Thursday, April 12, 2012

Marantz 2270 vs 2275: tone defeat

One of my key issues with the Marantz 2270 receiver that I purchased in 1974 was the lack of tone defeat.  Actually, I didn't notice this problem until 1978 or so, when I did some testing and found that the preamp section in this receiver did not have exactly flat frequency response.  The response goes to the extremes, but showed a bit of variation in-between related to the tone controls not being nulled exactly.  When you put the tone controls at the top position, not only are they not switched out, they are not necessarily providing flattest response.  That might require a position just a few degrees left or right from pointing straight up.

Well, that did not leave me with a good feeling.  I had previously discovered that the detents on the tone controls are just that...detents.  These controls are normal potentiometers, not stepped switches.  That had already made me feel ripped off.

Other extremely expensive preamps may have used stepped switches.  I wonder about the Marantz 7's.  It looks from this picture that the 7T does use stepped controls for tone controls, and I think that is true of Model 7 (tube) as well.  Dynaco had a special trick, where when you put the tone controls straight up, they contact a special pad in the control which provides flat response.

Now I see that the model that was replacing the 2270 just at the time I bought mine, the 2275, does in fact have tone defeat.  Back in the day, I had figured that tone defeat would only reduce tiny amounts of noise or distortion by removing an extra stage, because I figured my tone controls set straight up were already providing flat response.

Lack of flat response may indeed mean that comparing two 2270's you might hear slight differences.  And you might prefer the one with less flat response.

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