Bugera 333 INFINIUM FX loop issue

[Edd Shred]

Hello guys, please, i need help with this amp. I bought It recently (1 month) and it's been played only a couple of times in band rehearsals. I've noticed that when i'm on the FX loop and Crunch Channel, after 10 minutes of full band playing, the amp starts buzzing (minimal noise), the LED channel indicators sparkles and suddendly It changes to clean by itself. Also, the INFINIUM indicators starts to light on and off randomly. I've heard this problem searching on the web but only on old Bugera's (mine is 2011). Other thing is that i've checked the band rehearsal room and It seems that the electrical installation is somehow bad 'cause it's not regulated (never had a problem with other equipment before). All the stuff is connected to one wall socket and i think that it's sucking a lot of current so the Bugera is getting a voltage drop. Could It be possible that the electrical installation have fried some internal component? Or it is the usual problem with this amp un the FX loop? A voltage regulator would fix It? Please help!!

[nevetslab]

Oh, first of all, Welcomr to the Forum! 'Yours is 2011'...so I gather you bought this used. The symptoms sound like the age-old problem of solder joint fractures...something that eventually happens on gear that gets moved a good deal, from gigs to rehearsals, etc, and Bugera's engineering dept made mechanical decisions that over time results in solder joint fractures, from PCB assemblies being supported by pot terminals, jack terminals instead of mechanical supports...that sort of thing. I looked at the photos on line to see this is a a product with multiple circuit boards, and could be a challenge to pull apart and begin searching for the causes.

With the whole band's equipment powered off of one wall socket in the rehearsal room....I don't really think this is the cause, with the AC mains fluctuating, though hard to say. I've only been inside one Bugera, owned by one of the studio clients where my shop is (CenterStaging, Burbank, CA). Internally in your amp, there would be a power supply regulator to yield stead voltages for channel switching and such. I don't know how much of the tube circuits make use of low voltage analog circuits (IC's, analog switches, FET's and such). Does the switching change without the foot pedal plugged in?

We'd need more info to start diagnosiing the problem(s). Do you have experience working on equipment like this, and equipped with the essential tools, voltmeter, etc? We'd also need a schematic....just to make the task easier, though not impossible without.

[Edd Shred]

Thanks a lot! actually this one is new. I bought it through an authorized dealer, so i the warranty is going on, but regarding the voltage issue i'm assuming It would be fixed if i were connected to a independent socket before taking It to tech support. Unfortunaley i think here in México the tech care Will last forever so i'm thinking in a alternative solution. The problem starts with the whole band playing (we have two 200w guitar and bass amps, a voice mixer/ amp and a fan, haha) connected at the same current take and that for itself i think is a major problem with the electrical installation. I've checked that the voltage regulator inside the Bugera's heats a lot and causes the problem, but this amp is new and only happens when we're all playing (at moderate volumes). I have tested with the footswitch on and off and It doesn't switches with the amp alone, but again, if we are playing, boom! FX loop turns off and it's a pain. I'm a newbie on tube amp's, this is my first one. For the equipment i have voltmeter and the essential tools, but before the surgical procedure/ taking to tech support i would check if we need to move on and find a safest rehearsal room and if the voltage regulator would fix the problem. What do you think? Thanks!

[Edd Shred]

Thanks a lot! actually i bought It new from an authorized dealer so the warranty is going on. But before taking It to tech support (i think here in México will last forever to take care) i would like to know of the local electrical installation is the problem and if a voltage regulator or an UPS would fix it or it's the voltage regulator inside the Bugera's that heats up a lot due to the famous FX loop switching issue problem. The problem starts when everyone is playing (moderate volumes) and when they stop and i play alone, the sparkles, the switching and everything calms down in the amp. It's my first tube amp and veeery little electronics knowledge so my theories could be crap, i know what do you think? Thanks!

[Edd Shred]

I posted a reply but i can't see It

[nosaj]

I posted a reply but i can't see It

I had to validate your posts which are now done.. Carry on

nosaj

[nevetslab]

As you're trending to the problem only happening when the whole band is playing, all pulling current thru the one AC outlet at your rehearsal space (obviously with power break-out boxes to feed everyone), I would find some way to pull power for your amp from a different source...no doubt having to get it from outside the room, hopefully from a different circuit branch within the rehearsal complex, and see if the problem continues. You may well be right...it being related to everyone yanking on the AC mains and the Bugera amp is too sensitive to that. I'd do that and exhaust that possibility before thinking about voiding the warranty. And, as you admitted not being that knowledgeable in troubleshooting to component level, this amp may well be a bit beyond what it would take to tutor you thru the process.

I've no idea what warranty repair services are like in Mexico to support this amp. There's lots of us here on the forum who do this daily, including diving in with no documentation, but we have years and decades of experience doing it. See what you can find out from the suggestions above first. Happy hunting.

[Edd Shred]

Thanks! Greetings 🙂

[Edd Shred]

Sorry for the delay! I was hoping to try your advice before posting an answer, but i've been occupied for the testing. The problem is that we haven't played this week so the only test i've made is connecting the UPS into the socket. This device has a "Building wiring fail" indicator witch turns red even when is attached to any socket outside the rehearsal room. I've tried in my own house and It that indicator doesn't turn on, only the "On Line" LED, so i somehow think the problem is the electrical installation. My concern is that the Bugera has been overheated at the FX Loop voltage regulator so it would be damaged already. I've seen that installing a more capable VR on the board, or a Heatsink (even with a fan) would solve the problem, what do you think? Would It be an expensive mod? Thanks a lot!

[nevetslab]

Sorry for the delay! I was hoping to try your advice before posting an answer, but i've been occupied for the testing. The problem is that we haven't played this week so the only test i've made is connecting the UPS into the socket. This device has a "Building wiring fail" indicator witch turns red even when is attached to any socket outside the rehearsal room. I've tried in my own house and It that indicator doesn't turn on, only the "On Line" LED, so i somehow think the problem is the electrical installation. My concern is that the Bugera has been overheated at the FX Loop voltage regulator so it would be damaged already. I've seen that installing a more capable VR on the board, or a Heatsink (even with a fan) would solve the problem, what do you think? Would It be an expensive mod? Thanks a lot!

You're plugging this Bugera amp into a UPS. What is the load current/wattage capacity of the UPS? Your amp has an average current draw of about 1.3A/130W, and playing thru it loud, probably around 2 to 2.5A/250W or so @ 120VAC. Amongst the dead carcasses here in the shop are some UPS units that are probably equipped with dead back-up batteries. One of the better devices I have are Topaz Line Voltage regulators...NOT a UPS. They're expensive, and do a great job holding steady line voltage output while the input can sag to at least 90VAC. I'd have to look at specs to see just how low they can tolerate. Sola is another brand of that sort of thing, though they run hotter than the dickens and sound like bad florescent light fixtures when running.

Unless you've already been inside your 333 Infinium and confirmed voltage drop-out on the bipolar regulators that run the non-tube circuits in the amp, I'd think their circuit design would be stable and capable of working ok.....but, you're right about one thing. Drop the AC mains down to less than 105VAC, internal power supply regulators tend to stop providing clean voltage, and then the noise/hum comes thru, as they've dropped out of regulation. So, finding steady AC mains no doubt IS the order of the day. I'd hate to recommend Honda or equiv AC voltage generators as a solution. What I and others here on the forum have done when faced with ineffective building power, is getting at the incoming AC mains at the building power entrance, connect via breaker'd power distribution system of our own, and distribute solid safe AC mains from a known good distro system and feed the band from that. This, of course, means someone associated with the band has that expertise and equipment, and that you have the permission to connect to the main breaker panels. That's lethal stuff, but it gets you as close to the local power substation feed as you can get.

Where my shop is, CenterStaging in Burbank, CA, we have a number of our rehearsal studios equipped with connection facilities in the rooms where bands that travel with their own AC mains distro system can attach and feed from their AC mains system instead of the wall outlets.

[hrbay]

Hey , I had a Bug 55 HD clean / dirt switching pedal that did the same sort of switch witchery, had two new pedals sent from the sellers before I got a good one, I guess the salt air on the boat got to the little micro pads inside the box on the way over. D5 would work for a few weeks but not a permanent fix for the cheap micro switches they use. Good hunting