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in a set of SE 45 amps???? Who makes an amp of this caliber and does it cost more than my life is worth?
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If memory serves, the MI200 was an industrial amplifier. Where I worked we used one to drive a shaker table.
I fail to understand the "magic" you are seeking in an audio application.
shaker tables I am not trying to drive. Your failure is not helping answer my question.
I think the answer is implied. If the amp was designed to drive a shaker table, it would be very difficult, if not impossible to make it into a top notch audio amp. However, if that were my goal, I would try to find a audio amp schematic that used the same or similar tubes and then modify it to that circuit. The big question is: Are the output transformers wide-band enough for audio? You should answer that before proceeding further. If it is wideband enough, I would look to McIntosh audio amp schematics. A McIntosh K-107 is a likely suspect. It used the same chassis and is 20Hz-20Khz. It would be a very cool amp if you could pull it off!
Dave
Edits: 10/28/14
Dave your response is way off but I should have worded my question differently. Thanks, BC
That is correct.
Don Brian Levy, J.D.
Toronto ON Canada
It would seem odd to look to a SE45 for that, they are dramatically different designs. It would seem to make much more sense to look for another good push pull amp, if you don't need the power maybe an EL84 or 6L6 amp. Admittedly I haven't heard an MI200 but I find it doubtful that it would have similar sonic attributes to a SE45, so if that's what you like it would make sense to look for something more similar.
Dave
Possibly pp 1626 could do it. I dont want more than 2 wpc...
Buy the cheapest 45 amp you can find, then run the signal through two miles of wire before it hits the speaker terminal. Shazam- there's your Mac magic.
nt
Buy the cheapest 45 amp you can find, then run the signal through two miles of wire before it hits the speaker terminal. Shazam- there's your Mac magic.
LOL. You mean drop the B+ on the Mac amps from 450vdc down to about 90vdc and then run a mismatched load on the speaker terminals and that will give you that single ended magic of high 2nd order distortion. Argh argh...
"
Bobby
They are two different type amps..The Mcintosh leans on correctness of sound with almost no distortion and the little 45 SET amp is going to be lacking in dynamics,transient energy,and second order distortion is going to be much higher..In other words,it ain't gunna happen.
"
when your speakers are 104 db with 1 watt everything you just said is incorrect.
Kind Sir.
The Mind has No Firewall~ U.S. Army War College.
But you still have an amp that compresses the negative half of the wave form relative to the positive half. And since that's due to SET topology it's not correctable. But I admit lots of listeners like that sound.
Now Eli,he likes that high second order with the severely rounded clip on the sine wave you get with SET amps but I like honest.I can't convince him tho..LOL
"
"Norman Crowhurst wrote a fascinating analysis of feedback multiplying the order of harmonics, which has been reprinted in "Glass Audio," Vol 7-6, pp. 20 through 30. He starts with one [ideal] tube generating only 2nd harmonic, adds a second tube in series (resulting in 2nd, 3rd, and 4th), and then makes the whole thing push-pull (resulting in 3rd, 5th, 7th, and 9th), and last but not least, adds feedback to the circuit, which creates a series of harmonics out to the 81st. All of this complexity from "ideal" tubes that only create 2nd harmonic!"
"D.E.L. Shorter of the BBC Research Labs and Norman Crowhurst both proposed weighting harmonics by the square or cube of the order to [better] reflect audibility and annoyance-factor, and it's a shame their suggestions were never carried out. To this day, it's the 2nd harmonics that dominates THD device measurements, but it's the ones that are higher than that (even though they may be 20dB lower) that we hear. That's why a THD spec, without reference to the complete spectrogram, is essentially useless, and not only that, potentially quite misleading."
From Lynn Olson's webpage.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
SSshhhhh....Mike. All of these SET lovers think they are listening to low distortion amps. Don't burst their bubble!
I'm told by designers that that nice second harmonic is a result of the asymmetrical SET amplification. But no amp is perfect and I guess we choose our favorite colorations. A friend once wrote an article called 'Color Me Perfect'. And Nelson Pass, who I respect greatly, knows about the asymmetry but likes the sound which is why he designs single ended solid state amps.
LOL
When I posted that about how I like honest,that's a little inside joke between Eli Duttman and myself we both like correctness in amps and I was hoping he read that and commented.We like some second order distortion as well but not to excess and I agree with what you say as well when it comes to perception of sonics for certain individuals.AAMOF,here is an excerpt from the article from the early 60s called,why hifi experts disagree by J Gordon Holt. It more or less sums up audiophiles.
Many writers of books and articles about high fidelity advise the prospective buyer merely to choose what sounds good to him. Certainly there is no sense in anybody's choosing a music system whose sound he doesn't like, but in a field where definite standards of quality exist, simply liking something does not necessarily mean that it is good, by those standards. A person who likes abstract art, for instance, may be judging it by any number of criteria, but resemblance to the original scene is not one of them. If it were evaluated on the basis of its "fidelity," or resemblance to the original scene, it would have to be judged a very poor copy. Similarly, the listener who prefers his sound shrill and brassy is perfectly entitled to his preference, but he is not choosing on the basis of fidelity, either.
This raises the question of whether high-fidelity can, or should be, better than the real thing. Certainly it can be made to sound richer, or bigger, or more highly detailed in a recording than it ever is in the concert hall, and the net result may actually be more exciting than anything heard at a live performance. The gimmicked recording may even, on occasion, serve the intent of the music better than a concert hall performance, but whether it sounds better or worse than the original, it is not true to the original, and thus cannot be considered a high-fidelity reproduction.
Sound recording may eventually become a creative art in its own right, producing musical sounds that bear no relation to any natural sounds. Indeed, some branches of it—pops and so-called electronic music—are already well on their way in that direction. This is not high fidelity, though, and there's no sense pretending that it is.
As long as we are concerned with the realistic reproduction of sound, the original sound must stand as the criterion by which the reproduction is judged, and most hi-fi experts agree that this is as it should be. The problem, however, lies in defining this original that is to be duplicated.
F'rinstance, take one symphony orchestra, place it on-stage in one concert hall, and then try listening to it from a) the front row, b) the twentieth row, and c) the fourth row of the second balcony (or peanut gallery). The orchestra will sound quite different from each location, so which of its sounds is the one that best represents the orchestra? Obviously, the sound that is heard from the best seat is the best representation of the orchestral sound, but who is going to claim that his preference for a seating location is the only valid preference, and that anyone who prefers to sit elsewhere has bad judgment? Nobody but a dyed-in-the-wool nut will take this attitude.
"
Your last paragraph about different seats is why I'd argue that frequency response is secondary to sounding like live music even though it's necessary for accuracy.
I don't recall the article by Gordon Holt. I'll have to check my back issues from the 60s. But mentioning him makes me a bit sad. We were friends in the 70s in the Philadelphia area and stayed long distance pals until the end. He was a special guy.
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Hah! Please tell me I'm not the only one who heard the gag.
what I WANT is the realism of a Plasma tweeter, the realism of a planar midrange, and the realism of a Khorn bass bin.
Trouble is, the wave launch of all three is distinctly different.
And yet... to me those three drivers embody the purist sound I have encountered. Hence, why I own Quads and Khorns {JBL 2360 horns/2445J drivers} and Khorn bass bins.
The Mind has No Firewall~ U.S. Army War College.
Just curious, which do you listen to the most?
Dave
Sorry I took so long to post... working out of town.
The modified Khorns.
The Mind has No Firewall~ U.S. Army War College.
which is why sometimes it's better to compromise on given drivers for specific band widths to choose ones that go together better. It's the sum of the parts that's most important.
Ken
I'm aware of the virtues of 45 and 2A3 tubes. With the right speakers,they are very nice. The points I was emphasizing were strengths of the Mac circuit.I have a pair of AES SET amps and they have their plus side but all in all,I like my amps to have lots of transient energy and when you have ESL,you need extra horsepower.
"
Edits: 10/24/14
Yes, Sir. When I had Magnepan Tympani I's, was using a CJ Evolution 2000, a zero feedback tube front end 114 lb monster... Mike, the Transformer weighed 49 lbs...! could drive a 2 ohm load all day long. Those panels were black holes for power. Am not aware if your Martin Logans are that thirsty.
The Mind has No Firewall~ U.S. Army War College.
Actually,the Martin Logans aren't too bad.Naz runs ML statements with a pair of 845 set running about 70wpc. My CLXs are 91db but,the panels have nothing below 60hz going thru the panels..Maggies are an easy load for any amp even tho they can handle a lot of power..One guy was driving his 3.6s with a 2A3 set amp..You can't run the Maggies at blistering levels but they are very listenable up to about 90db.If you biamp with a paralleled 300b set amp,you would have enough power to drive Maggies with most material.
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so there are no really good sounding 45 set amps?
Of course there are good sounding 45 SET amps. But, we are comparing apples and oranges here.
A 45 SET amp needs special speakers of very high efficiency. With the 'right' speakers, the 45 SET midrange excels IMO. But, I prefer the dynamics of a carefully designed PP 45 amplifier vs a SET.
PP 45 vs SET 45? Which one is better? Everything is a compromise of some sort, but most important is to design an amplifier around the speakers.
Exactly!
"
What part of the MI-200 are you chasing?
With a 45 based SET you going to get ~3 watts - hardly comparable to 200 Watts of PP.
The sound. All of it except the size and power rating. 2 or 3 watts is more than enough for me these days.
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