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Author Topic: Best Amp ever..........  (Read 11298 times)
Pit Hinder
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« Reply #30 on: December 06, 2013, 05:09:05 PM »

"It is, after all, only the last 5' of a very long wire..."

John, if an affordable operation could make both of us gay I´d say let´s get married.
One meter 50 of cable, costing megabucks and handcrafted from unobtanium by professors with a Doctor of Stupidity title -
I eat pretty much everything, but I can´t swallow that load of shit.
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sonic
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« Reply #31 on: December 07, 2013, 08:02:25 AM »

I'll buy into this to a certain extent.
 Not that I know that its true but the best explanation of the differences in power cords, that I've heard, is that it has to do as much as keeping shit from going back on the line, as supplying good power.

It is, after all, only the last 5' of a very long wire...John   
What about the last few inches inside of amp?  It's the standard "cheap" wire from the chassis power plug to the power supply circuit.  Tongue  No worries though because the power supply circuit filters out the crap anyway.

So, what's with the fancy power cord?  It's all psychology, man!  Kiss
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Ed Schilling
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« Reply #32 on: December 07, 2013, 10:30:23 AM »

Guys, I was once with you all the way.....how could the last 5 feet matter? Well they do! A lot! And not only that I can prove it!

At Hornfest one year Bill brought some cords he'd made. I gave him a lot of grief. They were braided "well wire" solid conductor.

On the last day I realized I could prove the cords made no difference because I could swap them with the amp playing and the p/s in the amp was big enough to not even burp when I switched them. I pulled the reg. in and out a few times with my back turned so that no one could see me when I switched them.
The INSTANT I plugged his is the music seemed to come from a blacker background and everyone there heard it right when I made the switch. They could not have known when I did it. We ALL heard it.

I bought that cord from him.

Now, that is not "proof" but this is certainly a possible explanation for how power cords can affect equip and why some never hear it.

I have an RFI/EMF meter I bought many years ago. I remembered it and dug it up. As I got close to my normal black cords the meter pegged all the lights. All but one or two just poured out trash. This trash is being generated right up to the IEC jack. But yet Bill's was NOT. Yep simply braiding the conductors eliminated anything my meter could see. Get it? The trash being generated by the other cords was appearing at the IEC but NOT with Bills. Hmmmmmmm.

So I started stripping the outer jackets off. The results were conclusive. ALL the cords that poured trash out were unshielded with parallel conductors running inside. The black ones that did not pour out trash were ALL either tightly twisted inside or fully shielded with foil. Braiding is as good as twisting and foil shielding.

By replacing ALL you cords with braided or shielded ones you eliminate a major amount of trash from being generated at the back of all the the equipment. It effectively puts distance between the parallel conductors in the wall and the trash they make.

Here's the trick........you can NOT tell is a black cord is twisted or shielded. If you happen to have shielded computer black cords you will not hear any change and will never believe they can. If you don't you will.

It is impossible to tell unless you strip off the outer jacket.

So, make your own SOTA cord........take a black cord, cut the MALE end off, strip outer covering off, braid the 3 wires and put a new end on the wire. Save a fortune.

There is no magic in the connectors used in power cords, just get an end from wally world!

And there you go, a perfectly logical and easily measured explanation.

Ed










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Pit Hinder
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« Reply #33 on: December 07, 2013, 12:52:55 PM »

Ed, with you there, all the way - but...

It´s fighting the symptoms rather than the causing sickness.
"Dirty" AC isn´t what we pay for. It should not be there.
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Ed Schilling
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« Reply #34 on: December 07, 2013, 02:02:05 PM »

Hey Pit, I must not have made my point clear. the "dirty" AC is caused in part just by the parallel conductors carrying AC voltage. The Romex in the wall is producing it just by carrying the AC voltage! Regardless of how "clean" the power on the line, it is the actual line itself to some extent!

By using a braided or  shielded cable you physically separate your equipment from this source. That source being parallel conductors carrying AC voltage.

My EMF/RF meter clearly shows this. I can use it to find the wires in the wall. Having that stuff being radiated all the way to the IEC can not be good. Power cord with shielding provides distance from the wires you can not shield.

Hope this helps!
Ed
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Pit Hinder
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« Reply #35 on: December 07, 2013, 03:32:44 PM »

We may agree to disagree.
But as to "wires in the wall"... Angry

Please be nice and never mention that s(word deleted) again.
Knocking the plaster off in the whole apartment just to make sure the shack doesn´t burn down -
"been there, done that, didn´t laugh" one may guess?

Pit
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DoS
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« Reply #36 on: December 07, 2013, 10:26:29 PM »

Your lines running in the house can collect what's in the air. But also it's just anything else in the house, sometimes the neighbors, sometimes from the power plant, whatever. It all collects to add up to an inhibitor.

When you braid the lines there is a small amount of cancellation that occurs, phase cancellation. It only works on some of the higher frequencies. But also when AC is twisted/braided you get some stability in phase of the peaks. Otherwise they have a tendency to shift. AC lines actually stay cooler by being twisted together, where as DC heats up. Both vice versa's are true as well. It can be a serious concern when running very long lengths of high power stuff in commercial settings.

Again people overlook the fact that the most immediate noise is from the equipment itself, sharing. Small transformers aren't big enough to have proper insulation so they end up building capacitance and the creating undesirable common mode noise. On top of that when the equipment "rejects" noise, it's sending it back to your powerstrip/whatever and can then go into your other equipment. There isn't a lot of equipment that uses phase cancellation; which truly eliminates the noise to varying degrees. That's a reason why good cords and other forms of filtration are valuable even when you do your best with things like having a separate sub-panel etc.

Even if you collect noise all the up to your AC receptacle, that last few feet can still be used to phase cancel as much of what was collected as possible. So yes, it does matter. Plus you want good copper since you aren't using Romex. If you are, I don't envy moving stuff around in your system Roll Eyes

The quality of your earth ground can also be a concern. Fact is most people won't ever upgrade to the best situation, but recording studios do because they just such a low noise floor. It involves a special mixture that forms into a block that's in the ground.
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DoS
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« Reply #37 on: December 08, 2013, 11:46:42 PM »

Hey Ed want the cheapest and easiest upgrade for you BAC?

Attach a diode or two across the DC in, cathode to positive. On both mono-blocks obviously.

Let me know what you think. I haven't been able to try it on class A, but single channel DC power going into class D loves it.

Actually I am not sure at what point is to many. Running 8 on my amp has benefits. Trying to decide if there is a negative return at some point. Got to wait till I can play loud to know for sure.
« Last Edit: December 09, 2013, 12:42:09 AM by DoS » Logged
Ed Schilling
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« Reply #38 on: December 12, 2013, 11:15:35 PM »

DoS, I'm not sure the switching p/s would like a diode across it. The Pass ACA's are dead silent. With the system on and your ear an inch from the cone there is nothing. You can not even tell it's on.

I should mention that this will not be the case unless you use shielded IC's.

Ed
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DoS
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« Reply #39 on: December 13, 2013, 02:05:28 PM »

DoS, I'm not sure the switching p/s would like a diode across it. The Pass ACA's are dead silent. With the system on and your ear an inch from the cone there is nothing. You can not even tell it's on.

I should mention that this will not be the case unless you use shielded IC's.

Ed


Switching PSU's (smps) don't care at all having a diode with cathode attached to the positive. That means that current can only flow through it from the ground to the positive. The SMPS doesn't actually ever make current for that direction. You can hook it up backwards to an amplifier and some still work that way, but the SMPS never makes reverse current. Your amplifier won't even know about it.

What happens is it acts like a bypass for the small amounts of AC that SMPS's make or have inducted. It's a filter. Using multiple diodes is better than one so far is my finding (essentially the more used, the less noise flows through the amplifier because it's going to divide among each component).

Your amplifier might be dead quiet, but that has nothing to do with quality of sound from noise reduction. You don't actually hear the noise from AC/DC power that you want to remove, you hear the effects on the music itself. Trouble is you don't know that it is having an effect on your music until it is gone.

I could go into some details on why a class A is dead quiet without anything playing, regardless of noise most the time, but it's not that interesting. What is, is the fact you probably have dozens of diodes sitting around to toy with  Grin .
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johnnycopy
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« Reply #40 on: December 13, 2013, 02:40:15 PM »

Ed, Henry,

Have you guys seen the 2.2 resistor change they are talking about to the amp that raises output to six watts and seems to improve sonics further and heat the house a little better.  Nelson approved.

John
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Steve F
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« Reply #41 on: December 13, 2013, 02:42:31 PM »

While sitting in the hospital waiting...
I really don't put much stock in that either. About the only time I see cords getting in the way are totally non-shielded in use around amps with lots of radiated energy. Like OTL's. Ed should send me a sanctified cord to make a comparison.  Count me among the non-believers until proven otherwise.
Steve
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Henry
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« Reply #42 on: December 13, 2013, 03:19:04 PM »

Ed, Henry,

Have you guys seen the 2.2 resistor change they are talking about to the amp that raises output to six watts and seems to improve sonics further and heat the house a little better.  Nelson approved.

John

Hey John, I haven't seen that.  I'm going to build another one to try some 10uF film caps.  This one will have larger heat sinks that could take care of a little more heat.  I'll look on the diyaudio forum for that topic.  I will say the stock amp is nothing short of awesome with the Horns and power isn't an issue.  I'm sure many users do need more power.  Wink
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Henry
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« Reply #43 on: December 13, 2013, 03:35:23 PM »

Thanks John, the tweak looks promising.  Here's a link:

http://www.diyaudio.com/forums/pass-labs/215392-amp-camp-amp-aca-146.html#post3700465
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Henry
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« Reply #44 on: December 13, 2013, 08:21:07 PM »

I added the resistor, it was simple since my amp still resides on an audiophile approved chunk of maple (some may call it a cutting board  Wink ).  I perceive a very slight gain in power, but it could just be wishful thinking or the pain pill, or both.  It sure didn't hurt the sound, so I'm happy.

I guess Nelson wouldn't shit-up his own creations.  Cheesy

P.S. - The ACA kits are back in stock, so forget about the March 2014 date they told me.
« Last Edit: December 13, 2013, 08:23:42 PM by Henry » Logged
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