The Devil is in the Cartridge Setup (and a good phone pre)...

I’ve had my hands inside of more equipment than some have seen with their eyes.
from $5 to $100k+, every single one of them could be improved upon.

The better built, the more time it might take to find a spot or point that can be properly improved, vs simply made different, but the record is as it is. The improvement may not be viable or practical, but they do indeed exist as things that could be done. Everything can be improved.....

I’d wager that the better designers feel the same, but in the end, it’s always a trade off.

Eg, one can take the lid off a $10-30k-etc amplifier and stand there with you, and talk for half an hour (pointing, explaining, and so on) on all the things that could be improved upon. Some practical, some not.

Everything has to have and does have a price point --and price points have trade offs.

You could say, "here’s a $10k mc transformer/pair, considered to be the best and perfect", a simple device, right? And I could say, "not so fast....let’s cut that open with a bandsaw, and talk about this". Like, the insulation dielectric on the wire(10-20 minutes right there), the formulation of the wire element/alloy (another 20 minutes), the core material and design, changes to the core material, solders, casing, noise rejection, mounting. winding technique, RCA jacks.... a whole pile of stuff. Might be a one hour talk on what looks like a simple transformer--but is not all that simple, in the end.

I recommend cleaning the stylus after playing every LP side. And apply some Stylast after cleaning.

Talk and more talk. Mods always reduce resale value unless performed by the manufacturer. I would never buy a piece that I knew was modded by an end user, even if returned to stock. Time and time again arguments are made for doing this, and it’s fine as long as the user appreciates the work they’ve done on it. But in the market, it’s a fool's errand.

Stevecham, 

Your question assumes what it seeks to prove:  that I think Manley doesn't know what it's doing.  On the contrary... I love Manley.  I think the Chinook is an amazing piece of gear.  In fact, it's the last piece of gear I'd ever sell.  So, I have no idea what you're talking about.  

Next: I have no intention on ever selling the Manley.  It's that good. I do, however, have curiosity and realize this is a hobby.  

 I have tinkered with electronics since I was a kid.  I'm 44 now.  I've built 3 tube amps.  I'm not sure what your perspective is or experience in this area is so I'll be sensitive.  Op amp removal and install is perhaps less involving than changing speaker cables over and over during the life of a component.  Sometimes an op amp can be soldered.  Other times, and I think IMHO, usually they are drop in.   The takeaway--op amps are no different than fuses.  Would you say that a user made a terrible mistake by swapping fuses?  What if the fuse goes out?  

As far as making many changes in a row, thank you for stating the obvious.  That's exactly what I did and knew it.  Life is busy.  

But above, all, I'm super curious as to why folks drop in to voice opinions in this way.  

And finally, on the issue of modifications.  The amps that I've built have never had one issue and I've swapped in and out caps, resistors, output transformers, power transformers, and so on.  But I've bought some expensive gear and had to have it repaired on multiple occasions--usually with good service from the manufacturer.  

In no way am I suggesting that modifications are better or always safe or don't have an effect on resale (maybe for the better).  What I am saying is... why did you drop in here?