Replacement tube recommendation for a Mcintosh amplifier?

Last night I thought it began to rain and then I discovered one of the tube amplifiers was giving off a crackling sound. Probably one of the small tubes is not working and there's six of them. And they are only a couple months old.

They are stock tubes, probably JJ.

There are six small tubes with two being for the preamp. Maybe I need to replace them all or just the preamp tubes. 

The amp is a MC 2301. When I disconnect the incoming RCA interconnect there is still crackling sound coming from the speaker even when it's muted. Also see the needle jumping around with no incoming signal.  Sometimes noisier but consistently annoying.

Wish there was a way to figure out which tube is bad.


It may not be the tubes, but it is always a fundamental question isn't it.

"probably, maybe, wish there was ...."

an inexpensive tube tester will take the guesswork out of it. anyone with tube equipment should have one, otherwise ......

30 day returns


I use this one, very portable




1. switch amps, noise should move with the noisy amp. Good amp/speaker quiet, speaker is good.

IF noise remains on the originally noisy side, then something on the speaker's crossover is going.

2. you can switch tubes, 1 at a time, from one mono-block to the other, see if the problem goes away. or moves to the other amp when ____ tube is moved.

if tubes from noisy amp are NOT noisy in the now quiet amp, then it ain't the tubes, it's something else with the amp.




+1 yep, it is a pretty simple logical task of switching tubes to isolate it to one or a few tubes. From what you said it is in one of your amps… so you can use the tubes in the good one to trouble shoot the one with the noise. Macs are well made so it is the most likely a tube problem.

I always order a spare set of tubes when I get a tube component. You can use these to narrow any tube issues to an individual tube, then get a replacement. Remember the same tubes on a single side should be matched.