dave
New Member
Posts: 7
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Post by dave on Apr 28, 2007 3:37:56 GMT -7
Early in the second set last night we started having a feedback problem, sounded like it was from the the foldback, the usual swelling humming sound, and this sent the sound man into a spin trying to trace it. Well it was from my Z-28, took a me few moments to realise. I was beginning to think something was wrong as I was losing headroom and struggling to get any sort of clean sound. Thankfully I had my Ghia with me had that set up pdq.
A post mortem this morning revealed a very microphonic EF86 that could be induced to oscillate when tapped. It was a fairly recent (and not cheap!) NOS telefunken that I had swopped with the original Svetlana. Nothing wrong with the latter, the Telefunken seemed to give me a bit more headroom. The Svetlana is also slightly microphonic (you can hear the tapping but no hint of oscillations when you touch it) and wondered if that was normal.
Anyway I thought preamp tubes lasted forever once you found a good one!? Any similar experiences?
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Post by billyguitar on Apr 28, 2007 7:45:17 GMT -7
Try some rubber bands wrapped around the offending tube. If you can stop the vibration you might be able to save those expensive tubes.
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Post by Curt on Apr 28, 2007 16:24:44 GMT -7
EF 86's are strange fragile birds IMO.....but the sound damn good !
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Post by jwr on Apr 28, 2007 20:09:20 GMT -7
I've had good luck with Dario, Mullard and GEC EF-86's so far. Got the Mullard and GEC from KCA NOS Tubes. Good Stuff.
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Post by rcrecelius on Apr 28, 2007 22:24:09 GMT -7
Ive yet to have an ef86 last more than 6 months before going microphonic beyond the point of useable...and that includes an expensive mullard. However, that was before knowing about the rubber band/o-ring/tube dampener thingys so I need to stick that mullard back in and try it again.
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Post by sudsysul on May 8, 2007 6:40:20 GMT -7
I read this post last Friday. We played out Saturday night. We were running a little late, so I rushed to set up the PA and then finally got to set up my guitar rig. When I plugged into the Z28 head and Z1X12 bottom it sounded very muffled and low volume. Aha, I'd been bitten by the EF86 bug and no spare on board. So I raced out to the trailer and grabbed a Marshall head and ran back in to plug it into the bottom... same sound came out.. must be a blown G12H. So out the door I go and unlock the trailer again and race back in schlepping a spare 2X12 bottom and plug in.. same sound. With band members ready to go and looking unsympathetically at me, I realized that the wah wah pedal was engaged. I don't know if there's a moral to this story or not.. just thought you'd get a chuckle out of it if you've ever had a stupid event like that happen. I've had many over the years.
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Post by flem on May 8, 2007 9:45:21 GMT -7
LOL! Too funny! Well, funny after it happens. I've had batteries die in my fx pedals and cut/mangle the sound, leaving me paranoid that a volcano was about to erupt from my amp.
My Z28 came stock with 2 heavy rubber rings that contact the tube glass and the wiry tube holder connected to the chassis of the amp, reducing vibration. I'd think some flameproof gromets at the right size would do the same thing?
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Post by rcrecelius on May 8, 2007 14:21:43 GMT -7
I read this post last Friday. We played out Saturday night. We were running a little late, so I rushed to set up the PA and then finally got to set up my guitar rig. When I plugged into the Z28 head and Z1X12 bottom it sounded very muffled and low volume. Aha, I'd been bitten by the EF86 bug and no spare on board. So I raced out to the trailer and grabbed a Marshall head and ran back in to plug it into the bottom... same sound came out.. must be a blown G12H. So out the door I go and unlock the trailer again and race back in schlepping a spare 2X12 bottom and plug in.. same sound. With band members ready to go and looking unsympathetically at me, I realized that the wah wah pedal was engaged. I don't know if there's a moral to this story or not.. just thought you'd get a chuckle out of it if you've ever had a stupid event like that happen. I've had many over the years. Wish I'd been there for that
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Post by groovergeorge on Jul 9, 2007 21:58:59 GMT -7
Same thing happened top me a few days ago.............whatdya know the old rubber band around the suspect ef86 trick!
Problem solved.
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Post by Curt on Jul 9, 2007 23:21:03 GMT -7
I read this post last Friday. We played out Saturday night. We were running a little late, so I rushed to set up the PA and then finally got to set up my guitar rig. When I plugged into the Z28 head and Z1X12 bottom it sounded very muffled and low volume. Aha, I'd been bitten by the EF86 bug and no spare on board. So I raced out to the trailer and grabbed a Marshall head and ran back in to plug it into the bottom... same sound came out.. must be a blown G12H. So out the door I go and unlock the trailer again and race back in schlepping a spare 2X12 bottom and plug in.. same sound. With band members ready to go and looking unsympathetically at me, I realized that the wah wah pedal was engaged. I don't know if there's a moral to this story or not.. just thought you'd get a chuckle out of it if you've ever had a stupid event like that happen. I've had many over the years. Wish I'd been there for that LOL I HAVE been there for that Too many times.
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Post by UnclePat on Jul 10, 2007 5:59:55 GMT -7
I read this post last Friday. We played out Saturday night. We were running a little late, so I rushed to set up the PA and then finally got to set up my guitar rig. When I plugged into the Z28 head and Z1X12 bottom it sounded very muffled and low volume. Aha, I'd been bitten by the EF86 bug and no spare on board. So I raced out to the trailer and grabbed a Marshall head and ran back in to plug it into the bottom... same sound came out.. must be a blown G12H. So out the door I go and unlock the trailer again and race back in schlepping a spare 2X12 bottom and plug in.. same sound. With band members ready to go and looking unsympathetically at me, I realized that the wah wah pedal was engaged. I don't know if there's a moral to this story or not.. just thought you'd get a chuckle out of it if you've ever had a stupid event like that happen. I've had many over the years. Classic! ;D Wish I could say it's never happened to me... My Z-28 as a combo was really bad for trashing EF86's too. Broke it out into a head/cab and problem solved, but this rubber band trick sounds like the way to go. Where exactly do the rubber bands go on the tube...midway, or towards the pin end....then I assume it rides against the glass, between the glass and the spring clip?
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Post by groovergeorge on Jul 10, 2007 7:30:48 GMT -7
I just wrapped the rubber band a few times around the diameter of the width of the glass somewhere approximately in the middle.
Weird but it worked!
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Post by dixiechicken on Jul 10, 2007 8:45:41 GMT -7
The NOS Dario Miniwatt EF-86:s is what Dr-Z himself likes best with his designs.
Cheers: Dixiechicken
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Post by detuned on Jul 10, 2007 11:48:47 GMT -7
Don't try that trick with an EL84...
Those suckers get hot!
Don't ask how I know. :-)
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Post by rcrecelius on Jul 11, 2007 6:42:47 GMT -7
Don't try that trick with an EL84... Those suckers get hot! Don't ask how I know. :-) Rubber bands or O-Rings? Ive got O-rings on my 84's right now and I havent smelt anything burning...
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Post by groovergeorge on Jul 11, 2007 6:52:31 GMT -7
I just wrapped a small rubber band around the offending EF86 but O rings are a darn good idea.
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Post by Curt on Jul 11, 2007 7:31:50 GMT -7
Check ebay, search tube dampers ;^)
Or search the tube section here as there is a thread or two with links, etc.
Doc ships EF86 amps with them installed these day's.
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Post by groovergeorge on Jul 11, 2007 18:19:12 GMT -7
Thanks Curt, I think that's a really good idea. I will check Evil bay now.
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Post by detuned on Jul 17, 2007 10:12:38 GMT -7
Rubber bands or O-Rings? Ive got O-rings on my 84's right now and I havent smelt anything burning... 'bands.
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Post by UnclePat on Jul 17, 2007 12:56:06 GMT -7
I did the rubber band thing last weekend. Three not-too-snug wraps with a single rubber band, and pulled the spring clip back on. Worked like a charm!
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Post by bobsyeruncle on Aug 11, 2007 18:54:19 GMT -7
Hi everyone, You get a device called Duende Criatura Tube Rings. They fit around the tubes(comes in different diameters for different applications and work really well. They will solve all your microphonic and oscillation. problems and withstand the heat. See thetubestore.com where I bought mine.
Cheers
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Post by zdogma on Aug 12, 2007 19:26:02 GMT -7
Hi everyone, You get a device called Duende Criatura Tube Rings. They fit around the tubes(comes in different diameters for different applications and work really well. They will solve all your microphonic and oscillation. problems and withstand the heat. See thetubestore.com where I bought mine. Cheers I use these too. Very good product, but a bit pricey.
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