"Original" equipment vs. upgraded equipment

One example would be an ARC Ref 75 being upgraded to a 75SE. Is the upgraded version inferior to an original 75SE?

In this example I would say that though the upgraded unit may sound the same, the original 75SE will have greater resale value on the used market.

Why? Because in the upgrade process, only certain parts are being upgraded, not the whole amp. So if you are buying an upgraded used 75SE, 70% of your parts may be a couple/few years older than a used original 75SE.

Outside of that, there are qualified modifiers outside of original manufacturers. Folks like Steve McCormack, Chris Johnson, Bob Backert, Bill Thalmann, and others who perform modifications outside of the original manufacturer. Many of these certified modifiers products may idea sound better than the original. However, you will lose about 80 of your modification investment on resale.

Then there are other lesser qualified modifiers (all DIYers), whose work actually devalues the original product on the used market.

At least to me, an upgrade is a change in the internals of a unit developed by (and in many cases done by) the manufacturer. Like the Vandersteen 3 to 3A to 3A Sig or a VAC Ren 30/30 to a 30/30 Sig. In my mind, the value of such units is increased as they are brought to more current designs and parts.

Yes, the value is increased, no doubt, but not up to the level of an original Vandersteen 3A Sig or VAC Rev 30/30 Sig in your stated case.


Look at what @oregonpapa  did:

I owned the REF-75. Replaced the KT-120’s with the KT-150 for a nice upgrade. When ARC came out with the REF-75-SE I sold the REF-75 and bought a new REF-75-SE. 

There is a reason for this, and I just did something similar.
I just bought an original ARC Ref 5SE, and now have my ARC Ref 5 up for sale.
It would have cost me another $2,000 to have ARC perform the upgrade to 5SE, and even then, they are only upgrading some of the internal parts (maybe 20%).
When I am buying used items, I always get the serial number to look at the age and service history of a component.
Eg: I would rather buy a 3 year old original component than a 7 year old component that was upgraded 3 years ago, as would most others. 
The 3 year old original will have more value on the used market than the 7 year old upgraded version.

Bottom line: Updating a few of the parts doesn't make it equal to a newer unit. Hence the value of an original unit is greater on the used market than even a unit upgraded to current standard.