Help :( Speakers making constant static sound I cannot figure it out

Are you hearing the noise in both channels?

I would guess it's a bad tube, but I'm guessing. 

I also think bad tube,  bad Input or driver.    Turn amp off,  remove input tubes. Turn on .  Noise gone?   If not turn off, replace input tube(s) and pull driver tubes.   That should help isolate a bad input or driver.  

Do you hear music if you play music?  

You have isloated it to the amp.  some switch has gotten flipped is most likely cause.

PS  if it is a tube in the amp, it is the rectifier as that is the only tube that affects both channels.

The Rogue is SS power supply and lacks tube rectification. I had a similar situation in a SS amp that was less pronounced and it was a diode issue. Contact Rogue, use the listed phone number before you get too carried away. 

There is an odd number of tubes.  Maybe both channels go through that twin triode tube in the center position?  

This is great info. A simple tube replacement is really the best I could have hoped for.

So the test would be to remove it and power up and see if the sound is gone? I just want to confirm that there is no danger to the amp or speakers to power it on with that tube out of the socket? They last a good long time so this is actually my first time having had to replace any of them, and don’t want to make a costly error.

Also, assuming that the rectifier tube mentioned is the center one of the 5 smaller tubes, since it is between the channels?  Or similarly, is it safe to remove to test each of the smaller tubes one at a time until the issue is isolated?

If so, I’ll order another and be back in business, and thanks to the audiogon community for your diagnostic expertise.

There are no rectifier tubes in your amp, it uses solid state rectification. 

I see, but still sounds like the prevailing opinion is that one or more tubes are failing.  Would the procedure for determining which tubes need replacement then be to try powering up the amp with one removed, and check for that sound, and repeat until I find the instance where removing it eliminates the static?  

Also, if I do need to replace a tube, is it advised to replace the tube in the same position on the opposite channel as well?

You don't have spare tubes?  Do you have spare lightbulbs in  the house?  tubes are consummables.  always have a spare set.  

Powering up with a tube missing will generally not cause a problem but will not tell you anything since the amp will not work with the tube out.  the static will likely go away, but a new tube may not fix it.  In other words, you have to replace it with a good tube to know if you've found the problem.

Jerry

Do you have any extra tubes? I wouldn't run it with a tube missing. I don't know if it would hurt anything. 

It looks like the 12AU7 is a preamp tube common to both channels. If you are getting noise in both channels, I would replace it. 

If you are only getting noise in one channel, move the tubes on the left channel to the right side and vice versa.  If the noise moves to the other channel, it's probably one of the tubes on the side that is noisy. 

Even though it appears a tube is the most likely culprit and since you have no spares to check it out, I’d still call Rogue, explain to them what’s up, and see what they say about ways to possibly rectify it without causing damage.

When a light burns out, I go to the store and get a lightbulb, I'm not living in a bomb shelter full of soup cans.  Tubes last for years and can be pricey depending on what they are, so no sense in blowing money just to stick them in a drawer for half a decade and let them collect dust.  

I'm happy to replace what needs replacing now, just need to determine what exactly that is.  There's a repair shop near here that probably has some, I can see what's available and use those to test each socket until I find the culprit.  Maybe I'll take this opportunity to try some alternative tubes vs the stock ones supplied with the amp, it could turn out to be a fun development after all.

When you see today's prices for quality nos tubes, you're gonna wish you bought them a half decade ago!

Have you said if it's one channel, or both?

Tubes don't always last a long time. It depends on the design of the component.

It is both channels, the sound is the same from each speaker and is not effected at all by turning the balance all the way left or right, it remains equal through both.

You might get lucky and it's the 12AU7 preamp tube that appears to be common to both channels.  I would replace it first. 

I emailed rogue all the details as well, they’ve always been good about getting back to me pretty quickly. Just in case they think they know what it is.

If the amp is using a 3 prong power plug, use a cheater to remove the ground pin to see if it is a ground loop noise. 

@wturkey ,

I would think that would be more of a buzzing sound, but good idea and easy enough to eliminate it as a possibility.

@sls883 I agree! Aging tubes tend to get noisy! Good to have some spares on hand!

Is there any visual check or device to test the age (in terms of usage, not years) of a tube to get a reasonable impression of how far along in it's useful life it actually is?  Do they flicker like an old lightbulb when they get old, or burn brighter (or not as bright)?

Besides visual inspection and putting it on a tester, I don’t know.

Visual inspection would entail a broken wire, a white powder if it lost it’s vacuum...

Incidentally, does your Rogue have auto-biasing of the power tubes?

It does not have auto-biasing, but I did test the bias on the power tubes when I had everything opened up and they all tested normally, nothing looked out of the ordinary.

Many good ways to attack the problem are presented here, the most effective in my estimation is to replace one tube at a time until the problem vanishes. Since the dual triode tube is likely providing preamplifier duty for both channels, I would start there. Moving thru the tube chain until you find the problem. If you have replaced no tubes recently, you might consider getting a couple of extra sets to keep on hand in the event you have another problem crop up later. For the price of a couple of sets of tubes, you might very well be able to find a nice solid state amplifier that would not have the maintenance issues that tube-based equipment presents. I fully realize that if you are a die hard tube fan that suggestion is laughable. Its ok, I promise not to be offended by your fondness for tube equipment if you promise not to be offended by my suggestion to go to the dark side of solid state. :)

Oh it's a perfectly reasonable suggestion.  The truth is tubes are where I started and so I've just been with them ever since, but as I've periodically traded up in the same line, starting at the original Cronus Magnum and eventually the v2 and now 3, I've managed to never actually have a tube burn out on me, so never had to really deal with much in the way of headaches/maintenance during those ~15 years.  

So I have no negative feeling personally about solid state amplification, I just haven't had a reason to feel strongly about making a change.  I've heard SS systems at dealers and shows ranging from "shrill" to "meh" to "holy crap that's the most beautiful thing I've ever heard" (though I could never afford the latter), but it would come down to something that played nicely with my existing system and general tastes.  

I promise, every time I ever move apartments and have to lug that beast by hand, I wonder about switching to some modern high-tech class d that weighs 10lbs and fits in a briefcase, but then when I curl up at night with just the light of the fireplace and the tubes glowing and hear something that sounds just a little more romantic than clinical, I forget about the inconveniences.

After taking a hard listen, this sounds as much like thermal noise in some component in the amp. It could be a resisitor, cold solder joint, possibly even a leaky capacitor. While replacing tubes may address the problem, I am guessing this is something goes deeper than tube level. I have to ask if this is a noise that has always been there or if it is a recent problem? If it has always been there, it may very well be just thermal noise in the tubes and a consequence of the amplifier design. I realize this is not a definitive answer, but it does give you some food for thought. If all voltages are normal and you don't find a flaky tube...you will likely have much trouble chasing down the culprit. Please when you do figure it out please post what you find. Inquiring minds want to know... :)

Good point!

Let us know what Rogue says...

Yes absolutely, once they weigh in I will hopefully either be able to address it at home with fresh tubes or possibly bring it to a local dealer who is able to service the amp if it needs something more serious addressed (and could test it outside of my own system to more fully eliminate the possibility that it’s something other than the amp).

I’m definitely hoping to avoid sending the entire amp several thousand miles to Rogue and back again, but I’ll cross that bridge when I come to it.

I did have a conrad-johnson preamp that produced a static sound out of one channel. Replaced all of the tubes multiple times. Fortunately, the seller let me return it. From the research that I did, it could have been a resistor, but I didn't want to go through the pains of trying to get it fixed. 

So a rep from Rogue who I’ve been messaging back and forth with is also stating that he thinks this is "tube rush" and that while some amount is to be expected with tube gear, the amount I recorded likely indicates that the center 12ux7 preamp tube is wearing out.

I used a phone app db meter to get a baseline measurement for the noise I’m hearing. I set the amp volume knob at 12 o’clock and took the measurement from as close to the speaker as I could without actually touching it [~50 db].

I got hold of a new set of just the same tubes that the amp ships with because I wanted to keep any new variables out of the mix for now, and I went through, first swapping in just a new center tube [~31 db], then checking noise again, then swapped the two other 12ux7 tubes [~41 db, higher?], then swapped in two new 12ax7 tubes and checked again [~40 db].

So new preamp tube had a measurable positive effect, then new tubes in the other positions had a lesser but measurable negative effect. Unclear on why it went up but happy to just leave those other new tubes out of the system for now.

Then I needed to add some source components back to confirm that the the amp was the sole cause of the issue, which I tested the following day. Plugged a Bluesound Node into aux1, and measured again, [~45 db], so close-ish, if slightly higher than nothing plugged in the previous day. Then switched to the amp’s internal phono, which doesn’t have a source plugged into it, but is set to MC/100ohm [~50 db], then tried my Parasound phono amp plugged into aux2, also set to MC/100ohm [~55 db]. The Rouge rep seemed to expect this as the result of the phono amp’s higher gain and that seems reasonable.

So now, I feel like I need to put the bad tube back in the center and get measurements with both sources, but the improvement, while audible, is not as much as I had hoped for, and I guess I’m wondering what an acceptable amount of "tube rush" actually is in an amp at around this level. I’m unclear I guess on whether I’ve addressed the issue as much as I can, and the rest is just the cost of doing business with tubes, or if I should press the Rogue rep to help me further investigate?

Additionally, if it is actually a factor of the tubes themselves moreso than the amp (not their age, but specifically the make/model etc.) and this could be better addressed by using different tubes than the stock ones, I’d love anyone’s personal recommendations (within reason, I can’t switch to ultra-rare $200-a-piece tubes just to shave off a few more db of noise).

[There was also a fun moment where I thought I had somehow made the sound much worse, but it turned out that when I was putting everything back after cleaning, I had tried a different layout where the turntable was between the phono and amp, but this put the cartridge too close to the amp I guess.

It caused a very noticeable hum that went away when I moved the turntable back over to the left side and the phono in the middle.

I’m also going to try to move the phono amp inside the console on an internal shelf since it doesn’t get hot at all, and this would leave much more breathing room between the turntable and amp, but I have to cut a hole in the back to run the cords through, so that’s a job for another day.]

Certainly sounds like tube rush to me, not sure I believe anything malfunctioning here. Tube audio equipment self generated noise variable, this level of tube rush may be normal or inherent to your amp/speaker combo. I have 104db speaker and both 300B and 845 SET amps, the 845 is noisier than what you have, 300B less. Rogue would be the best judge as to whether this normal tube rush or not, you've tried changing tubes and virtually no change, this answers that part of question, unless the exchanged tubes noisy as well.

@chrisryanhorner 

Why did you ignore @wturkey 's good advice above:

If the amp is using a 3 prong power plug, use a cheater to remove the ground pin to see if it is a ground loop noise. 

A cheater plug is only like $1.00 and eliminates a few variables.  If your amplifier is putting out enough noise that you notice it when listening to music from a few feet away after changing to all new tubes and it is not some kind of ground loop it is in need of service.