Trouble with New Custom 50

[FenianEMT]

As you may have seen on my other thread, I brought home a gorgeous Two Channel Custom 50 combo from Experience. When I set it up and started playing through it (quietly) last night, it initially sounded amazing, but a couple of issues quickly appeared. I'm guessing the biggest will probably require a trip back to Stevensville, but I wanted to see if there's anything I should try first.

1. The LED for the channel button on the foot switch is always the opposite color of the channel LED on the amp. So when the clean channel is active, the foot switch LED is red, and when lead is active, it's blue. I'm guessing this is a simple issue of somebody having soldered pins of the LED backwards.
2. This is the big one. After playing through the amp for ten minutes or so, a low pitched, but very noticeable audible tone appeared (it seemed to quickly fade in). The tone seemed to be unaffected by changing the channel. I'm not sure now whether it was affected by changes in Master Volume, but I can test that today if it would be helpful. When I switched the amp to standby, the tone (unsurprisingly) went away, but it came back quickly (but I don't think quite instantly) when I switched back to on. After powering the amp all the way down and then back on (with a pause on standby), the tone returned after a few minutes (this time without a guitar plugged in). I generally turned it to standby or off fairly quickly after the tone appeared, but the time I let it go the longest (trying to figure out what was wrong), I heard an occasional crackling sound that I'd describe as almost similar to breaking glass.
3. I'm the least sure of this one because #2 showed up while I was investigating this, and that got all my attention. It seemed like the reverb was not really noticeable even when turned all the way up. This my bear some additional investigation, though.

Does anybody have any suggestions on these issues? Should I just call my dealer (who is out in Montana)? Or call the PTC? This is my first tube amp, so I'm not familiar with the symptoms of all the issues that might arise. I also don't have any spare tubes handy to troubleshoot with.

Any assistance would be greatly appreciated. Even if it's just confirming what I already suspect, which is that my new baby already needs a trip back to Stevensville.

 

[squirrel211]

PTC responds very quickly!

 

[Dusty Chalk]

The oscillation (or whatever it is) definitely is a PTC issue -- it's borked, should be fixed.

The LED for the channel button on the foot switch is always the opposite color of the channel LED on the amp. So when the clean channel is active, the foot switch LED is red, and when lead is active, it's blue. I'm guessing this is a simple issue of somebody having soldered pins of the LED backwards.

It might be. It also might be the settings -- you should set the amp to the clean channel, then unplug everything, then plug the pedal into the amp, then turn on the amp. My theory is that the switch is just a toggle, and "came up" initialized the wrong way. If that's what you did the first time, try it the other way.

 

[FenianEMT]

So I just played on the amp a bit more (with the Vela this time), and it seems like the major problem is confined to the reverb. If I turn the reverb knob down to zero, it works just fine. This actually seems to fit with my experience last night since the problem only really came up once I started experimenting with reverb. The strange thing is that using the foot switch button to turn the reverb off does not solve the problem. I haven't tried to pull-out to defeat reverb on the lead channel, but based on the foot switch, I'm guessing it's not going solve anything.

I was unable to resolve the LED color issue.

So, this raises an important question: Is it safe to keep playing on the amp with the reverb turned all the way down until I am able to get it to the PTC? The other thing I rediscovered from before things went wrong last night is that this amp produces incredibly beautiful tones. I don't regret my choice at all despite the issues. I'd really like to continue to enjoy what I can of it in the interim.

 

[László]

Well, of course the obvious first step is to check the reverb driver tube, and also to make sure the leads from the chassis to the reverb tank didn't somehow get unplugged or loose.

Other than that, I got nothin'.

 

[FenianEMT]

Thanks for the suggestions, Les. I'll pull the back panel off and take a look for anything obviously disconnected. What should I be looking for in terms of the reverb driver tube? I obviously don't want to do anything too involved since I manifestly have no idea what I'm doing, and I definitely don't want to make anything worse or void the warranty.

 

[László]

Thanks for the suggestions, Les. I'll pull the back panel off and take a look for anything obviously disconnected. What should I be looking for in terms of the reverb driver tube? I obviously don't want to do anything too involved since I manifestly have no idea what I'm doing, and I definitely don't want to make anything worse or void the warranty.

Very easy...just replace it with a known good tube of the same type. If it solves the problem, you've found it, and if not, then you know it's something else.

I don't have a Custom 50 so I don't know which tube it is, i.e., V1, V2, etc., however, many amp makers use a 12AT7 as a reverb driver, so you might look for that.

 

[aristotle]

A few questions...

1. Are you using the loop?
2. Regardless of 1, how do you have the loop dials on the rear panel set? Make sure that you don't have the level knobs on the back set wonky (like input on 0 and output on max or vice versa).

I'd disconnect the footswitch for the moment and debug this without it to try to solve one thing at a time.
Once the footswitch is disconnected, disengage the reverb (this disengages for channel 2 only.) Then check to see if you get the tone for channel 1 only with the reverb dialed up.

 

[FenianEMT]

I'm not using the loop, and the level pots for the loop are both set at noon.

I spoke with my dealer, and they suggested that since I'm in Baltimore, the easiest thing is probably for me to contact PRS directly. They're happy to help if they can, of course, but they're far away. I'll call PRS customer support tomorrow.

 

[bodia]

I'm not using the loop, and the level pots for the loop are both set at noon.

I spoke with my dealer, and they suggested that since I'm in Baltimore, the easiest thing is probably for me to contact PRS directly. They're happy to help if they can, of course, but they're far away. I'll call PRS customer support tomorrow.

Which, of course, means you'll be taken care of with kid gloves! Bumme that you've got issues, but you know you'll be well taken care of!

 

[Dusty Chalk]

I'm not using the loop, and the level pots for the loop are both set at noon.

I spoke with my dealer, and they suggested that since I'm in Baltimore, the easiest thing is probably for me to contact PRS directly. They're happy to help if they can, of course, but they're far away. I'll call PRS customer support tomorrow.

I'm going there this week. It's not that bad of a drive if you time it right, but I have to take some time off work to do so -- it's 3 hours round trip from where I am, minimum.

 

[andy474x]

Congrats again on the new gear!

For a brief few days, I was secretly enjoying being the envy of someone on the forum for once, rather than the other way around Then you went and got a McCarty 594 with that amp, and I'm right back where I started! I bet that is a smokin combination. That 594 sounds SO GOOD in every clip I hear of it, and the Custom is such a good amp. From the size of the cab, I was guessing that was a 20 in your other post, looks like they packed a punch in a small package!

So, when it comes to tube changes, don't be afraid to swap tubes on your amp... it's part of normal maintenance, and you'll need to do it occasionally to keep your amp running properly. And, the PRS amps are designed to make it especially easy for the user to do their own tube maintenance themselves. Which is awesome, because taking your amp to the tech is a pain, and needlessly expensive. Most often tubes are the thing to fail in an amp, they're fairly delicate, and can be defective or wear out. Luckily, they're also the easiest thing to fix!

As Les said above, the reverb tube is probably a 12at7, there are two in your amp. There's also a 12dw7, aside from the three 12ax7's that are the gain stages. I believe the 12dw7 is either for the phase inverter or the effects loop, but reverbs are almost always 12at7's. Any local shop that sells tube amps will probably sell 12at7's, so you could pick one up next chance you get and put it in your amp. When it comes to actually putting it in there, it's very easy - you just take the back grill off your amp (probably has 4 screws, one in each corner), identify the existing 12at7's, which if you are looking into the back of your amp, they will be the two furthest to the left, way in there in the row closest to the front of the amp. Of those two, it's probably the one on the right. Swap it with the new one, see if the problem goes away. Do be careful, if the amp has been on the tubes will be fairly hot. Sometimes I use a dry cloth or a clean sock to grab them if the amp has been on. Simple as that! Apologies if you already know all this, I just know you said this was your first tube amp. Hope that helps!

 

[Boogie]

Good advice, all around. And if you have spare tubes hanging around, then there's no harm in conducting tests. But this is a brand new amp - it should be perfect! Doug and Jeff wouldn't tolerate a single molecule out of place, so let the amp department clear up the problem. I'd call customer support and setup an appointment today.

 

[FenianEMT]

I just talked with Matt at PRS, and I'm going to take it in Wednesday morning. He said they very well might be able to fix it while I wait, which would be awesome! Yet another reason to love PRS!

@andy474x, the amp sounds just absolutely amazing no matter which guitar I play through it. At first, I wasn't sure if the 594 was just that magical. Well, it is pretty awesome, but the Vela sounds great through it, and so does my Strat. I haven't tried the Hollowbody yet, but I'm pretty sure we all know what the answer will be there, too.

Also, thank you for all the information! I did take the back off the chassis, but I didn't figure much out. I have no idea what the reverb tank looks like, and I didn't know which preamp tubes were which. I couldn't even see any identifying markings on the one I took the cover off of. Of course, I didn't remove the tube (do they pull straight out, or do they have some sort of screw lock?), so I would imagine if I actually pulled it out, I could probably find something. But I decided in this case to let discretion be the better part of valor since I really didn't know what I was doing. Hopefully I'll be able to ask a few questions and learn some more when I'm at the factory on Wednesday morning. It would be nice to at least feel competent to change tubes and set the bias for the power tubes (I understand the probe points, but don't know what the target numbers are or where the adjustment pots are).

 

[andy474x]

Very glad to hear you're liking it!!!

If you're heading to the factory, I would try to tag along to where the magic happens and let them show you how to change tubes and bias your amp. Easy stuff for them to show you, don't hesitate to ask!

 

[FenianEMT]

Just an update in case anybody is interested in the outcome:

I took the amp to PRS last Wednesday morning, and left an hour later with everything working perfectly. They didn't let me watch what they did, but that's okay. They replaced the reverb tank and the foot switch. The reverb works just fine now, and it sound great! The LED on the foot switch now matches the color of the LED on the amp.

 

[bodia]

Just an update in case anybody is interested in the outcome:

I took the amp to PRS last Wednesday morning, and left an hour later with everything working perfectly. They didn't let me watch what they did, but that's okay. They replaced the reverb tank and the foot switch. The reverb works just fine now, and it sound great! The LED on the foot switch now matches the color of the LED on the amp.

Sweet! I love a happy ending!

 

[dmatthews]

This is why I am proud to be a PRS toady/fanboy. Excellent!

 

[Deleted member 5962]

Great news. Enjoy the amp!

 

[László]

Nice!