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Post by fatcontroller on Aug 24, 2008 11:38:43 GMT -7
Sadly, while playing last night, my Stang Ray started humming/buzzing loudly (had never done so before) and after about three minutes (during which I grabbed a different cable, then a different guitar and checked all connections) stopped working all together. No sound at all, no smoke or acrid smell, jewell lamp still lights up, 3 amp fuse looks good, can't see a filament in the 1/2 amp fuse. If it's the fuse, why did the fuse blow? Bad rec tube? Any thoughts before I go diggin?
I am going to cross-post this to the Ray forum. If that's bad form, apologies. As you might imagine, I'm a little anxious...
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janlf
Full Member
Moment's Notice
Posts: 173
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Post by janlf on Aug 24, 2008 12:00:15 GMT -7
Hi! I'm sorry to hear that Hope you got through the gig somehow. Seems to me like you have a broken rectifier. Get a new one, and I think you'll be ok All the best from Norway, JanLF.
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Post by Lefty on Aug 24, 2008 12:45:41 GMT -7
Never trust the eye on fuses. Get a meter and check for continuity. Bad recto or power tube is my guess.
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Post by benttop (Steve) on Aug 24, 2008 13:00:28 GMT -7
Yeah, it's most likely tubes. Could be power tubes or rectifier. The hum business makes me lean towards power tube problems though. Get a good matched set of JJ's or GT's and check the fuses with a meter.
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Post by fatcontroller on Aug 24, 2008 13:25:41 GMT -7
Thanks, gents.
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Post by Phil (aka Phil) on Aug 24, 2008 14:46:15 GMT -7
Yeah, it's most likely tubes. Could be power tubes or rectifier. The hum business makes me lean towards power tube problems though. Get a good matched set of JJ's or GT's and check the fuses with a meter. I agree. Sounds like a bad power tube or tubes. EL84's do that when you least expect it.
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Post by fatcontroller on Aug 25, 2008 6:40:11 GMT -7
OK, so...
Everything but the 12ax7LPS is glowing and warm (including rectifier tube). Swapped in a stock sovtek 12ax7, which started glowing, but still nothing (my blown fuse diagnosis is visual and I haven't replaced the fuse(s))
A few questions:
* Is it necessarily the case that if a tube is gettin' warm and glowing it's functioning?
* Would a fuse blow as a result of a bum pre-amp tube?
* Difference btwn 12ax7LPS and 12ax7?
* Suggested source for tubes and fuses? Couldn't find 1/2 amp fuses at Antique Electronic Supply. Are stock fuses slo-blo?
* Any benefit to bucking-up for tubes other than the stock variety that come w/ Dr. Z's?
Appreciate the help!
Chris
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Post by benttop (Steve) on Aug 25, 2008 6:56:36 GMT -7
OK, so... Everything but the 12ax7LPS is glowing and warm (including rectifier tube). Swapped in a stock sovtek 12ax7, which started glowing, but still nothing (my blown fuse diagnosis is visual and I haven't replaced the fuse(s)) Not all tubes have very visible heaters. You can't make that connection - a bum tube can have functional heaters. It's not as common, but there is a possibility. The thing is, the power tubes and rectifier are MUCH more likely when a fuse pops. The LPS is a matched tube, i.e, the 12AX7 has two gain stages internally, and the LPS has them matched. Not sure about fuses - I usually get them at Radio Shack. For tubes, you can get them a lot of places online, such as eurotubes.com (they sell a lot of JJ tubes there). Many other places online, and you can get NOS tubes at kcanostubes.com. Yeah, there can be. The NOS stuff can be considerably different, ie, more gain, or different tonal character. Some guys spend all their free time swapping in a variety of different tubes. That's what this place is about. There are a lot of experts here, and I'm certain some others will chime in with their views.
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Post by fatcontroller on Aug 25, 2008 7:09:47 GMT -7
Wow, cool, Benttop!
One more for ya' - Are the stock fuses slo-blo?
Oh, and re: tube swapping - yup, I get that there is much chitter-chatter about NOS tubes and the like. I should have phrased my question better: "Are Z's optimized for use with commonly available, mass-produced modern tubes?" My Savage, for instance, is. And so, if I'm going to order a set of replacement tubes, should I just get a new set of what came with the amp, or is there any common wisdom in these parts re: better choices?
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Post by benttop (Steve) on Aug 25, 2008 7:22:19 GMT -7
Wow, cool, Benttop! One more for ya' - Are the stock fuses slo-blo? Oh, and re: tube swapping - yup, I get that there is much chitter-chatter about NOS tubes and the like. I should have phrased my question better: "Are Z's optimized for use with commonly available, mass-produced modern tubes?" My Savage, for instance, is. And so, if I'm going to order a set of replacement tubes, should I just get a new set of what came with the amp, or is there any common wisdom in these parts re: better choices? I do believe the stock fuses are slo-blo. As far as tubes go, it's all very subjective. My Maz Jr. has the tubes it came with in it, and I can't imagine it sounding much better. But I know that folks here change them for a variety of reasons. For example, some guys want more clean headroom, so they put a 5751 in the V1 position to lower the gain. Some folks like to try the spendy tubes because they think Mullards probably sound way better - maybe they do. It's all subjective. I'll say this though, you won't find a company who spends more time listening to tubes than Dr. Z. He's put a lot of thought and listening into every one of his designs.
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Post by myles on Aug 25, 2008 19:39:46 GMT -7
If the B+ fuse was bad there would be no high voltage to the output tubes and there would be no sound.
Sounds like an EL84 bit the dust.
Now here are my questions ... how many hours do you have on those output tubes? .... did the amp receive any bumps or jolts on stage or in transport?
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Post by myles on Aug 25, 2008 19:40:29 GMT -7
Yeah, it's most likely tubes. Could be power tubes or rectifier. The hum business makes me lean towards power tube problems though. Get a good matched set of JJ's or GT's and check the fuses with a meter. Rectifiers are either good or bad and when they fail there is no sound at all from the amp.
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Post by myles on Aug 25, 2008 19:41:41 GMT -7
OK, so... Everything but the 12ax7LPS is glowing and warm (including rectifier tube). Swapped in a stock sovtek 12ax7, which started glowing, but still nothing (my blown fuse diagnosis is visual and I haven't replaced the fuse(s)) A few questions: * Is it necessarily the case that if a tube is gettin' warm and glowing it's functioning? * Would a fuse blow as a result of a bum pre-amp tube? * Difference btwn 12ax7LPS and 12ax7? * Suggested source for tubes and fuses? Couldn't find 1/2 amp fuses at Antique Electronic Supply. Are stock fuses slo-blo? * Any benefit to bucking-up for tubes other than the stock variety that come w/ Dr. Z's? Appreciate the help! Chris Chris, A 12AX7LPS is a long plate 12AX7 and this particular version has an encased heater ... you do not see them glow.
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Post by myles on Aug 25, 2008 19:46:29 GMT -7
OK, so... Everything but the 12ax7LPS is glowing and warm (including rectifier tube). Swapped in a stock sovtek 12ax7, which started glowing, but still nothing (my blown fuse diagnosis is visual and I haven't replaced the fuse(s)) Not all tubes have very visible heaters. Correct .... MylesYou can't make that connection - a bum tube can have functional heaters. The heater in most cases does still work with a bad tube .... and the heater voltage is not the same voltage as the B+ for the output tubes ... MylesIt's not as common, but there is a possibility. The thing is, the power tubes and rectifier are MUCH more likely when a fuse pops. A shorted output tube will blow the B+ fuse at then there will be no sound from the amp. A bad rectifier will generally not pop the fuse until the amp is taken off of standby .... and then it will pop the AC main fuse more often than the smaller value B+ fuse..... MylesThe LPS is a matched tube, i.e, the 12AX7 has two gain stages internally, and the LPS has them matched. A Sovtek 12AX7LPS is not matched any more than any other 12AX7. It has to be cherry picked to find a matched one ... MylesNot sure about fuses - I usually get them at Radio Shack. For tubes, you can get them a lot of places online, such as eurotubes.com (they sell a lot of JJ tubes there). Many other places online, and you can get NOS tubes at kcanostubes.com. www.tubesandmore.com .... MylesYeah, there can be. The NOS stuff can be considerably different, ie, more gain, or different tonal character. Some guys spend all their free time swapping in a variety of different tubes. That's what this place is about. There are a lot of experts here, and I'm certain some others will chime in with their views.
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Post by benttop (Steve) on Aug 25, 2008 20:10:38 GMT -7
The LPS is a matched tube, i.e, the 12AX7 has two gain stages internally, and the LPS has them matched. A Sovtek 12AX7LPS is not matched any more than any other 12AX7. It has to be cherry picked to find a matched one ... MylesAh, thanks for that - I thought that was one of those matched units you guys used to sell.
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Post by fatcontroller on Aug 26, 2008 7:50:32 GMT -7
Geez, Myles - know a little about tubes and tube amplification? You guys are my heroes. Thanks so much. Chris
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Post by myles on Aug 26, 2008 8:34:49 GMT -7
Geez, Myles - know a little about tubes and tube amplification? You guys are my heroes. Thanks so much. Chris Chris, All I try to do is pass on what I know. Hopefully my advice on things like marriage and relationships will be ignored by everybody Myles
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Post by fatcontroller on Sept 1, 2008 8:48:48 GMT -7
Quick update - since I bought the amp used and didn't have a good sense of where it had been/what it went through, I ordered a complete re-tube kit from Eurotubes. Also popped a couple of new fuses in for good measure. The Ray fired right up and sounds spectacular. The icing on the cake is that my Gold-loaded 1x12 cab arrived the day before the tubes. Everyone who *chimed* in to suggest the Gold was spot-on - great sounding speaker with the Ray. Heck, a great sounding speaker period!
In any case, thanks for the help, gents!
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Post by detuned on Sept 2, 2008 8:20:48 GMT -7
+1 for Eurotubes - JJs sound great in Z amps (IMO!).
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Sept 2, 2008 8:29:24 GMT -7
I love reading these threads just so I"ll be more prepared when things go wrong for me. Thanks to all those who contributed this great wealth of info.
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