L-pad attenuator

[dimefan90]

I want to build a simple attenuator for my 40 watt valve amp and i need to know if this is the correct L-pad to use.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300481745035&ssPageName=STRK:MEWAX:IT

[bluesman1218]

IMHO this is too simple a solution. For one thing, you don't know how much attenuation your dialing in and anything over 12 dB will degrade your tone. L-pads are generally used in PA/distributed sound systems.

[dimefan90]

L-pads are commonly used in attenuators for low wattage amps.

http://www.guitarpug.com/2008/07/diy-wattage-attenuator-box/


I would just be using one that is rated for a higher wattage.

[Hides-His-Eyes]

200W sounds good. Don't attenuate/crank too much or you'll @#$% the output tubes.

[Johan]

I've used one of those on a 50watter and it works well. one thing thou...it get HOT, so dont rely on just the solder, but make sure you wrap the cables around the tabs before you solder them. and make sure the "pot" gets the hot air vented. mount it on a bracket not in a box.
J

[bluesman1218]

I've used one of those on a 50watter and it works well. one thing thou...it get HOT, so dont rely on just the solder, but make sure you wrap the cables around the tabs before you solder them. and make sure the "pot" gets the hot air vented. mount it on a bracket not in a box.
J

Heat will definitely be an issue, that's one reason I don't use L-Pads. In any event, for this version, use an extruded aluminum enclosure with ribs (for holding a pcb), mount your L-pad to a side with ribs, applying a layer of silicon heatsink compund between the pad and the case. That will give you a better mechanical build. Good luck.

[ayayay!]

I've used one of those on a 50watter and it works well. one thing thou...it get HOT, so dont rely on just the solder, but make sure you wrap the cables around the tabs before you solder them. and make sure the "pot" gets the hot air vented. mount it on a bracket not in a box.
J

Heat will definitely be an issue, that's one reason I don't use L-Pads. In any event, for this version, use an extruded aluminum enclosure with ribs (for holding a pcb), mount your L-pad to a side with ribs, applying a layer of silicon heatsink compund between the pad and the case. That will give you a better mechanical build. Good luck.

Great advice.  May as well drill some good looking holes in it while your at it for added ventilation.