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MC240 input voltage question

Smileysmile

Smileysmile

Member
Hi,

I have a new tube preamp that I want to plug into my MC240 tube amp. Now this amp is used to receive a typical 2.5 volt output from a McIntosh preamp. My new preamp outputs only 1 volt a the pre out RCA jacks. My question is, at which position should I place the twin inputs volume pots of the 240? 3 o'clock, 4 o'clock or maximum? Also, is there any risk to run the 240 volume pots at it's maximum input level permanently? Of course, the preamp has it's own volume control and might not be set to it's maximum level all the time.

Thank you for any input.

JP
 
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The stereo position is fixed at 2.5 volts. The twin input has a maximum sensitivity of .5 volts. I would set the controls at 12:00 at first. And try using the pre-amp see if you hear distortions at normal listening levels. If you have a owners manual you will note Mac says set the volume control on your pre-amp at 12: 00 and advance the amp volume controls to a level set a bit above your critical listening level. This will optimize the two units. Now just because your pre-amp is rated at 1 volt doesn't mean it can't develop the extra required. Most pre-amps have extra head room or safety margin.
 
Thank you, this makes a lot of sense.
But the second part of my question has not been answered. No problem to run the volume pots at their maximum position? I never use electronics, tv or any machine in a hard way or with their controls to the max.
Thanks.
 
Max on the controls won't hurt it any as long as it is clear and undistorted. If there is not enough drive to begin with then it would not distort being maxed out anyway.

I was just thinking about this just other day while playing my Motorola 3 channel console. The turntable has been long gone so I use my MP3 player with it. I have to turn it up to almost 8 on the 1-10 scale but as long as it is clear, it is fine and I don't worry about it because it is doing what it was designed to do without any unnecessary overloading.
 
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