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Post by johanj on Dec 18, 2006 5:00:23 GMT -7
Hello! I have just purchased a second hand CG 2-10 combo. Z amps are amazing, nuff said... A couple of questions: 1. Think i might have to change the tubes as i get weird noises at times. Is it safe to plug and unplug tubes after disconnecting the power-chord, or do I have to drain the amp first? 2. Havent checked the preamp tubes yet as they have metal casings round them but the EL84s says "HARMA EL84 Superior Grade" on them... Is Harma the make? Also, can i take off the metal casings round the preamptubes and tighten all the screws on the outside of the ampchassi (the actual amp, not the cabinet)) without draining it? Think something is vibrating ceating a buzzing noise at points.. Basically, think im trying to say "What is safe to do without draining it?" Any comments would be greatly appreciated! Thanks guys Johan
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Post by tjstrat on Dec 18, 2006 6:14:32 GMT -7
It should be safe to work around the tubes without discharging the caps, although if you know how to discharge them safely it probably wouldn't hurt to do so. I'd definitely retube if the amp was purchased used. The Ghia isn't expensive to do this with at all. The 5751 in V2 will possibly be the most expensive tube you have to get.
"Harma" sounds like the name... Someone else here will surely be familiar with them if they are. As far as tightening any screws, as long as the chassis isn't wide open and vunerable to a misplaced screwdriver shaft, you should be safe.
Incredible amp, by the way. Absolutely incredible.
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Post by billyguitar on Dec 18, 2006 6:33:08 GMT -7
Just turn the amp off long enough for the tubes to be cool. I've changed tubes with amps on and just turned down. It won't hurt anything.
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dave
New Member
Posts: 7
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Post by dave on Dec 18, 2006 9:18:52 GMT -7
Harma is indeed the make and I have Harma EL84's in mine at present on the advice of our UK tube guru at Watford Valves. He sold me a GEC 5751 with them and it was this tube that made all the difference to the sound. This was the set up that BW used at his 100 Club gig in April and the word was it was loud and slightly cleaner than usual.
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Post by drew on Dec 18, 2006 12:20:35 GMT -7
welcome Johan, The ghia is a great amp. The only thing I can add from the previous post is: some el84 output tubes can rattle when pushed. There are tube dampers to help but I've no personal experience with them, see the thread below for more info. I had an odd rattle in my ghia at louder volumes. I didn't hear it through the output just from the actual unit. I replaced the el84 output tubes and the rattle went away. Your issue might be something completely different. drzamplifiers.proboards41.com/index.cgi?action=display&board=ghia&thread=1162667664&page=1
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Post by guitarboy02451 on Dec 20, 2006 20:58:25 GMT -7
Johanj, Hey there... welcome! You can remove the tubes without taking the power cord off. Just remember to turn the power off. The rattling that you hear is the EL84's and rectifier. Go to this site and get tube dampners: herbiesaudiolab.home.att.net/The best EL84 tubes for Dr.Z's are the Groove Tube EL84 #6's. You should probably re-tube the EL84's since you don't know their age. EL84's should be changed between 300 and 600 hours. Check the pre-amp tubes. You should have a Ecc83 in P1 and a 5751 in P2.
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