fyi, here is google's cached version of the old Oade page describing the 4 upgrades doug offered to the mod sbm1. NB that none of them references replacing the a>d converter. i've attached a pdf of the page.http://188.8.131.52/search?q=cache:-hoZ2JpKwq0J:www.oade.com/audiocenter/upgradesbm1.html+oade+sony+sbm-1+upgrades&hl=en
The Sony SBM-1 , is a fine convertor. It is our first choice for in the field A/D conversion. We offer four performance upgrades for this unit.
The first involves replacing the mic preamp circuit. This upgrade is similar to our D7/8 mic input upgrade. It allows for a higher input level before overload and lowers the noise floor, producing a cleaner recording with less hiss. We charge $125.00 for this service.
The second is a Digital I/O upgrade which provides a coax digital output cable. We use the 7 pin cable end to provide a passive 7 pin to Coax "y" adapter for use with the D3/7/8 or in the second Digital I/O port on the SBM-1. The end result is a sturdy 7 pin to RCA "y" Digi I/O cable and a standard coax output on the SBM-1 all for only $150.00.
The third is a line input upgrade which increases the line input gain stage to allow for line in recording with mics that have SLIGHTLY less output than needed for line level input. This upgrade only increases gain. We charge $50.00 for this one.
The fourth is a complete line stage rebuild which dramatically improves the sense of depth and detail in the SBM-1. An additional 6 dB of gain is available at your request, we recommend this only if you are NOT using an external preamp. We disable the mic preamp for this upgrade as the stock chips use too much power. We charge $250.00 for this service. We can do this upgrade with the Mic Input upgrade or either of the first two. There is no discount for combining upgrades.