thegarehanman Posted October 11, 2005 Report Share Posted October 11, 2005 (edited) Ok, I have a Carvin ValveMaster 100 watt head. You'll have to bear with me as my amp knowledge is close to none. I bought it used with offbrand tubes. It uses 12AX7's(5) for the preamp, and 4 EL34's for the power amp. I'm debating replacing all of the tubes with Mesa Boogie tubes as I've read(harmony central) that it makes a noticable improvement, particularly on the gain channel. The amp can accept either EL34's, 5881's, or 6L6GC's as power tubes. Would there be any difference in the tone of the amp if I used a type of tube other than the EL34's? Also, when I turn the reverb up, the amp starts to hum a bit. Is there anything I might be able to do about this? Perhaps the reverb tank is going on me? Quite honestly, I'm tickled pink about the clean channel. It's one of the nicest clean channels I've ever heard. I don't really use the lead channel, but I'd like to know it sounds good so it's there when I need it. The reverb would be really nice to have. I'm always hesitant to crank it up because I don't want the hum, however minor it may be. I appreciate any advice or experience you can share. peace, russ Edited October 11, 2005 by thegarehanman Quote Link to comment Share on other sites More sharing options...
lovekraft Posted October 11, 2005 Report Share Posted October 11, 2005 Russ, what kind of tubes are in it now? I'm not sure M/B branded tubes would necessarily be an improvement - in fact, they could easily be exactly the same tubes you already have. If the reverb hums, it could be that the tank needs shielding and/or grounding - a reverb tank has a coil in the output side that can easily pick up hum if it's not shielded well (or if it sits too close to a transformer). There's usually some slight hum with reverb maxed even on the best of amps, but if it's enough to be annoying, you might need to check the tank and the cables. Quote Link to comment Share on other sites More sharing options...
crafty Posted October 11, 2005 Report Share Posted October 11, 2005 I'm not as well versed in tube amps as some others here, but it's my understanding that 5881's and GL6GC's are a little "harder and modern" than the EL34. In fact, both Joe Satriani and Steve Vai had Peavey and Carvin take basically off-the-shelf amps and replace the 6L6GC's or 5881's with EL34's and tweak the EQ for a more vintage power response. You don't need to pay any more money for the Mesa name. Just use Groove Tubes, Sovtek, or Svetlana--all quality tubes. Quote Link to comment Share on other sites More sharing options...
thegarehanman Posted October 11, 2005 Author Report Share Posted October 11, 2005 I didn't think MS would really be any more expenxive than groovetubes. I totally forgot about those brands though. Let me check the one's that came with it...I can't see any writing on the preamp tubes, but the power tubes have this purplish/red coating and have a logo that says "JJ" on them. I'll open up the amp tonight to see if I can find anything else; I'll check the reverb tank while I'm at it. Lovekraft, if the reverb tank doesn't have a ground running to it, can I just ground to the case. I was under the impression that the tank is naturally grounded via the rca cables that run to it. peace, russ Quote Link to comment Share on other sites More sharing options...
rob Posted October 11, 2005 Report Share Posted October 11, 2005 JJ's are some really decent quality tubes, if they are shot though, the deffo should be replaced Quote Link to comment Share on other sites More sharing options...
thegarehanman Posted October 11, 2005 Author Report Share Posted October 11, 2005 Oh, ok. I was just hoping I could get some better tone out of my lead channel. I have no clue what brand the preamp tubes are; I may replace those in the near future. None of the tubes are shot though. I could always replace 'em and keep them as backups. I need to check into that humming from the reverb. peace, russ Quote Link to comment Share on other sites More sharing options...
lovekraft Posted October 11, 2005 Report Share Posted October 11, 2005 Those JJs are about as good as it gets without getting into the super-premuim audiphile stuff or NOS. IIRC, most reverb tanks are built with the jacks isolated from the case, but a quick check with a multimeter will tell you what you need to know. If it's not grounded, just tie a ground wire to the case. If that doesn't eliminate the problem, unplug the tank and crank the reverb pot - if the hum is still here, it's a problem on the return side. About those preamp tubes - does the lead channel sound bad, or are you just looking to upgrade? Quote Link to comment Share on other sites More sharing options...
thegarehanman Posted October 11, 2005 Author Report Share Posted October 11, 2005 (edited) Yeah, the lead channel really does not sound good. Like I said, the clean channel is awesome. I use a Visual Sound overdrive/distortion pedal which sounds great, but there's some sort of comfort I feel knowing that the lead channel sounds good also. I can't blame it on any bad tubes. All 5 glow when the amp's on. I guess it could just be poor design. It's just odd to me that the clean channel could sound so good and the lead could sound so "bad." It's not like I'm looking for extreme mesa distortion. I'd be more than happy with a bluesy overdrive. The lead channel just sounds "dead." Testing the tank for ground will have to wait, I won't be home to pick up the multi tester for a few weeks. peace, russ PS A nice feature of this amp is its presence selector switch, but it's just not enough to get that lead channel sounding sweet. Edited October 11, 2005 by thegarehanman Quote Link to comment Share on other sites More sharing options...
ansil Posted October 12, 2005 Report Share Posted October 12, 2005 Yeah, the lead channel really does not sound good. Like I said, the clean channel is awesome. I use a Visual Sound overdrive/distortion pedal which sounds great, but there's some sort of comfort I feel knowing that the lead channel sounds good also. I can't blame it on any bad tubes. All 5 glow when the amp's on. I guess it could just be poor design. It's just odd to me that the clean channel could sound so good and the lead could sound so "bad." It's not like I'm looking for extreme mesa distortion. I'd be more than happy with a bluesy overdrive. The lead channel just sounds "dead." Testing the tank for ground will have to wait, I won't be home to pick up the multi tester for a few weeks. peace, russ PS A nice feature of this amp is its presence selector switch, but it's just not enough to get that lead channel sounding sweet. ← what tone exactly are you looking for. thats a very versatile head. man. they had one at the music store i worked for some time ago. i was going to buy it but i was short of cash at that time. I mean slipknot it isn't . but if its functioning properly it has ample gain. and i found it quite nice. but it depends on what you are looking for. have you checked to see if any of the tubes are microphonic cause if they are it could alter the tone. Quote Link to comment Share on other sites More sharing options...
thegarehanman Posted October 12, 2005 Author Report Share Posted October 12, 2005 microphonic? I've never heard that in relation to tubes Quote Link to comment Share on other sites More sharing options...
lovekraft Posted October 12, 2005 Report Share Posted October 12, 2005 Some tubes can become microphonic, meaning that vibrations outside the glass envelope can cause enough movement in the internal parts to induce a signal in the output. Worst case is an amp that'll squeal uncontrollably when the standby switch is flipped off, but even much less evident problems can cause funky resonances in the preamp. The test is to lightly tap the glass with a non-conductive tool like a chopstick - if the tube rings like a bell, it's microphonic, and will generally need to be replaced fairly soon, since the problem usually gets worse over time. Back to the bad tone - have you pulled out the tubes and cleaned the pins? Even just swapping preamp tubes from one socket to another can change things, and dirty pins and sockets can cause tone problems also. If you wipe/spray the tube pins down with a gentle contact cleaner (just a light coating, not dripping) and plug them back into the socket a few times, it should all be squeaky clean (needless to say, don't go unplugging tubes unless the amp is powered down first). Try all that first, before you invest in new tubes. Quote Link to comment Share on other sites More sharing options...
Paul Marossy Posted October 12, 2005 Report Share Posted October 12, 2005 My vote is for J&J EL34s. Quote Link to comment Share on other sites More sharing options...
thegarehanman Posted October 12, 2005 Author Report Share Posted October 12, 2005 I took all of the tubes out, cleaned the contacts with electromotive a few times(after putting the back in/taking them back out), and I can definitely say I hear a difference. I appreciate the advice. Once I get my multitester back I'll have to check the reverb tank for a ground signal. peace, russ Quote Link to comment Share on other sites More sharing options...
ansil Posted October 15, 2005 Report Share Posted October 15, 2005 Glad to hear that there is a difference in tone. that amp is a good one in my opinion. whatever that is worth. Quote Link to comment Share on other sites More sharing options...
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