Yeah, it’s my VOIP phone for work; it plugs into a hardware VPN box and thence to my home network. I’m not fond of it – there’s a about a 1-sec delay btw me talking and someone hearing it on the other end. And vice versa. Conversations consist of each person interrupting the other repeatedly.
I have no clue - you’ve crossed that line into “I actually understand electronics”-Land that I will never gain access to.
E-Bay auction guitar ID, simplified: LOOKS LIKE A 1991 FENDER STRATOCASTER DELUXE BLUE. Gosh, I wonder what maker could have made a guitar that looks like that (Note the headstock shape)?
Oops, fixed link.
Nom De Plume wants to talk about the Variax modeling guitars.
Also, Squeegee: I don’t think it’d do any damage, so why the heck not? Just remember where it came from.
So my Blues Junior started doing this this morning. Basically turn it on, wait a bit, and after it gets warm enough it starts spitting (really loud) static. It happens even with nothing plugged into it and all pots at zero. So I guess I’ll be seeing how Fender service centers work. Theoretically I have a five year “limited” warranty, and I can’t see how this can be anything but a defect. The amp has never even left my office since I bought it 13 months ago. Luckily I have the sales receipt and there’s a Fender service center up in San Jose.
Anybody have any experience getting Fender to fix one of their amps?
Microphonic tube, I’d say. Should be an easy fix. Sounds like someone whacking a microphone.
http://www.ehow.com/how_2043383_-locate-microphonic-tube-amplifier.html
I may be entirely wrong!
I got my XV-440 in yesterday! Mine is black. It also has a small blemish on the headstock (that you wouldn’t notice if you weren’t looking for it) and some on the upper edge of the fingerboard so that you see them looking down from playing position but not from the front (if that makes sense). It plays great, and even came set up pretty well.
It doesn’t seem to hum much more than my Tele, but I haven’t compared them head-to-head. I notice that it hums a lot more when I take my hands off the strings, which my old Strat also does but the Tele doesn’t.
It seems like a fine axe for $130. It doesn’t call out to me in the night the way Big Red (the Tele) does, but for screwing-around purposes I’m very pleased.
Meanwhile, if the storms don’t carry us off tomorrow I think I’m taking the acoustic down to the open mike at my friends’ bar. It’s a little intimidating, since the people who show up tend to be really good, but I think I can hang.
So I decided since the Blues Junior was busted anyway, I’d fiddle around inside and see what I could see. I popped off the back panel off the amp, and poked around a bit, but didn’t see anything remarkable. Here’s what it looked like. The tubes are on the left, circuit board on the right. The little tubes are the preamp tubes, the big ones are the power tubes. Note the spring-loaded clip holding down the power tubes, we’ll return to that later.
So next I lay the amp flat and let it warm up again. 10 or so minutes later, it does it’s thing, making really loud static-y noises. On impulse, I tapped the power tubes, and one of them seemed to be contributing to the noise, so I thought maybe it was a little loose and tried pushing it in the socket. The damned thing came apart in my hand! I turned off the amp and let it cool, then lifted that clip, and as you can see, the outside glass of the tube popped right off. Tubes don’t work that well without vacuum. Here’s another view of that busted tube + the hold-down clip.
So, anyway, hopefully the broken tube is the entire problem. It is possible that I busted it when I tried pushing it into the socket, and there’s some other problem with the amp, but I’m hopeful this was the problem and a new tube will fix it.
Thinking out loud here (like I wasn’t above, sheesh): that hold-down clip seems too narrow for what it’s doing – the glass of the tubes are very tight in the channel, and in fact I had the darndest time getting the top of the busted tube out of it, it was really wedged in there. Maybe this contributed to the tube breakage? It seems like some sort of cushion against that hold-down clip would help.
Congrats, DoctorJ! I hope you two are very happy together.
re. this:
Hmm, that’s unfortunate. The strings should be grounded; the ones on my 440 are, though I don’t know exactly how. The usual way is via a small wire attached to the tailpiece or bridge of the guitar, and the other end attaches to ground. Considering the quality wiring job that Guitar Fetish did on my 440 (ha!), I’d bet a wire is indeed attached to the bridge/tailpiece and just not hooked up right in the control cavity, in which case it’s pretty fixable. Just a thought.
Hey, best of luck tomorrow. Break a leg and all that.
Find a Blues Jr. Modding site and see what is written up about tube sockets or tube issues, e.g.,:
http://home.comcast.net/~machrone/bluesjunior.htm
http://thegearmall.com/amp-mods/all-fender-blues-junior-mods-enhancements
http://bluesjuniorfansite.com/mods-parts-extras/
(there might be a bit of info out there ;))
Bottom line, you got either a clip issue or simply a poorly-manufactured tube. I would suspect the latter, but I am not there. Check out those sites and see how different replacement tubes are rated (there will be a ton of tube geekery, I am sure, on those sites).
Where’s **Small Clanger **or now **Shakester **or additional tech folks like you guys?
I’m confident in dealing with guitar wiring because that’s harmless, amps worry me because they contain enough voltage to seriously spoil your day. Modern amps are a lot safer than vintage amps, of course, but I only mess with things that are plugged into wall sockets if I’m 100% certain I know what I’m doing.
Valves (or “tubes” in American) are risky. They get very hot, and quite a lot of voltage goes through them. They get stressed; it’s part of the magic. If a valve happens to be a bit dodgy, it can fail. Probably what happened to squeegee is that the valve was in the process of failing and that’s what caused the unpleasant noise.
I’d say squeegee was lucky that he finished off the valve the way he did: if it had failed while the amp was on it could have damaged the amp or even (for all I know) have killed it. It can happen.
Those valves are EL84s, power amp valves, Groove Tubes by brand. GT don’t make valves, they just re-badge Chinese or Russian valves. I’d replace both the survivor and the dead one with something else, just to be certain.
I think if the metal clip thing was damaging the valve, that’s where it would have broken. It looks to me, from the pics, like the problem was the plate at the bottom of the element, which (in my understanding of how valves work) is the hottest bit. It seems to have overheated and weakened the glass around it.
Don’t even think of using anything to “cushion” the pointy bit at the top of the valve; it will burn, and kill the valve very quickly. That metal clip thing is probably a kind of heatsink.
[QUOTE=WordMan]
Where’s **Small Clanger **or now **Shakester **or additional tech folks like you guys?
[/QUOTE]
Hey, I’ve had a busy day. Dying valves tend to make frying noises, I’ve never had one physically fall apart on me, though mine would qualify as “new old” since I’ve had them forever, probably more consistent quality back in the day. Mullards I think are indestructable. That said I’ve just had to swap one out because it’s gone microphonic I’d guess that one was over thirty (three-zero) years old. OK make that “old old”, but still functional.
I doubt the clip is a heat sink, my Park has a very similar setup - EL84s with springy retaining clips - but no substantial metal.
Gotta run, I’ll post more if I think of anything useful.
Thanks for all the tube commentary, Shakester and Small Clanger. I really hope that replacing the power tube solve this issue. I hate being w/o an amp. I can just plug into my computer and do amp simming, but it’s just not the same sometimes.
Do I really need to replace both? I ordered a single replacement tube last night. It was free shipping, so I suppose I’ll just order another, no big deal.
Re the clip, I guess I’ll leave it as-is, since nobody I could find online seemed to single that out as a problem, and I gather that both of you think it’s probably fine.
Sorry for the bolding, but its true. You want tubes that have been bought and installed at the same time and have matched biases (again, I have NO clue what I am talking about, but I think a tube’s bias is spec’d upon manufacture, but there is a lot of variability, so you want to buy them from someone who has measured and matched a pair of tubes so they operate within the same real-world specs…)
I have been told to think of the tubes like batteries - always replace them in sets unless you are stuck at a gig and need to swap one in on the fly…
OK, I’ll take your word for it. I just ordered the same tube again (this one) to make a pair.
Hey, New York Guitarists!
This sounds like a fun thing to stare at.
[QUOTE=WordMan]
You want tubes that have been bought and installed at the same time and have matched biases…
[/QUOTE]
The bias isn’t really a property of the valve(s) it depends on the design of the amp, the HT voltage and the bias resistors (not surprisingly). When you set the bias you are deciding how hard the valve is working when the amp isn’t actually amplifying (remember that class AB stuff?). The amp expects the valves to be within design specs and if they are way off you will get a valve that runs either too hot, or under powered. A badly unmatched pair is obviously not good. A pair of the same make/vintage are much more likely to be well matched than say mixing one of my 30 year old Mullards with a new Chinese jobbie.
squeegee Sounds like one of your EL84s was running too hot, good luck with the new ones.
What’s funny is I was told here (I don’t remember if it was this thread or another) that I shouldn’t worry about changing tubes as they take forever to wear out, perhaps years, and maybe not even then. I bought this amp new, and since then I’ve had two tubes go bad (a preamp tube went microphonic a while back), so (with the extra power tube for ‘matching’) I’ll have replaced 3/5th of my tubes in just 13 months.