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Post by beachwail on Jun 25, 2007 5:37:37 GMT -7
it seems like lately i can't keep up with my band volume-wise.
i'm running a Z-28 head into an avatar 1x12 cab with a weber ceramic blue 50w. it's always been a perfect volume to get a warm clean and use my pedals for shades of dirt and a booster for solos...
i've always ran all knobs at 10am (pretty low) to preserve the clean (p90 and mini-hums guitars). most importantly, once the tubes are warm i'm completely out of volume headroom past this point. if i try to boost the front end (RC booster) it gets fat and saturated, but no volume boost. cranking up the RC just makes the Z-28 get out of control 'loose' and feedback-prone, but not any louder.
it's currently tubed with JJ's 6v6's and GZ34, about 2 years old with some heavy use in the past 6 months. could my problems be a result of worn power tubes or rectifier?
can i change these myself? i'm doubtful that there is a decent amp tech in my area.
thanks for any advice, etc. mike
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Post by James on Jun 25, 2007 6:52:12 GMT -7
Mike,
A new set of power tubes will probably do the trick. Probably don't need to touch the GZ34. You would have to set the bias for the new tubes.
I do this myself with a "weber bias rite". Safe and easy. The tool is about $100. If you have no tech in the area, this tool is your ticket.
However...............Setting the bias should be a super basic job for any decent amp tech.
Good luck!
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Post by zdogma on Jun 27, 2007 12:53:08 GMT -7
Agreed. I'd start with a fresh set of JJ's or tung sols, that usually does the trick for volume loss and will make the amp sound better/clearer in the process.
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Post by beachwail on Jul 2, 2007 8:59:28 GMT -7
I figured I would do a couple tests with my preamp tubes first...
First tried swapping out the EF86 with my backup (Sovtek) but that didn't help. So I changed the 5751 with a 12ax7 (it's all I had) and wow, that was a big difference. I got more volume AND more headroom (which seems contradictory). I could go all the way up to NOON on the volume knob and still get a volume boost from my pedals.
This is really all I needed. For reference, the 5751 is a JAN/Philips and the 12ax7 is a GE. Is it possible that the JAN 5751 is bad or 'weak' ?
I keep reading over and over that the 5751 provides MORE headroom than a 12ax7
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Post by genobluzgtr on Jul 3, 2007 12:30:42 GMT -7
It sounds like your 5751 has problems. It's likely that it was failing or starting to and that's why you were breaking up too early. The 12AX7 should be 'gainier' in that slot than the 5751.
Pickup a new 5751 and try it out (they aren't too expensive).
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Post by zdogma on Jul 4, 2007 5:42:29 GMT -7
I recently switched the PI to a 12AX7 in mine and it increased the gain considerably.
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dave
New Member
Posts: 7
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Post by dave on Jul 19, 2007 14:52:22 GMT -7
Try running the bass level a bit lower - for max twang I run bass at 8 or 9 o/c, treble at 10-11 and volume 12-2 but with the guitar volume low enough to give the clean I want.
A Z-best gives you a significant volume boost - in fact I find the Ghia now keeps up with the band no problems.
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