ok...questions about my amp

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ElectricMud
Junior tube assistant
Posts: 1
(1/29/04 7:16 am)
  ok...questions about my amp
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 I finally got the message to post. I'm new to this forum, and i thought it would be a good way to get some insightful info. I'm not a amp guru by any means, so please bear with me. About a year ago, I decided to re-tube my Fender hot rod DeVille with KT-66. The tech that did the work seemed to think it would work out ok. I got the amp back, and after about a week of playing, I started getting this faint crackling noise in the background. I called up the tech and he said to bring it back in. I was living out of town at the time, and didn't have the time to travel back to where the tech was located. I called up Groove Tubes(where the KT-66 came from), and they praised these tubes....and said everything should've worked out fine. I explained the problems to them and how it was getting progressively worse. They agreed to let me send the tubes back and they would send me a new pair. They got the tubes from me, and said they tested out fine, but I was reluctant to go with the KT-66 again. I decided to go with the Svetlana 6L6. I finally got the amp to a different tech and the tubes put in. Everything sounded much better, but after several months the noise came back. It got worse, and eventually the amp crapped out on me very gradually over the course of a week. One day the volume just slowly decreased to almost nothing while i was playing the amp. I can hardly get a sound out of it, even turned all the way up, and the tone is horrible. The amp had just been sitting and collecting dust for a while now. The amp has definitely had a personality of it's own for the longest. I'm no amp wiz, so I don't really know what is wrong with it...maybe the KT's were too much for it?...maybe it wasn't biased correctly?...maybe this was just a problem that had been existing in the amp?...If anyone might have a clue as to what is wrong, It would be greatly appreciated to get any info on this matter. I've thought about several options...1) leaving the amp stock and having it repaired to fix the existing problems 2) having the amp modded, like the mods Jim Price is doing with these amps on the Omega amps web site...or...3) completely gutting the amp...removing the PCB circuits and replacing them with a point-to-point circuit ala Hoffmann. If anyone would like to help me out, I would be very thankful....any info...pros, cons, etc.....thanks
 
GroundhogKen
Forum Moderator
Posts: 2233
(1/29/04 9:56 am)
  Re: ok...questions about my amp
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 I would just get the amp fixed first.

KT66s draw more heater current than 6L6. The only thing I can imagine they would have done is damaged the power transformer heater winding, but even that seems unlikely.

Let a tech bring the amp back to life and do all the necessary routine maintenance. Then decide if you like the amp or not. Then decide if you want to sell or modify.


Ken
 
6G6
Junior tube assistant
Posts: 64
(1/29/04 10:29 am)
  Re: ok...questions about my amp
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 Yeah, what Ken said.
 

Of course, you can probaly get a lot of suggestions around here and if you want to bail out on it, someone here might want it.
It sounds like it was some problem that already existed before the KT 66s. They may have caused some borderline part to go over the edge, but I think it may have been coming anyway.
 
jc
I only work on Fender's
Posts: 664
(1/29/04 7:21 pm)
  Re: ok...questions about my amp
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 Does that amp have an effects loop? If so try putting a cable in the loop (don't put any effects just take a cable and put one end in the out and the other in the in). I have a Laney head that does the same type of thing and it is the 1/4 jacks for the effects loop are bad (coming un-sprung). Worth a shot...
 
ElectricMud
Junior tube assistant
Posts: 2
(1/29/04 9:40 pm)
  Re: ok...questions about my amp
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 thanks for the replies....I'm pretty much on the same plain as Ken and 6G6...do any of you two have a clue about this problem...just a guess maybe? And Jc....I'm just curious about the fx loop suggestion...what am I suppose to be acheiving by doing this. I currently have the chassis pulled out, so it's a slight inconvenience at the moment.
 
ElectricMud
Junior tube assistant
Posts: 3
(2/12/04 3:44 am)
  Re: ok...questions about my amp
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 UPDATE: This is an update to the message I posted several weeks ago. I finally got my DeVille to a tech here in town for service. I found the reciept, and it was still under warranty(good for me, right?) Most techs hate doing warranty work anyways. This guy claimed to have a mandatory $25 fee for warranty work, even though he's an authorized fender service person. I had only talked to this guy on thephone,and he buttered me up and shit, telling me that he works on Eric Johson's gear(like it means anything to me...hell, I'm not Eric Johnson) Anyways...I took the amp in and dropped it off at the service desk...the tech agreed to fix the amp for $25 and pop in the new Svetlana tubes that I had mentioned in a previous post, and he said he wouldn't charge me for the bias fee. (mandatory $25 fee seemed a little fishy to me) but i figured it was a small price to pay to get my amp working again. About a week later they call me to come pick it up. I walk in and test the amp out for about 20 minutes. Every thing seems cool, all is well....it works...sounds pretty decent...but the reverb doesn't work now. So I leave the amp at the service desk again...(and I have still yet to meet the amp tech face to face at this point). Turns out that he replaced anopen plate load resistor in the driver circuit...whatever that means....I'm not an amp tech...back to the story. Got another call a few days later, and I went back in for pick up once again. Started testing it out and everything is sounding pretty good, actually suprisingly good for a Fender Hot Rod DeVille...not that they're bad amps by no means....butit was sounding exceptional to my ears. I sat there for about 30 minutes jamming on my amp, and the whole time I'm smelling this funny ass odor. I figured it was just the room I was in...the room was full of brand new amps and the air smelled like tolex...lol. Finally I look up at my amp, and it's smokinglike a broke stove...I look in the back of the amp and the tubes look like Roman candles. I turn the amp off and unplug it....run up to the service desk and tell the guy I've got to speak with the tech(I have still yet to meet him in person...why are amp techs so reclusive anyways?) The guy at the front desk can tell I'm not in the best of moods. He calls down the tech, but ironically...he's on his damn lunch break. At this point, I'm determined to be a thorn in his side. I wait......and wait......and wait some more. Finally he comes down stairs and he's talking to the guy at the front desk, not even acknowledging me. And finally...the guy at the front desk told him..."By the way...this is the guy that needs to speak to you"...lol.....he looked shocked. He said.."well...let's just see what the problem is....I gotta see this for myself"..basically implying that he didn't believe me, and he thought I was just some young punk who didn't know shit. We went back in the room and plugged it in....turned it on...and after about 1 minute, the tubes turned into heat lamps again. Thay were melting the fucking tolex they were so damn hot. He obviously knew then that there was a problem, and by the look on his face...I'd say he felt pretty stupid about the whole thing. He took the amp back upstairs to his shop to see what the problem was, (and I even requested to tag along just to see what was being done with my amp, I mean....it's not a fucking Dumble, but it's still my amp none the less) He declined, and told me that wasn't a good idea. At this point I'm getting really bad vibes from this guy. He burned up my brand new Groove Tube 6L6 R-2 Svetlana's pretty badly. The logo used to be red...now it's ink black. He comes back downstairs after 30 minutes of doing whatever, and says it's gonna take a while....he thinks the bias pot is bad, and the voltage isn't being regulated....or something of that nature. I keep waiting....and waiting....and finally....he brings the amp back down to me. And he tells me with a real smart ass vibe..."When you decide that you're satisfied..THEN you can leave." Kind of pissed me off, by I let it go. I played the amp for about 20 minutes or so and everything worked ok...sounded decent, but not as good as it did. No smoking or burning going on. I figured everything was cool. So he comes back in the room to remind me to show my ticket to the guy at the front desk so I can pay before I leave. I take it up to the front of the store, but now this service desk guy is on his lunch break, and there's some other lady waiting to be helped. So I'm thinking...($25 for a service fee....sounds like bullshit to me...the way I figure it, he made his $50 dollars off of Fender, at least that's what it said on my reciept) (So I'm thinking...fuck this guy....after all the hassles he put me through)...About that time, one of the other guys at the counter across the store who had been witnessing what was going on with my amp....asked me..."did he fix it?"....I said, "Yeah...I guess so...but he burned up my tubes pretty