ArthurDaniels
Posted
3 years 9 months ago
The Cambridge 851A Puzzle Continues:
Last Tuesday (3 days ago), the owner of the shop to which I had taken the unit for possible diagnosis and repair, called me to report that he had subjected the unit to a number of tests, but had been unsuccessful in replicating the right-channel lower-volume output problem I had described to him.
I thanked him for his effort and retrieved the amp, brought it home and installed it into my system. While installing, I decided to try a slightly different connection approach. My external Cambridge DAC Magic 100 has both Balanced and Unbalanced (RCA) audio outputs. The amp offers a pair of Balanced/Unbalanced inputs and a separate group of several Unbalanced inputs. The pair of Balanced/Unbalanced inputs are controlled by a set of switching relays, while the separate group of Unbalanced inputs bypasses the relay board.
My thought was to be able to easily switch from Balanced to Unbalanced inputs if the problem recurred, in order to determine whether or not the problem was somehow related to the switching relays. When I first fired up the unit, I was listening in the Unbalanced mode and the problem occurred. I applied the usual fix of playing a mono test track through the right channel and the problem immediately corrected, including hearing the "Pop" sound just before the right-channel volume corrected.
However, I have now been listening to the unit for 3 days and the problem has not recurred. I have turned the unit off and on a number of times; I have switched between Balanced and Unbalanced inputs several times; I have repeatedly changed the Volume control to a variety of different volume levels -- no issues whatever in any mode or at any time.
I am "holding my breath" when I type this, but it appears that something has changed somewhere because, previously, the problem would have repeatedly occurred during a typical listening session. Perhaps the "Little Audio Gremlin" sensed his end-of-life status in my amplifier and moved on to hassle someone else.
In any event, I am enjoying listening to music without right-channel volume problems.
Happy Listening, everybody
Art
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