The re-issue '63 Vibroverb uses a diode stack in lieu of a GZ34 tube rectifier. There are likely other (more minor) detail differences as well. Frankly, this 20-year old amp has done extremely well and has earned a trip to an "amp spa", to be pampered and coddled by real professionals who know its landscape and can return the amp to full performance specs.

JMO, YMMV

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY

The way I look at it,If your EQ went too.It might be the AC running in your house.I've killed a sub and almost killed a bassman 60 with the horrible power running in my house.Pedels don't like too much power,and they don't like too little power.Now I'm no amp expert,and your amp is older than me But that may be your problem.all I know is things that suck a lot of power or suck very little power don't like being under or over powerwd.

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I LIKE PIE!!!!!

IF I DO SOMETHING STUPID,DON'T SAY A WORD...

I don't know about that super kid,but it's possible....my voltage coming into the house is around 125vac. per leg.
That's always been a concern to me with my vintage amps that were designed to run at 117vac. and some that were even lower than that.I just got a voltage limiter from a company that will drop your line voltage either 6v or 12v going into the amp......but with newer amps that were designed to run on higher volatges you won't need it.
I'm with Arjay...it needs to see a pro.

I could tell it was a diagram for the original Vibroverb, because of the tube rectifier and the wires to the ground switch; the reissue has a solid state rectifier and the ground switch is a dummy, for appearance purposes only (no switchable ground needed for a power cable with three prongs). The printed circuit board is the third difference between the two.


That is an amazing talent; it might get you some money on America's Got Talent or a good position as a spokesman for a large corporation! (just kidding!)

If I can't find a bad/microphonic tube...

It looks like my baby's going in the shop...now I've gotta find one that's worth a bean up here in Texoma...

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Good Vibes To Y'all!



Screamin' Armadillos
Texas Roadhouse Music
Guitar/Slide Guitar/Harp/Vocals

hopefully I haven't gotten my head up my ying/yang yet!
Keep us posted armadillo...I'll bet that's a great sounding amp....hope it's restored to it's full potential.

Here's a site SA that may shed some light on the problem you have, worth a look at anyways
http://www.geofex.com/ampdbug/ampdebug.htm
hope you get it up and running soon

After tapping the tubes/valves/whatever and finding no distinct issues (i.e., nothing indicating an individual tube or tubes were microphonic), I have decided to send her for some "R&R"...

On a side note, I have discovered that it is possible to change the preamp tubes for just one of the channels to set that channel up for harp...it appears that I can have the "NORMAL" channel to be harp, and "BRIGHT" channel to be guitar.

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Good Vibes To Y'all!



Screamin' Armadillos
Texas Roadhouse Music
Guitar/Slide Guitar/Harp/Vocals

Run a craigslist request for a good amp tech here http://texoma.craigslist.org/msg/ worth a try. Got a couple great ones here in Tulsa. Hope this helps..........Mike

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The blues ain't nothin but a good man feelin bad.

UPDATES:

I've learned more about harp tube amps in the last few days than I have learned in the previous twenty years.

I think I've always "lucked out" (although I don't believe in luck) with my amplifier choices. Of all the tube amp I've owned in my lifetime, only one (a silverface/master volume Fender Twin Reverb) sounded bad for harp (but to be fair, I didn't like it much for guitar either; it was too loud and it was heavier than my cousin-in-law's right flank ).
With such fortunate circumstances, I never really investigated what tubes (pre-amp and power tubes) do differently for guitar or harp...because I was mostly satisfied with my tone.

But after a recent gig where I played harp all evening (something I hadn't done in years), I decided to start investigating all the "hoopla" regarding an amp set up specifically for harp vs. guitar.
Added to the equation the feedback issues that have started creeping up, necessity forces me to learn more.
So here's what I've learned (and this will undoubtedly be refined and changed as my curiosity and knowledge grow):

First of all, for harp, a 12AY7 preamp tube (as opposed to the stock 12AX7 usually put in there) will help prevent (but not entirely eliminate) the feedback issues naturally inherent with a distorted or overdriven microphone. I can replace the 1st preamp tube in my '63RIVV and it will go a step closer to making the "NORMAL" channel the "HARP" channel. It pushes about 30% lower gain, and it will still be nasty and growly, as harp players want their amps to sound.

The second thing I had heard about years ago, but I had another tech (whom I no longer trust as much as I previously did) say, "No, that sucks, it won't work, don't do that..." so I never pursued it.
I can replace the normal 6L6 tubes (standard in the '63RIVV) with 6V6 tubes, tweak the biasing (which will require some modification, since this amp is set up as a "set bias" amp) and it will lower the wattage by about 40%...which means I can get a bit more breakup at a lower volume (I don't expect it to sound like I have my TS9 on MAXIMUM, but it should overdrive much earlier than the current ear-bleeding level required).

Combine the ability to overdrive at a lesser volume with the lower gain (12AY7-injected) channel, voila! I have a better harp amp...but the beauty of it is, the "BRIGHT" channel won't sound significantly different, other than breaking up at lower volumes, too, which is a good thing to me...as much as I love pedals (anyone who's seen my Big Ol' Pedalboard of Sonic Bliss can attest to that), I would like to be less dependent upon them for overdrive.

Third thing: In setting up by pedalboard for guitar, the noise gate/supressor should be one of the last things in the signal chain (before echo-o-o-o or delay-ay-ay-ay) to knock down any noise created by the conbination of pickups + pedals.
With harp, to help prevent feedback, put your noise gate in front of any pedals you might have going with the harmonica microphone...by gating the noise (caused by the microphone) before it's boosted/effected/processed, it greatly knocks down feedback issues. This helped reduce the amount of feedback I'm currently experiencing, but it hasn't "fixed" the issue, either (which is obviously an issue with my amp).

Consequently, there will be a thread in the near future about the re-configuration of my pedalboard...this will include my assessment of the first pedal I ever bought (last week) that was engineered with harmonica mics in mind...

Final bit of knowledge I did not know: If a reverb tank is failing (tanking? ), it can cause some of the feedback problems I currently suffer. I have noticed it's worse when the reverb is on, but since I rarely use reverb, I thought nothing of it. The tech I spoke to today said it will affect the amp even if I have the reverb set to zero and turned off. This will be investigated at Chez Armadillo this evening, after homework and dinner.

I'll keep you updated--whether you want to be updated or not!

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Good Vibes To Y'all!



Screamin' Armadillos
Texas Roadhouse Music
Guitar/Slide Guitar/Harp/Vocals

I have a '63 Vibroverb RI that is slightly modded, and have never had a problem with it. Back when I had my original tweed 4x10 Blue Deville, I read a article in ToneQuest from Mark Baier of Victoria Amp about installing FREDS in guitar amps http://www.tonequest.com/askour.htm (scroll down the page).

I called and talked to Mark, ordered a set for me, and a set for my friend that owned the Vibroverb. I had the amp tech at Abell Audio Pro Audio Repair http://www.abellaudio.com/ install the FREDS and he was amazed, he commented that the amp sounded more 'musical'.

My friend that owned the VRI, was really impressed as well. He later wanted to sell the VRI, and I was tired of lugging that BD (plus I had brought a Cyber-Twin) so I sold the BD and brought his VRI.

I'm not sure if Mark still has any FREDS, but you can contact him to see.

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Tony Houston

Hi. I'm Screamin' Armadillo and I'm ignorant. I thank everyone here who supports me and give me ideas. I'm also glad there were some people nearby who could help me in person.

I was resigned to the fact that I was going to have to drive a round trip of 175 miles to get my amp checked out--probably twice, because the guy wouldn't be able to fix it in one day unless I paid a gouging upcharge.

But just for grins, I went to the small guitar shop here in town and asked if they would let me try a 12AY7 preamp tube for the Normal channel of my 63RIVV and if they had any ideas about the issues with this amp.

The shop itself did not have a 12AY7, but one of the guys had a 12AU7 (even less gain than a 12AY7, which might work well for my harmonica needs) in his personal stash. He didn't want to sell it to me, but he said he'd be glad to let me try it out. I switched it out, and instantly, there was no feedback on that channel--even with my nastiest harp mic (1940s Astatic A200) and my new Lone Wolf Blues Harp Break harmonica overdrive pedal (there will be a different thread regarding that pedal later). Problem solved, at least partially.

The other problem was the feedback issues with guitar. I mentioned that the squeal came out worse when the reverb was turned on. Well, I learned one thing and re-learned another:
First, when you check if a tube is microphonic, you really have to whack that sucker...I was politely tapping the tube, and hearing nothing out of the ordinary.

Second, since I rarely use reverb (my first two amps either didn't have it or the function didn't work properly), I rarely notice when there is no reverb on my live sound...my tone, "in my head" is rather dry and spanky. On my 63RIVV, the reverb only functions on the Bright Channel...something I knew, but I forgot (due to the fact that the knob is rarely turned above "2" and the button is rarely stepped upon).

There was an old man working there, and he was the one who got down and started whacking tubes--when he whacked preamp tube #2 (from the right-hand side, which is the preamp tube for the "Bright" channel), the "sproing/ting" of a microphonic tube was evident, and when he turned the reverb way up and did it again, the sound was more akin to "SPROING/tinggg". The feedback was worse because of the fact that the tube was microphonic AND any exaggeration of that channel (whether it was volume, tone knob(s) or reverb) made it considerably worse..

First, we tried putting the 12AX7 tube from the Normal Channel into slot #2, but it was microphonic (which we expected). They had two 12AX7 tubes in stock, and the first one we plugged in (a Groove Tube, by the way) was as microphonic as either of my tubes...I had a brief moment of, "Oh, crap, what if it isn't the tube, and it's a problem with the amp?" We then placed a Sovtec tube into the slot, and it was perfect--my old amp was back!

All the other preamp tubes were ok, no microphonic properties.

The old man said, "Well, it looks like you're fixed up. You got your harp channel and you got your guitar channel like you wanted!" I reminded him that his younger compadre (who owned the 12AU7 tube) would not sell it to me (I said this without malice or irritation), and the young guy had pity on me and sold it to me.

12AX7 tube: $14
12AU7 tube: $14
Realizing you're an idiot and it's nice to have friendly, helpful people with more knowledge than yourself (both on the internet and in person): Priceless

Thank you for all your help and putting up with my long ramblings...

PS--I'm still going to track down a 12AY7 tube for my Normal/Harp channel, to see if the higher gain level (higher than 12AU7 but less than 12AX7) would give me a bit more grit without bringing back the squeal monster...

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Good Vibes To Y'all!



Screamin' Armadillos
Texas Roadhouse Music
Guitar/Slide Guitar/Harp/Vocals

Everything is older than you, Superkid...I've got boots older than you!
That's ok, when I get old and doddering (next year) you'll still be young.

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Good Vibes To Y'all!



Screamin' Armadillos
Texas Roadhouse Music
Guitar/Slide Guitar/Harp/Vocals

Glad to hear everything worked out really well for the vibro-verb and you as well, goes to show if you just poke around a little bit usually something interesting and educational pops up. I'm interested in if it's possible for you to play both channels at the same time ...ie. can you get harp and guitar going at the same time on that amp?

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Common sense and a sense of humor are the same thing, moving at different speeds. A sense of humor is just common sense, dancin'