is beyond me


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