McCormack SMC Audio upgrades: how good are they?

Hello Chiho -

With respect, I would suggest that you are barking up the wrong tree with your question. No matter what opinions are offered in response, the only opinion that matters is yours. It is ultimately up to you to decide the value or quality of your system, and it takes time and experience to develop an informed opinion.

Your DNA-125 Gold-upgrade is an excellent amplifier, has made quite a few audiophiles very happy, and certainly competes strongly in the price range you mention. Is it the “best” amplifier in your price range? Well, reasonable (and unreasonable) people will disagree. This is a question without an answer, or one that only you can answer in the end. I can tell you this: your DNA-125 Gold is an essentially honest, very transparent amp. It will drive most speakers well, and will accurately reflect what you feed it. Feed it well, and it will treat you well.

It bears mentioning that the great majority of any system’s personality is largely determined by your room, your choice of speakers, and the location and setup of your speakers within that room. I urge you to give this due consideration before you change equipment. A bit of effort (and perhaps a few dollars) invested in room acoustic treatment will usually pay-off handsomely. Experimenting with speaker position is crucial, and there are a variety of helpful guides available online if you will search. One simple example: say you have your speakers setup along the short wall of your room and you are unhappy with your bass performance and soundstage size. In this instance, your listening position may lie on top of your room’s major bass cancellation nodes, and your speakers may be close enough to the side walls to cause soundstage constriction. Shifting the speakers to the long wall can go a long way toward correcting these problems. That may be simplistic (and easier said than done), but I hope you get the idea - be sure you have done what you possibly can to get the most from the equipment you have before assuming that changing any piece of gear will suddenly deliver you to sonic nirvana.

Whatever choice you make, I hope you will find your way to a system you can sit down with happily and enjoy beautiful music.

Best regards,

Steve McCormack
SMc Audio

Just a couple of additional comments if I may... A previous post alluded to the need for a solid-state preamp if you went with the further Platinum upgrade, and this is not strictly accurate. Your current DNA-125 Gold has a high input impedance (100KOhms) which makes it suitable for use with any type of preamp. The Platinum upgrade normally includes the addition of balanced inputs, and the method I use for this reduces the input impedance to 10KOhms (also true for the monoblock versions). This means that whatever preamp you choose should have an output (source) impedance of 1000 Ohms or less, and this leaves out a few tube and resistor-based passive designs. Most preamps can drive a 10K load with no problem, but you do have to pay attention to impedance matching when making a choice.

On the other hand, all of our work is effectively custom, and you are not required to add the balanced-input option if you don't want it. For your DNA-125, the real step-up is to the Plitron power transformer which more than doubles the amp's current capability. Then there are a variety of capacitor, resistor, and wire upgrades that lift performance considerably further.

Food for thought...

Steve McCormack
SMc Audio

Hi Luigi -

I now use Lundahl amorphous-core transformers in my amp upgrades (and in my VRE-1 preamp). I started with Jensen transformers, but switched a few years ago when I found the Lundahls offered better transparency. I originally used input transformers to provide a balanced option, but I then found that I preferred the sound of my amps with them, regardless of which input (balanced or unbalanced) I was using. First of all they provide complete immunity from DC and RFI, and well-designed units have outstanding common-mode noise rejection (CMRR). This allowed me to simplify my amp's input stage, and the net result was sound that I hear as cleaner, clearer, smoother, and more "pure" if you will excuse the expression. And keep in mind that my design handles both balanced and unbalanced signals via the same path (the only difference being the input jacks) so you get the benefit of the transformer either way. Of course this only works well with great transformers, but that is the only kind I use ;-)

In short, I feel the input transformers are a sonic benefit even if you use only the unbalanced inputs. The only downside is the relatively low 10KOhm input impedance, but this is an issue with only a small number of preamps.

Best regards,

Steve McCormack
SMc Audio

Hello Audiogoners,

I would prefer that my amps turn on-and-off silently but the nature of the design allows for a bit of a turn-on thump, and the amount varies somewhat from one amp to another. I find a small thump acceptable and I would never ship an amp that I thought was doing anything that could cause damage. But I am listening with speakers in the 90dB sensitivity range, and anything higher will make the noise louder. Even so, this should not ever be any problem - your speaker crossover will eliminate any low-frequency energy from getting to the tweeter, and there usually isn't much high-frequency energy in the thump. I realize that a turn-on thump can be annoying, but I have never heard of any damage of any kind being caused.

The new circuit board I use in the DNA amp upgrades no longer requires the mute relay of the original, so it was eliminated. This will not have any consequence at turn-on unless your preamp has some DC offset, and this is unlikely.

Tlcshop, I'm sorry that your turn-on thump is causing concern. If you would like to call me to discuss this, we can see if there is something that might be done to reduce or eliminate the problem.

Best regards,

Steve McCormack
SMc Audio