Next step up from JMT Cmoys?
May 31, 2002 at 2:40 AM Thread Starter Post #1 of 26

Alleria

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I have a JMT-built Cmoy with the 470 uF cap upgrade, and I'm looking for suggestions as to my next amp upgrade?

Headphones are the Sennheiser HD-600s w/ Red Clou, and the Ety 4S/4Ps (have both pairs.)

Like to keep budget under $350 if possible, although not strictly so (i.e. if you know of a Max with stepped attenuators that you're selling for $US 450 ... :p ) Does _not_ need to be portable in this case.

I've not had a chance to audition anything, but I get the feeling after reading this site that the Cmoy is very, very good for the price -- I keep hearing comparisons to the Creek OBH, and varied Airheads. Is my next step up something from Antique Sound Labs? Or other suggestions? (Or anyone wanna sell me their MicroZOTL for $400? heh...)

thanks in advance,

--Alleria
 
May 31, 2002 at 3:51 AM Post #2 of 26

eric343

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Well, if you like solid state you could wait until the META42 comes out and have either JMT, Tangent, or myself build you one.

Or, you could grab yourself an MG Head and roll the tubes, if you want to try something with tubes in it...
 
May 31, 2002 at 4:34 AM Post #3 of 26

TimSchirmer

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currently, I am using a single ended MOSFET which is in the projects section. It sounds wonderfull out of a cd deck, but not powered enough from a pcdp.
 
May 31, 2002 at 1:02 PM Post #4 of 26

Matt

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...the Headroom show (Orlando) I was able to hear a JMT and a Meier Porta Corda side-by-side and I must say that I was extremely impressed with the Porta Corda. Compared to the JMT, it had a more active treble which was not at all harsh or over-emphasized. All it did was bring more life and presence to the musical presentation. In that it was also able to convey emotion better, I'd call it overall more musical by a pretty substantial margin.

The crossfeed was really nice and though there were losses, they didn't detreact, in my opinion, from the singing musicality of the unit. The crossfeed was also (obviously) far less mentally fatiguing. I feel it is definitely a best buy.

Of course, that's way below your budget and you've got cash burning a hole in your pocket...

Maybe a Grado RA-1 at $350? More than one person has sung it's virtues with not only the HD600's, but the Etys, too (mostly the Senns, though). From what I recall of it, it would be great with Etys...it was smooth, detailed, punchy and pretty damned delightful.

- Matt
 
May 31, 2002 at 1:17 PM Post #5 of 26

fiddler

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I also have a Corda (the big one, not the Porta) and I must recommend it. I also have a CMoy that I built myself, and I agree with Matt's assessment. The treble is just so much airier and more extended; the CMoy sounds rather rolled off in the treble in comparison. I also find that the bass is tighter on the Corda. It's a clear step up from a CMoy. You can get an assembled Corda HA-1 for $325. ($260 if you want to build it from a kit.)
 
May 31, 2002 at 1:27 PM Post #6 of 26

Matt

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...that the Grado RA-1 is considered a value leader, i.e. you get a lot of price/performance for your $350. I don't know if this is widely considered true of the Corda, but I wouldn't doubt it. The Porta Corda had delightful construction (and this very Western European look to it), equally delightful sound and I wouldn't doubt the the Corda is a good amount better. All I can do is wholeheartedly recommend the RA-1 as a value leader that has been very positively reviewed with HD600's and Etys.

(As an aside, fellas, shouldn't it be "performance/price"? With "price/performance," if the price-numerator is high and the performance-denominator is low, a product gets a higher numerical rating!)

- Matt
 
May 31, 2002 at 4:17 PM Post #7 of 26

daycart1

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Does your JMT CMOY have crossfeed? If you have and like this feature, there are only two choices in your range: the Corda and the Little. Each has its advocates....
 
Jun 1, 2002 at 1:19 AM Post #8 of 26

Alleria

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Thanks everyone for your suggestions.

eric343: thanks ... what exactly is the META42? Is this an improved or totally redesigned Cmoy type DIY amp?

Further musings: My Cmoy does have crossfeed available, but I don't really think it adds or detracts much. I guess I'm just not that sensitive to crossfeed overall, although my friend who's using the amp right now on his HD-580s complains loudly about having sounds localized to being behind him(!) when he has the crossfeed flipped on, hehe.
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I have a Grado dealer locally with the RA-1. I listened before, and was not terribly impressed, but then again, it wasn't a formal audition, and I'm not a big fan of the Grado RS-1s I listened on anyway...


I've been posting on AA as well, and it seems that the Headmaster may also be something to look into? At that price range, it seems I start to run into a variety of options, including various Headroom amps, the MicroZOTL, and even the Headmaster, which apparently lots of people here like as well. Given that I like the whole hyper-detailed style, I assume this is the way to go?

I was hoping to spend relatively little, so the Corda HA-1 looks interesting, but the Headmaster especially is very tempting especially since I'm looking for a pre right now also, even if the unit is rather expensive. One question remains: does it drive the K-1000s?
 
Jun 1, 2002 at 4:02 AM Post #9 of 26

eric343

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alleria: The META42 and the Cmoy are two entirely different amps. The only thing they have in common is that their circuit topology is somewhat similar.

The META can be biased into Class-A mode, uses real buffers instead of the Hansen/CHA47's gain==1 opamps, is designed for the AD823/825/8610 chips (which outperform the OPA13x used in the Hansen/CHA47/Cmoy design by a fair bit; and the AD8610 might outperform the OPA627s used in the high-end HeadRoom amps), and is generally a heck of a lot more versatile.

With any luck, it will be one of the better opamp-based DIY amps out there. IMHO it's a great sounding amp, but that's just off my early-revision prototype boards. Tangent's boards should sound better...
 
Jun 1, 2002 at 4:12 AM Post #10 of 26

Vertigo-1

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The Altoid with 220 caps does not sound rolled off to me.

The Cmoy + 470 caps does sound rolled off to me.

The Cmoy + 220 caps does not sound rolled off to me.
 
Jun 1, 2002 at 4:43 AM Post #11 of 26

Alleria

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eric343: thanks for the information! I think I've joined the ranks of those who await this new creation with great anticipation.
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Vertigo-1: ah, so it's not just my ears. And there I was thinking I was going deaf. :p This crappy SBlive! in the computer right now isn't helping either. Can't wait to get back to my normal machine with the delightful M-Audio AP 24/96, heh.
 
Jun 1, 2002 at 4:56 AM Post #12 of 26

eric343

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Vert: You mean rolled off in treble or bass?

What's likely is that the 470uFs, being larger, have a slower response time.

Which is why Tangent went with 2 220s per channel for 440uF without the disadvantage of slowness. Add that to the ~1uF and ~.1uF polypropelene (way faster than electrolytic) bypass caps to speed things up a bit...
 
Jun 1, 2002 at 5:09 AM Post #13 of 26

Vertigo-1

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Rolled off in the treble. You do trade off some bass deepness though for the increased treble.

I have two Cmoys right now and the Altoid with the various caps I mentioned earlier. The two Cmoys distinctly sound different from each other.
 
Jun 1, 2002 at 5:58 AM Post #14 of 26

Alleria

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Interesting -- everything you've said agrees with what I've experienced: the first impression that I got from the Cmoy was that it gave the HD-600s serious, visceral bass that I'd just not heard before from any other amp.
 
Jun 1, 2002 at 8:27 PM Post #15 of 26

morsel

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I don't usually read this forum, but I just happened to see this thread and can't help but wonder what opamp Alleria's cmoy uses. Going from an OPA2132 to two AD825s on a BrownDog opamp adapter would do wonders for the treble, it would be cheap, and still have decent power for a straight cmoy. You could also try the new dual AD8620 on a standard SO8 adapter for less current but more finesse in the high end.
 

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