New Amp Photo and Schem

Tube or solid-state, this section goes to eleven!
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DougH
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Post by DougH »

http://www.aronnelson.com/gallery/v/Dou ... attWonder/

I've had this finished for a few weeks but just got the chrome knobs.

Haha... I just realized I *still* need to replace that temporary plastic washer on the power switch with a metal one. Oh well...

Thanks to John Lyons for instructions on how to finish the wood. :D

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analogguru
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Post by analogguru »

Nice job... but why 10W-Wonder ? Why not 15W (18W) output ?
How are you satisfied with the gain/overdrive? only one pre-amp stage ?
And finally how are you satisfied with the tricky master-volume circuit ?

analogguru

EDIT: Ah I see now you are using the ECL 82 (6BM8) so only 3 tubes in total and 10W output....
Reminds me to the Hagström 39 (which was based on a mullard application).
http://www.hagstrom.org.uk/Schematics/S ... ematic.jpg
Here is the mullard application:
http://www.bonavolta.ch/hobby/en/audio/ecl82_2.htm
Note the uncommon phase-splitter-stage.
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.

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DougH
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Post by DougH »

Thanks.

The Master Volume works about as well as any other I've tried. The one thing it does is bias the PI colder as you turn it down. This creates more PI distortion which tends to compensate for the lack of power amp drive. I like that aspect of it. In all honesty I usually run it wide open and I rarely use the top-cut control.

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Post by analogguru »

The one thing it does is bias the PI colder as you turn it down. This creates more PI distortion which tends to compensate for the lack of power amp drive. I like that aspect of it.
I was assuming this.

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There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.

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DougH
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Post by DougH »

I forgot to mention- the EF86 preamp provides plenty of drive. I'm pretty happy with the amt of gain and I can get a lot of different sounds with this amp.

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DougH
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Post by DougH »

Just wanted to mention that I found a couple mistakes on the schematic. The corrections have been uploaded. It should be fine now.

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CS Jones
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Post by CS Jones »

Hey, my favorite low watt guitar amp tube! It's about time. Excellent job Doug.

Mine looks like a real bodge job, I know, but I just love the sound of this thing. I actually planned this crappy looking thing out through the whole amp building cycle... A first for me with no intentional clonage... an "am I just full of crap or can I really do this?" moment. I accounted for as much as I could - taken from data sheets to real time measurements...from the power supply through each device through each stage to the output. I
Congrats on yours Doug. As always, yours looks good.

https://img.photobucket.com/albums/v223 ... bm8top.jpg

https://img.photobucket.com/albums/v223 ... inside.jpg

https://img.photobucket.com/albums/v223 ... 8tubes.jpg

Note. Ooops. Sorry... I forgot about the no straight pic req

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DougH
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Post by DougH »

Thanks, Clay. I basically followed the AC15 schematic for the audio, did my own power supply, set up the output stage a la the datasheet. The "tone selector" was inspired by the DC30 rotary switch- since I had the SPDT switch lying around.

Sometime I'll open it up and take a pic of the inside.

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