Pete,
Having something modified by TRL is like taking a leap of faith. When I was looking at upgrading my digital gear I ran across some posts here on TRL Sony 595 and Marantz SA-14 modded units. I decided to contact Paul Weitzel about modifying my Quad-77, but in the end after several converstaions with him discussing my needs and interests in digital sound he referred me to someone who had a TRL modified Alesis ML9600. This unit is a CDP, CDR, and has the ability to record music to a HD via analog or digital inputs. As it turns out this unit is best suited (by Paul's admission) to be a transport, which ultimately led me to the D1 as the companion DAC.
TRL does not have a "mod" list like other vendors. This scares off some people who absolutely need to know everything that was done to their unit. In talking to Paul about my Alesis I know that they did most of the mods on the digital side which is why he said I'd be happier with it as a transport. The error correction was disabled and there was some chassis dampening done to it. Other than that Paul was mum. I do know that if I take a store bought CD and upload it to the HD, then burn it on the Alesis that the BLER is reduced (this was tested and verified by TRL) and the CD sounds better than the store bought version. I can also record 24 bit CDs.
I know this sounds like a lot of magic dust but in essence you send $550 (standard fee) and your unit to TRL and it comes back with their signature house sound. Very open with a deep soundstage and a sound that is the closest I have ever heard to analog. You should talk to Paul if you have any concerns about TRL capabilities. I will also say if you are happy with your D1 as it is, don't modify it. For me this is a curiosity more than anyhting else as I want to compare the TRL house sound to Vlad's design. I had an opportunity to buy a used D1 here on Audiogon a couple of weeks ago at a great price so that is why I'm going ahead with the TRL mod. Otherwise I'm very happy with the D1 and have just asked Vlad to build me a tube phono stage. So I have faith in his work as well.
If you like email me to discuss further. You may also want to visit the TRL thread here for more information.
