20 amps times 120 volts is 2400 watts at 100% efficiency. Take that time maybe 85% efficiency per pass through device (power conditioners and power supply) and you get a more realistic 2400 *.85 *.85 = 1734 watts (1300 watts with a 15 amp circuit).
That's for everything sharing that outlet. Most systems can live with that just fine.
Short of CLASS D amps, that have real issues with RF noise (and a bunch of other bad stuff in wide-band use)if not handled properly, good capacitor filtered power supplies are pretty quiet.
I still haven't seen any results on Vcc DC bias variation on "sound" and fundamentally this is really what all that upstream stuff is supposed to improve. OK, people "say" when the Vcc bias changes, imaging and dynamics suffers.
That's one of the general "improvement" of class A amps, the engine is at red-line all the time so it's ready to go NOW! But at an efficiency cost. A/B amps have to accelerate up to speed, slowing transient responses. High bias A/B amps cheat a little and hold the throttle in class A for 15-30 watts. Other improvement is distortion which is inversely related to bias current and of course, no PNP to NPN notch distortion to manage.
Some of the "power" improvements I'll try to hear with a PLINIUS SA-103 amplifier verses my ODYSSEY KISMET MONO low bias A/B amplifiers. This, with the units AC line noise defended by the on board power supply of each amplifier.
To say a power supply is inadequate is somewhat intriging. The caps recharge at the RC time constant of the circuit, which is pretty fast and with full voltage charge from ZERO in five or six time constants. If a big drum beat pulls down the supply, then the only drum beat that will sound good is the first one you hear! The time even between drum hits is PLENTY of time for the caps to recharge. There is a measurable supply sag that can be designed for.
As far as caps needing to sit for "days" to charge fully? This sounds like a fairy tale as again, music is happening faster than that, and the power supply of a good amps seems to manage without waiting days between bass transients or high intermittent current draw. A more continuous draw? Well, I guess your amps don't sound good anymore until you leave and come back in a day? Amps are tested at a steady state 3/4 load cycle and then swept to full power to make sure long duration operation is decent.
The data says power supplies work on a much FASTER charge cycle than "days" or even seconds. The Vcc sag is an indicator of this attribute as that's where the rubber hits the transistors. No supply can never sag, so it's the amount (dips) and character (spikes) that is in question to fidelity. |
...Borrow or have someone construct some for you and have a listen...
Did that, heard nothing. A three foot piece of cord is not an intellegent attribute to sound in this block of the circuit. You might have crappy contact (IEC's are especially terrible)and the oversized contact thickness can firm them up some. I used good quality hospital grade plugs for better contact pressure and high grade IEC plugs. The 14 AWG wire going between the wall plug and the pre amp is more than plenty. The AC circuit to your electronics is no better than the WORST part, and in no way does it equal the best part. We sure like to think so, though.
Once the AC gets to the power supply block, THAT block better do it's job plain and simple. DC coming out is agnostic to what AC is coming in if a power supply is any where decent at all. And, a passive power cord's influence the AC line noise or current delivery is moot. The power supply block should take control.
DC power is DC power. It has to supply the current draw without VLD (voltage level deviation) and current sag while efficiently removing line noise. Anything past that is physically not there unless you plain decide that it is. DC is DC.
Lower voltage 110 that should be closer to 120? Yes, you can bump it to 120, but the current delivery will drop in relationship to the voltage increase. You can't get something for nothing. The watts delivered have to remain the same. Not to worry, the current is still amply high at 120 bumped from a 110 source with a power conditioner.
For AUDIO, once the power supply provides VLD absent DC of the right voltages, you're set. More current delivery than the circuit consumes is simply not going to help. Removing the magnetic fields can certainly be of help...but that's not the power supply per say, but stray magnetic field issues. Audio can't effectively shield magnetic fields as you need low permeability (stuff magnets stuck to) shields to isolate components. And, this is not very practicle. Magnetic fields are a squared field magnitude law, so MOVING them is easiest. Witness all the outboard power supplies. Foil and braids do nothing for 60 cycle hum. You need CMRR (common mode rejection ratio) using twisted leads and better yet into balanced inputs for the best passive(twisted pairs)and active (balanced inputs) effects. RFI noise is easily removed with a torrid (often called a CHOKE) around the power cord that looks like a load to RF and RF is converted into heat. This keeps noise INSIDE your equipment that it makes, and RFI noise OUTSIDE from getting in. It can't "remove" it, but you can STOP it's circuit path. Wide bandwidth amplifiers can clip trying to amplify RF as this is a hugely inefficient task. So yes, make sure RF is not a problem as the clipping will be superimposed and heard at audio levels.
Inky blackness in background noise is good thermal shot noise control (you tube people know this) and A/C leakage control and not the DC power coming in. DC can't make noise. A power cord can't fix a power supply.
Why is audio the only electronic discipline that can't be measured? "Sounds" funny to me.
PS - And, a car does NOT peform better and better with higher grade fuel. Premium gas is actually not higher grade at all if you count BTU capacity, it actually is WORSE! The increased compression ratio "premium" fuel allows over lesser octane fuels has to be positively offset with higher torque at lower RPMs in properly designed higher compression engines. If an engines is unchanged, you want to use the LOWEST octane grade you can to meet the highest level of performance. Drag racers all know this by heart. |
I would be VERY curious to see the DC line voltage monitored with a differential scope that records the AC leakage of any sort (anything that is not DC) and see what it tells you all.
DC is DC, and what you think is coming in is 100% immaterial till you show it out the DC side of the supply. An HP differntial voltage meter is thousands of times more sensitive than the human ear. If your DC signal has noise in it, what is it and what magnitude? I really can't see where a 0 dB offset average over time is going to be "heard". This test measures anything that isn't pure DC to the set reference value (sag, spikes, ripple...you name it) and records it.
Most wall to electronics issues are crappy plugs that change contact resistance with heat due to poor contact pressure. All those expensive cords fix that, but what's in the middle is what people think they get! No, it's usually the plugs. An IEC plug is not even an 100% usable interface distance. The plug makes make spec "contact" till about two-third of the way in. A good hospital grade plug has spec contact pressure almost immediately. Go play around with them and see. My IEC plugs work loose on my equipment all the time. The hospital grade wall plug? Never.
Romex right from the wall to the transformer with twist lock caps? Way better than a poor retention IEC plug (I HATE those plugs!). A hospital grade wall outlet and plug on the back of your amp would be about three times the retention force of an IEC plug / socket. The continuity is all about the contact pressure with temporary sockets. |
I mean the Vcc voltage supply rail regulation from the power supply. Audio components use a constant Vcc in many stages so it does indeed apply in small voltage transistor circuits. Not every stage is unregulated like a power amplifier (and even some of those are regulated). So yes, there are chips inside many components that feed on a constant supply voltage rail.
The higher the Vcc voltage (30 volts verses 5 volts), the better the dynamic range and the lower the noise. You can use RF isolation decoupling capacitor filters with resistors with higher voltage, too.
So you need enough DC Vcc to provide the voltage swing at the AC output with as good a dynamic range as you can get. A side benefit of higher Vcc seems to be better Vcc line filtering (all that line noise we're talking about).
That's about the best of my memory on op-amp circuits. Someone can probably explain it all in real easy to grasp terms that use them every day.
A good power supply should eliminate noise as you go through each block. Several small filter in series beat one big one every time and, they catch noise throughout the circuit. |
...Decent well set up system with decent gear should be able to let you hear differences between power cords, fuses, interconnects and speaker wire, and it should be as easy to hear these differences/improvements as it is to hear differences in one power amp to the next...
No, they shouldn't. A carpenter judge a roof by what gets into the house, not standing on the roof outside considering what "could" get into the house looking at the sky. It's irrelevant to what's going on inside the house. The weather is already taken into account with the selection of the roof / power supply.
The power supply is the "roof" and should provide a pure DC inside environment. People measure all this "stuff" outside and NEVER measure the DC rails from the "inside". The power block should be isolated from the signal block, too. If it isn't the "roof" had a hole in it from the start, the type of shingles used makes no difference at that point.
I'm sorry, but I don't accept "outside" metrics to determine what's going on inside my equipment, and neither should you. What comes OUT of the power block (leaks through your ceiling) is the final, and only, verdict to the performance of your gear. DC is DC. It has no sound except to allow something else to make a sound. If your supply rail is DC, and doesn't sag...case closed.
Now, if you have crappy power block to signal block isolation, that could be considered a fault since a "perfect" power supply would be isolation by design. But, perfect isolation can't be achieved with a power cord or external device(changing the weather outside doesn't change the roof!).
So, what we see are external power supplies. Magnetic stuff is squared law diminished with distance so distance is your friend if you have magnetic permeability shield problems inside the power supply block.
Could a unit need an external supply to sound better? Sure, but MEASURE where the effect is going to be seen. In this case, the power supply could be 100% fine except for magnetic emissions that show up at the AC signal blocks. So, move it, or redesign the isolation. A power cord upstream to the wall won't fix it.
So until such time that we can accurately look just past the DC power block feeding the AC circuit, it's REAL hard for me to "buy" anything outside a line conditioner that stabilizes the input AC voltage if you have a rowdy AC line. This is indeed a problem.
So yes, you have to get in the game and at the right place. This is electronics, not emotion. Music is the emotion.
Hearing conductors? No, what I hear is the capacitance and inductance determined by the dielectric composition of the cable. There is no evidence of common conductor differences at "DC". Like it or not, 20-20K is DC with regards to the electromagnetic spectrum and the laws physics. The signal is 100% diffusion coupled through the wire from 20-20K at audio.
In the 1980's, a company let us listen to four speaker cables with four different dielectric properties, same conductors through out. Then, we listened to ONE of the four designs but with four different conductors; solid copper, stranded copper, silver coated stranded copper, and silver coated solid copper. In a BLIND test, we could differentiate TWO of the four speaker cable dielectrics sound but NONE of the conductor designs using the same dielectric.
When the emperor is naked, I say so. The only sound that was heard with expensive conductors was the ring at the cash register. |
We all "want" something to change the sound, but what is important is what "needs" to happen in order to do so. The later is knowledge and the former is emotion. I don't like endless arguments. I like to argue forward.
Yes, you can say something sounds different but until you can define the attribute responsible for it, I'd be real careful to decide you "know" what it is.
Everyone like to touch and feel cords, fuses, ETC and think that since we can change these items, they are somehow outworldly responsible for what we hear. Why? They make up a very small part of the AC circuit that has several feet of PC board traces, NPN and PNP junctions an all sorts of resistor and capacitor signal traces. I would suggest that the "bottleneck" for the signal is far removed from a power cord (AC signal never even see's that circuit) or a fuse.
What effect does a NPN or PNP transistor have on the sound? We can't change it or really "see" it. The doped silicone is hardly esoteric in nature and yet we seem to feel it is of minor consequence to the sound. How about your PC board AC singal block traces? Those are far more critical to sound than 18 AWG unbalanced leads extrernal to your pre-amp or power amp.
A FLUKE test of AC line noise is NOT a measure of what the line noise does at the END of the DC block. Show me a test of the influence of the DC Vcc noise relative to the AC block and we'll talk. If we can't show what the "needs" are to hear what we "want" to happen (sound changes)are we learning?
Of interest,
...I wonder if Rower's sound is different late at night than it is during peak demand hours?...
There have been studies done that show or senses CHANGE with conditions. Our eyes improve with bright lighting and our ears are less monitored by the brain over what we see. At night it is the opposite. So what's really better late at night? The surroundings (dark) benefiting or senses, or do we want to decide it is AC line noise reduction? To be fair, I enjoy music in a dark room. But, I'm not going to say it's better late at night. I can make the basement pretty dark during the day. That mouse chewing inside my old apartment wall was always louder at night though!
Also...
...if the power supply in a component is less than perfect, wouldn't it be affected by the power that is delivered from the wall?...
You can make a pretty darn good power supply with three terminal regulators that have very low ripple with modest capacitor banks (we want to evaluate VOLTAGE chnges, not CURRENT draw). A power supply is pretty boreing in that the task is;
1.0 right DC level (regulation of voltage clamping).
2.0 no sag under current demand over time (capacitor banks).
3.0 isolation of magnetic fields from the AC circuit (crappy transformers).
If it does those three things it's working. A dumb transistor just needs pure DC potential. The three terminal regulator voltage clamping circuit is pretty robust to variations in line voltage as the DC voltage levels are WAY under the line voltage anyway. Get a three terminal regulator and make a power supply to prove it to yourself. Vary the AC from 100 to 120 and watch the three terminal regulation output DC value. Stayed the same right. The heat thrown off will change though, as that's how those HOT little buggers work when they regulate the voltage. Most "cheap" voltage regulators are less than 2.0% regulation like a LM340.
Fuses in speakers effecting the sound? Sure, a fuse is a device that works by HEATING and CHANGING physical attributes / electrical (it MELTS when it works!). Also, a fuse is the predominant component in a speaker "lead" relative to the speaker cable itself. Since they melt in order to work and...do you think they act the same just prior to melting than at room temperature? Silver fuses? Well, silver melts before copper (lower tmperature) so it's worse, not better all things being the same. You need to balance silvers lower resistance with its circular mil area to arrive at the same wattage at failure. To say one is better than another is to say you MATCHED the thermal resistive gradient to be the same. Otherwise, you are simply using a "big" fuse over a "small" fuse where the bigger fuse is changing less relative to the current drawn through it, and sounding better. A fuse that is moat linear resistance over a wider temperature range prior to melt is going to be better. I would guess, because I am, that a material that has a high change in resistance with temp will sound worse than a material that doesn't. And, the "sound" of the material is NOT what you hear, but the consistency of the resistance of that material. Where is this data?
I'm a real answer kind of guy. I just don't accept the audiophile acceptance of unproven sonic attributes. Sound different...sure, just don't pretend you "know" why when it can't be proven with measurement. You can't measure it you say? Than just STOP right there and say you don't know why.
That component on your shelf is FULL of real answers as to WHY it sounds like it does, even if WE don't know what they are. The designer sure does. I find it funny that a few cords and / or mystery dielectrics we set the unit on (or things on the unit itself) make outwardly big changes in the sound. Really? And the likes of Nelson Pass and their ilk are unaware that a few accessories make such huge changes in the sound?
My experience with three different preamps says no. The designer blows me away. No amount of prudent and cost effective designed cords made any one unit sound like the other. They are all good, but all very different. Inside those units lies the answers, too. Not outside. |
I have a Mercedes too, and it is a high torque engine at low RPMS. To maximize low RPM torque you need high compression...but high octane fuel is then needed to offset the detonation. Do it right, and it's a benefit. Do it wrong and it's a waste of money. Premium in my Focus makes it work worse, in my Mercedes...better. Doing something can change things, but not always to the better just because it is "higher" octane (that means nothing till you use the science)or a higher price (it cost money to make fuel worse on a BTU factor).
DC energy has not grain, phase or sound.
View things as a component void of "price" making it good or bad. Garbage in can be expensive things, too.
NASA has an expensive ball point pen designed to work at any angle in weightless space (it made it to the consumer market afterwards). The Russian's? They used pencils.
We can have a, "throw money at it and it isn't my fault if it sounds bad" mentality with all this. Oh I listen, but DC is DC you guys. A power cord cannot change what's coming out of the wall to any degree a good power supply should not be able to address on it's own. Move the supply? Yes. The cord? No, haven't heard that. Been trying for 30 years to hear it.
We can also have a, "you can't hear quality till you do all this" mentality. Ummm...no. I don't buy anything till it clearly is better. So if that means I use 1694A with gold gas tight compression RCA's, so be it. That's my reference point and why not, it's affoprdabel, logical, and sounds good compared to all the high buck cords I've used, still.
Yes, I can hear speaker leads since this part of the system is so low an impedance and real vector load magnitude that seemingly small inductive and capacitive changes alter the load factor efficiency significantly. The science backs this up.
Not so much interconnects and power cords where things are much less sensitive once you get the basic cords right.
In the end, it isn't a "compromise" at all. It's better, or it isn't devoid of price. making it work right at the lowest posible price is the challenge in this hobby. You have to think, and shun peer pressure to match crowd. |
...Further proof that bad power can equal bad sound, and that even some components are the culprits, never mind your neighbour with the basement full of electrical motor powered wood working tools...
It is? A power cord is a passive device and cannot prevent a weak power supplies back EMF into the power line unless it is a choke equipped cord, which is hardly an expensive addition. Copper and insulation can't do that.
Everything cable related gets better with "age" (except us, I guess) and nothing gets worse with age in audio. Astounding!
I've worked with dielectrics for 30 years and every one gets worse (treeing performance, withstand performance, T&E's you name it) with age.
A good dielectric should not be able to "align" a charge as that indicates it isn't pure. Treeing is a common phenomenone caused by impurities in a dielectric. You don't want your dielectric to store a localized charge. It's properties should be very dull and consistent.
Noise in the power-line means nothing. It's what come out of your power supply on the DC rails that matters. TAHT is the food your electronics eats. The power supply should have ripple and transient supression that correspond with common line noise. Measure your DC rail for 24 hours and THEN decide what's a problem.
Better yet, measure a swept A/C test tone at the amplifier output and sync it to a clock and measure the difference (flip the phase) and see the remainder and try to line it up with the DC output noise. I just see a lot of wishing and no testing. I don't think the guys that sell all those cables and such really want you to, either.
Looking at the power cord is like going to the doctor and having your butt examined for a cold. We're looking at the wrong end first. Why go downstream until you prove imperfection at the destination and work back from there? I just don't see any data that supports the supposition(s) on power cords or even line conditioners. Sure, they get rid of noise...but that doesn't mean the unit you plug-in didn't too, or to a degree that is sufficient to be inaudible. So of course they "work" but that still doen't mean they do anything.
I'd also like to see the results of the DC Vcc on a transistor bank varied with noise components and measure the A/C output distortion component. What does it take to be heard? Do a double blind random tests. This would be VERY interesting.
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