MATRIXSYNTH: 1979 Oberheim SEM Moog 904A Bass Synthesizer Rig System Leland Sklar

Sunday, February 09, 2020

1979 Oberheim SEM Moog 904A Bass Synthesizer Rig System Leland Sklar

via this auction

BRAND: 360 Systems / Oberheim / Moog

MODEL: Slavedriver/Live Performance Synthesizer

FUNCTION: Live Bass Synthesizer Rig

PRODUCT DESCRIPTION: This listing is for a One-of-a-Kind custom built bass synthesizer system built by Wayne Lentis of 360 Systems for Leland Sklar which he used while touring with artist Billy Thorpe supporting his hit song "Children of the Sun" in 1979!

We recently removed this system from Lee's gear locker here in Los Angeles where it has been in storage for 40 years!

What we have here is the Synthesizer section of a very special bass rig that was built for Leland to power his massive 3-Way Klipsch System touring rig. See above for the only known photograph of Lee with it and nearly knocked "unconscious" from its mind blowing power!

As Leland tells it:

"Billy Thorpe was a huge child star in Australia. We did this album and it was a conceptual album that he came up with. Spencer Proffer produced it in his studio in Hollywood called Pasha. We cut it as a trio: it was me and Billy and Alvin Taylor on drums. Billy was great. He was so strong and powerful and into it. He had such a commanding presence.

When we did that album it was another one that became a deep, deep cult thing. We went out and did a few gigs with it and it was really, really fun to play live. I’ve got a bass rig sitting in a warehouse that I put together specifically for playing with Billy. We played Santa Monica Civic out here in L.A., and it took over a semi just for our three guys’ band gear. When they pulled my bass rig in and set it up, they thought it was the PA system. The bass bins were two “W”-folded cabinets that are so huge that it takes like four guys to lift each one. I had two of those, then on top I had four midrange cabinets that were the same shape but they were front-loaded. Then I had four high-end speakers mounted on top of those. I made a trade with the guy who owned Altec Speakers. I had a pile of Yamaha P2200 amps and he wanted a couple of those. I gave him two of mine and he gave me two Altec 1000-watt mono amps. So each bass bin was run by a 1000-watt mono Altec amp. I had six more P2200’s driving all the midrange stuff, and then I used an SVT as a preamp for the rig.

Bob Easton at the time had come up with the 360 Systems Bass Synth, which was a pickup system that ran off the bass, and a guy named Wayne Yentis put this whole thing together. I had a transposition pedal hooked up for the bass synth that I could literally hit my low E string and drop it almost three octaves. We were getting down in the area of 6Hz at probably about 130dB. The first time we actually tested it we all threw up and cracked a wall in the warehouse. It was fantastic. It has been in moth balls since that tour. It is a true hi-fidelity system originally designed for theaters to be able to adequately represent earthquakes and things like that." - Leland Sklar


Built by Wayne Yentis for Leland Sklar
Oberheim SEM Module in custom Blue (housed in custom rackmount panel)
Moog 904A Voltage Controlled Low Pass Filter
360 Systems/Oberheim Live Performance Synthesizer
Sequential Circuits Model 700 Programmer (custom wired; I/O jacks removed)
2 - 360 Systems Slavedriver (with custom side panel controls)
4 - DeArmond Volume Pedals Model 1602 Mounted in beautiful wood Pedalboard w/ Multi-pin Cable
2 - 1U Patch Panel w/ Gooseneck Light Modules
2 - 4U Sliding Drawers (w/misc hand tools and extra parts)
Custom double space wood rack touring case.

PHYSICAL CONDITION: Very Good - Some of the panel labels are "dummy labels" and add to the decor of the unit and do not coincide with any functionality. Many of the lights are also. All modules have some wear but their functional controls are intact and in very good shape. Overall condition is very good.

There are many knobs and lights on this system that are for show only and have no function, unless you know what "Schmook" does!

WORKING CONDITION: Not Fully Tested - All modules power up and appear to be working, how well they are working could not be fully tested without a hexaphonic pickup connector which is required by the rig's input jacks. Several knobs turn very stiff and will need lubrication and exercising. Two of the pedals have a hard time moving the range, but the button-switches on the pedalboard are functioning fine as is indicated by the LED indicators changing along with the pedal switching. But the overall functionality could not be fully tested in depth.

We did no further testing or troubleshooting on this and decided to leave this "as-is" and sell it as very worthwhile project for someone to restore and bring back to its full glory.




  1. Replies
    1. That is the tiotle of an incredible bass solo by Leland on I think the first The Section lp. As a moog player it made my jaw drop when I heard it. This must be the rig used on it.



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