10 gauge power cord. Too much power for tube amp?

Tube amplifiers tend to be sensitive on incoming voltages. Is there a chance a bigger gauge power cord like 10 gauge may not be a good thing?

My amplifier tends to shut down occasionally upon start up. maybe moving to a higher gauge might be better. Does it matter?


no.  and no that won't fix your problem.

large power cords are necessary to support relatively subtle improvments in sound.  the amp will run fine on any power cord.


Get something like this to monitor your incoming voltage.  If the voltage changes significantly during the day you may need a regulator.  If the neutral to earth is more than 1 or 2 volts you may need an electrician. :)



Not at all. As mentioned above, that sounds like a problem with your amp's circuitry or your tubes. 

Are power tubes or signal tubes more sensitive to incoming voltage issues, or amplifier power protection issues, which can lead to an amplifier shutting down?


Are power tubes or signal tubes more sensitive to incoming voltage issues, or amplifier power protection issues, which can lead to an amplifier shutting down?

No, if anything they’re less sensitive to incoming voltage issues than solid state components. But a bad power tube might draw a lot more power which could trip protection circuitry. Why don’t you tell us about the actual amp in question?

No chance 10 gauge has any negative effects… the gauge unless tiny is not going to change voltage fluctuations. In every case… for instance in installing direct lines, and power cords, larger gauge has produced better sound quality.

Also, @mulveling +1


Amplifier shutting down is going to be caused or enabled by some issue not related to the gauge of power transmission.

Something’s going on, but it’s not the power cable.

I’ve used one of these on a tube amp. It lived up to the hype, but after many scotch tape repairs to the candy wrapper (as approved by Pierre’s staff) I switched to over priced fancy stuff.

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Just in case you didn’t, did you check the power cord for nicks? If the male and female ends are operable did yah look there too? This is 99.8% sure not to be it.

Did you switch cords? Tap tubes for microphonics? Swear a lot?

The amplifier is a Mc2301 from McIntosh that's giving blinking red lights after warm-up frequently. Power tubes have been replaced with new ones, maybe it's a signal tube. Sometimes it works fine, as long as amp stays on for at least a minute after warm-up.  

Power cord has nothing to do with the amp shutting down. The protection circuitry is kicking in. Don’t know how it’s wired but it usually senses overcurrent at the output stage. This can be caused by a failing power tube, a total loss of bias voltage or loss of bias at an output tube, an intermittent short in the output stage or a mismatch between connected load and speaker tap.


The power cable can’t generate power however as mentioned the wrong sized cable, I.e. too small can restrict power. Put the OEM cable back on and if the problem persists, contact McIntosh or at least Audio Classics. The problem is in the unit and they will suggest a possible fix or ask you to send it in for a check up. I have dealt with McIntosh many times over the years and they are great people to work with. They have an enormous pride in their products and equal appreciation for their customers.

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The gauge of a power cord refers to its physical size and electrical current carrying capacity. A higher gauge power cord will have a larger diameter and can carry more current, which may be necessary for high power applications.

For a tube amplifier, the power supply voltage and current must be carefully considered to ensure that they are within the amplifier's specifications. If the power cord is too small, it may cause voltage drops or current surges, which can affect the amplifier's performance and even cause damage. Therefore, when using a tube amplifier, it is recommended to use a power cord that meets the amplifier's power requirements.

In your case, if the amplifier shutdowns occasionally on startup, it may be due to the power cord's ability to handle the initial surge of power when the amplifier is turned on. A higher gauge power cord may be able to handle the initial surge better and prevent such shutdowns. However, before replacing the power cord, it is recommended to check the amplifier's specifications to ensure that the new power cord meets the requirements. It is also recommended to consult with a professional technician for help to ensure the safety and performance of the amplifier.

If your powercord. Is aQuality  brand then go for it , for the lower the number the

thicker the guage awg 10 is good lower resistance ,another bottle neck 

could be what do you have it plugged into ,that too might’ve restricting it 

and a dedicated  4 wire 20 amp line would be good witha common ground and separate isolated ground on its own buzz bar grounded , for line conditioner 

you have to make sure it can handle the load ,how many watts per channel is your amp ? Is it a dedicated separate amp, power amp ? I sh h the sourse, then preamp 

goon first then the amplifier, and when shutting off in reverse order.

If you do end up sending it in to McIntosh for repair bear in mind I'm told it's a 1 year wait at the moment for non-warranty repairs.This came directly from an employee. 

Isn't ALL our equipment running on DC (internally)? With all the discussion (in the esoteric faction here) about power to feed them, why is no one making (or offering a stripped down version without power supply) DC equipment (from DAC to amp to transort, etc)? All we then need is the battery section (of a photovoltaic system) and gone are all our 'power cord', 'clean power', etc discussions. We can still continue blowing pixel dust over the interconnect cables, turn tables, vinyl washers, etc, so no esotericer will be seriously harmed by the loss. 


Just to clear up any misconceptions about AC supply from a wall outlet. If you connect a properly operating tube amp, or any other amp to a 20 amp AC wall outlet, with a 20 amp rated cord, and that device only requires 3.5 amps to run, all it’s going to draw from that 20 amp supply is 3.5 amps. Notice I said ’properly operating’. If it has an internal fault that causes it to draw 20 amps, it will try to draw 20 amps and then your problems start. Under normal operating circumstances, no electronic device will draw more current than it requires regardless of how much current is available. Voltage is a different matter. It will try to use whatever voltage is presented to the wall outlet. When trouble shooting a problem like this, the very first step should be to verify that the outlet is properly wired and to see how much voltage is being supplied. The tester erik_squires linked is exactly what you need for that task. If the outlet is good, then you visually inspect the power cord for damage and use a multimeter to test it’s continuity. Easier still, just try a different cord of the same size/rating and see if the problem is still there. As others have suggested, you could still have a defective small signal tube or, more likely, a rectifier tube if that model of McIntosh uses one. I personally would replace all the small tubes one at a time before shipping the amp off to McIntosh for repair. To that end, I always have a full replacement set of tubes available for my tube amp.

Not a tech expert but I’ve had a signal tube go bad in an integrated amp as well as in a DAC and in neither case did the component shutdown. Also, I have 11 gauge power cords on my 3 tube integrated amps, zero issues.

Just for clarification, the larger the gauge number or awg, the smaller the wire is, not bigger. For example, 10 awg is a larger diameter than 12. As mentioned previously, when you check the outlet’s wiring, make sure the ground wire is firmly connected. If you have an outlet tester, use it. If you aren’t using a high quality outlet like Hubbell, now would be a great time to install a Hubbell hospital grade outlet. Most 20 amp circuits use 15 amp receptacles unless it is a dedicated circuit. Hope you don’t need the amp repaired.

Electrical devices will attempt to draw whatever current they need - and no more than that. 12 Ga. is likely just fine for anything reasonable but having 10 Ga. won’t "hurt" anything. Just a bit overkill. I mean, your own house wiring from the junction box is only 12 Ga.

Moonwatcher, unfortunately, it isn’t safe to assume the home has 12 gauge romex. If the panel has 20 amp breakers, then the wire is probably 12 gauge. If the breakers are 15 amp, the wire is probably 14 gauge. This can vary by local codes and builder. Some builders try to save money and use both 14 and 12 gauge based on the intended use. 

There are many posts here that assume that small tube amps don't need a heavy power cord.  Nothing could be further from the truth.  I hooked up a 6 wpc tube amp to a stock 14 awg power cord and was disappointed with the bass.  Assumed it was just a fact of life with a small tube amp.  a few days later a friend suggested a heavier power cord.  I didn't think it would help but had one available.  I was shocked.

Bottom like, the power cord supports fast changing dynamics such as bass notes.  tube amps often don't have robust power supplies that can supply this ready power and must reach back into the power cord.  OTOH, if your amp has huge caps in the power supply, you may not see much difference.


@moonwatcher power cables have mediocre connectors and stranded wire for flexibility soI like to go one size bigger on my power cable than the wire in the wall--except my dedicated circuit is 10 awg from the breaker box so I use 10 awg power cords.


@carlsbad2 yes, if you have a dedicated 10Ga service from your junction box then no reason not to use a quality power cord having the same gauge. (10Ga on average has about 36% less resistance than 12Ga for the same length). But the differences we are talking about over a 6' length are in milliohms. 

@moonwatcher indeed milliohms (or less) and but we are talking about milliamps or less but they are changing over a time of picoseconds....how does this all add up?

It is beyond my detailed understanding of electricity and if I didn't have a full time day job and several hobbies I might do some experimentation.  I am a physicist with esperience in national labs.  

Instead, I tune my understanding of what is going on to match what I hear.  and while I'd have to admit it is all theory at this point, it supports the facts.

Take care,


Yes, it's like using Cardas copper in interconnects (which I've read many science labs do between instruments). It might be overkill, but who is to say that using the best you can doesn't make a difference? Enjoy.  I love the idea of a dedicated 20 to 30 Amp connection from your junction box. I live in a rural area and am lucky to have fairly "clean" power, at least for now. 

I have an Ayre power amp that would go into protection mode at times, I found out it was a certain rectifier tube if used in my DeHavilland preamp.  Changed recifier tube and the problem was solved.

Sounds like some kind of in rush current problem. I don't know anything about your amp but I'd guess it's something in the rectification (wrong tube type?) or voltage regulators. 

You ever measure what's coming out of your wall socket just for curiosity sake? Mine gets as high as 125v certain times of the day..although that still shouldn't be an issue if everything is working correctly. I've seen people post numbers as high as 128v in older homes, which can eventually wreck havoc on older tube gear. Get you one of those Amprx Brown Box or their Linestage models from a place you can return it if it's no help. Works wonders on older tube gear and it seems like it cleans the power signal as well if compared to bypass mode. Cheaper options do exist.  Although I think your issue is a problem in the circuitry if not the Rectifier. I'm no repairman though. Definitely not a power cord issue. 

The McIntosh model you're using is a monoblock.  A 300 watt tube monoblock.  So if you're turning two of these on at the same time and they're connected to the same 15 amp outlet that might push things a bit, especially if that outlet and its associated breaker isn't dedicated solely to those amps.  The manual says they draw 5.5 amps/120v, 6.6 amps/100v.  

Tubes seem very sensitive to ac quality and what you need is good power cable and a good power conditioner. 

I got weary of the day to day variable sound from tubed equipment and gave up. 

With all solid state now I have given up a bit of warmth and pleasant ambiance but have gained more detail and day to day consistent sound quality. 

@cundare2 The usual suspects (Fluke, etc.) make very expensive power quality analyzers. There are some EMI/RFI to audio toys made by a couple of people just for the audiophile crowd.

In the middle of the actually useful pack is a digital oscilloscope with the right probes. I found the frequency measurement features in mine to have been very difficult to use.

Lastly, you can build something that will let you input the AC to your audio jacks via a step down and isolation transformer/instrumentation amplifier. This is the cheapest solution that will let you use off the shelf PC scope software but requires the most amount of care in building to ensure you don’t electrocute yourself or your PC.



 As others have mentioned, it is not the power cable. Also tubes are surprisingly robust and will tolerate more abuse than any MOSFET.

You could use a PC that's has a greater cross-section than 10AWG without any problems, in fact could reasonably expect a slight improvement, the amp will only use the power that is being demanded but there could be a capacitor in the power supply that is going/gone faulty and pulling more current (amps) than the protection circuitry allows. I have experienced a similar problem with the PSU bleed resistor going low ohms.

Perhaps do a visual inspection of the power caps, they will be positioned close to the power transformer, and look for any dicscolouration, swelling or residual smell.

You have already received probably the best advice:  Contacting McIntosh would be the sensible thing to do.


what problem (technical, aesthetics, prestige) are you trying to solve? what brand your tube amp is, how much power etc? 

good audiophile quality brands have good PC included, and only need to replace if broken etc..

Too large of a AWG can be an issue as can too small. As mentioned, size the wire for the load. I would guess, all that one can do without trouble-shooting, is that there is a thermal protection sensor on the fritz. Maybe a rectifier issue, tube or diode bridge. A transformer issue, maybe, but I would guess that's where the thermal protection would be. A bad solder joint can act up like this, too. Heater circuit on a tube, or bad bias... That's way too many guesses right there.

Do you have the OE Power Cord?

if you do plug it is and see if this solves the issues. If it does problem solved and move on, if not then you need professional help. 

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