Manley Chinook Owners Tube Rolling

yes parts connexion or percy audio both sell them.

yes, bugle boy amperex tubes.

the best sound I have had from the chinook, was with bugle boys from Holland. quite the musical tube.

the other HUGE improvement you can do with the chinook is replace those loading resistors on the rear PCB. From the factory they are metal film.
Install some Vishay bulk foils there and the noise floor will drop, you will get more micro detail, and imaging will improve.

try the amperex Holland bottles, and better than any tube rolling is getting rid of those .47uf wima caps in the SS stage. replace em with .47 film and foil Nichicons.  you will be shocked at how much the Chinook opens up.

you'll have to find a tech in your area. The replacements are Nichicon XY series film and foil. The originals from manley are metalized film.
you can buy the parts from digikey.com
https://www.digikey.com/en/products/detail/nichicon/QYX2A474KTP/2117731
It takes 2 min to change the parts, hard part is all the pre-disassembly work first.

forgot to add the other thing that makes a huge improvement is replacing the metal film load resistors with Vishay VSR metal foil types. You will measurably drop the noise floor by at least 6db. 
@rbtstock , if you contact me off line, can send you plenty of pics.

best