Rush fan Mark Z recently acquired an old rough cut demo tape of Rush's Presto that had been discovered amongst the belongings of a former Alex Lifeson guitar tech who passed away (likely Jimmy Johnson). The old TDK cassette tape was labeled RUSH Rough mixes, and included the Le Studio logo and address/phone. With the help of fellow Rush fan Danny de Hoyos, the pair digitized the cassette and made it available on YouTube. Here are all the details via Mark Z's post to the Neil Peart Drums and Drumming Facebook group:

As an avid collector of all things Rush, I recently stumbled upon something that I feel needs to be shared. In my ongoing hunt for some obscure piece of Rush history, I was given the opportunity to acquire an old school TDK cassette tape, simply labeled RUSH "Rough Mixes" July 1, 1989 along with a few other band related artifacts. The fact that it had a Le Studio label really caught my interest. The date on the cassette and the tracks listed, albeit out of order, made it obvious it was the album Presto. The owner of this tape was not a fan of the band, just a guy that flipped houses. Turns out he discovered the tape in the old residence of one of Alex's since deceased long time guitar techs. After striking a deal for about a dozen itineraries from the Power Windows and Grace Under Pressure tours, a super cool SRO patch and a bunch of random other documents from Le Studio, I decided to take a chance on the cassette. Was it blank? Was I scammed?
When the casette arrived, poorly packed in just a bubble mailer, I realized I had no device readily available to actually play it! Off to the garage to find my Fisher dual cassette CD Boombox with detachable speakers. I found a different cassette, pressed play, and my boombox still worked. Sigh of relief. Now what about this 35 year old TDK SA90 I just got. I didn't expect much, and cautiously pressed play, and right out of the gate, Show Don't Tell, was somewhat different! I'm playing a 35 year old cassette in a 30 year old cassette player... and it sounds AMAZING! Literal chills. I'm sitting there listening to Rough Mix versions of songs very few people have ever had the opportunity to hear..... until now. Needless to say, the original tape has since been backed up I am honored to share this piece of Rush history and I hope you all enjoy it. Please share it.
Special thanks to Danny de Hoyos for all his efforts and assistance in putting this all together on YouTube.

You can check it out yourself below or on YouTube. Thanks to John at Cygnus-X1.net for the heads up.