Interesting B215 factoid..B710 the same?
I thought I had an issue with one of my B215s, as I had noticed recordings had lower output than other decks that were recording the same thing at the same time, yet the meters were set close to the same levels. I was using SA tape, dolby C, and set the peaks at about +5. When I checked it on the bench I found something strange. With Type I and II tapes only, 0 db recording level in at 400 Hz, becomes +8 db indicated on the level meters at 18kHz. Yet when played back, all frequencies are at 0dB. I had contacted ANT and asked him about it, and he suggested it might be normal. I poured over the schematics, located the meter circuit, and sure enough there is a switch that when non-metal is selected, and in rec mode, the gain on the initial op-amp increases with frequency. Then I did the obvious thing, and tried the same thing on my other B215 and it was exactly the same. But since on that one I'd been primarily using Type IV, I never noticed it. I'm assuming Revox did this in order to allow about the same recording levels on the deck meters regardless of tape type chosen, but if there is a lot of high frequency content, then the EQ would show higher than the actual level to the head, and record lower to prevent saturation distortion. I guess they felt that metals could handle a lot more highs before that happens (which is true). I just wondered if the B710 does the same thing..anyone ever try it with test gear?
|
02-06-2010, 08:43 AM
Linear Mode
