Print through is very common and I have a lot of experience with it.  
It is caused when the magnetized part magnetizes the next layer of  
tape when wrapped around in contact with it. This is the reason  
studio and professional tapes were left tails out - tails out puts  
the print through AFTER the sound, while heads out (consumer tapes)  
put the echo before the sound... called pre-echo. If you listen  
carefully you may hear the echo several times, diminishing each time.

It happens most when the tape is freshly recorded, and does get  
stronger with long term or poorly climate controlled environments.

Unfortunately there is nothing you can tdo about it on playback,  
except perhaps to process the sound with noise reduction - if it is  
voice and the echo comes in the slience between words, a gate or  
expander can help, but it can also make it hard to listen to if over- 

Different formulations of tape have more or less a problem with  
printthrough, and there were specific formulations (such as 3M 208  
instead of 206) that were specifically low-print tapes. And, it  
affects thinner tapes more than thicker tapes.

Hope this helps a little!
Lou Judson  Intuitive Audio

On Mar 31, 2009, at 12:39 PM, Steven Smolian wrote:

> It's call print-through.  If it's not covered suffciently on the  
> internet, email me again.
> Steve Smolian
> ----- Original Message ----- From: "Frances, Melodie"  
> <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Tuesday, March 31, 2009 3:25 PM
> Subject: [ARSCLIST] Old reel to reel 'echo' problem
> All,
> I am not even sure 'echo' is the correct term, but with our old  
> reel to
> reel tapes (and I have had this experience with personal cassettes),
> there is this thing I am calling echo - where what the person says is
> repeated at a fairly low level - you can usually only really hear it
> when there is silence - and it is basically a repeat of what had just
> been said - so not really a echo but more like a delayed  
> repetition. Is
> this a head cleaning problem? Or a problem that can be fixed? Does
> anyone even know what I'm talking about, and if so, what is it called?
> Thanks
> Melodie Morgan Frances