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

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.