Upgrading question

henrylr · « **Reply #40 on:** 5 Feb 2016, 12:39 am »

I'm amazed at how the seeming increase in rhythm and pace make very familiar tunes sound like they are now playing at a more realistic tempo. This is an unexpected and really appreciated improvement.

Being a playing musician, tunes now sound much more real. I expect more surprises as I let it play for more hours. In fact SMC said to keep it on all the time to realize the best performance.

mresseguie · « **Reply #41 on:** 5 Feb 2016, 02:57 am »

Hello, Henry.

Until now, I've been lurking on your thread because I was pretty sure I had nothing to contribute other than more noise.

I just wanted to say I'm glad you've found a solution to your problem. McCormack amps have a great sound.

Enjoy your music!

Michael

RDavidson · « **Reply #42 on:** 5 Feb 2016, 03:25 am »

Good to hear, Henry. Glad I didn't steer you wrong.

henrylr · « **Reply #43 on:** 6 Feb 2016, 07:11 pm »

Hi all and thanks for all the helpful replies.

The McCormack DNA-0.5 manual says it is beneficial (my words) to use the grounding spike which screws into the bottom of the amp. It reads like it is a damping device and I can't imagine it doing any electrical grounding as described. Am I missing something?

My used amp didn't come with it but I can easily make one on a lathe. Does anyone know what it is made of or if the material is important?

Thanks,
henrylr

RDavidson · « **Reply #44 on:** 6 Feb 2016, 07:57 pm »

Yes, I think it is just a vibration damping device. I have yet to see a used McCormack amp come with this accessory. If I recall, the feet on the amp are soft rubber (sorbothane?). With that being the case, I think it is more important to just put the amp on something nice and solid but also with damping characteristics....like a thick piece of maple. Before that, just talk to Steve again and see what he says. He'll probably have the best advice overall.

henrylr · « **Reply #45 on:** 6 Feb 2016, 09:35 pm »

The equipment is in a roll around wood cabinet with glass front door and open back. The CD player and preamp are on 1/4" thick dense felt pads. When the stand is in position the four feet rest on squares 1/4" thick sorbothane.

I think the very thick Mod Squad sorbothane feet on the amp will probably be best to decouple it from the cabinet and wood floor. I think the spike would just couple it through the cabinet to the vibrating wood floor. The speaker stands were on the wood floor and there was to much unruly bass generated by vibration. I put the stands on thick carpet and the bass is now tight and musical.

The speakers and stand are quite heavy. The stands are steel, each speaker is topped with a 12" x 12" x 1 1/8" thick piece of granite and the stand bottoms have the same sized pieces of granite on them. The outboard xovers are mounted on their own stands which are decoupled from the floor.

Nick B · « **Reply #46 on:** 7 Feb 2016, 07:50 pm »

Congratulations on getting the McCormack. I bought a stock DNA 1.0 a few years ago for $900. I then had Steve (Kris) do the Gold mod for about $1,800. What an excellent amp

henrylr · « **Reply #47 on:** 16 Feb 2016, 07:16 pm »

Hi all,
I've read some posts, on various sites, about damping heatsinks and their fins on various amps and would like to try it on my DNA. Are their any pictures of this anywhere? What materials are usually used and how are they applied? I am putting a sheet of sorbothane between the faceplate and front of the case. Any other damping suggestions will be greatly appreciated.

Thanks,
henrylr

RDavidson · « **Reply #48 on:** 17 Feb 2016, 12:45 am »

I think I've seen people just use strips of silly putty on the heat sink fins. Maybe it was something else?

Something that might work, that would be a little more tidy, are stick-on felt strips.

Tone Depth · « **Reply #49 on:** 17 Feb 2016, 02:26 am »

What ever damping you do, remember that heatsinks/fins are meant to radiate excess heat, and it doesn't make any sense to coat or insulate them and prevent them from doing their job. That would be an effective way to damage sound quality, rather than improve it.

Quote from: henrylr on 16 Feb 2016, 07:16 pm

Hi all,
I've read some posts, on various sites, about damping heatsinks and their fins on various amps and would like to try it on my DNA. Are their any pictures of this anywhere? What materials are usually used and how are they applied? I am putting a sheet of sorbothane between the faceplate and front of the case. Any other damping suggestions will be greatly appreciated.

Thanks,
henrylr

mresseguie · « **Reply #50 on:** 17 Feb 2016, 02:52 am »

Henry,

Damping heatsinks is new to me. Personally, I wouldn't do it for fear of preventing their dispelling heat as efficiently (I agree with Tone Depth).

However, I have heard of folks using bitumen (one side has adhesive) strips or small squares along the insides of the case. This will help damp the amplifier case. I've seen pictures of tiny squares of bitumen applied to the tops of capacitors, but I can't help but wonder if this might somehow create heat dissipation issues for the caps(?). There is a 3M product that may be helpful. [Please note I have not used this 3M product and do not know exactly how it was used, but I can find out.]..looking for the link now....http://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-EMI-Shielding-Fabric-Tape-CN-3190-1-in-x-54-1-2-yd?N=5002385+8709319+8710676+8710748+8711017+8711066+8717906+3294764915&rt=rud

Best of luck!

Michael

vonnie123 · « **Reply #51 on:** 17 Feb 2016, 07:30 am »

Quote from: henrylr on 30 Jan 2016, 01:31 am

I agree with the above. I think it captures what most if not all of us want to experience... but how about some input on the Parasound Halo 23 question?

I've had Parasound Halo A23.....had two of them behind a Parasound Halo P3 pre. Competent performer - a little better than the Adcoms. I also have had Adcoms (GFA-555 first generation, and a couple of multichannel amps by Adcom GFA-7607. & HCA1205A). I changed out my system about three-four years ago and now am an admitted Class D convert. No heat issues - one my reasons for changing.

henrylr · « **Reply #52 on:** 17 Feb 2016, 05:39 pm »

I've read a number of posts on various sites were people have recommended damping heatsinks as well as the chassis.

Initially I was think of putting something on the bottom of the fins since heat rises. Now I'm thinking of putting something along the outer edges of the fins so airflow is not impeded. Maybe a strip of some type of rubber, on each side, running from the first to last fin and held against the outer edges of the fins with two sided tape.

Regarding chassis damping, I have a gut feeling that is what the spike on the bottom of mccormack amps is for. Just a guess. Maybe Steve Mccormack will kindly shed some light or recommendations.

Thanks,
henrylr

vonnie123 · « **Reply #53 on:** 17 Feb 2016, 06:29 pm »

Quote from: henrylr on 17 Feb 2016, 05:39 pm

I've read a number of posts on various sites were people have recommended damping heatsinks as well as the chassis.

Initially I was think of putting something on the bottom of the fins since heat rises. Now I'm thinking of putting something along the outer edges of the fins so airflow is not impeded. Maybe a strip of some type of rubber, on each side, running from the first to last fin and held against the outer edges of the fins with two sided tape.

Regarding chassis damping, I have a gut feeling that is what the spike on the bottom of mccormack amps is for. Just a guess. Maybe Steve Mccormack will kindly shed some light or recommendations.

Thanks,
henrylr

Is your amp in a location without good airflow (enclosed)? Heat was a big problem for me due to how my system was enclosed in a cabinet. (WAF). I was able to set some fairly quiet fans which activate when things get too warm. My cabinet temps usually run in the 80f range.

henrylr · « **Reply #54 on:** 17 Feb 2016, 08:53 pm »

I think my system with the mccormack sounds very good. It's just that I've read a number posts about subtle improvements realized after damping heatsink fins, and parts of the chassis, so thought I would give it a try.

While the amp is in a cabinet, there are 1/4" gaps around the door that covers the equipment area and, the back is completely open.

Even after listening for hours, to jazz CDs played at a realistically loud level, the heatsinks are only very slightly warm to the touch.

I don't know if it is an A/AB amp or just AB, or if the bias is such that it transitions from A to AB at a wattage that is below the listening level I like.

At the same listening level in my other system, with the Aragon 8008BB, the heatsinks run very hot...I think of it as an electric space heater... because it is biased to run in class A up to 26 watts before switching to AB. The speakers in that system are fairly efficient, with sensitivity of 90db, so the amp is probably not getting into AB territory.

Nick B · « **Reply #55 on:** 18 Feb 2016, 01:21 am »

I don't know if it was mentioned previously, but I am sure you can contact Steve McCormack and he will answer all your questions. He and his partner Kris are great to deal with. If you have any interest in upgrading, they can do custom work based on your budget. Highly recommended
Nick

henrylr · « **Reply #56 on:** 18 Feb 2016, 01:36 am »

After a little research I learned mccormacks are push-pull. Can someone tell me what class they are? Also are some solid state class A amps push-pull and other solid state class A amps defined by some other class of amplification?
Thanks,
henrylr

RDavidson · « **Reply #57 on:** 18 Feb 2016, 02:37 am »

Yeah.....push/pull doesn't really tell you much, except that it isn't single ended. Yes, I believe class A SS amps can be push/pull or single ended. Pretty positive Nelson Pass has built both types.
More than likely your McCormack is class A/B with perhaps just a tiny bit of class A power (ie not enough worth specifying). Ask Steve McCormack to be sure.
At the end of the day circuit design is more important than topology. If it sounds good, then it is good.

henrylr · « **Reply #58 on:** 18 Feb 2016, 04:33 am »

Thanks for all the replies RDavidson and others. It's aways a pleasure getting responses. I agree that it's the sound that matters. I'm just curious about the various types of amplification.

But I must also say my gut tells me that an Amp that runs so hot you can't keep yours fingers on it for more than a very short time may not last as long as a cooler running amp. Also the cooler running amp won't heat up your room in the summer or make one's electric bill go up as much.

One of the things I like about the mccormack, besides it's great sound, is that it runs only very slightly warm. Since it is in a cabinet I consider that a plus.

On another thought: the mccormack replaced my Adcom gfa 5400 and I planned to use the adcom in my HT room. Now, after reading some good reviews of the newer class D amps, I plan to sell the Adcom and get something like a PS Audio or other well reviewed class D amp. Any thoughts on a good class D amp brand? I only need a two channel with around 100 watts per channel.

Thanks,
henrylr

vonnie123 · « **Reply #59 on:** 18 Feb 2016, 05:55 am »

I am using Class D Wyred4Sound. They are based in Atascadero, CA. They have a variety of amp options to choose from. Service is good. They have a few dealers or you can buy direct.

I've had their DAC-2 DAC for four years, and Integrated amp STI-500 (2x250) and multichannel amp (7x250) for over three years.

Very pleased with the quality, reliability, and sound. Plus they don't use much in the way of electricity.

I think the lowest power WPC they currently make in two-channel is 250x2.