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Post by steveinnashville on Jan 7, 2007 15:16:22 GMT -7
OK, I checked the fuse- the coil appears to be broken- which means that the fuse did blow, right? I'll try a new fuse out on Monday. Is there any reason why I shouldn't try this? It's $35-50 to have somebody look at and/or fix an amp... The only reason I'm hesitant is that a co-worker who deals with more electric stuff than me (not at work!) said that there is no reason why a fuse would just give out if the amp has been stationary for a while and was plugged into a power strip (which it was)...
Thoughts?
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Post by kruzty on Jan 7, 2007 16:27:32 GMT -7
Chances are your rectifier tube went bad. You could replace that at the same time, or replace the fuse and if it blows again, then change the rectifier tube (and fuse).
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Post by zdogma on Jan 7, 2007 20:33:15 GMT -7
Power tubes will do it too sometimes. Get a couple of sloblo fuses or three, and try first the rectifier, if it blows with a fresh rectifier, try the output tubes.
If still nothing look inside the chassis (carefully, depending on your comfort level) to see if a screen resistor has burned, that happens sometimes when a power tube goes, (i think the ghia has one, but i've never needed to look), it will look black and charred. That's a small repair, if its gone.
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Post by steveinnashville on Jan 8, 2007 0:49:38 GMT -7
I just got it back from the shop about three months ago- it has a new rectifier tube already! I hope that's not it- I think I'll take it to a better guy this time (I have one in mind- going to give him a call tomorrow)... My electronics knowledge is not a "working" one... Thanks for the suggestions...
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Post by kruzty on Jan 8, 2007 6:43:31 GMT -7
What brand of rectifier is it? Is it NOS or new production? If it is new production, some of those have hit or miss reliability.
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wilzgt
Full Member
I plumb for Z-Tone !
Posts: 151
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Post by wilzgt on Jan 8, 2007 12:25:18 GMT -7
Not to worry!
Fuses are used to safe guard your electronics. They are the weak link of the chain. So, when current exceeds the circuits capability, the fuse will blow and thus shut off the amp.
Stick a similar sized/valued fuse in and see if the amp will power up. If so, then look at the back and see whether both of your power tubes are lit. Radio Shack has fuses.
I once owned a Carmen Ghia and had one power tube short out. As it shorted out, the circuit drew too much current and blew out my fuse. So, I stuck in another fuse and the amp powered up with only one power tube on. I then shut it off and got a pair of new el84's.
I think your power tubes are the culprit!
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Post by steveinnashville on Jan 8, 2007 22:34:04 GMT -7
Well, I took it in to the shop. Now it just needs a new set of power tubes (that's what shorted out)... I thought I had some, but I can't presently find them. This means that they are either somewhere around the house or that the last trip to the shop for a fried rectifier tube also cost me a set of matched power tubes (I had one extra set, so either they got replaced or the dude swiped them)... Oh, well. I guess I'll check some tube websites... I was using JJ/Tesla EL84s, I see them for $20 at KCA NOS Tubes so far... should I get those or go with the $22 matched pair of Ei tubes?
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Post by steveinnashville on Jan 9, 2007 11:29:42 GMT -7
JJ/Tesla EL84s are on the way, thanks Mike (Z) and Mike (KCA)!!! A Sweet Sound MojoVibe just arrived yesterday and I'm also having an old German tape echo unit restored- they will sound so much better through the Ghia. My 2nd amp is an '80 Fender Champ II (Rivera-era Fender)... It is pretty good, run through the Leslie it's a good match for the Ghia, but unless you open it up, it's not the warmest sounding amp- my fuzz pedals don't like it, and my obligatory BOG/Hendrix noodlings are suffering with the octavia->Champ II... Soon the Ghia will be back on top (of it's 1x12")...
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Post by steveinnashville on Jan 15, 2007 3:55:43 GMT -7
Hmmm... so, I got it back and the tubes came after a couple of days (fast shipping @ KCA)...
I popped them in and fired it up... Ah! The Ghia had returned. It sounded great. But after about 3 minutes, the amp smelled like something burning. So, back to the tech it goes! Woe is me (and so is the amp!)... Oh, well... As long as it's not a transformer I'll be OK I think...
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Post by DRZ on Jan 15, 2007 6:22:38 GMT -7
Steve your conjunctive filter came unsoldered. A Output tube failure on an older Ghia yours is a circa 1999 I believe, can cause the conjunctive filter to overheat.
New Ghia's don't have that problem.
The filter is a 10 K resistor in series with a .0022 uf cap., let your tech know.
DR.Z
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Post by kldonegan on Jan 15, 2007 11:27:42 GMT -7
Nashville Amplifier Service does really great work. Don't know who you're taking it too, but they'll treat it right. I had a VOX giving me trouble right before a Christmas tour, and Jeff took care of it super quick. 615-591-7556.
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Post by steveinnashville on Jan 15, 2007 15:25:19 GMT -7
I take my stuff to Mark Ferguson (helping him move his shop across town today actually!)... Ferg's Amp Repair.
Dr. Z/Mike, thanks so much! I will let him know! Thanks again!
I wonder if that 3 minutes of playing definitely blew the fresh set of tubes I had just put in, there's $20 down the drain... Oh, well. I'll have Ferg test them anyway just in case they're still good. Good thing KCA has that $40 minimum order- otherwise I'd be all out of tubes again already!
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Post by Dana {aka gp} on Jan 19, 2007 11:16:20 GMT -7
Steve your conjunctive filter came unsoldered. A Output tube failure on an older Ghia yours is a circa 1999 I believe, can cause the conjunctive filter to overheat. New Ghia's don't have that problem. Hey Doc, Is there a retrofit for older Ghia's than can help prevent this phenomenon? Thanks, -Dana
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Post by Phil (aka Phil) on Jan 19, 2007 14:29:36 GMT -7
Dang, Steve, your Ghia has conjunctivitis.
PDW
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Post by myles on Feb 5, 2007 9:33:48 GMT -7
Well, I took it in to the shop. Now it just needs a new set of power tubes (that's what shorted out)... I thought I had some, but I can't presently find them. This means that they are either somewhere around the house or that the last trip to the shop for a fried rectifier tube also cost me a set of matched power tubes (I had one extra set, so either they got replaced or the dude swiped them)... Oh, well. I guess I'll check some tube websites... I was using JJ/Tesla EL84s, I see them for $20 at KCA NOS Tubes so far... should I get those or go with the $22 matched pair of Ei tubes? Not the Ei's .... sound pretty good but I have found them to be quite unreliable.
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Post by steveinnashville on Mar 19, 2007 21:45:48 GMT -7
OK, I haven't been around much lately... update:
The Ghia got new JJ/Tesla EL84s (I also found the older pairs I have), sounded great, but then started producing that burny smell. It sat in a corner for a long time and it turned out not to be a conjunctive filter issue, but in fact a 5751 (jan/phillips? I don't remember and I couldn't read it at this point)... my tech said he doesn't like 5751 tubes- not manufactured very well in his opinion. Anyway, he dug out an old GE that he says is actually a rebranded mullard 12AX7 and put that sucker in there- sounds great- even better than before! He ran it through his oscilloscope and the clipping was coming out almost perfectly square- awesome! Thanks for the suggestions... I will get to play through it some at home tomorrow (it hasn't met my mojo vibe yet!)
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Post by myles on Mar 20, 2007 11:04:54 GMT -7
OK, I haven't been around much lately... update: The Ghia got new JJ/Tesla EL84s (I also found the older pairs I have), sounded great, but then started producing that burny smell. It sat in a corner for a long time and it turned out not to be a conjunctive filter issue, but in fact a 5751 (jan/phillips? I don't remember and I couldn't read it at this point)... my tech said he doesn't like 5751 tubes- not manufactured very well in his opinion. Anyway, he dug out an old GE that he says is actually a rebranded mullard 12AX7 and put that sucker in there- sounds great- even better than before! He ran it through his oscilloscope and the clipping was coming out almost perfectly square- awesome! Thanks for the suggestions... I will get to play through it some at home tomorrow (it hasn't met my mojo vibe yet!) You should tell your tech that NOS 5751s were made for the military to be a slightly lower gain 12AX7 replacement and were intended originally for phase inverter use. They were more closely selected and tested than 12AX7s, and also had to withstand 600G's (I have no idea how this was tested unless they were shaken in some sort of machine as 600 g's would break the glass with ease). The were perhaps the pinnacle of 9 pin tube construction.
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Post by sae2111 on Mar 28, 2007 10:20:06 GMT -7
600 g's? It's been a while since I've studied such things, but won't a couple of hundred g's kill a person? When were those tubes made? I'm trying to figure out how far aeronautics had advanced at the time and for what kinds of applications they would have been used.
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Post by steveinnashville on Mar 30, 2007 11:24:33 GMT -7
it might not have been a NOS tube at all- no label left... i'm no expert... my amp sounds great and works great now, though!!!
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