Anyone done TRL mod on Ah Tjoeb?

Call or email TRL. They have worked on a lot of Marantz players and of course are experts at tubes.
They could help you assess your options and are not pushy.

The email I received from TRL didn't give anything up. They indicated that their work is satisfaction guaranteed and no one has ever been disappointed, ie. taken them up on their guarantee. They've modded many Marantz units but didn't indicate any experience with the Ah!. They also seem reluctant to say what exactly they do on the mods. It tends to go against better judgement to blindly send anyone $550 and not know what they are doing. The many positive posts on TRL mods are leaning me towards going against "better judgement".

Go against better judgement. I did and have never looked back. You really have nothing to lose with the money back guarantee.

It tends to go against better judgement to blindly send anyone $550 and not know what they are doing. The many positive posts on TRL mods are leaning me towards going against "better judgement".

No they won't tell you what they do specifically. I can tell you what to expect that seems to be their "signature" changes after several modded digital and amps from them.

1) Lower noise floor. It is startling what they do here on any unit. You don't realize how noisy something was until the noise is removed.

2) Removal of electronic and digital glare or hash; hence people feel that they get units to approach an analog type sound.

3) Premium on detail
4) Premium on neutrality- no artificial lushness that gets passed off for warmth when it actually smothers detail
5) Bass extension

I would recommend them, but there certainly many viable options. The AH Tjoeb istelf is an already modded Marantz, so I one cannot be sure what the ceiling is for that unit.
I do know they regularly work on units that have already been modded by other well known modders.

Good luck!