We’re having a hot, muggy summer in LA this year. I’ve been spending more time in the pool than in the workshop. However I have had a bit of time to start preparing my ASR10’s for sale. In doing so, I made an unfortunate, albeit interesting discovery.

I had made a clone of the SCSI board (model SP-3) for the ASR-10. The first batch I did used the same SCSI controller as the original board, an AM33C93 from AMD. For the second batch, I had found some Western Digital WD33C93. The EPS16 SCSI board had used the Western Digital version, so I figured everything would be cool…unfortunately not.

I had done most of the testing on a first-run ASR-10 with a mainboard dated 1992. All the testing with the second batch of SCSI cards was good. However the past week when I was preparing another ASR10, I found some issues. Although it would boot from a SCSI drive, the ‘change storage device’ and ‘copy OS to drive’ would give ‘file operation error’. Long story short, the ASR10 in question had a mainboard dated 1993 which had been redesigned. The newer mainboard did not like the WD33C93, but was happy with the AM33C93. In fact the AMD version worked properly with all revisions.

I did a bit of research and found that the WD versions had several revisions; the latest being 00-08. The chips I used were a mix of 00-04 and 00-06 which were reported to contain various bugs, although I was not able to get the specifics on what was affected. Apparently the AMD version was equivalent, or derived from, the 00-08 version of the WD controller. Perhaps the first generation ASR mainboard was designed to be compatible with the WD controller, and once they switched over to AMD, this compatibility was removed…

So…for anyone who bought the SCSI board with the WD controller (it’s the only square chip and has WD printed on it), I’ll happily replace the board or just the SCSI controller. Contact me and I’ll get it sorted out.

I haven’t posted in quite some time. The usual excuses apply: work, family, lack of motivation. However I have had numerous requests for a solution for the CEM5530 IC. I designed such a board back in 2000, and the bare PCB’s sat collecting dust in a drawer until somebody mentioned that I had some of them. Within a few weeks all 30 boards were gone (including the ones in my two Prophet VS’s).  I had re-done the design as a 4 layer PCB to make it even smaller and the latest batch are built and assembled by a factory (instead of being hand assembled by me). The price of the boards is 50.00 each plus shipping.

The DSM-1 project has stagnated a bit. However I will be revisiting it soon.

The DSS-1 kits are almost sold out. As of today there are two left. I won’t be making any more until after the DSM-1 kit is done, the new DSS-1 kit will be based on the DSM-1 kit.

The new 5530’s getting ready for wave soldering at the factory:



My move to the new house is complete, so I’ll begin manufacturing DSS-1 kits shortly. I expect them to be ready by end of March. There are 20 kits left at $250 each. As always, installation by a professional service center is strongly recommended.

EDIT: The new kits have arrived! The PCB assembly company did a great job. There was a bit of a delay due to some components I forgot to order.


I’m at work, sick as a dog, replacing the mounting bolts of our surround speakers in our mixing rooms. I hope everyone is having a relaxing and enjoyable holiday, and maybe even making music with their favorite synths!!

When I get a minute or two I’m finishing up my final batch of OB-Mx voice boards that I started building over 6 years ago. I put them on hold since I didn’t have any CEM3374’s or CEM3382’s to finish them. But thanks to John Leimseider in Canada, and Vintage Planet, I’m going to have another 12 voice OB-Mx to play with.


I have just recieved a shipment of ASR-10 SCSI boards, so if you’re interested send me a message with the contact form and let me know your PayPal address if different than your regular e-mail. The price is 299.00 USD plus shipping (10.00 USA and Canada, 15.00 rest of the world).

I’m having my boards assembled at a factory now, instead of building them myself, so once I’m sold out it takes longer to get new ones.

Here’s a short summary of where I’m at with my current projects. I’ll be moving (finally) and won’t be set back up until mid December at the earliest. That means that once the existing stock of kits is sold out, there won’t be any more until early next year.

DSS-1 upgrade: 7 kits available now, another 20 after the new year. After that I’m going to focus on the DSM-1 upgrade.

ASR-10 SCSI kit: 30 being built, expected availability 11/15/2013

ASR-10 Digital I/O kit: 15 available. Still have to figure out the rack ASR problem with overheating.

EPS-16 SCSI kit: 20 available

Prophet 3000 memory expansion: being beta tested. Basically working but having some issues with memory test giving false errors.

Prophet 2000 memory expansion: Not started, but I think Wine Country Productions have them in stock

Korg DSM-1 upgrade: Being researched, I’ve got the code around 30% disassembled and commented. After that I have to decide which microcontroller I should use.


I’ll soon be moving to a new house, and until then I’ll be suspending work on all projects. I’ll have some upgrades available in limited quantities. Also, I’m currently preparing to have all my board assembly done by another company. I’m just not able to keep up with the backlog of orders.

I’ve also sold out of the modified DSS-1’s. I won’t be selling any more of these myself, but I have several sources that can modify a stock one for you. I have around 25 kits left, and after that there won’t be any for a while, as I’ll be focusing my efforts on the DSM-1. Please feel free to submit ideas and enhancements.