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Allen 20 watt amp

Rex Everything

Rex Everything

are you Shpongled?
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Well.....I finally got motivated to start on the Allen 20 watt amps I have. I was considering modding the circiut but I've decided to give it ago stock for now. I've completed the recap on one at this time.

All caps were replaced save for one that goes to the extension socket. The carbon comp resistors were replaced with metal film 1% resistors. The red resistors were left for now as they are supposed to have "mojo" to them. Can cap was replaced with a 40uf + 40uf can on top and 10uf underneath.

Fired it up and it was nice and quiet. No red plating and no noise. Listening to 20 minutes or so of music and all is well.

It's been running now for about 40 minutes or so and no issues and it's not hot.

Time to get going on a second so I can hear these guys in stereo

Before:

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After:

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Those look like pretty sweet little amps :yes: nice job on the work :thmbsp: I would love to hear those in a stereo pair as well :D

AB
 
Alison Krauss & Union Station sounding mighty fine. :music:

I'm considering removing the wires to the external socket on the other before moving them to the main tube rig for testing.
 
Put these out on the Chorus II's a Bit ago. Strong amps. I think there is a bit much gain though.

I know on the 75's a lot of folks skip the first stage. I wonder if that would be a good plan on the 20's. Anybody know or have an idea?
 
Looking good there buddy. Perhaps I will get a chance to here them in a bi-amp set up sometime. Thumbs up.
 
I think I'd posted the mod's on the 20's I did here somewhere and removed that first gain stage.
(yah most if not all the Allen amps have quite a bit more gain then needed/wanted for home use)
 
Kegger said:
I think I'd posted the mod's on the 20's I did here somewhere and removed that first gain stage.
(yah most if not all the Allen amps have quite a bit more gain then needed/wanted for home use)
Click to expand...

Hey Kegger, I do have your mods but I decided to keep the amps stock for the time. Now I'd like to remove the first gain stage but need a bit of guidance as I only have the info for the modded amp.

Any and all help will be appreciated.
 
DanO55 said:
Looking good there buddy. Perhaps I will get a chance to here them in a bi-amp set up sometime. Thumbs up.
Click to expand...

Thanks Dan!

Not sure about bi-amped but I'm sure you'll hear them by themselves. Thinking of a possible audio meet in late March.
 
Pretty Simple thing you can do here.. (not much needed but wire)

A quick n dirty approach to the way you have the amps now would be like the following.
Since these have 2 inputs you can leave one original an mod the other, I'd suggest this.

This way the pot and both input gain stages stay intact, and the second eliminates the
first stage and goes around the pot, I'm assuming your using an preamp/external volume.

That way the amps can stay just like original, an have the other input be without 1 stage.
Attached is original, and modded version circled in red pertaining to those changes needed.
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Well...Just wanted to drop in and say I did the first gain stage mod above and am very pleased with the results.

Need to go back and do a few checks on voltages soon but I've really enjoyed listening to these amps. Excellent across the full spectrum. Kinda wondering why I waited so long to work on them.

I'll be posting up on the 75's next as I'm gonna need help getting them going.....
 
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