More Sorcerer musings. Cassette interface issue, or a MESS programming issue?

Thanks for the encouragement RE: the Exidy Sorcerer BASIC ROM-PAC. This weekend I'll unpack the ROM burner, read the docs that come with it and take it from there. In the meantime here is another thing to ponder. I had problems loading in machine-language (not BASIC of course) software seem to load successfully expect for the shortest program. Ok, so I figured the tapes were just old and degraded. Googling around and trying things out I found I could make sound files (WAV) from cassette binary archives of Sorcerer software using the MESS emulator. Hooray! BUT...loading these into the Sorcerer via soundcard seemed tricky. No matter how much I fiddled with the volume and tone controls, an error always seemed to appear about 45 seconds to a minute into the run. Very fine adjustments made a slight difference, but the only program I could get to load in was actually a copy of the short file (Martian Invaders) that I'd successfully loaded via real tape. Off the top of my head I think it was just over a minute long (it could be longer). I looked at the WAV file with Audacity. They were nice square waves with a good amptitude. They certainly LOOKED ok. Hmmmm.... After scratching my head a bit, I started to wonder if it was a timing issue? I wondered if somehow the Sorcerer was eventually losing synch with the input data. Acting on this hunch, using Audacity I converted the sound file so it was 5% faster. No improvement. Then I tried 5% slower. Wow, I found that the load got further. Instead of falling over after about 45 seconds it was about 1.30 seconds or so. The volume also didn't seem quite as critical. Eventually after playing around and finding the limits I discovered that if I made the WAV files 8.5% slower I'd always get a successful load no matter how large the file (actually tolerance seemed to be between 7.5% and 9.5%). The more I moved outside those tolerance parameters, the quicker a load failed. Now the question is this. 1. Was it caused by an error in code in the MESS emulator, in that the sound files were created with the timing 8.5% faster than it should be OR.... 2. Is there something out of whack with the cassette interface in my machine (a cap out of tolerance maybe) which gives an incorrect timing/synch on load. Making the files 8.5% slower counteracted this fault, so a successful load was (always) accomplished? Any thoughts on this? At first I assumed it was just an error in MESS. That someone just got the timing wrong when writing the tape output routine. Thinking about it, now I'm not so sure? I couldn't seem to get any of the REAL tapes to load except for Martian Invasion (the shortest one). Happily as well as having a real tape, Martian Invasion was also in the binary archive. Before changing the speed, I could also get the Martian Invasion WAV to load with fine volume fiddling. So maybe it is the Sorcerer that's out of synch rather than MESS? I don't know, but it would be good to find out which one of the hypothese is correct. I might try to digitize the tapes. If I get nice square wavs, I'll see if I can slow these down by 8.5%. If I do, then can successfully load them into the Sorcerer, this would indicate that the problem is with my machine rather than MESS. Terry (Tez)