Will new power cord make that much difference?

[Neal_C]

Hello to everyone.
I'm new to this forum and a new owner of Rotel equipment.
I picked up the RMB-1075 about 2 weeks ago to power my Def. Techs. I read the reviews on the power cord and most people weren't impressed with it. I agree with them. Seems like a 1k component could come with a better power cord.
So would upgrading the power cord make that much difference?
I have the 1075 plugged into my Monster HTS3600 for protection. I know many people say plug it straight into the wall, but I tried both ways and it sounded the same to me...so I went with protection.

Thanks,

Neal

[Claude D D]

Check this out http://www.venhaus1.com/diymains.html

[Neal_C]

Thanks for the link. Informative and interesting read.
Seems I may have to take the plunge and either make my own or buy a better power cord.

Thanks,

Neal

[Claude D D]

No problem.If you feel like tackling the project yourself( I did it's easy) check this place out. http://takefiveaudio.com/connectors_parts_cable.htm it's in Canada so it would be way cheaper in U.S. dollars. Use a Flavor Two for the power amp and a Flavor Three on the Pre/Pro. After breakin (Chris says 100 hrs) you will notice a lower noise floor and just better over-all sound quality.

[Andrew Pratt]

Claude to make a link "clickable" simply highlight it and then press the URL button. You can edit your own posts if you like.

[Claude D D]

Thanks Andrew.You are wise beyond your years!!

[Andrew Pratt]

Just doing my job

[Neal_C]

I guess its a good thing my wife is getting a nice bonus on Friday Must be my duty to spend it.
How much would you have to spend on a power cord (pre made) to match the quality of the DIY one?
I have been looking at this one: http://signalcable.com/magicpower.html
as a reasonably priced option.

Thanks again,

Neal

[Claude D D]

Give it a try.At that price if you're not happy you can always put it on your PC,or you can use the connectors that are on it and order the Beldin cable.

[Heiko]

I see that snake oil has found its way into this forum.
If you want my opinion find something better to spend your wifes
bonus on.
Power cords among general cable questions is one of the most discussed topics in the audiophile world.
Take a look at the power supply of your 1075 and you will notice a hugh toroidal transformar which is known to be excellent in filtering
harmonics coming through the powerlines. Generally you can say
that power supplies these day do a very good job in filtering noise
coming in from the AC line. They don't need the help of voodoo/magic cords.
The only problem you should be aware of is that power cords are radiating. That does not effect your amp but might effect other components in your system. So just make sure you keep your power cords separates from your ICs and you should be fine.
That might be an explanation why some people claim to hear a
difference in power cords. By replacing the old cord they rearrange
their cables and this might change overall system response.

Just my opinion. You decide which way you want to go.

[LEVESQUE]

My dealer just sold a 4000$ CDN power cord to a rich dude. He was feeling guilty selling this...knowing, like he told me, that it won't do any difference compare to a regular power cord...

But, he's in business to do money, and the guy just send 3 if his firends to buy some more saying that it was a "bargain" at this price... 8O 8O 8O 8O

And I tought that selling pills would make me rich...I should recycle in "power cord builder"...

[Claude D D]

Snake oil hmmm. Spoken like like someone who has never tried a higher quality power cord.$60 is not a large amount to spend on a cord with higher grade connectors that grip the sockets better (providing better conduct) and have a larger grade cable.Different cables(interconnects,speaker wire and yes power cords ) can have a noticable effect on the sound of your system despite what members of the Flat Earth Society might lead you too believe. The bottom line is you be the judge and listen for yourself,on your own gear in your own environment. Ask Lex his opinion.

[Neal_C]

Thanks for the replies.
What is everyones opinion of the power cord on the 1075 (those who own one)? And did you get a different power cord? If so, which one? Notice any improvement? Just feel better knowing you have something that should be better? If you kept the stock power cord, why did you keep it?

I'm thinking of trying a new power cord and just see how things go. I don't think it could do anything but keep things the same or make them better.

Thanks again,

Neal

[SIH]

Neal,

I replaced the power cable on my RB-991 amp with a Signal Magic cable. I can't say that I heard a difference in sound but the IEC connector on the Magic cable fit much better into the back of the amp than the stock cable. I think the Magic cable is a good low cost alternative to DIY and a good way to experiment without breaking the bank. It's made from Carol 3 conductor cable and Marinco plugs. You can make it yourself from items from PartsExpress but you might as well buy one from Signal Cable for not much more money and save yourself some time.

[kendrid]

The 'earth is flat' people are the ones that believe that power cords make a difference and refuse to look at science. And does having the cord 'fit' better into the amp really matter? Did the Rotel plug come undone every couple of days?




------
Kevin

[sndtowne]

In thirty four years of being in the A/V business, I personally have never found a "better" power cord to make any audible difference in power amps. Once I had a manufacturer and his rep present me with various high dollar cables and power cords - saying how much they would improve the sound (and, of course, pointing out how much money I could make on them).

So - I put the rep to the test with his own products. After several hours of "critical" listening and swapping cables back and forth, the rep finally declared the factory supplied cables the "obvious winner." The manufacturer was highly embarrassed and both quickly left.

It is my opinion that if I am going to pay good money for better cables (power, speaker, or patch), they should make an obvious audible difference right away. If I have to compare for hours before I think I can tell a difference, then I am probably just convincing myself that the more expensive cables are better (because I honestly want them to be better).

I do believe that because of resistance and capacitance differences, some cables "match" better with some amplifiers than others. This does not mean, however, that more expensive cables will automatically sound better. In fact, sometimes the opposite is true.

But - each person has to decide for themselves.




Bruce

[Entice]

Right!
So we're all going to rush out, spend huge dollars, and change the power cords on our amps.

That will make them sound better, run cooler, and give 36% more efficiency.

But wait a sec... Should I change the wall socket for the power? And then..what sort of cable did the electrician use when he (or she...lets not be gender specific eh?) wired up the house?

Nah, stuff that...I'm gunna get someone to tap into the nearest (remembering the shortest run is oft the best) power station and run some 3 phase directly to the back of my amp. That ought to get some serious gains over the rest of you! Anyone who wants me to send them the spec and DIY form, just mail me a cheque for $1899 and I'll send it to u by mail....

The trouble with common sence is that it's not common at all

I can't possibly see how the "power" coming into the amp can be improved. If the supply is constant, and uninterrupted, what difference will the cable in that position make?

[Rock Dog]

How are your wall sockets connected to the fuse box? Is it 10,12 or 14 AWG wired? Copper or Aluminum? And something everyone misses. Are the wires at the socket wrap aroud the terminal screw, or are they pushed into that little hole on the back that traps the wire, locking it in.

Me? I re-wire all my sockets to use the screw terminals. That little hole is easy to use, but has a fraction of the contact area of the screw terminals. Th greater the contact patch, the greater the current path.




-Thomas-

The easiest way to find something lost around the house, is to buy a replacement.

Hey You! Make sure you stop by the HTguide Off-Topic section. It's FUN!!!

[Neal_C]

The friendly discussion rolls on
The power cord doesn't come out of the back of the amp every couple of days, but it definately doesn't fit very well in its port. I can't even move anything around in the rack or mess with any cabling without having to go back and reseat the amp power cord. I don't have to do that with my $200 Replaytv or any of my other equipment, they all stay seated quite well.
It is just a very cheasy power cord that comes with a $1K amp.
Whether a new one would provide an audible difference I guess I will have to check out for myself at some point.

Neal

[sndtowne]

>

I see what you mean. The word is: sense.

(Now don't everyone get upset. This is not a flame, just kidding around. Feel free to poke a little fun at me.) :LOL:




Bruce

[Claude D D]

Running out and spending hundreds of dollars on a specialty aftermarket power cords is not practical and in some instances will make slight if any improvement in ones system,but if a person can replace your power cords with a reasonably priced one ($50-60) made from better conponents why not? There are some very good DIY ideas out there that are very inexpensive to make.Low and no cost tweaking is one of the things that makes this hobby fun!

[Mats]

Ther will be no difference replacing your powercord. It might look pretty but no difference.

[PeterL]

Aftermarket power cords?- In my case they helped but this was part of a specific solution to the poor quality power problem where I live at present. The quality of your mains power is likely far better. I use the braided cords (Kimber) as well as a mains filter- which was probably responsible for most of the improvement. (As a matter of interest, we have 120 volt and 220 volt available here; the 120v measuring up to 137 volts on occasion. 220v is much more stable).

Peter

[Claude D D]

Here's some good reading material http://www.geocities.com/jonrisch/ac-cords.htm and this http://www.geocities.com/jonrisch/cables.htm

[Neal_C]

Thanks for the links...will have to check them out.

Neal

[Claude D D]

You're welcome Neal,here's some more good info http://www.tnt-audio.com/clinica/diycables.html

[ranzigepad]

recently i changed all calbes in my system to belden cables. both pre and power amps sounded noticalby better.

the next step whas the cd player and subwoofer. that also made a great diference. Rotel puts poor calbes on ther products. A thing thats coolis that the new 10 series has a detacable powercord.

[sndtowne]

>

Most companies include what are called "convenience cables" with their products. Most are pretty cheap. Manufacturers never know what brand of cables their customers desire so they just include the minimum to get us going when we take the product out of the box.




Bruce

[John LaCava]

I don't know how much difference the AC cable makes, not much if any I suspect, but speaking from a purely logical persepctive I suspect that a power conditioner would improve sound when a poorly regulated AC source exists. This would act like a prefilter removing power spikes or so called transients. The more homogenous the AC is on the way in the better your Hifi will be able to make use of it. Am I preaching snake oil or have contributed to our civilized and enlightened
society?

John

[Entice]

John, I think it is the latter...

I agree with you entirely...

[Claude D D]

Here's a good article for all power cord believers and non believers to read.

DIY AC POWER CORDS
by Jon M. Risch, - Last Updated 3-24-2002
jrisch@strato.net

I was not able to hear any significant differences
due to highly specialized power cords when I listened
exclusively to a Class A SS amp, other than using the
heaviest gauge to minimize voltage drop due to the cord,
and if the cord has shielding. The heaviest gauge commonly
avaialble for a pre-molded IEC type cord is 14 Ga. The
shielding available is usually a foil type shield (although some
have a copper braid), and this can help with RFI problems
sometimes.

Once I started listening to a Class AB tube amp, then I
noticed more of an effect with power cords.

It is easy to underestimate how much drop a typical 18 gauge
AC power cord will have on a power amp, and even how much it
might affect a preamp or CD player. Sheer heavy gauge AC
power cords will minimize any dynamic fluctuations and shielding
will help with localized RF or EMI interference problems.

By way of further explanation, I provide this copy of a post on
AC power cords I have made before:

AC Power Cord Effects

So, how in the world can a power cord make any difference,
if it is properly rated for the current draw, and is UL listed?
Like many questions about audio systems, this one seems very
logical and reasonable. Just use Ohm's Law to calculate the
current draw, and viola, we have the voltage drop, and we have
the cold hard facts, Yes?

No.

Like many overly simplistic answers, this one does not take into
account all the facts. Let's look at a hypothetical power amp to
start. Lets say it is a moderately high power design, and is rated
to draw about 8 amps from the wall at full rated power. That's
about 960 watts from the wall. We won't even get into side
issues of switching power supplies, which play total havoc
with the simple Ohm's Law approach, we will stick to linear
power supplies.

So if the AC cord is UL listed for 10 amps, it is likely an 18
gauge cord. Many 18 gauge power cords are rated for 10 amps
of current. How is this rating determined? By how hot the cord
gets while carrying the rated current, NOT how much voltage
drop there is.

In our hypothetical amplifier, the RMS voltage drop in the 6 foot
cord would be approx. 2/3 of a volt according to Ohm's Law.
This does not take into account the wall outlet contact, or the IEC
connectors if present, nor does it take into account any other
factors, just the resistance of the 18 gauge wires in the AC cord.

On the face of it, this seems quite harmless. How could two thirds of
a volt make any difference? Well, because the voltage drop is NOT
2/3 of a volt! Has Ohm's Law been repealed? Are engineers all
insane?

No, just an overly simplified analysis that failed to take into account
ALL the factors. So what could possibly make that much difference.
Well, for one, it would help to know that linear power supplies
refresh their DC reservior from the AC line in bursts of current,
current peaks that are in time with the peaks of the AC line. That
is when the filter capacitors are refilled, when the AC line voltage
its it's peak value, and the output from the secondary reaches a
level above that which the PS capacitors have been drained to.
Instead of a nice steady drain of 8 amps, we have current peaks that
last only for a brief moment, and the 8 amps is an RMS amount.

What this means is that because the current is being drawn only for
a fraction of the AC voltage cycle, or for about 1 thousandth of a
second (one half cycle lasts for 0.0083 seconds). The peak currents
can easily reach ten times the RMS value. What is the voltage drop
for 80 amps? At this point, the resistance of the AC plug contacts,
and even the bond inside the cord between the plugs and the
internal wires become a significant factor. It is not hard for the voltage
drop to reach 5 volts or more. The AC line peaks never reach the full
value, because the line cord has lost some of it.
Power amps depend on receiving the full measure of AC line for
their full rated power, so such a drop will reduce the actual output
power in a seemingly disproportionate amount. A 200 W amp may
be reduced to 170 watts before clipping.

The above (still simplified) analysis assumes a steady signal, and a
steady current draw. Musical dynamics make it a much less
consistent thing, and the dynamic demands will cause dynamic
perturbations.

This is not the only effect on the power amp. These current peaks
can easily cause AC line distortion, and the heavy current draw can
generate harmonics on the line, the hash from the rectifier diodes
can increase, a whole series of events occurs that are not
immediately obvious just by thinking of the amp as a simple resistor
and using Ohm's law.

Most house wiring is either 12 gauge or 14 gauge, while many OEM
cords are 18 or at best, 16 gauge. Most OEMcords do not have
shielding or any provision for reducing radiated EM fields, do not
have premium AC outlet plugs or premium IEC plugs for better
electrical contact at these junctions.

So what happens with a bigger power cord? Replace that 18 gauge
cord with a 14 gauge cord, and the voltage drop will go down by a
factor of about 2 and a half.

Include shielding in that cord, and the possiblity of radiated EMI/RFI
goes down compared to an unshielded cord.
Shielding and radiated EM fields might not seem relevant since the
house wiring has neither advantage. However, the house wiring is
not laying right next to the other component's AC line cords, or right
next to the line level or speaker interconnects. Reduced levels of
induced RFI and radiated EMI/hum fields would not hurt SOTA
sound reproduction.

Since the AC power cord is usually laying right in there with all the
other AC cords, and probably the speaker cables, and the
interconnects (some people even bundle them all together for
neatness, OUCH!), it is quite possible that a premium AC cord
will help reduce interference in the system, and raise the amount
of power available before clipping, and smooth any AC line
distortions, etc.

This is all without even going into secondary effects, or other
more esoteric aspects. Just a more nearly correct way of
applying Ohm's Law to the real situation. Add in ferrite filters,
built-in filter components, shielding effects, and the esoteric aspects,
and it should be obvious that AC cords are not at all simple, nor are
they a no-brainer.

There is the issue of resonant situations. Certain power cords and
power supply transformer primaries might tend to resonate at RF or
high frequencies. This resonance might make RFI/EMI problems
worse, changing to a different cord will change the resonant
frequency, and change the RFI/EMI effects.

The plugs are not a trivial issue either, and may be more responsible
for sonic improvements than the other factors. Hubbel and other
premium plugs and sockets will increase contact area and pressure,
reducing contact resistance and other contact related problems.
It has been claimed that poor AC plug contact can cause micro-arcing,
with it's attendant hash being injected directly into the audio component.

It is not as simple as just simple wire resistance. The connection at
each end of the cord adds resistance, the wall outlet socket adds
resistance, etc.
For the raw wire, round trip:
12 gauge, approx. 6 feet = 0.0206 ohms
14 gauge, approx. 6 feet = 0.0328 ohms
standard AC power cord
18 gauge, approx. 6 feet = 0.0830 ohms

Measuring real AC power cords, I get around 0.128 ohms for an IEC
18 gauge power cord, and about 0.022 ohms for a 12 gauge IEC cord,
not including the AC wall socket connection.

Why is the 18 gauge resistance so much higher than just the wire
resistance? Ever tear one of those cheap cords apart? poorly crimped
or barely soldered connections are responsible for the bulk of the extra
resistance.

Preamps and CD players all have their special requirements:
CD players require shielding to help keep the digital hash that
back-feeds from the circuitry out of the rest of the equipment, preamps
need a nice steady voltage for minimum noise, and freedom from
RFI, etc.

Fancy AC power cord geometries might also reduce the inductance
of the 6-8 feet of line cord, raising the available voltages, but this
would be limited to the ratio between the length of the power cord vs.
the wall run. Such geometries often reduce the radiated energy,
and aid shielding of the cord.

Some power cords might have a built-in filtering action, like the
water jacketed ones, that have the conductors and insulation
surrounded by a conductive fluid. This fluid might short out and
reduce/damp any EM fields the cord would conduct to the component
besides the 60 Hz AC power signal.

It also helps to keep in mind that we are not supplying a Sears rack
system, that any system which aspires toward the SOTA is going to
be more sensitive to minute effects and minute improvements. How
much does a big fat shielded power cord help things? Probably
about as much as upgrading from an OEM interconnect or zip cord
speaker cable to some decent aftermarket cables, some systems
are more sensitive to AC cords, some are less sensitive to cords.

As always, the bottom line is: you have to listen for yourself, and see
if their is any benefit for you, on your system, with your listening habits.

Do AC cords have the potential to influence high end sound? Yes.
Does anyone who believes this also believe that high end cord
costs are justified? No.

Some of the cord/cable manufacturers get carried away with using
only the very finest materials and assembly techniques, carrying
over the technology and costs from their high end audio
interconnects and speaker cables.

Is this necessary? I don't know, I will not discount it out of hand.
Does it make the cords cost a lot? Yes.

Does this make them dishonest or imply that they are deliberately
trying bilk the customer? Not at all.

While AC cords made from certain models of speaker cable may
provide some extra benefit, I have not been able to hear distinct
improvements when comparing them to just plain heavy gauge and
shielded cords when listening to a Class A SS amp. When I
started listening to a Class AB tube amp, then power cord
differences became more apparent.
Results in your system may vary. I have not
tried Belden 89259 in the cross-connected speaker cable hook-
up as an AC cord, but plan to sometime.

Below, I have listed information on DIY heavy-duty AC cords, both
pre-molded and raw wire.

Commercial numbers for these types of cords are:

PREMOLDED
****************
Belden
17604 6 ft. (Around $10)
17605 10 ft.

Still a big heavy cord, but 16 Ga. (and still better than
most OEM cords) are:

17602/3

17608/9 (right angle into gear)

These are now available under the Volex brand name,
Belden has them make the cords, see:
http://www.carlton-bates.com

For info on the Volex cords,. see:
http://www.volexpowercords.com/

http://www.volexpowercords.com/power_cords/powercord2.cgi
?view=17604&catagory=3_conductor_plastic_detachabl e&
area=other&mfgloc=&partnumber=&userid=

(To get to the section with the Belden type cords, take the hard
line returns out)

Otherwise, Belden and other cable companies offer a wide
range of UL listed portable cordage which can be used to
make up a power cord using 20 amp or hospital grade plugs.
These run up to 12 Ga., with four conductors available.
Using four conductors, one could wire the cord in a
star-quad (cross-connected) arrangement and conceivably
buy some gains here, as this will lower inductance and
reduce the stray field and external field pickup.

RAW WIRE
*********************************

Some numbers are:

19217 14 Ga. shielded, 4 conductor

19216 12 Ga. shielded, 4 conductor

For grounded cords (3 conductor):

19364 14 Ga. shielded
19354 " "

In assembling AC power cords, it is imperative that they
be wired correctly, and with a good mechanical connection.
Use an existing cord to check the connections for the
plugs. Always check with a VOM to make sure they are
not shorted!

Since the pre-molded cords are so reasonable in price,
around $12, there is no reason not to experiment with
your equipment and see if there is any benefit with your
particular system. Even making your own AC cord from
scratch is not that expensive, as the hospital grade plugs
and the raw cable shouldn't run over $20-30 total, which
is still much less than the retail high-end AC cords
running hundreds of dollars.

Don't neglect the wall outlets, many have found the Pass &
Seymour 5262-I, 5252-I and the 5242-I
and wall duplexes to be the best without going
to Hubbels, and some think they are better than the Hubbels.
There is the equivalent AC cord plug, too in that brand,
Wall plug Pass & Seymour 5266-X .

IEC plug for cords: Schurter 4300.0603 available from Allied Electronics, Allied Electronics PN 509-1215

Jon Risch