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(new) Valve Junior head noisy problem

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  • #1

    (new) Valve Junior head noisy problem

    Hi, Im new to this forum so Gooday to you all. My Q concerns my spanking new Epiphone Valve Junior head, which ain't sounding right to me: Ive built a cab with an Eminence 75w 8ohm in, but Im getting low-level noisy crackles which spoil playing at low volume; it doesn't increase with volume, is there with/ without guitar plugged in and starts after warm-up~ 20 seconds. Im also getting an irritating hum too (not buzz, more a 'mainsy' drone). Ive checked hook-up lead and mains plug both good. Any ideas/ help welcome- cheers. Captain
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  • #2
    If it's new I would return it.You'll probably void the warranty if you mess with it.
    Mike
    http://www.tonezoneonline.com

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    • #3
      Have you tried another guitar and speaker? The problem may not be the amp at all. g/l

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      • #4
        Originally posted by John_H View Post
        Have you tried another guitar and speaker? The problem may not be the amp at all. g/l
        Im sure the prob is the amp, or dirty mains even(?) without any guitar lead plugged in its there, and a new spkr it is too (not likely to be this Im told by Uk shop-Blue Aran). Ive also redone a quality connecting lead- still same.. if Id bought from a local store Id pop it back, but it was sent to Uk from Germany (Thomann, reputable store) and as Ive opened it just to peep & without touching any component, Its not so simple to return.

        Cheers, Captain.

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        • #5
          Maybe it was shipped by "Dropkick Express Parcels" and took a beating that knocked some of the valves loose or even damaged them. That's what the crackling suggests. The hum is probably normal as it's a single-ended amp without negative feedback: that's what http://www.valvejunior.com/ says anyway.

          Check the valves are all firmly in their sockets. Also try tapping them when the power is on, a valve with loose bits inside should give loud crackles through the speaker. You can swap valves of the same type around to track down a bad one too. (edit: that's not any help given that the Valve Jr. only has two tubes in it and they're different kinds!) All without voiding the warranty hopefully.
          Last edited by Steve Conner; 11-14-2006, 02:18 PM.
          "Enzo, I see that you replied parasitic oscillations. Is that a hypothesis? Or is that your amazing metal band I should check out?"

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          • #6
            Thanks- good advice. Although Ive not tinkered with a valve amp, I do have my suspicions that it could be a dodgy valve as you say. It did arrive with one wee bash to the packing.. Another cautious peep revealed no obvious loose things, or dirt in any sockets etc. I also tried a 4 ohm car spkr which sounds exactly the same too ruling out speaker issues. Ill see if Thomann are willing to send a valve replacement for a check- thanks for the help.

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            • #7
              Steve- correct you were- one dodgy el84 valve. Trying to get a replacement from Thomann; like blood out a stone! Thanks for the replies folks. Captain.

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              • #8
                Originally posted by The Captain View Post
                Steve- correct you were- one dodgy el84 valve. Trying to get a replacement from Thomann; like blood out a stone! Thanks for the replies folks. Captain.
                Hey- I was going to suggest that you replace the crappy tubes that Epi usually puts in their amps (bottom-of-the line EH for the ones I've bought here in the US).

                Have you been able to locate a schematic for the Valve Junior head?

                With the mods I did to my Valve Junior combo amp, everybody wants to steal it from me when I'm not looking!

                http://www.blueguitar.org/new/schem/..._lp_jr_amp.pdf

                I put in a Jensen ceramic 8" speaker, which worked here much better than the pricier alnico. I have a few more Valve Juniors to rebuild and the next one might be basically the same but with a pot on the grounded end of the bridged-T. Or not... I may keep the design the same so I can keep one amp in my trunk and one in my living room.

                I'd have to look but I think I put a GT reissue Mullard 12AX7 for the preamp tube and a decent EL84 for the power tube.

                Steve Ahola
                The Blue Guitar
                www.blueguitar.org
                Some recordings:
                https://soundcloud.com/sssteeve/sets...e-blue-guitar/
                .

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                • #9
                  Nice one- I cant do pdf things tho! argghh.. I/my pc just cant do it for some reason- F&&k knows why -its a laptop?! Im going for a jjel84, and sticking with the sovtek 12ax7 I think. The epiphone forum has unearthed reams of mod stuff just this last hour for me (specifically Mike..); interesting ideas on pots and .022 cap changing. My Vj sounds like a muddy old dog with my ep sg/ gfs 'fat paf' pickups. I must smell solder asap.. cheers Captain

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