Anything I can do about the hiss from the TA-30 fxLoop/Rever

The hiss/hum that comes on when the FX Loop and Reverb are engaged is bothersome when practicing at lower volumes. It is not a problem for live work, because the ambient noise at the venue completely masks the hum, but I would like to be able to practice at low volumes with my effects and not get the bothersome hum/hiss. Is this possible?

Guys have tried repositioning the reverb tank (flipping it) someone else tried putting some thin shielding between the tank and the tranny. Do a search and you'll find the old threads about it. The noise/hiss issue was a deal breaker for me, as much as I really liked the sound and feature set of the TA-30 (had two of them). Mesa and the tech guys have said that it is the nature of the amp. Some guys have learned to live with it (or just don't use the loop/reverb) and are happy with the amp. For 1600 bucks, it was not something I was willing to live with. I wound up snagging an Express 525+ combo at GC on clearance in early January and have been pretty happy with it.

Matt

What about sticking a noise gate pedal in the loop? would that stop the hiss?

I guess it couldn't hurt to try it but the hiss issues is endemic to the amp design itself. A noise gate could possibly help things going into the amp to make it less noisy but I doubt it would much to decrease the noise that is already inside the amp "natively". Best of luck!

MAtt

Is this a TA30 head or combo? If it's a head message me here and I may be able to help.

It is a combo...though I have heard people with the Head don't have this problem.

A concern looking ahead, how can I mic this thing for live use through a PA? I would have thought the hiss is loud enough to get picked up easily by the mic...that would sound like crap, no?

willrocks said:

It is a combo...though I have heard people with the Head don't have this problem.

A concern looking ahead, how can I mic this thing for live use through a PA? I would have thought the hiss is loud enough to get picked up easily by the mic...that would sound like crap, no?

Click to expand...

Actually it's the head that usually has noise issues with the reverb, because the reverb tank is in such close proximity to the transformer in the small head. The noise presents itself as a hum though, not a hiss. There are a couple of fixes for this in the head.

If you're getting a hiss there may be something else going on. Have you tried swapping out preamp tubes? You could have a noisy tube. I use a TA30 myself at my church gig miked up through a big PA and I don't have any issues with any hiss coming from the amp, and I know of two other guitarists using the amp in similar situations who are noise free as well.

Do you get this noise on both channels? is it only if the reverb/effects loop is engaged? And are we talking about a hiss or is it a hum?

Suggestion: Not related but could be.... preamp tubes.

The JJ 12ax7 tubes (mesa branded) are terrible. I removed them from my Mark V head and replaced with the old Mesa tubes I had (Chinese) from the early 90's. Those sound the best so far. Just for kicks I returned the original tubes that came with the amp just to hear the difference, nothing but hiss and very loud too. More like white noise. When playing it was not noticeable, but pausing or muting it was prevalent.

Tung Sol 12ax7 are quiet but may drift with age and begin to translate the 60Hz hum on tubes that are AC heated. What I found that works well is the Sovtek LPS tube in driver circuits. (do not bother with the Mullard re-issue, may look like the same tube but it is mechanically noisy). GT has generation 9 Chinese tubes similar to the old Mesa 12ax7a from the 90's. I will have to give them a try and see if they are as quiet.

I doubt that there is anything wrong with the amp, it is probably related to preamp tube.

Since I have both the Sovtek LPS and Mullard reissue tubes, I just did an experiment yesterday while tuning my Mark V for TAD power tubes. I stated that the Sovtek LPS is not the same tube as the Mullard reissue, I stand corrected, they have the same mechanical noise characteristics. Only servable location is the PI spot. Tone is about the same when used in V1 as well as the mechanical noise that will be annoying with increase vibration (worse in a combo amp). I have a few of the original Mesa branded (JJ tubes) and some of them vibrate considerably too besides the hiss. Since V1 is the most sensitive, best to get a really good tube for that position, medium to short plate (long plate 12ax7 can be mechanically noisy and cause rattle sounds in the speaker). I have found that the Tung Sol 12ax7 is relatively quiet and is not as dark as many would state. Although not as bright as the EH12ax7 (almost look identical) they are more stable and do not generate as much hum from ac heated positions (most common in driver circuits). In terms of clean channel, the Tung Sol's are amazing. High gain and cruch tones are really good too. However, my favorite preamp tube overall has to be the Mesa 12ax7a from the 90's. I am glad that I did not toss them. Even used they sound the best compared to current production tubes.

Regardless, I hope you resolve the hiss issue from your amp. If it is not preamp tube related, do tell how you fixed it.

fjs1962 said:

willrocks said:

It is a combo...though I have heard people with the Head don't have this problem.

A concern looking ahead, how can I mic this thing for live use through a PA? I would have thought the hiss is loud enough to get picked up easily by the mic...that would sound like crap, no?

Click to expand...

Actually it's the head that usually has noise issues with the reverb, because the reverb tank is in such close proximity to the transformer in the small head. The noise presents itself as a hum though, not a hiss. There are a couple of fixes for this in the head.

If you're getting a hiss there may be something else going on. Have you tried swapping out preamp tubes? You could have a noisy tube. I use a TA30 myself at my church gig miked up through a big PA and I don't have any issues with any hiss coming from the amp, and I know of two other guitarists using the amp in similar situations who are noise free as well.

Do you get this noise on both channels? is it only if the reverb/effects loop is engaged? And are we talking about a hiss or is it a hum?

Click to expand...

To clarify, it is more of a static/white noise sound that gets louder in volume as I turn up the reverb volume. It is on both channels and is only when the reverb/fx loop is engaged. When the reverb is at 0, the static/white noise noise is not present, but once the reverb gets about 3-4, the static/white noise sound comes in. It is completely quiet when the reverb/fx is bypassed.

I don't actually notice the hum much, which is always present, because the static/white noise sound overrides it.

I don't know much about amps/tubes in general. How can I check to see if something is wrong with my preamp tubes?

Also, looking into a decent noise suppressor pedal, like the EHX Hum Debugger, would that help with the problem?

My TA 30 does not have this noise. I'd start with V6 and V5 preamp tubes as they control reverb and the loop.

I send my TA30 head to a expert amp builder and he after many hours found that it was just a matter of reposition a cable inside the head, he said that it is just a matter of mm, and once is positioned correctly, the noise disappears. He send me an image that I can share is anyone is interested. This explain why some units do not make any noise at all and others do.

Mgreen,

Could you please send me or post a pic of the cable repositioning? THanks!

Matt

here is the image. Is the grey cable, and it is sealed with silicone. You have to unseal it and move it around until you find the spot in which the noise disappears, and sealed again with silicone.



Miguel

I forgot to mention that the cable is between the V5 and the V6 preamp tubes. Hope it works for you too.

Miguel

Thanks a million!

Thanks a lot I am going to see if I can have a mesa repair tech get this done under warranty. Please post any extra details of how you repositioned the cable to fix it, that would be very helpful.

From what the guy who did it , it is simply move around the cabl until you find the spot where the noiae stops , and then selaled with solicone. He says the the purpose this cable is just that, i do not remember the whole explannation he gave me, very heavy technical stuff, but it has to do with radio interferences. Of course this is somethng i would not recommend to do yourself unless you know what you are doing.

The units that do not make any noise are the ones that have that cable positioning correctly. This should have been part os the quality control od every unit out of the factory, but it seems that is not.

Looking at another Boogie to compliment my ROV25, and while the TA15 would suit me fine otherwise, I REALLY need a loop. If one does this minor mod with the cable, it might work. But would it also be fixed if one simply disconnects the reverb entirely? I can't say I care much about the reverb, as long as I can use the loop without the noise. Thoughts?

Has anyone else tried this fix with any success?