I guess you could sum up my main DIY goal as follows....

Excerpts from a great thread found on prodigy-pro.com

This model is a bit overlooked for the later ones. Its all transformer input, discrete transistor lushness.

This model plus the expander has an overlooked feature, when you adjust the level it also adjusts the gain. Thus its hard to overdrive. (It uses a ganged pot, I'm considering putting some concentric pots in so they can be individually adjusted) Makes it great for loud stuff. I had modified a few of these for others in the past but could never score one for myself.

I have read several articles about the Edcor RMX1 being used to replace transformers in some of the less expensive ribbon mics. (Mostly Nady RSM 4 and 5s)

Here is a good interactive page I found a while back that shows the comparison of various levels used in digital recording.

Click on the various ranges below the blue line - "Analog to Digital Conversion Calculator"

http://www.independentrecording.net/irn/resources/metergain/index.htm 

Example: For my Delta 1010 the max analog input = 20 This makes 0VU  at  +4dBu  =  -16dBFS

There are tons of discussions on the interweb about this and why its important, here is one from the TOMB that has some good info:

http://messageboard.tapeop.com/viewtopic.php?t=38430

I have just noticed that when I switch my input level from +4 to -10 that the signals phase is inverted. 
I found no mention of this in the manual. 

This seems like a pretty large omission.

This article describes how to convert the tube preamps found in Roberts and Akai Reel to Reel recorders into microphone preamps.  Some of the models: AKAI M7, M8.  Roberts 770, 770x.

I have been working on another version of my AKAI/Roberts pre mods. I’m naming this one “The Boris”. An engineer in London contacted me and wanted a pair of Roberts pres modified, with a few twists. After several emails here is what we ended up with.

Here is the latest Roberts AKAI I have been workin on, its nothing too special except I haven't seen one like this. Its all black. I'm doing this one for dubold. He said there was some kind of cover over it, so there is no markings on them. Just posting some pics because of the cool factor. These are a bit different because both inputs are high impedance, no transformers. dubold is going to build some kind of tranny farm (picture that).  I have a start for him on that, I should have some pics soon.