Bugera V55HD questions and concerns

[jackruby64]

Greetings! I recently purchased a Bugera V55HD head and had some questions regarding reliability issues, any mods, etc. First off, I have blown 3 fuses already, one the interior fuse and the back panel fuse twice. The interior fuse blew after switching the standby switch on after a break before the fourth set my bar band played one night. The external fuse blew when my 20 month old son turned the amp off while I was playing at home, so that's an obvious. Last night we played a 2 hour opening set, and towards the end of the set, the external fuse blew. I spoke to the local music store where I bought the amp after the first fuse blew, and I was informed that the local bars are notorious for having crappy wiring, and other guys have had problems. My concern and question is is this amp robust enough to be gigged at least twice weekly? I'm playing classic rock, country, some newer stuff as well, and I'm not running this amp anywhere near full bore. Would a power conditioner be a sound investment? Would it alleviate the fuse blowing under bar playing conditions? Any recommendations would be appreciated. I'm running into a Marshall JCM 800 4x12 by the way, and it really is a great sounding amp.

[Jazz P Bass]

Take it back & get another one.

[jackruby64]

Jazz P Bass, I'm leaning towards your thinking. Had a gig tonight, we warmed up/sound checked on a spirited blues jam, after about ten minutes, poof, external fuse gone. Replaced it, turned it on, poof, gone again. I had my trusty Crate Vintage Club 20 ready to go, played through it running into the Marshall cab all night. I've had the Crate for 10 years now, it's been a little work horse, sounds great through the cab, miced out of course. I'm taking the Bugera back Monday, going to tell them to get me a new one, see how that works out. My apologies to the forum, it seems to be a little more technically orientated than I am, I'm just a player who loves that good ol' tube tone. Been playing over 30 years, off and on in the clubs, just recently joined a working band gigging several nights a month. I thought the Bugera would be my new work horse, remains to be seen.

[Gtr_tech]

Not that it has anything to do with the fuse popping problem, but you shouldn't use the standy on set breaks. Turn it on, warm it up and once you put it into play mode....leave it there 'till the end of the night. Its hard on the output tubes to be cycled on/off stby several times for each playing session. Thermal expansion when hot (play) and the contraction (stby) causes output tubes to fail from mechanical stress.

[jackruby64]

Thanks Gtr_tech. I've been told to put it on standby during set breaks, but what you're saying makes sense. As far as the Bugera goes, i just replaced the fuse here at home and turned it on. Powered up OK, let it sit on standby for a few minutes, as I played through it, I got a low hum, and then the fuse blew after a few seconds. It's going back tomorrow.

[Jazz P Bass]

You know, the amp was shipped from China.
Trucked around to who knows where.
Picked up.
Set down.
Bumped.
Then you received it.
It "may" just be a bad tube.
Seeing that it is a new purchase & you are having fuse issues, yeah, take it back.

[jackruby64]

Jazz, what gets me is that it worked fine for a few shows. I spoke to my local tube amp tech, not affiliated with the music store where I bought the amp, but a guy I trust and respect for his knowledge. He feels it could be a burn in issue, but of course, he won't be tearing into because it's still under warranty. I'll have the tech at the music store check it out, and if it won't be reliable, it goes back for a replacement. Or maybe I'll swap it out for the little Egnater they have sitting around...

[Chuck H]

JM2C...

First, I disagree about using the standby switch. That's what it's there for. I can't say I've been privy to the same information about tube expansion and contraction but in a properly designed power supply the standby switch shouldn't cause any extra wear on tubes AFAIK.

Another vote for returning the amp. You say "If it can't be made reliable", well, that's a broad issue that I'll bring up in the next paragraph. But as far as any repairs go, what constitutes "reliable" to the tech your bringing it to? If he/she repairs it they send it out as repaired and in good working order. Unless the tech is able to find some acute issue that has been responsible for the reliability issues thus far and able to report that it is now repaired and these issues won't happen again, I would say that the "made reliable" criteria hasn't been met. Now...

If you want a reliable and dependable road tool for shows you need to spend more than $350. By todays market it puts that amp on par with the likes of Kay and Harmony or even Sears store brand amps from back in the day. If your going to be professional you need to be able to finish a show without problems. Sometimes that requires an investment. That's why you wouldn't hire a professional DJ trying to do shows with a Mr. Microphone or a doctor using two styrofoam cups and a piece of string for a stethoscope. Compared to real road gear that amp is basically a toy.

Just my humble opinion. I know it's offensive but if your going to be disappointed in a budget product it should be kept in perspective.

[Gtr_tech]

The standby switch is there for 1 reason only.....to let the cathodes heat to operating temp before hitting the plates with HT.

Do this: warm up an amp for a min on stby...then put it into play mode. Vol down, no input. Listen closely as the output tubes heat up from idle current. Hear the "tink" noises the tubes make? Kinda like a car engine after being shut off. Thats teh internal structure of the tube expanding. Let it sit until the noises stop.....then put it back into stby. You'll hear the same noises from the output tubes as they cool down from no current thru them.

The thermal cycling from using the stby sw correctly (leaving it in play mode all night) causes enough stress on the output tubes just from repeated use. You cycle it several times during each use and you'll damn sure shorten the life of the output tubes. Ever notice how a new tube will not rattle when you tap on it? And used tubes, even those used in vibration free environments, will have a mechanical rattle after a while......due to thermal expansion loosening up the internals.

[Chuck H]

I'll also add that IMHE certain power tubes, especially el84's, when they get old enough to actually wear out, usually do so in the form of internal mechanical vibration causing microphony more than loss of power or fidelity.

[Gtr_tech]

Right. Tubes are inherently mechanical devices that serve an electrical purpose in a vacuum. 98% of the time when/if they fail its due to mechanical failure long before the cathodes lose thier ability to emit electrons.

I'm not a fan of EL84s....'specially in combo amps. They get rattled to death in no time. I'll take 6V6s thanks....

[Steve Conner]

Behringer/Bugera might be a bit cheesy, but I think the comparison with styrofoam cups and string is a tad unfair. The amp has an obvious fault (I'd guess bad power tube) and you can get it made good under warranty. Egnater are probably more roadworthy, though.

Re the standby switch: I know the tinkling noises you mean. The standby switch is not for casually flipping dozens of times a night. The KT88 datasheet even states that the life spec is based on so many on/off cycles per day. (2 iirc?) But I don't think it does harm to use it during a long break. After all, heat buildup from the power tubes shortens the life of all the other parts. And, the temperature of the tube innards bounces up and down as you play. If it bothers you, well I heard of these new things called transistors that fixed all these problems. Tubes are basically born to die.


Are 6v6s really less microphonic than EL84s?

[Chuck H]

Are 6v6s really less microphonic than EL84s?

IME, yes. I build mostly with el84's for a couple of reasons. They're very affordable, they have two distinct characters depending on how you run them, people seem to like them (trendy right now) and I like the way they sound. But I do think 6V6's are more durable overall and much less prone to microphonics. And I do like the way they sound but not as much as el84's.

OK, two styrofoam cups and a piece of string was unfair. I tend to overstate my analogies for dramatic effect. I still stand by the point though.

I also don't know that I subscribe to tubes being basically mechanical devices. They pass electrons as their primary function. No levers, cogs, wheels or any device where energy is used to accelerate matter. The cathode is heated so that's a more or less a mechanical function but I might say there are mechanical side effects to a tubes means of electronic function.

[Gtr_tech]

OK, if you suspend something from your ceiling with a piece of wire, thats a mechanical connection right? What do you think is going on inside a tube? Grids are just a piece of wire wrapped around 2 posts for support. Plates are just formed pieces of sheet metal. Its just a mechanical structure until you take it out of the environment via a vacuum and add operating voltages. The closest thing a tube has to an "active" element is the cathode.

Mechanical doesn't *have* to mean gears, levers, and pulleys.

[Chuck H]

With all respect, all I get from this is how a tube is constructed mechanically. So is a transistor. So is a radar dish, an Xray imager and even a piece of lead wire. I would argue that with the exception of any srtuctural support offered by a piece of lead wire that it's not performing a mechanical function.

Definition of MECHANICAL
1a (1) : of or relating to machinery or tools <mechanical applications of science> <a mechanical genius> <mechanical aptitude> (2) : produced or operated by a machine or tool <mechanical power> <a mechanical refrigerator> <a mechanical saw> b : of or relating to manual operations
2: of or relating to artisans or machinists <the mechanical trades>