PRS MT15 (almost) 5 Years after Release - Still Issues with the FX Loop?

[@StompboxMods]

The problem actually is from the unshielded cabling inside the amp that connects from the circuit board to the effects loop. Once you replace it with shielded cabling, the noise is gone. You can also place a lower gain tube in there if you want. Takes about 10 mins for an amp tech to do. Easy easy fix!

[@LMGuitarCorner]

Hey Jason. Thanks for sharing this information. That's the first time I read that an unshielded cable inside the amp is the culprit! How did you find out about that? Did you let an amp tech fix your amp then or are you that tech savvy to work on an amp yourself? Cheers, Lukas

[@Nofarewell]

@@LMGuitarCorner kzbin.info/www/bejne/n2PVmneambCdpKc&pp=ygUqcHJzIG10MTUgZmluZGluZyBhbmQgZml4aW5nIHRoZSBub2lzeSBiaXRz

[@philknight6844]

I got one of these. Its a bloody fantastic amp. Beast.

[@LMGuitarCorner]

I absolutely agree! Does yours have any excessive noise or hum? Cheers, Lukas

[@maestro0428]

Recently picked up one of these. My first tube amp for guitar. I also use a Donner Noise Gate in line for overdriven tones (kills all the noise in my setup) and also noticed the noise (seems almost like a ringing) in my effects loop. Going to try a tube can and new tube and if that does solve the issue, it probably needs some wire management which would be next. Thanks for your video!

[@LMGuitarCorner]

You're welcome! Thanks for leaving a comment. I hope you can fix the noise issue. Cheers, Lukas

[@Acidus_13]

This amp seems to chug pretty nice :D good work! Cheers

[@LMGuitarCorner]

Thanks a lot Adrian! Ola: Will it Chug? Lukas: Absolutely

[@blkjckgtr3075]

Hey,Lucas good review,changing the tube did make a difference,Cheers!

[@LMGuitarCorner]

Thanks a lot, I think so too. Not a necessity, but a relatively cheap fix. Cheers, Lukas

[@Roady-13]

Great video Martin!! Enjoy your new amp!! ☮-Roady

[@LMGuitarCorner]

Thanks a lot Roady! Cheers Lukas PS: I'm sure you wanted to write Lukas instead of Martin ;)

[@27retrodaze]

I have an earlier version (6L6) and if I use the fx loop as a true loop, i have no issues with it... But when I try to use just the return with a preamp pedal (bypassing the MT15's preamp) it is basically unusable.. but... I absolutely love this amp... One of my favorite amps out of ANY size amp comparison...

[@zipporaid]

Did you ever try plugging in a dummy plug in the output of the effects loop?

[@MusicTherapyLaz]

Hey guys sorry I missed it… working and I didn't hear the Bing Bang. Hopefully I won't miss next one and I'll have some info for you guys about next summer!

[@fabianvasquezjr8852]

I had the same problem with mine but I used a boss ns-2 noise suppression through the fx loop it cured the problem

[@LMGuitarCorner]

That's another great option to get it quiet! Cheers, Lukas

[@EvilHomer1973]

I bet that the tube in the FX loop is picking up that hum from the power transformer. Put a tube can over the tube and see if it helps out.

[@LMGuitarCorner]

I need to try that, thanks! Cheers, Lukas

[@tanker1960]

Thank you.

[@LMGuitarCorner]

You're welcome. I hope the video helped. Cheers, Lukas

[@curtjohansen5742]

What about a noise gate using the 4 cable method?

[@LMGuitarCorner]

Hey Curt, I never tried it myself but did a quick Google search and found a post on the PRS forum forums.prsguitars.com/threads/mt15-noise-gate-4-cable-method-issues.48072/ Cheers, Lukas

[@nafis6668]

Sounds like ground loop to me. Have you tried using Isolation transformer like ART DTI ?

[@LMGuitarCorner]

Hey there. Nope, never tried any transformers or other devices. Cheers

[@peterodriguez2364]

Another utube video explains the problem being in the wire harness of the power section.. he also explains a fix.. other than that this amp seems to be a GR8 amp.. I'm still debating between this and the Engl fireball..although the price difference may be a deciding factor.. well see.. thanks for the video

[@LMGuitarCorner]

Hey Pete. Thanks for the comment, I'm glad you liked the video. The amp is indeed great! I enjoy it a lot. I guess you can't go wrong with either amp - Engl is fantastic too (I have an Ironball, we have a video about it as well). Cheers, Lukas

[@HesheR82]

Did you ever try a noise gate like boss NS-2 with 4 cable method ? I'm having same issue.

[@LMGuitarCorner]

Hi there. I never tried the 4 cable method with a noise gate myself but did a quick Google search and found a post on the PRS forum forums.prsguitars.com/threads/mt15-noise-gate-4-cable-method-issues.48072/ Hope this helps. Cheers

[@cdsellars87]

Dude what year is that Tremonti PRS SE? It looks like it has like a satin finish or something, I don’t think that’s normal. Did you have work done to it or something?

[@LMGuitarCorner]

It is indeed normal. Satin finish (including the back of the neck) and quilted maple veneer. It's a 2018 limited run. We have a separate video about it on the channel because I've upgraded it - but not the body/finish! Cheers, Lukas

[@cdsellars87]

@@LMGuitarCorner looks amazing. I wish it wasn’t limited because I would have been all over that. Gorgeous guitar.

[@vincecampos4050]

This is what I've been looking for! Thanks for the detailed take on the FX loop. By the way, how does it sound with Captor X's low attenuation level? This and the Captor X are on my wishlist for Christmas.

[@LMGuitarCorner]

Hey Vince. I'm happy it helped, thanks for your comment. With the lowest attenuation level the volume is extremely low and to be honest, I don't like that sound through the speaker. Instead I would rather use the cab sim and headphones. In my opinion, the speakers need some volume in order to sound good! I use the -20db setting which works well. Cheers, Lukas

[@vincecampos4050]

@@LMGuitarCorner so I finally pulled the trigger and got this yesterday. Man it's heavy af. However when I checked the effects loop, I notice a very loud hum when I plug a cable into the Send jack, with or without a pedal, but it's deal silent when I plug a cable into the Return jack. Closing the loop kills that noise though. Is this one of the known effects loop issues? My amp production date is 12/21.

[@LMGuitarCorner]

Hey Vince. Congratulations! I don't know if that is a known issues, unfortunately. Maybe you find the answer to that in a forum. If it is silent with the loop closed, I think this shouldn't be an issue, right? Cheers, Lukas

[@fabianvasquezjr8852]

I got the PRS mt15 and I got the captor-x hooked to it, I had to get a boss ns-2 noise suppression and run it through the fx loop and the front end through the send returns of the ns-2 it work amazingly to kill the noise and does not translates to the captor-x's simulation cabs out to my board with the noise gate on editing software sure helps. I'm running split cable into a helix rack trough a active DI dry signal to my DAW, in a wet/dry/wet set up it sounds like a stack of amps playing at a concert in my humble studio, it's a great combo and recording is ez with many different options to get your guitar to your DAW not to mention playing out live I send signals out to my live room with 6000 watts just takes it over the top! I live in a apartment building and can't do that to often. I record with Helix native too and use the two notes wall of sound software for cabs wow!

[@scentia_est]

Man sollte vielleicht anmerken, dass man mit dem Röhrenwechsel vorsichtig sein muss, auf Grund möglicher Restspannung. Müssen die Röhren nicht extra eingemessen werden, wenn diese getauscht werden? Würde meine auch ganz gerne tauschen, weiß aber nicht, ob das notwendig ist.

[@LMGuitarCorner]

Hey, danke für deinen Kommentar! Ja grundsätzlich sollte man bei Amps aufgrund der Restspannung immer gut aufpassen. Ist aber in dem Fall - hab mich im Vorfeld informiert - gut gegangen und nichts Gefährliches war in der Nähe. Das Einmessen (Biasing) betrifft übrigens nur die Endstufenröhren (Power Amp Tubes). Grüße, Lukas

[@scentia_est]

@@LMGuitarCorner Danke für die Info. Dann würd ich sagen, ab zum Röhrenwechsel :)

[@LMGuitarCorner]

Gibt's bei deinem MT15 somit nen hohen Rauschpegel wenn etwas im FX Loop ist?

[@scentia_est]

@@LMGuitarCorner Nein. Hab meinen seit Ende 2022 und bin total zufrieden. Nicht mehr als jeder andere Hi Gain Amp in dem Bereich. Alles völlig normal. Hatte zuerst auch Bedenken, weil es ein B Stock war, gibt aber nichts zu beanstanden.

[@LMGuitarCorner]

Wozu dann die Röhren wechseln? Einfach aus Interesse? :)

[@JaniceLalla]

i enjoyed the video

[@LMGuitarCorner]

Thank you Janice! Cheers, Lukas

[@fabianvasquezjr8852]

I got two 16 ohm cabs with mine only problem when hooking up to captor x only has one jack in for a 16 ohm speaker theres no way to attenuate both cabs without rewiring speakers even then how to get 16 ohms out of 2 16 ohm cabs??

[@hayabusa1300100]

All tube amps have a buzz I own 3 it’s a tube amp big old 6L6 tubes giving you some I’ve been looking at these myself to ease of weight for what I see it’s a fire breathing , clean playing bad boy with with big power tubes to place a smile on your face when you strum those chords I’m going to pick one up myself been looking for a few days now from what I’ve seen seen there built well everyone has there own playing style , pickups etc . from what I see it fits the bill for quiet a bit of genre’s I’ll have one next week

[@LMGuitarCorner]

Hope you enjoy it! Cheers

[@itsmechris14]

Bro, Genalex Gold Lion 12AU7

[@LMGuitarCorner]

Hey Chris. LOL... after seeing the price at Thomann - hard pass. They cost € 68 the piece. Do you have them in on of your amps? Cheers, Lukas

[@MarcAndreLevesque]

Many many many tube amps have that kind of hum with a tube powered fx loop, a jc120 has more hums than that by default with the power section, not even talking about fx loop. If fx loop noise is really a problem just use a 12at7 for the fx loop tube.

[@LMGuitarCorner]

Hello there. Do you thank that's even better than the 12AU7? I've seen that people recommend this preamp tube, can't remember to read anything about the 12AT7. Cheers, Lukas

[@MarcAndreLevesque]

@@LMGuitarCorner The 12at7 is used in audio amps, it is "pristine" clean as much a tube can be with loads of headroom, even more than a 12au7 which is often used in one of the preamp stages of amps like Fender amps and it is one of the secret ingredients of Matchless amps.

[@LMGuitarCorner]

@@MarcAndreLevesque Thank you, didn't know that. Cheers

[@barankaypakoglu7643]

My FX Loop picks up radio stations. Not cool.

[@LMGuitarCorner]

Sorry to hear that. I assume you also have a MT15? How old is it and do you still have warranty? Maybe swapping tubes might also help, but I'm no expert in this regard. Cheers, Lukas

[@barankaypakoglu7643]

@@LMGuitarCorner I watched your video until the end hoping that the hum would go away once you change the tube but nope. so no need to bother:) There might be something wrong with the grounding of my apartment too.. the amp is a year or two old. I found a solution though: not using the fx loop 😂 I put all my pedals at the input of the amp and it sounds okay. (no reverb pedals here sooo) Anyways, it was super useful to find your video. Thanks! Cheers!

[@LMGuitarCorner]

Yeah I was hoping to get it completely silent, but it's impossible to hear when playing and really not loud anymore. Not using the FX Loop is always an option *lol*. I just have reverb and delay in the loop, and as the amp doesn't have built in reverb, I think I will leave it this way. Thanks for the kind words! Glad you enjoyed the video. Cheers, Lukas

[@williyG70]

It should not have any hum at all. Other amps font have any .

[@LMGuitarCorner]

That would certainly be ideal... Unfortunately, it is prone to some home, I guess either due to its construction or the components used. Cheers

[@kaitam4192]

wonder people running delay after reverb….

[@LMGuitarCorner]

Hey Kai. What exactly do you mean? Are you saying that delay goes before reverb? Cheers

[@Aeon_Electronics]

This is REALLY bad design from PRS... This noise is not normal, if you design an amp properly. Not beeing fixed after all those years...

[@baroz11]

Soffri di acufeni

[@LMGuitarCorner]

I'm glad I don't :D

[@PooNinja]

Reduce the volume???? Your already on low volume output mode. I’d attempt to slap if I were there. Reduce the volume?!? Blasphemy !!!!! Storms out in a huff

[@PooNinja]

Returns in 10 minutes with a bottle of whiskey to apologize

[@LMGuitarCorner]

Apology accepted! Thanks for making me smile ;-) I'd love to turn it up all the time, it definitely sounds best this way. But I want to stay married :-D Cheers, Lukas

[@PooNinja]

@@LMGuitarCorner happy wife happy life 🤘🏽

[@davidhorvath6785]

It doesnt need to be quiet, this is not a problem for anyone other than nuub bedroom players and similar...just plug in and play guitar. People waste time on the dumbest shit.

[@LMGuitarCorner]

Just meant as a warning ;) I don't care that it's loud, if I want it to be quiet I use the captor X, which is also great for recording. Cheers, Lukas

[@tonysarrio8940]

GSAD.

[@dimebagtribute]

Personnaly I put 5751 and I shield the fx loop cable... Nothing more👍

[@LMGuitarCorner]

That's a great fix. How exactly did you shield the cable? Cheers!

[@dimebagtribute]

@@LMGuitarCorner I used high quality coaxial cable for all the wires in the fx loop circuit, I used shielded tube sockets as well... I also notice the use of a Torpedo Captor kill almost all the noise coming from the amp, it helped me a lot before to open and rewire the fx loop!