Mid-Fi Power Amp Comparisons

F1nut wrote: »

slbenz wrote: »

I would recommend having the MKII opt2 upgrade done to your amp. Will take it to a whole new level and more than double the output while making the amp sound more refined and life-like.

It should be noted that Mr. Carver does not approve of that mod. Something about overtaxing the power supply, IIRC and I know I've seen comments about some of the modded amps failing.

Bob (Carver) spent a good deal of time with a mkII opt2 M1.0t at Carverfest this past year, and absolutely loved it. He was impressed with the engineering behind the modification as well.

It should be noted that much of the actual modification is derived from the Carver TFM55(x) amp, which shares much of the same topology as the older M1.0t. The mkII opt2 achieves its increased power by increasing the rail voltage, and increasing the voltage handling capacity of the parts in the entire chain down stream.

If you were to sup-up the engin in a '60s muscle car, then beef-up the transmission, drive line, differential, tires and breaks, would you still say "there's no free lunch"?

I've been running a pair of mkII opt2 M1.0t amps on a pair of Infinity Kappa 9 speakers (a FAR more difficult load than ANY Polk) for a couple of years now, and I push them HARD. I have had zero issues - none. As with anything of this nature, there are hacks out there performing the modification. If you stick with Greg (nahash5150) or Wayne (wrf) on the carver site, you'll be fine. The warranty their work, and they are booked out for a year... That should tell you something.

I am with OldmanSRS on this one. Rick at Big Sky Audio did a full rebuild/modification on my GFA-585se and the last word I would use to describe the sound is "harsh".

No idea what your budget might be but here is the page with info on your amp. Rick works by himself so does not normally answer the phone but does answer his e-mail. He could tell you what the changes in sound might be with the new parts.
http://bigskyaudiomt.com/index.php?pr=ADCOM_GFA_555_II

daddyjt wrote: »

F1nut wrote: »

slbenz wrote: »

I would recommend having the MKII opt2 upgrade done to your amp. Will take it to a whole new level and more than double the output while making the amp sound more refined and life-like.

It should be noted that Mr. Carver does not approve of that mod. Something about overtaxing the power supply, IIRC and I know I've seen comments about some of the modded amps failing.

Bob (Carver) spent a good deal of time with a mkII opt2 M1.0t at Carverfest this past year, and absolutely loved it. He was impressed with the engineering behind the modification as well.

It should be noted that much of the actual modification is derived from the Carver TFM55(x) amp, which shares much of the same topology as the older M1.0t. The mkII opt2 achieves its increased power by increasing the rail voltage, and increasing the voltage handling capacity of the parts in the entire chain down stream.

If you were to sup-up the engin in a '60s muscle car, then beef-up the transmission, drive line, differential, tires and breaks, would you still say "there's no free lunch"?

I've been running a pair of mkII opt2 M1.0t amps on a pair of Infinity Kappa 9 speakers (a FAR more difficult load than ANY Polk) for a couple of years now, and I push them HARD. I have had zero issues - none. As with anything of this nature, there are hacks out there performing the modification. If you stick with Greg (nahash5150) or Wayne (wrf) on the carver site, you'll be fine. The warranty their work, and they are booked out for a year... That should tell you something.

I can vouch for Wayne (wrf) for the work he did for both my Carver M-1.0ts, Carver M-500t, Carver C-1, and Carver C-9. All of which works perfectly and the workmanship was first rate. Luckily he is only 20 minutes from my house. Great guy.

F1nut wrote: »

slbenz wrote: »

I would recommend having the MKII opt2 upgrade done to your amp. Will take it to a whole new level and more than double the output while making the amp sound more refined and life-like.

It should be noted that Mr. Carver does not approve of that mod. Something about overtaxing the power supply, IIRC and I know I've seen comments about some of the modded amps failing.

I'm not sure where the 'non-approval' comes from, but he's never voiced such a thing in my presence. On the contrary, there is a YouTube video from Carverfest 2009 (I think?) where he displays no concern whatsoever for the modification. He's had an M1.0t mkII opt002 in his hands (2013) and I explained all of the features of the mod, and all he said was, 'wow, he (Rich) did everything right'.

I've never asked for Bob's 'endorsement' because it's really not necessary. The amps perform just fine, and if it weren't for the bump in rail voltage, which is still very small in comparison (10% increase) there would be no fuss about this modification at all (at least on a technical basis). It's just a glorified repair/refurb that brilliantly upgrades the performance of the amp.

Rich has been doing this mod since 2008, and I have taken over the project (and thus, all of his repairs) for the last two years and have received a total of 2 amps during that time that needed repair (both repairs were small stuff - blown resistor, etc - they are vintage amps after-all). I have NEVER seen one where the power supply failed. So this mod has an 8 year record of proof that the rumors of power supply failure are false.

I should note however, that Russ Kall, who was doing the mod for several years, used inferior part - some of which turned out to be counterfeit, and that must be the reason for most of the recorder 'failures'. Some of my partners and I still get Kall amps that are indeed failed - at the output though, not the power supply, mostly due to extremely cheap **** parts. Well, those of us who honor a lifetime warranty use the best parts we can find, and they don't fail.

So even when the modification is performed by an amateur, with inferior parts, one cannot brick the stalwart (and underrated) power supply of the M1.0t (or M500t for that matter).

So to the point, while the mkII does increase the power rating and longevity of the amp, it also increases its value significantly. So even if you don't find the M1.0t or M500t to your tastes, you can sell it and 'upgrade' to a Sunfire or other entry level hi-fi amp which often cost over $1000 (unserviced!). In addition, if you own an mkII, you'll never pay labor for a repair - ever. And I'm confident claiming that because guess what - my bench has no repair backlog for mkII amps whatsoever, but I'm 18 months out for stock upgrades and repairs!!!

Cheers!

I'm glad to hear that you liked the McCormack.

I just purchased a un 8 year old, pre owned, DNA 125 and I'm picking it up tomorrow morning. Bob Backert of RHB Sound Dezign upgraded the signal path caps (Black Gate) and power supply.

Given all the positive comments surrounding this amplifier, I am eager to get it into my set up.

I will, eventually, be looking to add a preamplifier as well. Possibly a Peachtree unit that will accommodate my digital, PC based, media server as well as the analog outputs on my Pioneer SACD.

tonyb wrote: »

Is that the same Bob Backert from Backert Labs, who we are doing the demo round of the Rhumba with ?

Interested in hearing your thoughts too, so by tomorrow, 3pm ? lol

lol. I didn't know that when I bought it, but it looks like it. That's pretty

Unfortunately, I don't have a dedicated preamp in house, just the Marantz NR1402 with a set of pre-outs for the front speakers. I don't think that this is going to give a great impression of the amplifier's true potential or sound signature.

Any of the Illinois Polkies want to stop by Chicago with a pre for a listening session?

We can wait until I get the UniFi UB5 speakers in house and compare them to the RC10 and/or the RC70 speakers as well.

Oh, ya, it's a little chilly today so I'm going to have to let the McCormack acclimate before I can hook it up.

erniejade wrote: »

If I had more time, I would bring the Joule 150.

I'm in no hurry. They had the amplifier inside at my local FedEx since yesterday so, no need to wait for it to acclimate!

Got it hooked up and I am running pure direct through the NR1402.

Thus far, I am very impressed. First disc spinning on the Pioneer is Fiona Apple's The Idler Wheel Is Wiser Than the Driver of the Screw and Whipping Cords Will Serve You More Than Ropes Will Ever Do.

Her vocals are wonderful. She's right here in the room with me. It's haunting. So many layers and details in this recording brought to life with authority. This CD sounds good through the Marantz but it was a bit sloppy in the low end. When the funds allow for it, I'll be looking to add a separate preamp into the set up. Like I mentioned earlier, I may be looking for a Peachtree pre/DAC to control the Pioneer and the PC media server. I still have my SB3 so I may play with the idea of running it through the Micca OriGen DAC or through the built in DAC on the Peachtree.

There are other preamps that I have my eye on but the lack of funds has me window shopping for now.

The DNA 125 is really amazing. The amplifier runs very cool to the touch as well. I was very sad the day that I had to sell my Sanders Sound System ESL amplifier. I'm happy that I came across the McCormack brand and the reviews here on the forum. I don't think that it's an apples to apples comparison between the two but I do like what I'm hearing with the McCormack.

Cheers everybody and my apologies to the OP for the sidetrack.

Nice bro, the Sanders is no slouch by any measuring stick either. The thing I also like about McCormack amps is their sound signature doesn't change as you move up the chain. You just get more of it. You could be happy though with that puppy for a very long time. I would love to hear Ern's Joule mated to it, I think it might be a match made in heaven.

Nice!!!!