My latest build -- a REAL Lunchbox combo ...

[jbefumo]

http://www.wattwerx.com/amp-models/watts-4-lunch/


I'm really pleased with the sound of this, though it remains to be seen whether it will have sufficient air circulation under continuous usage.  This has been a multi-year project, interrupted by a bothersome bout with cancer, but hell -- gonna take more than a mere disemboweling to keep ME down! ;^)


I just LOVE these 6BM8 tubes.  I figure if air circulation is a problem I'll just move the circuit to a Tweed Champ cabinet/chassis and have a loud 12W combo with only 3 tubes.


Thanks to ALL the folks in this, and a few other forums, who have helped me reach my current level of competence, such as it is, over the past six years or so.


Any comments, critiques, suggestions, etc., will be gratefully appreciated.


and ....


MERRY CHRISTMAS!

[birt]

that looks like a really nice amp :-)


from a designers point of view i would change the appearance a bit.i would put the speakers in the bottom part with grills (round or square but fitting with the style of the box) on the front.
this means the chassis could come so it's partly in the lid. then i would make something that keeps the lid open for just 2 inches when the amp is in use so you have the control panel right there pointing up and forward. for the air circulation you could add some vents on the backside. (take a look at old Philips and Bouyer tube amps)


this could lease just enough room for the power cable and instrument cable under the lid when you travel with it. the only moment when you would open or close it completely is during setup and travel.


but that is just esthetics ;-)

[sluckey]

I really enjoy seeing projects like this.

I'm puzzled by your tone stack switch. It seems that when the Fender position is selected, V2B grid loses it's dc resistance path to ground which makes biasing V2B impossible. Do you have a resistor for that grid that's not shown on the schematic?

[jbefumo]

Thanks -- good suggestions!


Have since disassembled it, as it was just too tight in there for easy maintenance.  Thinking of a lower-power circuit using just one single 6BM8.


Joe

that looks like a really nice amp :-)


from a designers point of view i would change the appearance a bit.i would put the speakers in the bottom part with grills (round or square but fitting with the style of the box) on the front.
this means the chassis could come so it's partly in the lid. then i would make something that keeps the lid open for just 2 inches when the amp is in use so you have the control panel right there pointing up and forward. for the air circulation you could add some vents on the backside. (take a look at old Philips and Bouyer tube amps)


this could lease just enough room for the power cable and instrument cable under the lid when you travel with it. the only moment when you would open or close it completely is during setup and travel.


but that is just esthetics ;-)

[jbefumo]

Thanks!  Honestly, will have to go back and look at what I planned versus what I posted versus what I actually did -- will get back on that -- just don't want to derail my steam-powered train of thought just now ....

I really enjoy seeing projects like this.

I'm puzzled by your tone stack switch. It seems that when the Fender position is selected, V2B grid loses it's dc resistance path to ground which makes biasing V2B impossible. Do you have a resistor for that grid that's not shown on the schematic?