RA100 noisy reverb

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iceman

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The noise on the clean channel when the reverb is in engaged is really bugging me. Is this something that is common on all RA100s? I've swapped all the pre-amp tubes, power tubes, not the PI though. Can be heard when there is no input and master is off. Really annoying to have a high dollar amp (or any amp) not be dead silent. My MKV and Roadster don't give me this issue. Is this a design flaw or just my amp?
 
iceman said:
The noise on the clean channel when the reverb is in engaged is really bugging me. Is this something that is common on all RA100s? I've swapped all the pre-amp tubes, power tubes, not the PI though. Can be heard when there is no input and master is off. Really annoying to have a high dollar amp (or any amp) not be dead silent. My MKV and Roadster don't give me this issue. Is this a design flaw or just my amp?

I don't have an issue with the reverb on my RA-100. You swapped power tubes for an issue that you narrowed down to being related to the spring reverb tank of the amp? Why would you do that?

If you swapped the tube for the reverb, the next thing I would to would be to check the connections of the wires that connect the tank to the amp. Pull them out and reseat them into their respective sockets. Turn on the amp and give it a go.

If you are having noise in your amp that is being further amplified by turning up your reverb, the problem isn't the reverb tank. Reverb tanks and reverb units in amps take the signal and any noise (good or bad) from the preamp and send it to the power tubes for amplification. If you hear a noise that gets louder with the reverb knob turned up, with nothing at all plugged in the amp, I would think the noise would be emanating from a faulty preamp tube. If the sound is happening in all channels, it is safe to say you have a bad PI tube (V-7). I had a noisy V-7 tube and swapped it out for a good tube and it solved my noise issues. Try one of Mesa's SPAX7s for that slot. They are quieter and ideally used for V-1 slots, but can make a world of difference in the PI due to their quiet nature.

Don't forget that if you swapped around tubes, you may have overlooked that the V-3 slot MUST HAVE A 12-AT7 tube and NOT the AX7 tube in it. That is the effect loop tube. With the Royal Atlantic, the effects loop is bypassed when there isn't an instrument cable hooked up. Therefore, your elusive noise issue probably isn't originating from the V-3 slot. Still though, I'd be sure that you have the right tube in V-3.
 
You swapped power tubes for an issue that you narrowed down to being related to the spring reverb tank of the amp? Why would you do that?

I hadn't narrowed it down to the reverb at that point. I had some extra tubes so while I had the back opened I swapped them.

you may have overlooked that the V-3 slot MUST HAVE A 12-AT7

I was aware of that and didn't swap that tube since I don't have a spare AT7.

Try one of Mesa's SPAX7s

Yep that is what I tried.


Thanks for the reply. Basically I'm trying to get a feel if it was something in general with the RA and the reverb. Somebody else had mentioned it as well. I'm glad to here you don't have an issue with yours that means I'll be able to sort mine out, thanks.

J.J said:
The reverb can be a bit noisey at low volume, but that is not an issue at higher volume.

Does the noise stop if you turn the master all the way down ? If not then it will likely be an issue with one of the power tubes or the driver tube and your shop should be able to do a change out for you under warranty.
 
iceman said:
You swapped power tubes for an issue that you narrowed down to being related to the spring reverb tank of the amp? Why would you do that?

I hadn't narrowed it down to the reverb at that point. I had some extra tubes so while I had the back opened I swapped them.

you may have overlooked that the V-3 slot MUST HAVE A 12-AT7

I was aware of that and didn't swap that tube since I don't have a spare AT7.

Try one of Mesa's SPAX7s

Yep that is what I tried.


Thanks for the reply. Basically I'm trying to get a feel if it was something in general with the RA and the reverb. Somebody else had mentioned it as well. I'm glad to here you don't have an issue with yours that means I'll be able to sort mine out, thanks.

J.J said:
The reverb can be a bit noisey at low volume, but that is not an issue at higher volume.

Does the noise stop if you turn the master all the way down ? If not then it will likely be an issue with one of the power tubes or the driver tube and your shop should be able to do a change out for you under warranty.

I heard a bunch of people complaining that their TA-30 had noisy reverb circuits. Allegedly, Mesa told them that it was the nature of the beast due to the proximity of the reverb tank to the transformers.

Personally, I have no idea what to make of that whole can of worms. What I do know is that I've scoured the 'net for RA information since I've had it. I honestly haven't come across anyone else with a noisy reverb issue. Perhaps, and most commonly and likely, you are experiencing a tube issue. You may even have a few noisy preamp tubes causing issues. Good luck diagnosing your amp and getting it in correct playing form!
 
You ever get this fixed? I had a similar issue with noise, and it was preamp tube related. Actually, it was only the first couple days I owned it. It was given a clean bill of health by a Mesa tech. He told me to let the brand new tubes 'burn in' a bit. The problem went away after a day of playing and has never returned. I've owned the amp since June, and just yesterday one of the power tubes died, making loud pops every few seconds. You could see lightning flashing in the tube too. Luckily, Mesa warranties tubes for 6 mos, so I'm getting a free pair (they're sold in matched pairs).

I love the amp. It sounds great, and is built like a tank. I will say that I believe Mesa's Achilles heel as of late is their tubes. Great amps, subpar tubes.
 
So I finally took the RA into a tech to look at it. He agreed that it was noisy. He then compared it to an RA sitting on the showroom floor and they were both equally noisy. So he concluded that there is nothing wrong with it because both amps were equally noisy :? An amp this expensive should be dead silent on the clean channel.
 
Dude, I will make it a point to record my RA tomorrow to show you that that RA's clean channel isn't supposed to be noisy. I don't know what to make of the amp you tried on the showroom floor, but I tried two RAs out (of which, mine was ordered custom) and they both sounded fab.

I don't know how to explain what you heard, but I think you need to take your amp to a Mesa tech, or call Mesa and ask to speak to Mike B.
 
I think you need to take your amp to a Mesa tech, or call Mesa and ask to speak to Mike B.

I took the amp to a certified Mesa tech, he did the comparison not me. I will call Mesa, I should have done that already.

Here is a recording I just took of the noise. No instrument plugged in, all controls at lowest setting, on clean channel. Reverb is off initially. You can here it when I click it on. Then I engage the reverb and sweep its level. I don't like the constant background buzz that is there even when the reverb is off, then the reverb just piles on.

http://soundcloud.com/acplasma/ra-100-noise
 
Iceman --

Sorry, but I haven't had the opportunity to record anything for you yet. I did listen to the clip you posted though. First, I don't think it is necessarily a good thing to turn your amp up (volume wise) without an instrument connected. I could be wrong though about that point.

Your reverb situation is definitely strange though. I notice with the reverb maxed on my amp I get the slightest audible buzz, but it isn't really an issue since the reverb at that level is pretty unusable.

Let us know what Mesa recommends, as your experience may prove to be helpful to the other Royal users in the future. Meanwhile, I will see if I can get together some clips of my amp tomorrow (Sunday).
 
First, I don't think it is necessarily a good thing to turn your amp up (volume wise) without an instrument connected.

I had the master and gain at the lowest setting (i.e. no volume). All knobs where at their lowest settings. I turned up the mic preamp gain to make it obvious.
 
I hope other RA users chime in here and back up what I'm saying about the cleans.

Sorry about your amp issues. Let us know what Mesa says when you call them. Having that type of hum is not normal.
 
I have the same issue with my Mark IV combo:

- When the reverb is on 0 without footswitch: dead silent.
- WHen the reverb is on 10 without footswitch: noisy
- When the reverb is on 10 with a footswitch switched off: noisy

So as soon as the Reverb knob is turned up it becomes noisy as hell... Wtf?
 
Hey y'all - new to the forum. Just picked up a Mesa RA-100 head recently and I'm loving it so far! I've also noticed the reverb circuit adds a little bit of noise - not enough to really annoy me but it's definitely there. The clean channel is dead quiet until I switch on the reverb. Overall, the RA is a pretty quiet amp and I'm extremely happy with the tone on all 3 channel modes - this is coming from a previous Marshall JVM owner (which I'm selling because of how amazing the RA is by the way :wink: ) and I've spent years modding and tweaking that thing to try to tame the noise/hum and it's still no where near stock RA. Mesa really knocked it out of the park with this amp!
 
ZakkWylde91 said:
I have the same issue with my Mark IV combo:

- When the reverb is on 0 without footswitch: dead silent.
- WHen the reverb is on 10 without footswitch: noisy
- When the reverb is on 10 with a footswitch switched off: noisy

So as soon as the Reverb knob is turned up it becomes noisy as hell... Wtf?

Unplug the fan and see if that still is an issue. My Mark IV combo is relatively quiet, does not matter what the reverb is set to.
 
iceman said:
I think you need to take your amp to a Mesa tech, or call Mesa and ask to speak to Mike B.

I took the amp to a certified Mesa tech, he did the comparison not me. I will call Mesa, I should have done that already.

Here is a recording I just took of the noise. No instrument plugged in, all controls at lowest setting, on clean channel. Reverb is off initially. You can here it when I click it on. Then I engage the reverb and sweep its level. I don't like the constant background buzz that is there even when the reverb is off, then the reverb just piles on.

http://soundcloud.com/acplasma/ra-100-noise

I am willing to bet that your power supply may have some ripple on it. You may have a leaky cap that is not filtering properly. The noise I heard definitely is power supply. However, it could also be a leaky tube, Heater noise bleeding into the cathode. You could always tap the tubes to find the noisy one. You could also pull tubes and check the sockets for metal fragments. I had found some shavings on one of my tubes that contributed to 60hz hum.

I do not have an RA100 yet but if the loop is similar to the early mark series amps, try the following: Does the noise go away with a bypass cable connected into the effects loop? (send to return). you could also try two cables into the effects loop with nothing connected. Should break the circuit path between preamp stages and final drive circuit. The mark III was similar with the jack/switch. Just plugging into the return would break the circuit. if the noise goes away you can rule out PI tube and power Tube circuits. This amp is simple in design since all the tubes are cascaded depending on which channel or mode you are in. It is just a suggestion, may not do anything at all.
 
Does it get better/go away when you use the attenuator on the clean channel????

My new RA100 head has noisy reverb as well...swapped some of the preamp tubes with my spare mesa tubes...helped a bit....but really huge difference when I use the attenuator.
 
I know this seems obvious, but have you tried another outlet or tried it at another location? It would make sense that yours had the same levels of noise that your tech found on the showroom amp. It really does sound like the typical 60 cycle hum from a noisy power source.
The other guitarist in my band played an RA-100 2x12 combo for a long time and it was dead quiet. It had one of the absolute best gain sounds I've ever heard and it was the heaviest amp I've ever lifted.
 
I now have an RA100. I got it though EBAY. When arrived, reverb cables were not connected. I have changed V6 and that made improvement. With the power soak on, the noise almost disappears.

Comments on the PI tube, if it was the PI tube, noise should be present even with reverb in bypass. In my case the amp is completely silent with the reverb turned off. I have changed V6 with other tubes just to hear if there is a difference. I also have moved the wires so they are not sitting on top of the transformer which has helped to some extent. I will try a jan/ge 5751 preamp tube in V6 to see if that helps. My next approach (if nothing else works) will be to borrow the reverb cable from my Mark IV combo. I believe the transformer issue more than preamp tube. I have replaced all of them except the 12AT7. I may as well get a new one while I am at it.

I also noticed when the reverb is turned up, volume and tone drop out. Sounds the amp is muffled considerably.
 
However much I liked the Jan/GE 5751 in v4, it really reduced the noise I was getting with the reverb with it installed in v6. I did try other tubes in the PI position (tubes that are known to be quiet) did not make any difference. I pulled the cables out and still had the noise but not as dramatic. So far the only tube I have not replaces is V3. None the less, with a lower gain tube in V6 reduces the hum considerably. Reverb sounds really good now.

Due to the design of the amp circuitry and considering how sensitive it is, the low level hum is tolerable. As for the other Mesa Amps I have, the Mark V is extremely quiet, audible transformer hum is difficult to notice unless you turn up the volume and gain to stupid levels. Mark IV, not too bad either, but will make similar noise as heard in the RA100.

Noise in the RA does not seem to be channel dependent. I will have to get a replacement tube for V3 and see if anything changes. I may just swap it out with a "known to be quiet" tube and see if there is any difference.

Even with the hum, it does not stop me from enjoying the amp. 8)
 
The jan/ge 5751 helped to reduce the noise somewhat by limiting the saturation of the reverb. Sounds a little better too.
Noise is still present but at your typical amp noise levels.

I did experiment with the Mark IV combo reverb. I removed the entire unit and plugged it into the RA100 reverb jacks. I was able to move the tank above the amp. Yep, transformer is definitely an influence. Seems that the current location where the RA tank is has the lowest pickup of noise. I also took a closer listen to the Mark V which sounds relatively quiet, Similar noise but not as robust.

I did check grounding on the reverb tank. The powder coated box is not grounded. The suspension springs are but not the enclosure. Perhaps a chassis grounded Faraday box made to fit over the reverb tank may reduce the magnetic pickup noise from the transformer. I will try to make one at work and see if it works.
 

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