blackoak
1 post
Apr 07, 2010
12:47 PM
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I have an opportunity to purchase a 1960 Fender Vibrolux at a reasonable price. Is this a good amp for classic chicago Blues? Are ther mods that might improve the sound????
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Bluzdude46
583 posts
Apr 07, 2010
1:39 PM
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Look up the tube compliment I think changing some of the pre amp tubes may make it a bit friendlier. But if it's in good condition you can't go wrong with vintage Fender tube but I admit I'm not familiar with that box. Tho' I know someone who played an early 60's Vibrolux and made it work. Make suure the cabinet is solid not soft in spots or weak joints. check the paper tag inside to verify it is what it is.. If you change out pre amp tubes you may have to have it rebiased.
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The Original Downtown Philadelphia Fatman... Accept No substitutes!
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blackoak
2 posts
Apr 07, 2010
7:53 PM
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Thanks so much for your input. Does anyone know what tubes I should use?
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Tuckster
461 posts
Apr 07, 2010
8:02 PM
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I've played through a buddy's mid-60's(?) blackface. Aside from being too hot for harp,it had a killer sound. Try a 12AY7 in V1 to tame the gain. I don't know a lot about it,but that might be a very collectible (read:$$$$$) amp.
Last Edited by on Apr 07, 2010 8:19 PM
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Sam Pai Kenpo
17 posts
Apr 07, 2010
8:19 PM
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I'm pretty sure James Harmon uses the Vibrolux and also a pre-amp.
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Joe_L
139 posts
Apr 07, 2010
8:35 PM
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If you modded an early 60's Vibrolux, you would kill it's collector value. That amp is worth some dough, if it is original.
James Harman used a Vibroverb. That's a different amp.
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Ev630
237 posts
Apr 07, 2010
11:59 PM
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Stock, with the tube set up from the factory, that amp will be stellar for harp.
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blackoak
3 posts
Apr 08, 2010
2:03 AM
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Thanks everyone,once again i appreciate the input.
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Bluzdude46
585 posts
Apr 08, 2010
7:21 AM
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Sorry I disagree, extra pre amp is another stage to gain feedback, and the tube set up from factory would be too hot to crank it up at all. Changing tubes even if re biasing is an adjustment not a Modification and does not hurt, but actually preserves a Vintage Amps value buy making it run better with a Mic, with less feedback. Guitar Amps were made for guitar not microphones and are set up for just that.
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The Original Downtown Philadelphia Fatman... Accept No substitutes!
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5F6H
56 posts
Apr 08, 2010
8:33 AM
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The 5F11 Vibrolux is pretty similar basically to a 6G2 Princeton, only half the 1st 12AX7 is used as an input/gain stage, the other 12AX7 is the phase inverter. 6G2 normally sound fine with 12AX7 in both positions, that's not to say a lower mu preamp tube won't help if you have a really strong output mic.
Preamp tubes are self biasing in every amp I can think of, rebiasing is not an issuewhen changing/subbing them. Power tubes, in fixed bias amps especially, should ALWAYS be biased/checked on installation, as Bluzdude says.
The tweed Vibrolux schem shows relatively low input loads at the jack (68K), a 1-5Meg input resistor may help. Biasing the output tubes to "just enough" plate current may help curb feedback (17-20mA), you'll know if you go too low, the tone will go dry & raspy, if so bump it up a few mA. A simple mod to try, and that is easily reversed, is to remove the 500pf bright cap between the volume & tone controls, this stops a degree of feedback inducing high end being bypassed around the volume pot. Other than that, they are pretty simple amps and scope for mods is somewhat limited/heading into the territory of diminishing returns.
If the amp is an original 1960 then a professional service & recap (filter caps, bias & cathode bypass electrolytics, not tone & coupling caps unless specifically identified asa problem) is a must if you're going to play out (not particularly expensive on an amp like this), a 3 prong AC cord will stop you shrieking, jumping about & cursing, like you would if you plugged a 2 prong in the wall the wrong way round & were subsequenty shocked!
Tweed fenders, & the brown/blonde amps were all designed to have microphones plugged into them (PAs in the modern sense didn't appear til late in the 60's, 50's tube PAs were just budget tube amps with less headroom than an equivalent Fender). Some stock Brown amps are as good a harp amp as you will find. It was really with the BF amps that the voicing was pushed more to suit guitar specifically. The Normal channel on BF (& later) Fender amps is throwback to the old "mic" channels. In fact, in a small/medium sized venue it's perfectly feasible to use a Fender Twin for vocals, with a lo-z PA mic & impedance transformer.
Last Edited by on Apr 08, 2010 8:34 AM
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strawwoodclaw
7 posts
Apr 08, 2010
8:36 AM
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I agree with EV630 it should work fine for harp as it is how far you can turn the volume dial up is not important, with a HIZ mic it will be loud enough on 2 - 4. Change the ax7 to au7 takes a way a lot of the amps oomth you can turn the dial up full but it wont have the same amount of Mojo - I had my American Bulldogs balls removed (not my idea) It might of chilled him out a bit but it has taken away his oomth ,it's a similar thing. A friend of mine uses a 60s Vibrolux & he loves it for Blues Harpin'
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Bluzdude46
586 posts
Apr 08, 2010
9:10 AM
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Well I agree changing to 12au on both would take the balls out of the amp changing 1 to a 12ay or 12au would allow you to feed the pre amp more for better break up.
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The Original Downtown Philadelphia Fatman... Accept No substitutes!
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Joe_L
142 posts
Apr 08, 2010
9:15 AM
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A lot of the old fenders had 12AY7's in the first preamp socket.
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Bluzdude46
588 posts
Apr 08, 2010
9:20 AM
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Yea, I looked at a paper label picture for a 60 vibrolux it said 12ax7. If they are single pre amp tubes I keep them at 12ax7 for more then 1 pre amp stage I usually change 1 down in gain. But it has a good rectifier tube for harp
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The Original Downtown Philadelphia Fatman... Accept No substitutes!
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5F6H
57 posts
Apr 08, 2010
9:21 AM
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Joe L wrote: "A lot of the old fenders had 12AY7's in the first preamp socket." Sure, but not the 5E/F11 Vibroluxes. A 12AY7 will work in the preamp socket (as will any of the 12A#7 tubes)...it may have a detrimental effect on the tremolo though? Obviously only a problem if you intend to use that feature.
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Joe_L
143 posts
Apr 08, 2010
9:23 AM
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If it has a 12AX7 in it, then I would just play it and hope the value continues to go up.
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blackoak
4 posts
Apr 08, 2010
10:57 AM
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Lots of great info on the vibrolux, thanks very much.
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