Mark A. Gulbrandsen said:
Test at the same levels? Ok. Now let's see how the things would go if you turn the PRO amps LOUD and then try to keep up with that home-made amp. I have a 3-way active x-over stereo system, thats with 3 chanels for each side (L&R). Seperate amps for low, mid and high frequencies. 1 kW for lows, 200 W for mids and 120W for highs. And when I turn it just at half power the sound is so loud and powerful, yet still clear and pure. NONE of the super-cool, super-high-quality amps can do that, simply, because they don't have the power. Sure, they sound better at low levels, but what's use of it, if I want it much louder? For example rock music can only be enjoyed when played back at high volume. It is when you phisically feel the music, not only hear it. And I think I am not the only one who likes loud and clear sound. But loud and clear cannot be achieved by a hi-fi system. You can call me deaf, I don't care. Cos' I know I'm not. I've tested that.
Mark A. Gulbrandsen said:
Would you wire your household energy supplies (AC 120 or 220V) with silver cables just because they are theoratically better? Would you feel the difference between copper and silver? I guess not. Hi-fi is mostly aimed for people who simply WANT to spend MORE on their gadgets. They want to brag in public: "Hey, yesterday I bought a stereo system for 20000$. Just thought you might want to know..." Don't say you don't know that kind of people. Most of the new russians are like that. The go in a car salon and simply ask for the most expensive car, they don't even care how it looks, how it handles or even how much passengers it can carry.
Sure, there you'll see only the best materials in hi-fi systems, but what's the REAL use of it? Don't tell me that you can really hear the difference between 0,03 and 0,04% THD.
I think it is wrong to judge the PRO and hi-fi amps, because each are made for different purposes.It's like arguing about the music styles. And we all (I hope) know how stupid it is to argue about music. It's the same here. For people like myself, we like PRO gear because it is powerful and clear. We like it loud and clear, and that's why we say it is better. For other people, they like hi-fi, because they are normal in terms of power, but ultra-clear in sound. And that's why they say it is better. But it depends entirely on WHAT and HOW do you all want it. I for example use an EQ to obtain exactly that sound I want to hear. And I don't care wheter it is "the correct" sound or what. I simply tune the sound so that I love it. Simply!
Tom, I think your Threshold had a problem. I have had alot of experience with the 800A(similar circuit) even in its early incarnations and never saw that sort of behavior from it.
Actually my Krells would still do alot better than the Pro amp would at the high power levels assuming that both amps had the same power output rating. Both my KSA-80B and my present KSA-50 double the output power every time the impedance is halved down to 1 ohm... show me a pro amp that does this with current limiting or IOC lights flashin or one that can even drive a 1 ohm load! Generally speaking except for my S-300 High end amps power ratings have been alot more conservative. The KSA-50 for example clips at 79 wpc into 8 ohms and the KSA 80 I once owned clipped at about 140 wpc into 8. Of course these doubled for each halving of load impedance. Now if you have very linear impedance speakers its not any bug deal but not many really great speakers have very linear impedance curves. This is where Pro Amps will suffer as they shut down and or limit theor output power so they don't self destruct. BTW: none of the Krells I've had or own have any sort of currnet limiting or protection except for DC protection on the output. Becaue of conservative design they just don't need it.
I quite agree and this is why I've refrained from having them at the Pass Shoot Out sessions. Are pro amps REALLY designed for listening to music anyway? Having them at the Shoot Out will definately change in the future and I will dredge this thread back up after we have the next one in a month or so.
Respect to those ideal characteristics of KSA amps. But would those K's of yours run 7 years 24/7 ? PRO amps are designed to do so at least the tough ones. Plus, we are talking kWs here not just some watts above 100W @ 8 Ohm. Could those KSA amps deliver let's say 1000W @ 8 Ohm, 2000W @ 4 Ohm and 4000W (!!!) @ 2 Ohm. Not to mention 8000W @ 1 Ohm.... Admit it, you can't beat PRO amps in terms of very-high-power/quality ratio. When you need a lot of watts and a reasonable quality, PRO amps are the best around.
Mark A. Gulbrandsen said:
That's simply not true. The Krells you mentioned are nice amps but there's plenty of nice amps around these days.
And here's one example of a pro amp that eats 1ohm loads:
http://www.directproaudio.com/product.cfm?directid=53802
7.5kw @ 1ohm or 15kw bridged into 2ohm. The Krell's look positively anaemic in comparison.
Thy owns a couple of these and has tested them thoroughly I believe.
Bogie said:
Put them in Jail, force them to listen to Barry Manilow, 24/7.
That should be punishment enough.
Oh yes. Class H/G type amps, all preamp/pre-driver circuits done with JRC opamps and ceramic buffer caps. Make sure the speakers/amps are White Van or Behringer type. Oh yeah, the room must be square too, and all cement walls. Painted too.
If they survive, they'll behave themselves - after that. Imagine the threat of returning to such a nightmare.
Yes, Many of the original KSA-50 , KSA-100, KSA-80 and KSA-200's are still out there running just fine having been made starting in the early 1980's!
Sure, the largest flagship Krell MRA amp is more than capable of doing that At 1000 watts per channel into 8 ohms, 2000 into 4 ohms, 4000 into 2 ohms, 8000 into 1 ohm, and 16,000 into .5 ohm. Pass Labs also makes the X-1000 which is 1000 into 8 ohms but does not double power down to 1 ohm, I believe it doubles at 4 ohms though.
Anemic, hardly, You need to study up on Krells line
Krell MRA
That big Crest and many QSC's have other distortions because of the Class H or G circuitry that it requires and the switching points that come into play. Don't forget that I repair all sorts odf amps and bench test them. I get to see the "Real" truth as to how these power saving circuits behave.
Then there is the Class D and PWM digital switching amp realm which can make that Crest, MRA, and the X-1000 all look like a mouse in comparison and with very little heatsinking needed! O believe that within ten years all "Pro Amps" will be digitally based since they are so cheap to manufacture. For Pro Companies the bottom line is all that matters.
Mark
If money is an issue then build your amp so you get the most bang for the buck! After all thats why you're at this site... supposedly.
I built my KSA-50 for well under 250.00 by utilizing a scrapped pro amplifier chassis(AB Systems) and mostly surplus parts as well as scrapped MJ21193 and MJ21194 OP transistors from doing QSC 1400 rebuilds. The most expensive part in mine was the new but surplus 1.5 kva Toroid that came from Bel Canto that cost me 85.00.
Mark
I built my KSA-50 for well under 250.00 by utilizing a scrapped pro amplifier chassis(AB Systems) and mostly surplus parts as well as scrapped MJ21193 and MJ21194 OP transistors from doing QSC 1400 rebuilds. The most expensive part in mine was the new but surplus 1.5 kva Toroid that came from Bel Canto that cost me 85.00.
Mark
Mark A. Gulbrandsen said:
Krell Master Ref is also out of the reach of anyone on this forum, except maybe one or two people. We might aswell be talking about the holy grail and what happens if you drink from it. For me and you its completely inaccessable. Pro amps and 'sensibly' priced Krells are within our grasp.
Anemic, hardly, You need to study up on Krells line
/pats Mark on head/
Of course.
Just like you need to do some more research on pro amps before saying daft things like 'show me a pro amp that does 1ohm loads' and other such stuff.
Most are here because they have an interest in building gear.
My attitude has always been that nothing is out of reach of anyone if they want it bad enough! Krell sells more of those amps than you might think. Pass labs also has sold more X-1000's than one might imagine... enough to justify bringing out the X1000.5 version.
Keep in mind that working in the Cinema Industry and attending all the major equipment shows on a regular basis I am well aware of whats out there and that I also repair alot of it.....
Mark
Or, buy a decent amp that is broken and fix it. Then start upgrading components. That can be extremely cost effective and most importantly...'Time management' effective.
I used to sell a $29 Video capture card on the AVS forum for $179US after I had done extensive modifications. I purposely chose a extremely bad looking video capture card (This was so people with HTPC's- Home Theater Personal Computer's could get s-video or composite video onto their projection systems) to start with. People raved about it's image fidelity, it was FAR better than anything on the market. Period. Unless you wanted to spend $1k or more.
I would allow myself one donut, as a reward....as I rode my bike to the UPS office to ship them, every day I shipped some. I had to drive right by the donut shop to get to the UPS shipping office.
I ended up gaining 10lbs, even though I was working out insanely, every day. I sold too many video cards. Hundreds.
This highly modified video capture card work was done to specifically illustrate one thing--- which most people missed the whole point!!!!
That: Parts quality and placement of those parts was far more critical than the circuit or brand name. far more. To illustrate than in modding or design, that the rules go, in level of importance 1 through 10, like this:
1ower Supply
2ower Supply
3ower Supply
4ower Supply
5ower Supply
6ower Supply
7:Grounding/circuit layout
8:Signal coupling and associated components
9: Other components (diodes/resistors, etc-ones not PS related)
10:Circuit design
(rules 7 though 9 can be interchanged in given instances)
I'm sure that everyone's list is different, but I've never found that there is much that has come along to change the above list, personally..this..after having my hands inside of electronics, specifically audio equipment, for the past 25 years.
I used to sell a $29 Video capture card on the AVS forum for $179US after I had done extensive modifications. I purposely chose a extremely bad looking video capture card (This was so people with HTPC's- Home Theater Personal Computer's could get s-video or composite video onto their projection systems) to start with. People raved about it's image fidelity, it was FAR better than anything on the market. Period. Unless you wanted to spend $1k or more.
I would allow myself one donut, as a reward....as I rode my bike to the UPS office to ship them, every day I shipped some. I had to drive right by the donut shop to get to the UPS shipping office.
I ended up gaining 10lbs, even though I was working out insanely, every day. I sold too many video cards. Hundreds.
This highly modified video capture card work was done to specifically illustrate one thing--- which most people missed the whole point!!!!
That: Parts quality and placement of those parts was far more critical than the circuit or brand name. far more. To illustrate than in modding or design, that the rules go, in level of importance 1 through 10, like this:
1
ower Supply2
ower Supply3
ower Supply4
ower Supply5
ower Supply6
ower Supply7:Grounding/circuit layout
8:Signal coupling and associated components
9: Other components (diodes/resistors, etc-ones not PS related)
10:Circuit design
(rules 7 though 9 can be interchanged in given instances)
I'm sure that everyone's list is different, but I've never found that there is much that has come along to change the above list, personally..this..after having my hands inside of electronics, specifically audio equipment, for the past 25 years.
Thats what I did with the AB Systems Amp that I inherited. I stripped the chassis after finding out that the six new Main caps cost more than the amp was worth. In fact it cost me less to put the KSA-50 into that chassis than it would have cost for the 6 new caps from AB.
Attachments
That big Crest and many QSC's have other distortions because of the Class H or G circuitry that it requires and the switching points that come into play. Don't forget that I repair all sorts odf amps and bench test them. I get to see the "Real" truth as to how these power saving circuits behave.
I tested my QSC PLX and Crest10k using a scope to see if
the switching distortion is visible. I couldn't find any visible
flaws with those two models, switching was seemless. If
I can see it, you can't hear it unless you believe in green
men from mars.
I tested my QSC PLX and Crest10k using a scope to see if
the switching distortion is visible. I couldn't find any visible
flaws with those two models, switching was seemless. If
I can see it, you can't hear it unless you believe in green
men from mars.
Bogie said:
Not worth the time and money. That same money can be
used to move out of the entry level model into a higher build
quality model.
I've done extensive PLX mods on the test bench with
power supply capacitance and I have measured data
to support the claim that it 'does something', but I'm also
not retarded to assume that I will hear voltage 'stiffening'
effects like many people claim. Even these mods aren't worth
the coin, if anything you know it measures nice but sounds
the same plus you have a modded amp bragging rights that
is really worthless unless you find a sucker that is interested
in buying your modded amp for a nice premium.
I used the lowest load that the amp is rated for to try to manifest
issues.
I don't believe in 'parts to billion' distortion is required for
a good amp, look at pass amps, rated for 1% THD at rated
power
Also, these amps trigger high rails on when driven hard,
most of the time they sit on low rails.
Comparing both scenarios, two amps with the same rail
voltage, the class H wins because it does switch to high rail
to prevent low rail clipping, the other amp will clip much severly
and it's the amp prone to bad SQ audibility.
It's not a fair apples to apples comparison, but if you
buy a high powered proamp that has the ability to switch
into high rail, that is a big bonus over the other amp which
doesn't especially if you operate both in the low rail territory.
issues.
I don't believe in 'parts to billion' distortion is required for
a good amp, look at pass amps, rated for 1% THD at rated
power
Also, these amps trigger high rails on when driven hard,
most of the time they sit on low rails.
Comparing both scenarios, two amps with the same rail
voltage, the class H wins because it does switch to high rail
to prevent low rail clipping, the other amp will clip much severly
and it's the amp prone to bad SQ audibility.
It's not a fair apples to apples comparison, but if you
buy a high powered proamp that has the ability to switch
into high rail, that is a big bonus over the other amp which
doesn't especially if you operate both in the low rail territory.
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