#124 and Matching 112 Speaker Cab

[ChrisM]

About two years ago I built a #124. At the time I finished the build I didn't have much time to tweak it, build a head cab for it and get a speaker cab for the amp.

Over the last two years I managed to build a head cab (two summers ago) and this summer I built a 112 cab for the amp. The last week I have had time to tolex the speaker cab with my winter break starting. Over the past few months I also got to look back on the amp, fix a few errors and tweak it a bit.

The build is fairly standard. Minus a few things...
- 50W output section
- 3 way bright switch, polystyrene caps. 110pF-off-50pF
- Correct polarity on presence cap
- Audio taper on both Level and Ratio controls
- Glaswreck's PAB mod, 470K+33nF in series with 22M PAB resistor
- 5.6K MF NFB resistor, using 8R load
- 350K OD trimmer set 96.9K from wiper to ground

Voltages spot on, 437V on 6L6GC's plates. 286V/294V on the PI. 190V on clean and 200V on OD.

Running Winged =C='s in the output section now, biased around 48mA. Liked these over the TAD, Ruby and NOS JAN 6L6GC's I tried. Gotta play with the bias a bit and find the sweet spot.

- V1 is an old RCA 12AX7
- V2 is a Mullard reissue
- V3 is a 7025 pull from an old BF Twin
Gotta swap some tubes a bit more and really dial in the tone and get her singing. Should be fun, looking forward to this!


The speaker cab is a 112 ported back cabinet. Built from baltic birch with box joints. Running a 12" Eminence Delta Pro in it.


As for the tone, so far so good! #124 is defiantly a great amp for strats (all I really play). Very sweet tones and nice and balanced too. Beautiful rich clean tone. And the OD just rips, super smooth yet just enough bite. I really think the slightly attenuated high end of the Delta Pro helps this setup.

Anyways here's some pictures...
[IMG:763:1022]http://img.photobucket.com/albums/v610/ ... es/1-2.jpg[/img]

[IMG:763:1022]http://img.photobucket.com/albums/v610/ ... es/2-2.jpg[/img]

[IMG:763:1022]http://img.photobucket.com/albums/v610/ ... es/3-1.jpg[/img]

[IMG:763:1022]http://img.photobucket.com/albums/v610/ ... es/4-1.jpg[/img]

[IMG:763:1022]http://img.photobucket.com/albums/v610/kurtlives/5.jpg[/img]

[IMG:763:1022]http://img.photobucket.com/albums/v610/kurtlives/6.jpg[/img]

[IMG:763:1022]http://img.photobucket.com/albums/v610/kurtlives/7.jpg[/img]

[IMG:763:1022]http://img.photobucket.com/albums/v610/kurtlives/8.jpg[/img]

[amplifiednation]

Chris,
Those look great. I have heard good things about the Delta pro! Great looking build on both amp and cabs!!

Taylor

[Structo]

Nice looking build and speaker cab Chris.

[Bob S]

Beautiful build Chris.
Must get back to finish up mine in the new year.
I'll be happy if it looks half as good as that.
Have Fun !

[dcribbs1412]

Congrats on a great looking build
nice voltages...I like old pre tubes also.
I might try raising my bias...I'm running my wing c's around 37ma
I have this same chassis for a future build, interested in how you mounted the chassis in the head cab.
Thanks for sharing


Darin

[Structo]

I find the Dumble amps like a cooler bias.
At least for my taste they do.

I have both a 50w and a 100w with 6L6 and I bias them both around 32-34ma.

[ChrisM]

I do tend to like the hotter bias. I know these amps do like the lower bias setting so I do still want to mess around with that. I just find a hotter bias provides a richer, warmer more interesting tone. Well that's just me though.


Chassis is held in place by "Twin" chassis straps. Since the chassis is deeper than a Twin the normal bolts do not work, they are too short. I had to go out and buy new #10 bolts that are 4" I think.

Then of course I had to carefully measure and drill four holes for the chassis straps and bolts.