i got these e-mails from SD today:
Thomas,
By all means you are welcome to swap parts in your MP-2. That said, Sound Devices service department performs repair service only, and only repairs to our original specification. We will repair or replace parts, as needed. Part substitution is only performed when a service part is discontinued. While Per Lundahl's (Sound Devices is Lundahl's largest single customer) new mic-level transformer may marginally improve the performance of the MP-2, we have not tested it. Since the MP-2 is discontinued, continuing-engineering has ceased on that product.
It sounds like you have an engineer who can do the work. I recommend that they document what they have modded and be able to revert back to the original state in case the mod doesn't help, or if some other voodoo occurs.
When our upcoming 722 recorder is released, you may want to take a look it. The mic preamp circuit in that product is a significant step forward in audio performance from our transformer-based topologies.
Good Luck!
Jon Tatooles
Managing Director
and this one:
Thomas,
Our chief engineer dropped me a note regarding the 1538 Lundahl part you where inquiring about. Here is a snippet,
"this transformer is not new, and it would degrade noise performance as it is a 1:5 step up instead of 1:7."
Again, you are on your own. Good luck.
Regards,
Jon Tatooles
Looks like the mod is not such a good idea.