# Allen Brown Jug Build



## ampaholic (Sep 19, 2006)

Yep, you read it correctly - "Brown Jug".
This is a new design that David came out with a couple of years ago - his take on a 6G11-A Vibrolux.
He doesn't typically sell this as a kit and as a result it comes without instructions.
Let the fun begin!


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## ampaholic (Sep 19, 2006)

For those that are interested here is the Tonequest review and interview with David Allen.
This is what kind of sparked my interest.
Haven't decided if I'm doing a head or combo. Leaning towards head.


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## Buzz (May 15, 2008)

Where does the California raisin go in the circuit?

good luck!


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## ampaholic (Sep 19, 2006)

Buzz said:


> Where does the California raisin go in the circuit?
> 
> good luck!


I wondered if anybody would notice him!


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## bgreenhouse (Jan 4, 2014)

Amazing. I have a custom vibrolux reverb and love it, would love to try one of the brownfaces out one day. Will watch this avidly. If you ever get a chance to get another kit let me know!

Sent from my Pixel 3a XL using Tapatalk


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## Latole (Aug 11, 2020)

Your post in 2020 ;








Allen Amp Kit Experience?


Hi folks, I'm considering an amp build and I'm curious about the quality of Allen Amplification kits. I'm not really concerned with the quality of the kit (I think the reputation seems solid), but rather the quality of the finished product. From what I read David's amps are well regarded and his...




www.guitarscanada.com






You may have this;


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## ampaholic (Sep 19, 2006)

Latole said:


> You may have this;


I do have this but thank you!
Allen's design is, as the saying goes, "the same only different". Only one channel, the bias board is incorporated into the main board and has external adjustment and test points, a slight bump in filtering, addition of standby switch, etc.
Also he adds his trademark "Raw" control along with one called "Darken".
I have the chassis pretty much together. Next step is populating the board. All the parts seem like good quality - stainless steel chassis, F&T electrolytics, Sozo coupling caps, etc.
I'm not in any hurry as I may also attempt to build cabinets (leaning towards head and 112 cabinet) but then again patience is not my strongest virtue!


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## ampaholic (Sep 19, 2006)

Well, I fired up the Brown Jug last night after going through the initial startup tests. Everything looked ok and I had sound immediately! (and no sparks or smoke!)
After plugging a Telecaster in however I noticed that I started getting a slightly overdriven tone with the volume on 3. It sounded ok, perhaps a bit flabby in the bottom end but after playing a while I thought there is no way this is normal for a 35 watt amp.
All of my voltages checked in the normal range so I started poking around. You can see in the photo there are a pair of blue Sozo capacitors running from the board over to the 5th potentiometer. This pot is a "Darken" control that Allen added to give the user all of the tonal options that were available with the original 6G11-A circuit. The original circuit apparently has a "darkening" capacitor across the plate load resistor in the second gain stage.
Well, I happened to notice that I had failed to trim the lead on one of the capacitors and it was shorting against the pot case.
Trimmed that and POW! - instant, glorious brown Fender tone!
The amp runs quiet as a mouse and has that killer vibrato the brown amps are famous for. Allen's proprietary "Raw" control is really effective and kind of gives you two amps in one. The external bias test jacks are pretty darn handy, as is the external bias pot (with a knob on it!).
So far so good. Now I need to figure out how to get a cabinet made!


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## Paul Running (Apr 12, 2020)

ampaholic said:


> Well, I happened to notice that I had failed to trim the lead on one of the capacitors and it was shorting against the pot case.


The old "cap shorting against the pot" trick...get's ya every time. Good to hear your success.


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## jb welder (Sep 14, 2010)

That's great that you got it sorted out quickly.



ampaholic said:


> The external bias test jacks are pretty darn handy, as is the external bias pot (with a knob on it!).


That can be good or bad. Usually the bias pots are hidden away or locking type so they can't get bumped accidentally. If that happens, you can end up burning through power tubes faster than necessary.


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## ampaholic (Sep 19, 2006)

jb welder said:


> That can be good or bad. Usually the bias pots are hidden away or locking type so they can't get bumped accidentally. If that happens, you can end up burning through power tubes faster than necessary.


I was actually thinking the same thing! I think I'll at least remove the knob which might make it a bit less likely to get moved.


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## Paul Running (Apr 12, 2020)

If you want a fail-safe trimpot, the locking, slot shaft type are an insurance. I will sometimes use a graduated scale, top washer for reference:


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