Krell KSA100 vs Threshold 400A vs McCormack DNA 0.5

HiI need a 100W amplifier to drive my Morrison speakers. I Can easily refurbish electronics if needed. Someone offered me a Krell KSA100 another one offered me a Threshold 400A I have to repair and finally a McCormack DNA 0.5 or 1 seems appealing but I dont have any I could  buy.  I hate over detailed sound and I love tube amps mids but do'n want a tube amp. As I couldn't buy a Morrison woofer if I burn it with a faulty amp. I need something bullproof. I never heard and couldn't hear any amps mentionned with my setup.  What would be your preference or do you have any other recommendations ?

I think the Krell would be the best choice here.  The KSA is a very smooth amp and will tame even the brightest/harshest speakers.  I think it has a lot of soul, kind of like a McIntosh with detail (but it is not too detailed).  Great midrange!

The Threshold is edging toward that "too detailed" type of signature.  The McCormick is even more forward and detailed (it could actually sound too solid-state as it is a very transparent amp that can reveal flaws in your source/preamp).

Another good amp for your preferred sonic signature is Aragon (4004 / 8008 / 8008BB).  Or maybe a McIntosh?

The Krell KSA will likely need to be re-capped because it is a full Class A amp and very old.  Possible same with the Aragon (the 8008BB is biased Class A for the first 26 watts, if I remember right).

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.

Agreed.  In my opinion, Mark Levinson does weird things to the sound.  Maybe it flattens/smooths the midrange and high in some weird way and maybe makes it sound somewhat "closed in" or narrow soundstage (not deep and wide).  In any event, it tends leave me wanting - it's just not exciting or dynamic enough for my tastes.  Many people love Mark Levinson sound, so it's entirely personal.

The Krell KSA won't do the same thing.  It will have a lot of attack and dynamics and resolution, but it will be very forgiving to bright/harsh speakers.

The Aragon amps are very warm and the highs are slightly rolled off and soft.  It wouldn't have as deep/wide soundstage.

The McIntosh amps do have more resolution in the highs than Aragon, but they are very laid back in a sense.  Not as dynamic as Krell KSA, but not as compressed as Levinson.

If you want dynamics and wide/deep soundstage, but still not too "over detailed", then I still think Krell KSA is your best bet.

McCormack amps are excellent, not expensive, and have many upgrade iterations.  It would behoove you to give Steve a call before you purchase anything else.  
I can get the Krell for $1200.  Power supply caps were already changed.  It is mint.
Seems like a typical price for KSA 100 (gen 1) is about $800-900 used.  Figure $300-400 for the main power supply caps plus labor, so $1200 is probably a good price.
I really like McCormack....  I have owned two and regret selling them.   The KSA100 was one of the best sounding amps of its time .   I would buy a clean one without hesitation 
If all you need is a 100 watt amp look and read up on an Audio Research 100.2. Great sounding amp that has a cult following for good reason. I owned one and if you want something close to a tube amp it’ll get you in the ballpark a little. Don’t worry about caps as some throw out all older amps need recapped... I’ve owned several older amps and know a lot of people with them and no issues except ML 300 series amps which just had bad caps to begin with; a lot older ML amps running just fine.

My experience I’d take a McCormack over the older Aragon amps. The 4004 was a amp with plenty of control but I always felt that attribute brought too much attention to it. I feel the McCormacks even stock were a little more balanced and played well with many types of music where the Aragon (only experience with the 4004 series I and II) definitely a better Rock amp. I’m not sure I’d throw a 4004 in with SS amps that get close to tubes amps though.

Krell KSA 100 is a Class A amp up to 100 watts that is a nice amp. Audio Video Logic had one for sale on here that the add expired on that I know they still have. I still think I’d take the ARC 100.2 over any amps noted so far... I preferred it with its balance inputs but sounded just fine with the single ended as well. Great amp.
Forget all of the above. Buy a Bedini 150/150 and experience a higher level of audio reality! I have!
As mentioned above, give Steve McCormack a call at SMc Audio.  He will tell you what he can do for a .5 and the cost to you.  Steve is a straight shooter and you may be amazed at what he can do for the .5 for the cost!

The DNA  (distributed node amplifier) design concept has truly stood the test of time.  The quick response to the input signal sets it apart from other fine amps.
Hello all who are recommending McCormack amps.  From what I have heard, the DNA is a very high resolution and detailed amp.  I would agree that this is an excellent piece.  However, if you guys read legarem's request, he "hates over detailed sound and loves the tube mids".  Listening to this, I always try to see through the OP's eyes and that is why I have put the Krell and McIntosh in the list.  Based on what he is saying, I think the Krell KSA is still his best bet.  The KSA is still very dynamic, but it is not going to be "over detailed".
@Aux - very considerate observation on behalf of the OP; this forum needs more people like you. I have to agree about detail in the McCormack DNA. I describe it as clear because "overly-detailed" seems such a derogatory term for an amp design that has received two decades of praise. 
To clarify...

The SMcAudio upgraded DNA amps have a wonderful textural smoothness and treble sweetnesss.  The greatest transformation is probably the huge soundstage.  @4hannons  Bingo on "clear".  The modded amps allow you to "see" deep into the soundstage.👂
Not familiar with ( have not heard ) Morrison speakers, but why not give the Nuforce STA 200 a try. $499. from Audio Advisor, and can be returned if you do not like it. I like it very much, and feel it is a "sleeper ". I do feel it betters many amps spoken about above. I am thinking of getting another one for a 2nd system. Research it though as it has some peculiarities about it. Enjoy ! MrD.
I've owned plenty of McCormack products (several of his preamps and still have two modded amps).  I've had multiple rounds of mods over the years, so I'm intimately aware of the performance from stock to various levels of mods in history up to as recent as 2 months ago (the last time I got an amp modded with the latest and greatest including some things he did for the first time on my model).  I also own ARC, McIntosh, Emotiva, digital amps, and many others over the years.

In terms of which one of the three above to buy, it's pretty much a no brainer.  In stock form, they are all long in the tooth and not going to be super reliable nor up-to-date.  If you don't want a tube amp, an old Class A isn't going to be much better in terms of heat issues. Plus, it's going to be less reliable.  The board is probably warping with all the heat/cooling over the years among other issues that I wouldn't want to deal with.

The only one you can get upgraded to be 100% reliable and warrantied is the McCormack. Plus, it's the only one you can get modded to state-of-the-art modern day performance customized for your speakers.  Part of the modifications that Steve does is tailor the voicing to your other equipment/listening tastes/etc.  You will never have to buy another amp again because you can always send it back for new mods like I have for like 20 years now.  It's night and day from stock form and my amp now makes the internals of the $55k Dagostinos look like a toy for a fraction of the cost.

One thing that people also don't realize is that you can modify the "looks" too.  I've never personally invested in modding the looks, but my friend has Ayon tube monoblocks that look great, so he wanted his modded McCormack to be aesthetically in a similar league.  As a result, they are doing some custom work on that end too.

In legacy stock form, I would agree/disagree with what's been said above.  It's probably not the amp for those that like "tube" sound. . However, it's not because of it's interface with speakers.  It's more about the source feeding it.  (BTW, in full-monty modded form, it's better than my ARC Reference amps)

In stock form, it was built to a modest budget level and delivered a surprisingly high ceiling performance, but building an amp to a modest budget is also a kiss of death.  Many people will mate a modest budget amp with a modest budget source that may not have the same performance ceiling.  (MFGs have figured this out and that's why prices are so ridiculous nowadays.  They stick a high price tag on their products, so you and reviewers will mate it with theoretically other high price/high performance gear and not feed it junk.)  Modest gear that performs on the same level as high priced gear often gets shafted and false reputations because it gets paired with lesser quality sources.  Krell and Threshold were far more expensive back in the day, so much of their reputation compared to McCormack is based on being also paired with higher level of sources in most people's systems.

Just to be clear though with my recommendation.  It's a "no-brainer" assuming you are getting it modded.  As good as it was in stock form, the McCormack is past it's useful life and all the driver boards need to be replaced at this stage of it's life cycle.  If you are looking at those 3 options for use in used stock form, I say the "no brainer" answer is to buy NONE of them.  Get a much more current used amp or something new from quality budget suppliers like Emotiva, Parasound, etc.

Good luck.
@labtec  +1!  Everything you said about what Steve McCormack can do for you is accurate.  If you decide to modify an "older" McC. amp. they send you a questionnaire about your system and listening preferences so they can tailor their modifications to your amp to optimize its performance with your speakers and associated gear.  Extremely reasonable price for the depth of the modifications.
I owned a Krell KSA100 since 1984. Coupled with an ARC SP-8 tube preamp it drove 1 ohm Scintillas effortlessly and with immense beauty. It will control any speaker. It was flawless and performed until (sadly) I sold it 6 months ago. It deserved a good home! My current pair of KSA-150s are 27 yrs old and I love them. You will not be disappointed.
I would go with the Krell also. Another amp to consider though is a solid state Conrad Johnson if you don't mind single ended. I had one in the shop around 15 years ago and it sounded great.
I lost the KSA100. Now there's an Anthem AMP2 which could be interesting but I didn't know this amp.
There are some good recommendations on here and I agree that they don't all meet your taste.  The AR 100.2 is a solid performer, natural sounding amp, it may be a bit more detailed than you want, but this is a nice sounding amp. What I believe is dead on what you are asking for is a Muse One Hundred Sixty... 
Then lastly,  another old amp that definitely needs to be updated, but a Son of Ampzilla properly updated really competes well with todays best.  
I think the real problem is just finding any of these ready to go.  
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.
@legarem   Congratulations!!  Great decision!  Many folks who were experienced listening to the .5 and the DNA-1 preferred the .5 for its sweetness.  So... you will have a nice sounding amp from the get go with the option to max. it out down the road with SMc Audio's upgrades. Happy listening.👂
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
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)


What does the seller have to say about the condition of the amplifier he sold you?  IMHO he should finance the new driver board you made or let you return it to him for a refund.

 Steve is being absolutely truthful.  Same thing he told me about my 21 year old DNA-1.  They are seeing a consistent pattern in the degradation of the driver board over time.  It is just not the unrepairable nature of the amp but rather that in the years that have passed, Steve has been refining his modifications to the DNA amps.  My previously modded DNA-1 was $1300 for a new driver board, wiring, input and output jacks and new improved soft recovery diodes.

The amplifier is now reference class!  It really is fabulous.  I almost feel guilty getting that much bang for the buck.

If you don't have the money now I can see how that is a problem in your case.,  But... you can't expect SMc Audio to repair something that is going to fail soon again.  
Another vote for Sumo products. I had a son of ampzilla and it was sweet but I don't think it was 100W??
there was a nice sumo nine up on one of the sites....
or go with the krell
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.
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.

Why would Steve offer upgrades to amps that will probably fail in the near future?
Steve is not doing that.  When I called Steve about updating the 18 year old mod. on my DNA-1 Deluxe, the first thing he told me was that if I sent it in they would have to replace the Driver Board as that is the part of the amplifier experiencing failure issues.  He offered to do more than that but said he could not repair the old driver board for reliability reasons, but that the board would be replaced by a new upgraded board.

Once the new board is in place you are good to go.  I went ahead and had the "Gold Special" upgrade done.  It sounds great and I have every expectation it will outlive me.
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
@legarem: That Son of Ampzilla for $460 is an excellent choice! I own two of them! And I bought one brand new in 1977 - and stupidly sold it! Still a contender for "best sound per dollar"!
@legarem I'm wondering why you didn't follow the advice given to you in this thread.  I specifically told you in my reply...

"Just to be clear though with my recommendation. (Mccormack) is a "no-brainer" assuming you are getting it modded. As good as it was in stock form, the McCormack is past it's useful life and all the driver boards need to be replaced at this stage of it's life cycle. If you are looking at those 3 options for use in used stock form, I say the "no brainer" answer is to buy NONE of them. Get a much more current used amp or something new from quality budget suppliers like Emotiva, Parasound, etc."

I'm not sure why you would ignore that specific advice, but don't make the same mistake again.  There's no point in buying an old used amp at a super cheap price to milk in it's stock form for whatever useful life is left. 

As I said before, either get your McCormack modified or buy a brand new Emotiva that fits your budget.  Their newest generation amps are excellent and steals at the price. The modular construction and direct sales allows them to sell for far less than they would otherwise.  I have a couple of them myself (as well as ARC, McIntosh, McCormack and others), so I'm not just making this stuff up. You get a full warranty and tons of power that will work with any speaker.

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.
@legarem I have owned SM70s, and they were quite a bit better when driven balanced. Quite a night and day difference, actually. Enjoy ! MrD.
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.

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.
Very interesting, and congrats on your results.  I applaud your persistence.  As an owner of a "dead" late 80s DNA 0.5 Rev. A amp, it gives me hope.