Custom designed and built vacuum tube devices Vacuum tube testing and sales Vacuum tube tester repair, parts, and sales (limited) Private recording or mixing services (for commercial studio services in the Eugene/Springfield OR area please see Sprout City) (for commercial Mastering services see Liquid Mastering)
Oct 2026 - News: New web site. I was way overdue in updating this site. The software I used was no longer available to me and it was somewhat painfull to preserve the parts I wanted to convert, but it is done. The new software I chose is not proprietary so that shouldn't happen again. I continue to be busy with custom work but the MPAG units are still being built in small batches each year and there are some new products coming down the line.
Mark-O-Matic and the MOM logo are trademarks of Mark-O-Matic LLC
More info:
See the archive area for DIY info
● SS83 ● Apex 460 mod ● V69 mod
Solid State 83 tube replacement
● individually made to order ● Please use the contact page to order ● 11.2 Voltage drop standard