|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
65.96.137.241
My speakers are 85db/w (ATC SCM-19)'s. I've tried a number of amps the past few years from various vintages. Amps include Mcintosh, Electrocompainet, Pass Labs, Yamaha, and DIY high powered tube amps.The tube amps are 90 watts and 120 watt monoblocks. They sound very good with the speakers, BUT, can't really push them too loud. The volume is sufficient for the most music listening.
The solid state amps are a different story. The SS amps that are 150 watts or less per channel sound stressed when pushed to even moderate volume. The only two SS amps that I've auditioned that sounded really good with them is a Mcintosh MC7270, and a Yamaha MX-D1 500 watt class D amp (the only class D amp that I actually liked so far).
Anyone else notice this with their moderately inefficient speakers?
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
Edits: 02/01/16Follow Ups:
It is dependent on the amps - there are watts and then there are WATTS!
With amps of even modest nominal output, if they have an amply designed power supply and operate a significant part of their time in Class A, you won't have any issues. I drive a Martin Logan set up (85 db and dipping to 2 ohms) with a 45 watt Class A amp with no issues.
BTW, depending on which Electrocompaniet amp you've tried, I am suprised that it didn't also drive the speakers very well. Even the original version with 25 watts or the Levinson famous ML-2 with the same output would drive almost any speaker well.
Yes on amp watts quality , regardless thou, if you require 200-300 watts for unclipped reproduction , the 45 watts is clip city ...
The ATC could be the issue as suggested by some, they do use a dynamic compressing dome mid unit , very good for nearfield listening ,not much for farfield listening ...
Edits: 02/02/16 02/02/16 02/02/16
"Yes on amp watts quality , regardless thou, if you require 200-300 watts for unclipped reproduction , the 45 watts is clip city ...
I run a couple of Class A amps that put out less than 100 watts into 8 ohms. They drive the hell out of the worst loads out there. When I bought them, they were driving Apogee Scintillas at 1 ohm setting (efficiency ~ 73 db) and drove the hell out of them. The reason is that they have very robust power supply circuitry and keep doubling down as you halve the impedance. They put out very high current - the Scintillas need up to 60 amps on music peaks.
The point is that simple output numbers don't tell the whole story - that 45 watt amp you look at may pump out several hundred into low impedance loads.
Some amps - Krells, Classe DR3 VHC, one model of Eectrocompaniet, an early Bedini, the rare Belles A, and one of the Adcoms were about it for the Scintillas.
Of my 3 systems, I have 4 power ams that will drive a Scintilla, and in my other one, a Class A/B amp (Rowland 5) that likely will but I've never tried it (150 watts into 8 ohms, 475 into 2 ohms
Some amps - Krells, Classe DR3 VHC, one model of Eectrocompaniet, an early Bedini, the rare Belles A, and one of the Adcoms were about it for the Scintillas.Of my 3 systems, I have 4 power ams that will drive a Scintilla, and in my other one, a Class A/B amp (Rowland 5) that likely will but I've never tried it (150 watts into 8 ohms, 475 into 2 ohms - Bill
Could you list the names of the 4 other amps you have tried on your Scinnie .....
Edits: 02/02/16
"Could you list the names of the 4 other amps you have tried on your Scinnie ....."I aid I had 4 amps that would run a Scintilla (and in fact a pair of them were doing so when I bought them) not that I currently own Scintillas - though I'd be tempted if I found a pair in good shape.
I run a pair of bridged Classe DR3 VHC to drive some Vandersteen 4As and another stereo VHC to run Martin Logan CLS (original version).
I use a Class AB amp, albeit one with considerable power supply (150 w into 8 ohms, 475 into 2 ohms), a Rowland 5, in the main system to drive some Wilson speakers.
I also own a Belles A not currently in use (recall that they made a hundred and something of them)
Edits: 02/03/16
Agree Bill ,Then You are not using a 45 watt amplifier , especially @1 ohm , same as the 8ohm rated amp at 100watts , that amp would be able to do 600-800 at 1 ohm and yes PSU is very important since your speakers are practically connected to it....
My point , you aren't doing it with 45 watts when the amp is capable of doubling down on a low Z speaker, at that point it is no longer a 45 watt amp ..
BTW , bass drivers work best with high voltage , so high powered amplifiers are best, as low output (voltage) amplifiers will not grip or drive the bass as well , even when operating at the same power level ...
Edits: 02/02/16 02/02/16 02/02/16
But, the SCM-19 uses a 6" mid/bass driver (at over 9kgs). It has a good sized center that acts as a midrange driver. Most listening is done around 3 meters or so.BTW, this is one of the few speakers that provides the illusion that there is a live performance going on when in another room (especially piano).
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
Edits: 02/02/16
That driver is basically ATCs 3" mid with a cone glued to it.
Obviously the basket has been changed but the motor assembly (and therefore largely the weight) remains the same.
I am not surprised about the amps at all.
If you play them at 95dBspl average which is reasonably loud you are using 10W.
Now add in the 12-20dB of headroom needed to prevent the amps from sounding strained you would need an amp capable of 200-1000W. Lo and behold the two amps you tried which sounded best were the two which fell into that range.
It is all well and good talking about the quality of watts one is feeding ones speakers but if an amp clips even for short periods all its watts are c**p.
Who is playing at an AVERAGE of 95db?? Not many people I can assure you.
With classical music the average SPL level is probably more likely in the high 70s to low 80s db range with peaks then of 20 db or so. That puts you just over 100db rather than 115db...a big difference also in terms of the power needed.
The one real issue for a speaker like the ATC is the thermal compression as they are rather insensitive (probably lower than the 85db rating) and will start compressing rather early as the VCs heat up. So, it might really need a lot more power than theoretical to even get to 100db because you no longer get 3db for every doubling of the power...maybe only 2 or even 1 db as more and more goes to heat.
The higher the sentitivity of the speaker the higher the SPL level gets before serious compression starts...at least for conventional speakers.
Cab,
Take your avg RMS usage and multiply by 100 should keep you out of trouble ....
I do frequently but then I'm usually more than 1m away from the speakers.
Are you talking 95db at 1m or at the listening position? In a moderately sized room the drop is significantly less with distance than the point source theory. Regardless, even an 85db average is pretty loud...at the listening position, and most music is rather compressed so not so much headroom is necessary.
At 1m of course. What else?
My own speakers are 95dB/1W/1m and I regularly see the bass and/or lo-mid amp put out 10-20W.
Can't be that bad for you (I'm in my 50s and can still hear my supertweeter cutting in at 15kHz) and is a lot of fun neighbours or wife permitting.
I tend not to listen to over-compressed music.
I have 96db speakers and they work just fine with my 20 watt JJ 322 and play more than loud enough cleanly. My 35 watt Wall Audio monos are overkill really.
if your avg rms usage is .25 watt then yeah , a 20 watter will work .....
If you have 95db+ speakers then it will be more like 100mW for 85db at around 3 meters in a real room, which has a much smaller drop off than the free space theory.
The driver is 6" (ATC's mid is 3"). It does look as if they glued the 3" mid to the 6" driver. The speaker plays up to 108db max. It sounds very clean even when playing loud.
I was careful to match component values when re-doing the crossover. The non-inductive resistors and caps improve the performance markedly.
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
Yes it does but the other way around: They glued a cone to the dome and modified the basket accordingly whilst retaining the 3" VC and the motor assembly.
At least that is what ATC said they had done when they introduced that driver.
No argument regarding the capacitors but it is usually futile to change inductors.
The one advantage boutiquey inductors have is lower DC resistance however to ensure the crossover is working correctly one has to match the resistance of the new part with that of the one it replaces by adding resistors getting you straight back to square one albeit with a lighter wallet.
Hmmm, was not aware, thought they used a dome driver for midrange , my bad ....
They do use a dome for their 3 way speakers and being 3 " in diameter it has very good dispersion. It is also quite linear dynamically(doesn't compress much) and very open and detailed.
No worries.
They got a very high rating in Stereophile.
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
The EC amp did drive the speakers very nicely...up to a moderate volume level. For rock and jazz, this was not much of an issue. The issue is with classical symphonic music. That just seemed to run out of gas with some digital recordings with a large amount of dynamic contrasts.
One of amps I tried was Pass Labs XA30.5. It was excellent at low to moderate volumes, but with some classical symphonies, it would sound a bit congested with some passages. The Mac 7270 does not have that issue. A Mac 150 does have that issue with these speakers.
I have looked at other speakers. The ATC's are really hard to beat when fed with the correct electronics. To get their clarity and dynamics with other speakers gets almost cost prohibitive.
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
I debated getting the 30.8, but didn't throw no it would drive my speakers.
The INT-60 does fine
Jack
THe 30.5 is class A up to 30 watts into 8 ohms. However it goes into AB above 30 watts and actually puts out close to 100 watts. It's called a 30 watt class A amp because it is up to 30 watts. That doesn't say it can't do more.
Damn auto-correct. :-(
Yes, Pass labs tend to be conservative with their power ratings. I had a long chat with Mark at Reno Hifi about that, and he basically said that the 30.8 would be iffy with my speakers at 87 db.
Jack
The XA30.5 just goes into class AB when it needs more power. There is something like 6db of headroom with the amp. It actually sounded pretty good at low to moderate volumes.
These speakers like high powered tube amps and Mcintosh amps of 250 watts or more. Maybe it's the output iron that matches up well. :-)
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
One of the stronger points of Class D amps. My current speakers are Ohm 5000s (87db), and they do work well with high power. I had a W$S, or a pair of d-sonics driving them at some point. Power was 250 and 1500W respectively. The later had macro-dynamics that were just unbelievable. I eventually settled on a Pass amp (60W). I gave up a little in sheer slam, but gained in nuance. Oddly enough, the Pass has deeper, tighter, more tuneful bass too.
Jack
Most systems are under powered , take your avg RMS use and times it by 100 , should get you pretty close ..
Edits: 02/02/16
You're right, my speakers are 86db/1 watt, avg. listening volume is 90db, and then x100 or 10db not enough is 200 watts. I need to start saving, I have a PS Audio 200C in the closet but I'm thinking it's not enough, I need POWER!!!
Edits: 02/02/16
Good amp have the 200CX version sitting ....
And improve bass response you should consider adding a sub. The speaker rolls off above 50 anyway. Getting a sub will allow better bass and as importantly you can then send less LF to the ATC's which will make the amp you drive them with operate much better. I was an ATC dealer and this was a good solution when done right.
ET
Done right is the real point. You need to pick the crossover point well and use a sub that is well damped. The ATC has a Q of 0.707 and if the sub doesn't do at least as well you'll gain bass and lose bass quality.
Thanks for all the responses. Lots of good questions/comments. I'll try to address some of the questions as follows:
1. The solid state amps (Pass Labs, Electrocompaniet) that I had on hand were between 120 and 150 watts at @ 8 ohms. Perhaps the 250 watt Pass Labs would have done the trick. Having said that, the Mcintosh amp at 270 watts sounds great with the speakers. Makes me wonder if a second 7270 in mono would be even better.
2. I do have subwoofers with the speakers. I have a SVS SB13 Ultra, along with an ATC C1 sub. The speakers are run full range, as suggested by the SVS team.
3. I have tried a number of preamps with this setup (Electrocompaniet EC4.7, Mcintosh MX-119, Classe DR-6R, Innersound, and a Thomas Meyer 6AH4 clone). The various preamp setups did not make much difference regarding when the SS amps started running out of steam. The Classe preamp seems to have a tad more drive of the bunch. It is a great match for the tube power amps as well.
4. The tube power amps actually provide the most pleasing playback (up to a moderately loud volume level). The Mac can actually get the closest to actual live symphonic levels with the SVS sub and still sound natural.
5. Lastly, recently upgraded the crossovers in the speakers with audiophile quality parts. The crossovers are now external, and sport foil coils, Mills non-inductive resistors, and Mundorf caps. I was surprised at the improvement in sound this provided. The speakers had improved clarity, low level detail, and dynamics. This is espcially true with both the tube amps and the 7270.
"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)
If you upgraded the crossover and changed the inductors I hope you have taken care to replicate the original inductors DC resistance as that is one essential aspect of crossover design.
If you haven't the speakers will likely not operate to spec.
For what it's worth (and you're not likely to want to hear this) I wonder if your real problem is your choice of speaker.
Several years ago, after years of hankering after ATC Active 50 speakers (which had been outside my price range), I found that ATC had a set in stock at a very good price. I drove to their works and collected these long-lusted after speakers. They are tri-amped with built in 200+100+50 watt amps. I fed the speakers directly from my Mark Levinson 390S CD player/preamp. Plenty of power, but not the sound I wanted. I wanted to play them loudly but they seemed to be wanting to be pushed another 20 ft from the listening position - far too "in your face".
ATCs are low efficiency and require beefy amps, but I wonder if you wouldn't be better off with better speakers to match your excellent amps. I came to the conclusion that the ATCs were designed for studio use and were not so good in domestic situations. After some consideration, and a chance reading of the Stereophile Equipment of the Year 2000 edition, I noticed they chose Avantgarde Unos as their joint best speaker. Reading the full review, it seemed that these speakers offered everything I found lacking in the equally costly ATCs. I bought the Unos and still find them an absolute delight to listen to, even after 15 years. Your Pass Labs and Mcintosh would be ample to power these or similar higher efficiency speakers and may be a great match.
Peter
Some times it's not the power but the speakers. Some speakers are just plain veiled sounding. No matter how much power you throw at them. But I'm obviously speaking having NO knowledge of your setup.
It looks like you've had some nice amps there. Also could be your source,preamp and even cables. Try switching sources around. Try a passive preamp, try some thing cheap and easy first.
You can build a passive preamp from parts at Radioshack just to try one out.
Just food for thought.
ATC speakers are not close to being veiled. They just need big quality amps.
You mentioned the Yamaha MX-D1 being the only class D that you liked. If you are even remotely capable of assembling a kit, I suggest you try one of the SDS amplifiers from Class D Audio (link attached). I use their SDS-254L kit (125Wpc/8ohms, 250Wpc/4ohms) to drive my 80db sensitive Adire Audio DDR dynamic dipoles to satisfactory levels (certainly loud enough to have to shout over the music) without any sign of strain. Their SDS-470C is even better.Not an employee of Class D Audio, just a VERY happy customer!
Dman
Analog Junkie
Edits: 02/02/16
What preamp are you using? You could be having an impedance or low gain mismatch between your preamp and amp combinations.
The ATC site specs the efficiency at 85 but I wouldn't be surprised if it tests out a bit lower. So for very dynamic music such as well recorded classical music a very big amp will be a good idea to handle those very short massive peaks sometimes in classical music and to properly show the ability of this speaker to handle the peaks linearly. It can be amazing how huge the peaks are relative to the average level of music, sometimes over 30 dB above average.As a good friend who manufactured 400 watt triode tube amps(that were underated) liked to say. A good big one will beat a good little one every time. There may be a few exceptions for VERY efficient speakers but those are few and far between. And ATC speakers are on the low side of efficiency, the price paid for their other good qualities.
Edits: 02/01/16
30 db would be QUITE the crest factor.
I use 20db or for ease of math, 10db. But I get it.
My low sensitivity panels have 200x2 per speaker. and will eventually have some kind of biamp using line level crossover of some sort. TBD.
I doubt you can have TOO MANY 'good' watts.
Too much is never enough
Piano is a big offender, one of the reasons it's so hard to really reproduce accurately. But even 20 dB is a factor of 100 so even a 90 dB efficient speaker needs 100 watts to do 110 dB peaks at one meter and 400 watts at two meters, still a very close seat for most listeners.
Edits: 02/02/16
It's a LITTLE off, but one of the advantages of a true BiAmp is that the amp is no longer required to reproduce 'out of band' signals. This is about like buying a 2x more powerful amp. And since my panels cross over at 600hz AND I have a low-cut to them, I figure each amp is about 50% of the total required power. The benefit is a gain in amp power of nearly 3db. Nice bump.
Planar speakers level drops with distance like all speakers. Just not at the same rate as box speakers. Because of line source? Dipole? Dispersion pattern?
My seat is ABOUT 3 meters from each speaker. Maybe actually 3.3 meters?
Too much is never enough
You're correct. Planars drop off linearly with distance. Conventional speakers drop off with the square of the distance which also means you have to balance woofer and planar at the seat. Closer then it will be too heavvy. Futher it will be bass light.
I had never thought of that, but your thought has MERIT.
Maybe Multiple subs help mitigate this phenom? (I can't afford THAT, either!)
I'll mull this over, but given limitations in my room, modest demands AND the fact that I'm in a good place means I won't be changing much Soon.
Though I AM EyeBalling the MiniDSP 2x8 which will allow me to go to a true BiAmp situation and reap those benefits, both real and imagined.
Too much is never enough
So the PASS and Electrocompaniet did not sound good on the ATC ...?
It would be interesting to see an impedance plot of your speakers, which does not seem to be available for some reason.
Still, the McIntosh is transformer coupled, which seems to suggest that the extra 3dB or so of headroom is very helpful for your speakers.
I also looked. Nominally, it's 8 Ohms, but that could hide some heavy load characteristics over the frequency band. It seems unusual that his amps. don't drive these speakers very loud. Could that be a system gain issue?
Electrical load curves are hard to come by if the speakers have not been measured on Stereophile.
One mfr. that does provide electrical load curves for all their speakers is Stirling Broadcast, although they are not all published. They are available freely on request, though.
there is a character of "authority" that high powered amps can impart to the sound that lends a natural ease to musical reproduction.
I find that 300 watt tube amps with 500 joules of power supply work very nicely. :)
I'd just bet they do work nicely! As room heaters too!
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: