Thursday, April 28, 2011

Judybox Revival Notes and Comments



I've recently acquired a couple of Judybox amps and I'm well on the way to becoming a self taught expert. Some of my findings are on my blog at http://cornponepapers.blogspot.com which you're welcome to peruse.

It's sort of odd because the reason I acquired the first one was because my wife's name is Judy and I thought it would be cool to have an amp with her name on it. I wasn't expecting much, having heard all the stories, but I can tell you that they are a great bargain.

The first one, which I've named Brownie, sounds a lot different from the second, the Redhead, which arrived here yesterday. The Redhead sounds thin on one channel, and I'm not yet in a position to comment on how much the Bad Betty speaker has to do with it. I've got a few things here to try out, as the Redhead is going in for some remedial work this weekend.

A bit of what I do is to ask what Leo would have done.

I'm in the process of developing a suite of technical information on these amps, and if you have anything available in that line I'd like to see it, including production figures, and maybe contact with the elusive Al Nelson or whoever was part of the original company or the successors. I believe most of these folks were or are in the Austin, Texas area as both these amps came from Texas. Any information on other amps that were built under the Judybox name is welcome, and if you've got one you're entitled to a guest spot here.

They're great bargains right now, and although they mostly seem to look like the assembly was a little hurried, with some product improvements they can be the equal of any handwired boutique amp on the market. Having just finished reconstruction of an older Dr. Z Rx, it doesn't take a whole lot to get there.

Some of the components that were used definitely are third rate and need replacement, and a general reorganization and rationalization of the layout and componentry is indicated.

As I am a part time amp tech and hobbyist, I'm in a position to help you realize the potential of this amp.

Brownie is a case in point. With some work and carefully selected glassware, it's got midrange bark and it does the Fender thing really well-sparkly tone with good balance and a hefty lower end. I expect the Redhead will follow along. The build was a little cleaner and it appears newer. I suspect it was a store remnant because it came from a music shop in south Texas with the hang tags still in place.

I realize a number of people got stiffed and lost money on amps that were never delivered, but I'm not part of that.

Even so, consider this your forum to tell your stories and post your comments.

Stay tuned for further posts as this project metamorphoses. I don't know where we're headed but the lines have been cast off and we're under way.

17 comments:

  1. Just got a Jbox and anxiously awaiting upgrade advise..Not big happy w/ it as is... noisy and thin-
    nasal sounding..

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  2. Hi William. Must need a little fine tuning, maybe in the speaker department. Both of mine sound pretty good, one has a Chinese Celestion and the other has a Bad Betty, maker unknown. Also the components used and build standard of the Revival was not the best-they can stand with some improvement and are just the thing for a person who likes to tinker with stuff. I've put down everything I know or have heard about these amps in this blog-I've got no connection with the original builders and or owners of the line.

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    1. Robert, Took your advise and upgraded the speaker to a cannabis rex ,[ from a Bad Betty], w/ good results...hooked up a cheap biyang digital spring reverb box and it's quite playable...Still very noisy though.

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  3. Both mine are pretty quiet. Preamp tubes? Lead dress? Shielding? Improve overall component quality? Lots of things to work on although one at a time, easy does it.

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  4. Are you still all original glass?

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  5. The original glassware went into my junk box. Because the plate voltage is low on these amps (@360v) I used some vintage Raytheon coke bottle 6L6GBs, a Mullard GZ34 I had hanging around and all NOS preamp tubes. I don't know what's in the Redhead because it's against the wall. Is yours a REvival or a Hooligane

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    1. I've got a red one which I assume is the revival..

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  6. robert,

    i'm a friend of william baker. his judybox has an excessive amount of hum. my experience with hum is very often filter capacitors. shielding COULD be a cause! my instinct is telling me to replace all 3 caps. one has to remove the caps anyway to test them, plus; i do not have an ESR! removal and re-installation is not too difficult! (DISCHARGING!! OF COURSE!!)

    i find it hard to believe it would be caps (or a cap!) in an amp that new, but am willing to try it! the originals look like low-grade caps anyway! i HAVE re-tubed with known, good tubes. (NO improvement!!) if you, (or anyone else) has any other advice, it would be appreciated! i've replaced filter caps on other, older amps (my mcintosh C-20 AND C-26!) and achieved GREAT results! these units, however; are well over 30+ years old!

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  7. Electrolytics are a good place to start. I would recommend some F&T caps to sort of get a baseline on things. Once that's under control you can start looking for things like lead dress, ground loops and the like. It would also be good if the tubes are properly matched.

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  8. -thanks! i'll let you know the status after i re-cap! the tubes i used were a "matched set" i 'borrowed' from one of my amps (ampeg B-15N) that is dead quiet! hopefully, the caps will solve the problem!

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    1. did the caps help .I just got a revival .love the tone but a lot of hum even with nothing plugged in it

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  9. Hey there,
    I just got a judybox revival, and really like the clean tone I'm getting. I'm mostly a jazz player, and was hoping I could get more clean headroom at higher volume so I can use it to play with drummers. I was considering swapping out the 12AX7's for 12AT or 12AU. My arch top is really liking it, but it's just not quite loud enough............. Any tips guys? Thanks in advance........

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  10. They are clean but in order to get any more volume you're probably going to have to mic it. The 12AX7 has more gain than the 12AT7 or the 12AU7, so substituting them would cause a loss of volume. You might also consider getting your local amp mechanic to install a line out and use a power amp of some kind. To tell the truth I have a Godin 5th Avenue Kingpin II that I have not yet tried through either Judybox I own.

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  11. Hey, thanks for getting back. I know there's less gain with the 12AT or AU, but I'm hoping for more clean volume before the amp starts breaking up, which starts happening if I turn it up to anything higher than 10 or 11 o'clock on the volume knob. It seems the amp could be loud enough as it is, but if more of that volume was clean, I would be a very happy man. Those tubes are cheap enough to just get some and try them out. Your Godin will probably sound great through the revival.

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  13. Hi Robert- I just purchased #15 on Ebay. No speaker and red/black cabinet. No tubes either but the price was right. I noticed several issues when I did a quick check out- tag board used improperly to provide good physical connection of many parts, poor grounding scheme, etc.
    I build amps under the Frugal Amps name and I will be posting observations of what I find on the Frugal Amps Facebook page as I go through the amp. Do you want me to also post what I discover here? I was going to maybe use the amp as a donor for a different build but I may decide to spruce it up a bit first and make it available to my customers- depends on how it sounds. For the price I could not resist trying it out.

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  14. They do sort of need a good going over to be ready for prime time. Let's hope that shipping cost wasn't for real-$136.17 is just about $100 too much.

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