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In Reply to: RE: Ordering from Magnepan, lol if it wasn't sad posted by josh358 on December 30, 2016 at 19:25:16
Hmmm, right you are. I never owned it but did hear the impressive organ recording at a friend's long ago. That gent makes us sound like wimps. In a room no larger that 7x10, he had megawatts of top-notch power amps. AND, to put things in perspective, among other things, he had 4 (FOUR) 18" woofers in the cramped space. Full sitting accommodations was 2 directors chairs, surrounded on both sides by equipment. Just clean raw power. Fabulously loud and totally undistorted sound...marred by a total lack of imaging.
Tomorrow I may be going for a walk at the local flea market. I guess I now have a good reason to get on my knees and search the many boxes of old moldy LP's that some vendors bring.
Follow Ups:
"Fabulously loud and totally undistorted sound...marred by a total lack of imaging."
Heh, reminds me of horns. If you add in a few annoying resonances, that is.
Speaking of bass, someone posted this on the Planar Circle yesterday -- check out these dipole tower subs -- I think they use the GR Research 12" servo drivers:
First, Happy New Year to all!
Wow, what a little system you show there! Satie must be salivating for a demo of those little puppies!
Anyway, I walked the Swap Shop on Saturday and searched for the Telarc LP; no luck but I'll keep my eyes open. I did see an LP album by Kenny G, new, unopened. For some reason I thought of Neolith. There must be an old thread somewhere here where KG was discussed? I thought I recalled the gist of the discussion and left the record undisturbed lest he lets the little ladies loose on me, LOL.
Celebrating the new year, I finally switched the system for class A end-to-end (at low to moderate levels) yesterday. This only happens from the PC, where the class A DAC goes straight to the Parasound HCA amps. After 10 continuous hours of listening today I could have gone on forever but my wife demanded her time minutes ago. Still, not a bad day at all.
I can't say I'd mind a tower of dipole servo woofers myself. :-)
Still thinking of going to Pass amps in the by and by, but meanwhile, the A-21 is doing a nice job without breaking the bank or turning my room into a sauna . . .
Well, Josh I know the feeling. With the right gear, it is so hard to pull away from that Pass sound. LOL, it would actually be downright impossible to do so if one lived in Antarctica -- tunefully trimming ice shelves along the way.
OTOH, an A-21 visits home every now and then. I also visit its home often. The beautiful sound via that unpretentious-looking smooth operator is what convinced me to go for its MOSFET HCA siblings.
Then, I did a bit of tap dancing with bias settings for more class A watts, primarily on the HCA 2003a amp that drives just the tweeters. Yup, it sure warmed up the room, but not as much as it sweetened the music. Oh man, get another A-21 and biamp at line level. That should be something!
I've been thinking of an A-51, because ultimately I want to triamp and also do some experiments with splitting the woofer panels. Not sure how it compares sonically to the A-21 -- I think the A-21 is the only one that John Curl recommends for high end use out of the box. And then there's that mod he has for the HCA-3500 -- apparently spectacular results, but I have os much to do right now that I don't think it's practical (still haven't even fixed my delam -- it's been cold up there since the radiator isn't working).
Sonically identical, like most of the JC MOSFET designs are (after the late 90's?) compared to the A-21, most of them cannot match its power supply budget per channel. That is a relative shortcoming in the A-51. To be sure, I was not able to tell so when I heard it, probably because it was not being driven hard...nor anywhere as low as to stay in class A, either. Yet, at usual volumes it is an A-21 sonic twin.Then you have the HCA-3500. I actually wanted one very badly at first. However, the real mods for it were the ones JC and his partner fooled around with and offered to do long ago. Along the way, I the realized that I would not have space for neither it nor the A-21 in my place. In an apartment, 3 power amps plus the rest of the audio gear can lead to a divorce.
In the end, finding the 2003A instead of the additional 1500A that I was looking for was a major blessing in disguise. With a beefy PS made for 3 channels, I use only two channels -- just for the tweeters -- and re-biased for a little more class A. Works like charm (though more by accident than skill :).
Which makes me think that if you "wasted" 3 of the A-51 channels...you'd still get great stereo class A for the tweeters...at probably a very decent price. Well, that's just a rough idea that you could polish.
Edits: 01/12/17
Good point -- I have to look up the power supply specs, and also the bias spec, for the A-51. I'd only be using four channels (annoying to leave one unused!) so I'd have more reserve. I'd also be driving the Neo-8's, which are incredibly efficient (and should never leave Class A) and the ribbon tweeter, which uses little power, so the A-51's power would really be overkill. But putting the little Passes on them would be expensive and run up my electric bill something fierce. :-)
Another thing to consider is that since I'd be tri-amping, I'd have the power supply budget of both amps.
Actually I'd really like six more channels since I want to experiment with splitting the woofers. But I guess I can perform those experiments before I do the Neo 8 mod, which isn't going to happen until I fix the delam anyway. One possibility would be A-21 for midbass, A-51 for low bass and tweeter, and tubes for the critical mids. Or the little Pass. But I figure I can cross that bridge when I come to it.
Awright, Josh! That's what I meant with "that you could polish". And I had forgotten the Neo's.
A couple of items for you to remember or simply evaluate:
-- One is this. If my blastedly cheap old MMG's insist in telling power amps apart, I bet the IVA's will do so much more.
Until the MOSFET-driven 2003A arrived, I had used a HCA-1000A for the tweeters. It has NO mosfies output but did well enough with class A at low volume, due to a re-tune into high bias.
Yet, in the few visits by the A-21 to my place, it was tried as tweeter amp, in place of the 1000a, with the HCA-1500A in its usual bass duty. The A-21 was also tried with the 1500A driving tweeters, as well as the A-21 doing bass. (The remaining possible combinations, by including the 1000 and a few other power amps, were also tried.)
Consistently, the MMG's were always "clear" that any combo of the A-21 and the 1500A was great. The same is the now case with the 2003A and the 1500A. I expect that the A-21 will get along grandly with the 2003A the day they get together. (That shared fundamental design PLUS the MOSFET output may explain it.)
Not so when others were in the combinations. Which surprised me at first because the 1000A has a very similar design, minus the MOSFETs.
-- Another point, however, is that all of the above may lose some relevancy if the Neo's decide to impose new rules.
-- Lastly, even when at moderate levels, "part-time" class A is sweetly worth it IF the whole signal chain can stay in it. (I mean, from the source to the power amps...and at a useful power envelope.) Starting the chain in class B always, for example, won't get this "fixed" by subsequent class A stages. Doing class A all throughout does not need to break the bank nor do space-heating.
The thing the MOSFET HCA's are doing here is to provide a very delightful class A delivery right at levels where mechanical distortions have not yet imposed a drowning effect. I suspect that the A-21/31/51 could deliver more sweetness still.
i can only say that the a51, however attractive is way overkill at the 200w x 5 8 ohm rating and near $5k mark. You would be better off trading for lower power rating and higher class A operation with better passive parts. There are ksa 50 clones you can have made to order and the classic "small" coda, Classe, threshold, plinius etc high bias class A/ab amps. the smaller theta multichannel amp (Intrepid) is a better choice as it is not designed with bass extending feedback but is focused instead on the best time domain performance for top notch mid and treble.
Alternately a pair of hybrid stereo amps would be perfect.
http://www.stereophile.com/solidpoweramps/625/#hTS25PSufebVI0Qs.97
Yeah, agree an A-51 is overkill, but I prefer to think of it as a 25 watt Class A amp! The question is can I do better on a per channel basis. IIRC last I checked A-51's were going or about $3500, so that's $1750 per stereo pair -- a bit more actually than the A-21. (But three A-21's, yikes . . . my back isn't what it used to be!)
So there's price per channel and then there's sound quality, which is hard to ascertain since I'm no longer somewhere where I can go to the dealer and swap out amps. Which is to say there are a lot of variables here, and given the importance of listening and the fact that I'm no longer near a major dealer it's hard to sort through them . . .
The Theta Intrepid goes for about $1-1.3k giving you 5 channels for 1/3rd the cost, Effectively $600 or so per channel pair. The downside is that because it is a non feedback design it has weak bass and midbass performance. Because of this, and because of the particular attention Reich puts into midrange and treble performance it should do the tweeters and mids a better service than any of the JC designs. My only caveat is that being a DC servo it might have a slight low level resolution problem as the TIVa mids have and the Neo8 do but to a much lesser extent. I have not found any review to mention that it is an actual performance limitation.
Of course, the Theta Intrepid is not going to drive the bass panels. It also needs a real ground so requires that you have 3 phase wiring in order to avoid hum..
The other issue and downside of a non feedback balanced design is that the THD is rather high in the presence of bass and IMD on adjacent freq tests would be higher. But it is 3rd order so rather innocuous. This is not far from my old DR-9 design (from which Reich derived the Theta line) in general behavior and I can assure you it works fabulously on both mids and tweeters. Class A operation is 8-10W as tuned at the factory, you can bias it up further but the amp does well in the class B portion of its output so it is not as critical as it is in the JC and Emotiva designs..
I read the review last night. The price is certainly great, but there are a couple of issues -- it won't drive the woofers, as you point out, so I couldn't use it for my split woofer experiment.
And then there's the ground loop issue. I'm about to try an experiment with my computer, I got a fanless power supply, low noise video card, and liquid cooler for my computer, and I'm going to see if it's quiet enough to use in my living room. But I have to disassemble it to install the components. Once I've done that, I can try reconnecting the ground on the A-21. I fear, though, that I'm right and truly screwed, even though I swapped breakers so that everything driving my audio gear is now on the same phase. Even an isoground system probably wouldn't fix the hum fields in this house (my tech power is isolated ground but I had to repurpose some existing circuits for my audio and the contractor didn't put in the access hatch I asked for so I'd have to rip open the walls to run new ones).
Without a real well grounded 3 phase supply I don't think the linear Theta amps are a practical reality. So unless you manage to sort that one out I think those are out.
On the other hand, there is more flexibility in having high feedback and much cheaper high power amps for the bass panels rather than using the much more refined and expensive JC multichannel. Think linear Crown mactrotech 2402 which you can buy by the dozen at the price of the A51. Or 3X 3600 or 3602. Though some surgery to replace the fans is necessary.
I don't have that kind of heads on comparison to rely on. The closest I did on comparison was with the mg20.1 + big Chords vs. Big Boulder. and on the Apogee Diva - Big Krell KSA vs. Classe monos VTL Wotan or Siegfried tubes and a couple of others.
The comparables are just that class A high power gives you a more tuneful tighter bass with subjectively deeper extension. It also heats the room very quickly. Even a large room. Tubes don't damp the membranes well enough and lose on tightness, making the bass sound a bit bulbous or elephantine. The class A/AB like the Classe was nearly as tight as the class A Krells but apparently started sagging. Some say the KSA bass is not natural. Compared to the rest of the things put on the Diva bass - or whole speaker, the Krell bass was most convincing.
What I get at home with the Crown is tight deep bass and extension similar to the Krell (and boulder)- but it is not quite as tuneful as the Krell with the caveat that the Krell can sound single note on occasion when playing hard. I think it is the high damping power - I am thinking that the back emf is about the same scale as the driving voltage since the diaphragm is so stiff. So 1000 damping factor is more useful for the bass panels than it would normally be. The Crown 5000 are about 70 lb and have little bias current. Trying to equate class A to an equivalent effective power on an AB amp driving a panel I think you have roughly a 2:1 ratio so at 8 ohms a 500W class A would be equivalent to a 1kw AB in bass panel performance. Which is roughly where the Crown 5002 stands. And the Apogee/Krell bass is close to what I get with the Tympani/Crown.
If you remember the JGH review of the KLH9 then his response to having the mids and bass come off the panel rather than go to a box woofer describes well what the panels sound like when driven by an ample amp vs. one that sags.
I would suggest that you should expect to match the power supply rating of the A51 to that of the particular Crown model you are considering and remember that you can bridge the crown for 4 ohms and that on the 3600 you can do a regular bridge and there is a parallel bridge option for 1 ohm if you ever need that.
You are probably ok with the 2400/2402, if not in stereo then bridged mono, and if you want to have extra power then the 3600/3602.
I looked at some on Ebay -- they all looked pretty beat up, as if they'd been on the road . . .
That is because that is where most of them went/are. The 2400 are common small venue amps. So have the highest likelihood of having been lugged around the country in vans with less than professional care.
Finding them in presentable condition is more difficult. I got my 5002 essentially new from a cancelled concert tour.
They have been out of production for a few years now so the search will get you many a beat up but working piece. But what I stumbled upon is not possible because they are not new any longer. Do any of the new Macrotech i series amps show up?
I see a 5000i but it's $1600. And much more amp than I need! Other larger Maorotech i's for even more money. OTOH, I just found a refurbished 2402 for $550 that looks to be in reasonable shape:
http://www.ebay.com/itm/CROWN-MACRO-TECH-2402-MA-2402-GMA-2402-2-CH-1050WPC-PRO-POWER-AMPLIFIER-AMP-/361850324652#viTabs_0
FWIW as a price reference I followed eBay Macro-Tech prices for a few months.
Used not under warranty 5000i lows ran from $1,600 to $2,700.
The lowest used 9000i was $1,850 and still under warranty.
I bought one new 5000i from PlanetDJ for $2,236.76 on a Black Friday sale and another new 5000i on eBay for $2,100.00 (came with plug for South Africa :|). The normal best new online pro store prices I found run from $4,300 to $4,600.
You can email crown support a serial number and they will give you the year of manufacture and tell you if it's still under warranty.
The dsp versions, I-Tech 5000HD, record hours used. Forum wonks advise not to get earlier models not ending in 'HD'.
Thanks, useful information. I think the 5000i is overkill for my application -- I don't need all that power -- but I found a refurbished 2402 for $550:
http://www.ebay.com/itm/CROWN-MACRO-TECH-2402-MA-2402-GMA-2402-2-CH-1050WPC-PRO-POWER-AMPLIFIER-AMP-/361850324652#viTabs_0
Think that's reasonable?
That isn't a bad price but it isn't a "deal" either.
Didn't realize you could get a 5000i for that kind of money. I heard good things about their performance at the mids and top end but have not tried them myself. The 5002 I have are not that great on top.
Zulugone, do you have a comment on midrange and treble and imaging performance of the 5000i amps?
Still scratching my head. Both the Neo-8's and tweeters can get by with a smaller amp, which means the A-21 really makes sense for the woofers. But then, I want to try separating the woofers, so need another reasonably-sized amp to play with (although I can just wire them together for initial experiments and keep the woofer and mid-woofers equidistant). The only reason for the second woofer amp would be to adjust timing -- I'm not sure a crossover would be a good idea since the panels aren't quite tuned as LF/HF, there's a lower bass segment in the midbass panel.
If you are dropping the idea of crossing over between the bass and midbass panels because of their complementary tuning to perform together as a single driver then you really don't need another high power amp. Your room is small enough so that it can be fully loaded with the power on hand via the A21 and there is little to be gained by powering the bass panels separately. .
In which case you don't need a high power amp but a good quality 4 channels of high bias class A/AB amps rated around the 50-100W range at 8 ohms.
Damn, could have sworn I replied to this when I saw it a few days ago.
OK, so my senility notwithstanding, the reason I need to biamp the midbass and bass is that they probably won't be equidistant.
Of course I could use a 100 watt amp to experiment with and then get a bigger one for the second bass panel if I do decide to split them. Which will depend on whether the split arrangement sounds better than my current one, which is starting to sound pretty good. I'd been eying the little Pass for the Neos . . . not sure what I'd put on the tweeter (or if it really matters, now that my ears are only good to 12 kHz).
Not really as I have little experience listening to different amps and so don't have much of a reference. I would say the Macro-Tech tends to add more detail over the XLS-2500 across the spectrum but I would guess that's just due to the power (relative to Maggie 4 ohms) which is stable to 1 ohm. It's a soft call (subjective perhaps :) ) but I notice this detail more in symphonies and less in say solo violin.
Over time I've heard more variation between recordings than anything else. I notice less 'choral-soprano-screech' with the Macro-Techs on some old favorite CDs but I also hear more bass in the background so that's hard to sort out.
I didn't investigate any of the older Crown amps. Among the discontinued series I recall the K's mentioned often for durability and home theater use partly because they have no fans.
My Macro-Tech i's are noisy running full speed on any power draw...another DIY project to fix that. I notice them when listening to quieter classical like solo guitar.
I found some useful info on a Crown forum: http://www.crownaudio.com/forums/index.php?/search/.
Thanks. I think I'd probably do what Satie is thinkingof doing -- put the amp in another room. Still, the fans are a drawback . . .
The fan within the 'audiophile' Crown Macro Reference (~ 24 years ago) was described as "its noise distracting when listening at low levels".
Read more at http://www.stereophile.com/content/crown-macro-reference-power-amplifier-lewis-lipnick#87XGZaruTj3sRYUC.99
Yes, the fan noise can be distracting. I have some tricks to take it down and got a spool of new low gauge wiring to allow me to move it to another room eventually.
How do you think the bass amps compare, though? I was easily able to hear the difference between the three I compared while feeding only the woofer -- which rather surprised me.
"I walked the Swap Shop on Saturday and searched for the Telarc LP'
I just found a copy in a thrift shop for 2 bucks.
Sweet, Russ, may you enjoy it grandly! I kept looking for the LP actively until this past weekend.
Then I learned that Telarc had actually taken the trouble to make careful SACD versions of it (Saint-Sa‰ns: Symphony No. 3 for organ, Eugene Ormandy/PO) and the original Tchaikovsky: 1812 Overture / Gershwin: Rhapsody in Blue...Kunzel. Not the LPs but I was VERY glad to get them. They are not the greatest performances but that Soundstream digital system captured some mighty sounds.
So, no LP's for me. LOL, my current vinyl gear may not even track those 1812 cannon shot grooves like the old set did so well in the 80's.
I don't think I've ever seen that before. I wonder if the room was designed as such?
They just came out this year. No reviews yet.
Heh, hadn't noticed that. It's a hotel room, so maybe it was?
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