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Post by pickupcentral on Feb 23, 2006 14:40:53 GMT -7
I was playing my Ghia (not red) last night and noticed when playing an open "A" chord there was a "crackling" sound during the chord's decay. I did not have the same problem with my Rx.
Volume was about 3 o'clock, guitar was a homebuilt tele with Fralins. Running two 8 ohm cabs at 4 ohms - a 1x12 and a 2x12.
Time for new tubes? Preamp? Power? Recto? All of 'em?
Thanks! -Phil
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Post by myles on Feb 25, 2006 11:23:13 GMT -7
This sounds like V1 but ....
when was the last time output tubes were changed?
Are the cabs in a Y adaptor to the 4 ohm jack?
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Post by pickupcentral on Feb 25, 2006 11:46:43 GMT -7
Hi!
The tubes haven't been changed in a long time (years), but the amp isn't my number one, so it doesn't get a lot of work, either.
The speaker out to one cabinet, then the parallel connection to the other cab.
Thanks! -Phil
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Post by myles on Feb 28, 2006 10:31:04 GMT -7
Change the output set if you are not sure how many hours are on the amp.
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Post by pickupcentral on Mar 21, 2006 20:46:12 GMT -7
Well, apparently it wasn't the tubes. I plugged in my G&L tonight, just to introduce them, and was immediately greeted by that horrible noise. The crackling was almost as loud as the chord. The tubes are new - a couple of EH power tubes and some GT 12ax7s.
I was plugged into a Mesa 1x12 wide cabinet with a C-Rex. I used this same guitar last week through my Rx and same cab with glorious results.
I'll probably just call the Doc - maybe he can look at it.
Sigh. -Phil
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Post by prowler on Mar 22, 2006 22:01:31 GMT -7
I had the same sort of issue with my 6545. I sent it to Z for repair. It turned out to be a bad tube socket. Z fixed the tube socket & installed fresh tubes & biased the amp. Excellent service as usual from Z.
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Post by myles on Mar 23, 2006 11:41:56 GMT -7
Since you have this same problem with two amps I would look closely at your guitar cable and speaker cable (if you are using the same one).
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Post by pickupcentral on Mar 24, 2006 14:34:35 GMT -7
Hi Gang!
Actually, it was different with the Rx. Good Rx.
The Good Doctor emailed me back, suggesting it might be the conjunctive filter. I am going to look into that. Hopefully it is not a tube socket, but I'll check that when I have the hood open.
Thanks for the replies. -Phil
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Post by G'OlPeachPhan on Mar 28, 2006 9:25:03 GMT -7
Phil, I've had this problem with my Ghia before, and it WAS the conjunctive filter... which is a relatively easy fix. Does the issue occur when you grab and hold the low "A" on the 6th string at the 5th fret? Sounds like static washing over your amp? .... That said, I also have occasional issues with a wash of static coming over my Ghia, and it only lasts a couple seconds, and it usually goes away as quickly as it arrives... Sometimes I just have to tap on the top of the amp a little too... I think the sputtering sound may be coming from one of the caps, but it doesn't bother me enough or occur often enough to worry about it. You have to keep in mind that the Ghia is basically a little hot rod, and amps that are tweaked out like the Ghia occasionally make some odd little noises. You can certainly try to find and eliminate those noises, but it's somewhat the nature of the beast! I used to get bugged out about anything like that, but now I just chalk it up to added mojo, personality, and character of the amp... it's got a couple flaws and loose screws just like me! You should be able to tell right away if your conjunctive filter is burned -- it's little resistor soldered over one of the tube sockets, and it will probably look like a little lump of carbon if it's been torched... which I think can happen when an output tube fails... Even if this is the case, you can still play the Ghia without worry of harming it... in fact, you could even snip that resistor out and the Ghia would be just fine, albeit it will sound a little different... a little more raw and nasty and the string-to-string balance would be lessened to some extent I believe. If you do 'pop the hood,' make sure you know what you're doing... and don't stick both hands in that chassis... it ain't fun.
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Post by pickupcentral on Apr 4, 2006 20:23:45 GMT -7
Yup, that was it - the conjunctive filter.
The leads from the cap and resistor (and the components themselves) were intact, but they weren't phyically connected. I imagine they were even making sporadic contact as they were sorta touching.
Anyway, I removed the offending components, and I could hear a pretty significant difference in volume and drive. With single coils I could turn the amp up all the way, get some overdrive without ear-splitting volume. Now, the amp is louder, with a great deal more gain. Even with single coils the sound is fat and beefy. Even on the bridge pickup (G&L S-500). With P-90s (Rio Grandes) the sound was even fatter.
Throwing caution to the wind I turned the volume all the way up. Sweet mother of Elvis! Who the heck needs a pedal! (Well maybe if you can't turn all the way up.)
Disclaimer: I changed the tubes just before I fixed this problem - I am sure new tubes are the main reason the Ghia has roared back to life. Still, I have rekindled my love of this amp.
At some point I will reinstall the C-filter, just to do a proper A/B.
Thanks for everyone's help and suggestions. And the good Doctor.
-Phil
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Post by G'OlPeachPhan on Apr 6, 2006 12:27:07 GMT -7
It would be cool to have the conjunctive filter on a toggle switch for exactly the differences you describe! I've thought about modding my Ghia this way for a while... I'm still struggling with whether or not I want to drill a hole in the chassis to do it... I don't have to worry about resale, as this amp will never be sold, so part of me says, "Why not?"
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dave
New Member
Posts: 7
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Post by dave on Apr 7, 2006 5:09:04 GMT -7
Can someone explain what a conjuctive filter is? What is its purpose?
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Post by G'OlPeachPhan on Apr 7, 2006 6:54:18 GMT -7
SIMPLISTICALLY: It smooths out the response of the amp and increases string-to-string balance. Without the CF, the amp gets even more raw and aggressive.
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Post by John on Apr 20, 2006 9:47:42 GMT -7
Actually, a conjunctive filter is an additional filter....most closely associated with European coffee machines. Because of the style of brewing done in Europe, along with the type of grounds they use, an additional filter, a conjunctive filter is needed to get a more suitable taste.
...is anyone buying this?
Hello....?
...tap...tap...tap
Is this thing on?
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Post by billyguitar on Apr 20, 2006 10:29:26 GMT -7
I know whereof you speak, daddy cool-cat.
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Post by bustertheboy on Apr 20, 2006 14:58:03 GMT -7
glad there's other lunatics out there- the world can be a straight place coffee...
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Post by pickupcentral on Apr 26, 2006 6:31:31 GMT -7
I wonder if you could stick a jack in the back of the Carmen and footswitch between the CF in and out of the circuit. Semms like it would be a simple thing to do, but I don't know if it would be bad for the amp or not. Or if it would make a big popping noise when switched.
-Phil
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Post by billyguitar on Apr 26, 2006 7:41:02 GMT -7
There's probably some real voltage associated with that filter so you wouldn't want to do that without a relay?
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