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drewkiewiet
Bronze Member
USA
86 Posts |
 Posted - 01/15/2009 : 09:33:23
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Hey, I bought a Vox AC15 (my first tube amp) and I have some questions about replacing the tubes. If I stick w/ EL84s (if I go w/ groove tubes or sovtek or something) will I have to rebias the amp? Is it simple to retube an amp if you don't have to bias it or no? Fill me in...my overall goal is just to not screw up the amp. Thanks.
Drew |
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Goran
Double Platinum Member
Sweden
2203 Posts |
Posted - 01/15/2009 : 10:15:23
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| I suppose that this VOX is cathode biased and that you don�t need to bias the tubes, but I�m not fully sure. Hope someone at the forum knows more. |
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FRANZONI
Double Platinum Member
Ireland
3543 Posts |
Posted - 01/15/2009 : 10:38:57
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I reckon no.... as far as i know your vox is class A like my 15 watt selmer and you shouldn't have to re-bias..you will have to stick with EL84's as i don't think this amp can except substitutions on output valves like a some of the bigger Class A/B type amps..i've had good luck with some JJ EL84's in my selmer(basically a 1961 amp similar to a vox AC15 and a big rival of vox's at the time in the europe).... i think www.eurotubes.com is the man on your side of the pond......i used sovtek EL34's in the past with decent/good results.... not too mad about groove tubes..... |
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drewkiewiet
Bronze Member
USA
86 Posts |
Posted - 01/15/2009 : 17:20:12
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| OK...sounds good. I've heard good things about JJ's too. I think I'll order some of them. Now...is it as simple as pull out the old ones and stick in the new ones or is it more complicated? Like I said...I've never owned a tube amp before, so I'm pretty much clueless... |
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drewkiewiet
Bronze Member
USA
86 Posts |
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FRANZONI
Double Platinum Member
Ireland
3543 Posts |
Posted - 01/15/2009 : 20:47:15
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Yep..thats them your AC-15 should take only two them in the power section..the 'other' tubes you refer to are the pre amp tubes...and depending on how old your AC-15 is it might have a rectifer tube as well..(ie the really old vintage 60's ones will have).usually unless the is a problem with noise etc...your pre amp tubes should be ok and last a lot longer than the power amp ones... if your cranking the amp full up every day obviously you will go through power amp tubes quicker...when i was using my little '61 selmer all the time i still got around 2 years out of a set of power tubes so with moderate use they should last a few years..really it depends on the year of your AC-15 to figure how many tubes are in it ..my little selmer takes 9.... and it's only rated at 14 watts because back in the early 60's the tremolo and the rectifer were tube based as well as were some amps with reverb...if yours is one of the later ones chances are the rec is solid state like most other tube based amps these days....if your buy the four tubes on ebay you can keep two as spares....if you don't mind me asking why are you changing the tubes anyway..is there a problem...?.......
P.S. ...is the speaker a blue colour...? |
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drewkiewiet
Bronze Member
USA
86 Posts |
Posted - 01/15/2009 : 22:08:35
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Hey, thanks again!
My AC15 is a 2006 or 2007...so its one of the cheaper chinese ones. Its got the lower end Vox wharfdale in it...not the Alnico unfortunately.
I'm changing them because after the amp has been on for a a 1/2 hour or so it will start making random noises. It's not a hum and it's not loud, but its annoying in the middle of a church service :) I play every weekend for church. Anywho, I told the dude I bought it from and he said it probably needs tubes...I suspect it has the originals in it and if they are 2-3 years old he is probably right.
So I'm thinking I will just replace both preamp and power tubes so I know exactly what I have in my amp. Would the pre-amp tubes be "el84" as well or what? Perhaps they are 12AX7? Can I get JJ's as well? ...actually as I'm typing this I just found a "Vox AC15 retube kit" on eurotubes website. I think I'll just go with that so I get everything from them and its exactly what I need. They seem to know what they are talking about. Here's the link: https://ssl.eurotubes.com/cart/index.php?page=view_products&category_id=130&sub_category_id=131
I'm going with the one up from the last one...the gold pin option. I play pop and rock worship music live so I like a smoother tone. Think I'll be safe with this? It's only 60 bucks for everything and its coming straight from Eurotubes so I know they are brand new and good to go. |
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FRANZONI
Double Platinum Member
Ireland
3543 Posts |
Posted - 01/15/2009 : 22:53:07
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Yep....looks good....for that price you may as well go for gold..!! no pun intended.... ..that guy in eurotubes has some good videos on his site to show you how to change the tubes and other bits and pieces on amps.... worth a look....good luck with the amp the AC 15 is a classic..some people reckon it's the best amp Vox ever made.....even better than the AC 30............... |
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drewkiewiet
Bronze Member
USA
86 Posts |
Posted - 01/15/2009 : 23:24:53
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Alright! Thanks again for all the help! I'm ordering them!
Ya, I like it so far...its a huge upgrade from my crappy 30w Crate solid state so it still sounds wonderful to me. I'm just starting to get a feel for what tones I really like and what what I don't and what amps sound really good and what ones are junk. I'm sure if I upgraded the speaker to an eminence or a celestion it would really open up my AC15, but I'm gonna save my money til the honey moon is over and I can actually tell the difference (ironically I'm engaged so I should probably wait til THAT honeymoon is over as well... ........or maybe I should do it before while MY money is still ALL MINE!) haha..thanks again! |
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drewkiewiet
Bronze Member
USA
86 Posts |
Posted - 01/18/2009 : 00:12:59
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| My tubes are in! Eurotubes is quick! I'm just going to pull the old ones out and stick the new ones in...and see what happens. Bob recommended you clean the ports out so I'm going to do that, but thats it. How long does it take for them to get worn in usually? |
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zerksies
Double Platinum Member
USA
3406 Posts |
Posted - 01/18/2009 : 00:51:06
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| usually you should run them for about 30 hours and then they are broken in. If you can hook up an mp3 player to the guitar jack that will work for a faster burn in |
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DeFrag
Moderator
USA
3409 Posts |
Posted - 01/18/2009 : 04:06:43
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| or you could just play |
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drewkiewiet
Bronze Member
USA
86 Posts |
Posted - 01/18/2009 : 23:39:19
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| I'm planning on just playing on them, but I'm gonna change them today and I've gotta play tues. night and and this weekend and I was just wondering how long it was going for them to break in. I don't believe its the end of the world to play on tubes that haven't been broken in yet??? Again, this is my first tube amp and my first "retube job," so I'm basically clueless. Thank God for self biasing amps! |
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DeFrag
Moderator
USA
3409 Posts |
Posted - 01/18/2009 : 23:49:26
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quote:
Originally posted by drewkiewiet
Thank God for self biasing amps!
+1 on that! |
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FRANZONI
Double Platinum Member
Ireland
3543 Posts |
Posted - 01/19/2009 : 01:23:42
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quote:
Originally posted by drewkiewiet
I'm planning on just playing on them, but I'm gonna change them today and I've gotta play tues. night and and this weekend and I was just wondering how long it was going for them to break in. I don't believe its the end of the world to play on tubes that haven't been broken in yet??? Again, this is my first tube amp and my first "retube job," so I'm basically clueless. Thank God for self biasing amps!
Drop them in and your good to go..... |
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drewkiewiet
Bronze Member
USA
86 Posts |
Posted - 01/20/2009 : 19:58:34
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Thanks again for all the help. I threw them in sunday and was nervous/anxious about turning it all one and everything. I flipped the switch on and as they warmed up the natural hum was going in and out quite dramamtically and I was kind of freaking out. I plugged my guitar in and went to set some levels to play and realized I had unplugged my footswitch (which controls reverb and tremelo...I usually just leave reverb on and tremelo off) and had my tremelo depth on like 10 haha....I turned the tremelo all the way down and then hum was just constant...I don't think I've ever been that happy to hear just a constant somewhat loud humming noise hahaha. Turns out the amp sounds quite a bit better than before and they aren't even close to being worn in.
On top of that, Eurotubes sent me 5 tubes and my amp only takes four...so I was even more paranoid before I turned my amp on...I'm just guessing they sent me an extra...I emailed them and am waiting for a response...
So...the moral of the story is....don't be newbie. Thanks again for all the help out there! |
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Topic |
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tube replacement on Vox AC15CC
