Is It Worh Modding An Amp

I had Ric Schultz mod my GaN1 and it sounds terrific,  but if I had to sell it I wouldn't recover any of the $500 the mod cost.  It's a risk.

I'll add some more.

If I need a repair of any precious equipment I know techs who only will replace non-working components and touch or re-touch nothing else if everything else is in tact. 

I've repaired already several vintage and modern components at reasonable prices paid mostly for labor and diagnostics and rest little for parts and their quality work brings many units back to original specs like fresh new strings on guitar or violin. 

They don't offer any upgrades for the sakes of keeping solid reputation. Far more than often those upgrades don't satisfy customer and require lots of uncreative labor. Real pros would never advise you to fall on that upgrade bait.

@treepmeyer Ugh. I sent something to Ric once and he sent me back garbage. Horrible soldering, bad attitude and bad treatment of my materials. Avoid this turkey and learn to DIY.

Give it a shot if you’re willing to gamble. I had a Conrad Johnson cav45 v2. Bought it from a guy that sent it back to CJ and did the SE upgrade which from what I understand is just rip out cheaper caps and add Teflon caps. He said it was a large improvement over stock caps. I loved that amp. 
 

Long ago had an Exemplar Audio modded tube Denon 2900 that was one of the best cd player I had ever heard so good I bought his newer Oppo version. I also had a chance to hear a stock Denon 2900, stock sounded bad next to the modded player. 
 

I was in your place once I had a Bruce Moore preamp sitting up not being used took out signal caps added some Jupiter’s and better resistors. Really made that amp shine for what it was. You just need to figure out what sound you want from V Caps to Jupiter and everything in between. Then there is new wire better resistors, RCA jacks it never stops. I think you can make that amp sound better if you don’t buy mismatched parts, beware.

CV4004 are long life Valves. When supplied with very good measurements, these are proven to be very secure Valves that have a very long usage life.

Note: Measurements shown in relation to Factory Spec' are the only description worth taking on board, I have received verbal descriptions and in nearly all cases they are proven to be very unreliable, causing Seller/ Vendor friction when Valves are wanted to be returned. 

Caveat Emptor is ones friend when purchasing Valves.

It could be a case where a 1000hrs are used by the latest owner of the Valves, the Valves are still presenting a very good measurement, this can result in more monies being remunerated than the original purchase.

This is one of the fuels that stoke the Vintage Valve Market and one I know that has benefitted my choices made for Vintage Mullard Valves.

Alternatively at a later date, an Amp' can be brought in for demo' purposes as a Amp' replacement, that has the same Valves used in the Circuit. This indirectly means that Valves already purchased with a recognised high end sonic quality, can be immediately used on the New Amp' to assist with the assessment. If the New Amp is the preferred Amp' the earlier amp' used can be considered for being sold on with original supplied Valves in place.