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L-Pad Attenuator

Started by sirbergersworth, January 09, 2013, 02:54:13 AM

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sirbergersworth

I built this L-Pad attenuator yesterday. $15 8ohm/100watt L-Pad, a few $2 switches, jacks, couple of caps, wire from a broken computer power supply and a $5 aluminum enclosure.
I installed a true bypass switch on-off-on bright switch with a 4.7uf cap on one side and a 10uf cap. Both non polarized caps. All 18 gauge stranded wire. I haven't drilled holes for the venting yet but from my tests with my amps I will not need a fan. I wouldn't use this with anything over 15-20 watts.

I haven't decided on a paint job or decals yet. Any ideas?





I plan to use this with my vht special 6 head for very quiet bedroom levels (kids right above sleeping)
Tested last night and today and it works good. Worked just as well with a tweaker15 to be able to hit its sweet spot and not irritate the neighbors.
With the s6 it was very nice. I will be able to practice with a real amp instead of sims (don't own amp with headphone out)

Thanks for allowing me to brag.

Rob
"Comes a time when the blind man takes your hand, says, "Don't you see?"
-Robert Hunter

Guitar Master

I got the same exact switches the other day! The switches look cool

stecykmi

wow very cool project, i bet a lot of people are gonna be interested in this one.

Is it your design? source on the attenuator?

sirbergersworth

Quote from: stecykmi on January 09, 2013, 05:35:41 AM.
Is it your design? source on the attenuator?

Not my design at all. I just googled "DIY attenuator" and found this page.
http://guitarprojects.weebly.com/diy-attenuator.html
i added two different bright switch options. I guess that's a mod ;-)
Very cool, cheap and useful project.
"Comes a time when the blind man takes your hand, says, "Don't you see?"
-Robert Hunter

sirbergersworth

L-pad is here
http://www.parts-express.com/pe/showdetl.cfm?partnumber=260-262

There are other l-pads on parts express as well. Don't pay attention to wattage. These are intended to be a tweeter control after a crossover, etc.

One guy used a stereo 8ohm 100 watt and wired to switchable to 8.or 16 ohms. I can't find that link at the moment.
"Comes a time when the blind man takes your hand, says, "Don't you see?"
-Robert Hunter

alanp

The layout for Ken Fischer's Trainwreck Airbrake is floating around the internet.
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Stomptown

very nice! I would love a DIY attenuator but I need 40 watts! Does anyone know how to build a Dr Z Brake Lite clone?

Ettore_M

Quote from: Stomptown on January 09, 2013, 08:18:14 AM
very nice! I would love a DIY attenuator but I need 40 watts! Does anyone know how to build a Dr Z Brake Lite clone?

I think the Dr Z Brake is based on the Airbrake (the one about alanp posted above).. You'll find it on the net. A little more complicated than the L-Pad attenuator, but it's supposed to sound better...

Hector
" I would first try what I call The American Approach, which is simply this: "If X is good, then 2X simply HAS TO BE twice as good."  ;D "
- Culturejam

raulduke

Nice build dude.

I would give it a nice hammertone finish.... but then I would say that wouldn't I  :D

An amp attenuator has been on my 'to do' list for ages now. Thanks for posting the links/info!

pryde

Nice build. I whipped up a simple LPAD for my 5E3 Tweed and it works great. Used a 3.3uf cap on the attenuator to retain some treble in the signal.

Haberdasher

I need something like this for my tweaker 15 head.  Thanks for the links sirbw!
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tenwatt

Quote from: Stomptown on January 09, 2013, 08:18:14 AM
very nice! I would love a DIY attenuator but I need 40 watts! Does anyone know how to build a Dr Z Brake Lite clone?

Try this:

http://ampgarage.com/forum/viewtopic.php?t=2402&postdays=0&postorder=asc&start=0
Not too bright....

sirbergersworth

Quote from: Haberdasher on January 09, 2013, 01:19:39 PM
I need something like this for my tweaker 15 head.  Thanks for the links sirbw!

It works fantastic with my tweaker 15.
Just remember that you still have to make sure you have a speaker plugged into the attenuator so you don't blow your amp transformer.
"Comes a time when the blind man takes your hand, says, "Don't you see?"
-Robert Hunter

sirbergersworth

Quote from: raulduke on January 09, 2013, 09:57:27 AM
Nice build dude.

I would give it a nice hammertone finish.... but then I would say that wouldn't I  :D

Thanks for the complement. I think I will do hammertone copper finish with a lawyer clear coat to make it alligator like crazy. Nah, that will take 4 weeks to cure out.
"Comes a time when the blind man takes your hand, says, "Don't you see?"
-Robert Hunter

hammerheadmusicman

This looks good man! I recently built a DrZ AirBrake for my Maz18, best decision ever, great live to give you more power tube saturation at lower volumes, and the bedroom playing too!

George
I play Guitar, and Build Stuff..