Krell KSA100 vs Threshold 400A vs McCormack DNA 0.5

I forgot to mention: Previously, I had a Mark Levinson ML-9 and It wasn't the best in my system. Image was not wide + mids and treble were too laid back.

I can get the Krell for $1200.  Power supply caps were already changed.  It is mint.

I lost the KSA100. Now there's an Anthem AMP2 which could be interesting but I didn't know this amp.

I can possibly get an old Son of Ampzilla with refreshed capacitors,

Finally, I'm waiting to receive a McCormack DNA 0.5 Deluxe.  Since I read good things about McCormack stuff, I should be happy.with this amp.

Finally, this was the worst decision I made. I received the amp and I will perhaps never hear it. The protection circuit stays ON and the amp made smoke. Regulator mosfet toasted in the amp. I wtote to Steve McCormack and here is an answer I got:

The problem you are describing is an issue we now see frequently on the original DNA-1 and DNA-0.5 amplifiers that are now over 25 years old.

It is an issue that we no longer consider repairable. The problem is with the through-hole plating between the top and bottom of these two sided driver boards.

Repairing failed components and mending the connective traces can sometimes revive the amp for a short time but doing this is not recommended. The underlying problem is still there and it will continue to get worse.

This problem only pertains to the main driver board, not the two output
boards.
Seller offered me to return the amp or send me back $200 so I could repair it. I have no problems to do repairs but as SM advised me, it seems risky to repair it. 

I hope this could help DNA1 and DNA0.5 future buyers. I know there's upgrade for these amps but they cost an arm ($900)

Finally as the amp is super clean, I decided to keep the amp and seller lowered the price a lot ($307). I must say first that the amp had a problem when I bought it. I payed it accordingly because he also thought it was only a bad cap to replace. There was a bulged cap inside near a mosfet regulator which I replaced. The amp worked for one day on the bench then failed when I connected the speakers on it. The seller gave me the choice to take it back. but I had to pay for shipping back. As i’m good and equipped for electronic repairs I really want to diagnose this beast. I will surely try to repair it and if I can’t, as Steeve wrote to me, I can at least get the money I payed for it. I know this is risky but.... The only thing I would have liked to get from Steve is the damn schematic for this amp. I got the power supply schem but not for the driver board. I already diagnosed a bad mosfet in a regulator feeding the front end and the drivers.The bad cap probably weakened the mosfet I hope everything is good after the reg.

Some peoples mentionned that GAS Son of Ampzilla is a great amplifier.  As my DNA 0.5 will be repaired this fall or winter, someone offered me an ultra clean GAS Son of Ampzilla recapped. As I need an amp soon I'm tempted if it is really an amp alone in it's class. At least,(not like the DNA 0.5)  it can be easily repaired or upgraded by DIY. Seller wants $460 USD ($600 CAN) for it. Any comments ?Thanks

I finally bought a pair of Monarchy SM70 class A amps. Presently I use them in bridged mode (70W) with my Morisson speakers. What a surprise ! Relax effortless sound, huge soundstage. I simply love what I hear. As they are pure class A, they heat a lot but in my basement this is a good thing even in summer. The McCormack will be repaired this winter but i’m really not sure it could dethrone the Monarchy amps.

But I think you can't use balanced input when you use them in bridged mode.

After reading the instructions, I tried them in balanced bridged mode.  WOW ! These marvelous amps take a step ahead from unbalanced to balanced mode.  These amps are simply amazing amps. I took a chance and I'm really happy with the results I have with these amps.  Good timbre with effortless sound is what I was searching for.

Wow Wow Wow !  I'm still amazed by these amps.  I tried a lot of amps but these are really special for the price they cost.  I would say they are the best compromise between tubes and solid state amps I tried.

I worked on the McCormack DNA 0,5 Deluxe yesterday and repaired it. One zener diode was shorted and two electrolytic caps were bulged with too much heat across them. I also redone all the solders on the main board because I didn't want to have the problems I heard with these boards. The amp was turned on all night on the bench and I tried it today in the system.  Sound is ok but this is night and day with Monarchy SM70 pair in balanced and bridged mode.  The SM-70 pair are effortless to listen.  The DNA 0.5 is a little harsh and lean in the mids. As the DNA 0.5 is considered as an old amp, I was tempted to give it a little more chance by recapping it. There's 32 electrolytic caps to replace and buying them is about $120 at Parts Connexion. I would do the job myself.

Now, do I loose my time and money on this amp if I do this job or it is better to sell it because I will never dethrone the SM-70 about sound quality even if it is upgraded ?
Please, don't tell me to ship it to SMC to do their upgrades. I consider this too costly.

Thanks

I want to do a followup about the amps I tried.
I lived with the Monarchy SM-70 pair in balanced mode during the time it took to recap the McCormack DNA-0.5. There was near 30 caps to change on the main board and the output boards. I also changed the emitter resistors with non inductive ones and redone all the solders on the main board This was a LOT of job. I let the amp work on the bench for 1 week before installing it in my system. When I heard it first, its sound was harsh with no soundstage. As this amp stayed rather cold with recommended bias, I decided to crank up the bias so the heatsinks reach 110°F. After 1 week with pink noise, the amp is now so good it stayed in my system. The SM-70 were really great but don’t have the DNA-05 grip. They were also a little too mellow in the treble. The McCormack is a keeper and should have a long life with all the job done inside it.