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Post by taswegian on Jan 14, 2008 3:01:13 GMT -7
Hi guys, my Bro in law just brought around his Z28 as it's not functioning properly and he has a gig tomorrow night. Basically, I fired it up and it has a very weak sound. Still quite toneful, only bedroom volume no matter where we dial it. My guess is the 6v6's have had their day. I have a spare rec here but doubt it's that. Anyone have any suggestions. I've basically ruled out stepdown transformer, speaker lead, guitar lead, and cab by running it through my gear.
If so, any suggestions for good 6v6 replacements? Looks like he'll have to use my Route 66 Wed night.
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Post by UnclePat on Jan 14, 2008 8:09:10 GMT -7
I have a spare pair of Groove Tubes 6V6's (5 or 6 rating like the stock tubes) on hand for that very reason. If everything I've read here is to be believed, then re-biasing isn't totally necessary (although it's probably advisable to check it)
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Post by taswegian on Jan 17, 2008 19:03:48 GMT -7
Thanks Uncle Pat, well I'll take it that everyone agrees with me on the power tubes then. I just hope something weird hasn't happened from playing through his Dr Z 4-10 with one speaker not working. Kinda weird cause he recon's he had it checked out and was still running at 4 ohms. I have no idea but I'm not a techy with electronics. I'll recommend he gets a nice GEC ef86, RCA 6v6's and a mullard GZ34 and be done with it all!
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Post by fishman on Jan 17, 2008 20:04:43 GMT -7
I'll recommend he gets a nice GEC ef86, RCA 6v6's and a mullard GZ34 and be done with it all!
I have the same tubes in mine, with the exception of the Ef86, I have a Amperex Bugle Boy..that tube compliment really makes these amps come alive...I must say the Mullard Rect. made the most sonic difference right away, other nuances appear as a bit more subtle. All in all, great recomendation!
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Post by arniez on Jan 18, 2008 7:44:30 GMT -7
I had a similar problem and it proved to be the 5751 phase inverter ArnieZ
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Post by taswegian on Jan 18, 2008 18:42:31 GMT -7
Hey thanks Arnie, I hadn't considered the PI but that kinda makes sense too. He should just get a whole new set and bias up...
Then give it to me for a couple gigs! ;D
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Post by arniez on Jan 25, 2008 13:39:57 GMT -7
And the problem was/is? ArnieZ
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Post by taswegian on Jan 25, 2008 18:20:10 GMT -7
Not sure yet as he has been using my amp while he orders some tubes. I think he might try a new 5751 first though. I'm trying to talk him into a new set of everything except his Dario miniwatt ef86. I can't wait to hear his amp through my Ulbrick 1-12 cab.
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Post by arniez on Jan 25, 2008 20:05:32 GMT -7
You can always substitute a 12ax7 just to see if that's the problem, if there is not a 5751 around. ArnieZ
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Post by taswegian on Jan 25, 2008 21:04:05 GMT -7
Hey yeah, I just remembered I have one of those GT 12ax7 matched PI's around here somewhere. I'll try that. Thanks Arnie.
If you read this Lance, come and get it or bring the amp over and we'll try it out.
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Post by taswegian on Feb 6, 2008 21:47:44 GMT -7
Well we tried a new PI but didn't change anything, so I stuck a spare EF86 I had lying around in and VOILA, the amp is back to normal. Was an Amperex EF86 that went down too. Now maybe I could use the Z28 for my Fri night gig? ;D
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fixed
Full Member
Posts: 133
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Post by fixed on Feb 7, 2008 15:07:44 GMT -7
So you can substitute a 12ax7 for an EF86? Of course it wouldn't sound the same, but would it work? I had to take the EF86 out of my Z-28 and put it in my RxES in a pinch.
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Post by kruzty on Feb 7, 2008 15:20:47 GMT -7
So you can substitute a 12ax7 for an EF86? Of course it wouldn't sound the same, but would it work? I had to take the EF86 out of my Z-28 and put it in my RxES in a pinch. I'm no expert, but I think bad things will happen if you stick a 12A type where an EF86 belongs... I think they were talking about the phase inverter tube.
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Post by taswegian on Feb 7, 2008 19:48:39 GMT -7
So you can substitute a 12ax7 for an EF86? Of course it wouldn't sound the same, but would it work? I had to take the EF86 out of my Z-28 and put it in my RxES in a pinch. No, no no, don't even think about it! The EF86 must be replaced by an EF86. The 5751 can be substituted by a 12ax7 for less headroom and different feel.
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