madbeanpedals::forum

Projects => Build Reports => Topic started by: pryde on February 10, 2014, 01:39:38 AM

Title: BIG DUMMY
Post by: pryde on February 10, 2014, 01:39:38 AM
OK its not a pedal but still a fun build in the DIY spirit. I finally built an "official" dummy load for my amp repairs/builds. 4 big-honking 120 watt, 16-ohm wirewound resistors wired in parallel with a switch for 8-ohms/240w or 4-ohms/480w. I mounted them with some nylon stand-offs to reduce direct heat to the wood. These don't get too toasty but I run a fan on them if need be.

Also built up a cool little adjustable chassis station. Got tired of grabbing whatever was handy to prop up amp chassis when working on them. It will hold a little fender champ all the way up to a 100 watt JCM.

(http://i1025.photobucket.com/albums/y318/jpparlier/Dummy%20load/IMG_3992_zpsf4ba2281.jpg) (http://s1025.photobucket.com/user/jpparlier/media/Dummy%20load/IMG_3992_zpsf4ba2281.jpg.html)

(http://i1025.photobucket.com/albums/y318/jpparlier/Dummy%20load/IMG_3991_zps52ed1ef3.jpg) (http://s1025.photobucket.com/user/jpparlier/media/Dummy%20load/IMG_3991_zps52ed1ef3.jpg.html)

(http://i1025.photobucket.com/albums/y318/jpparlier/Dummy%20load/IMG_3990_zpsc060b352.jpg) (http://s1025.photobucket.com/user/jpparlier/media/Dummy%20load/IMG_3990_zpsc060b352.jpg.html)

(http://i1025.photobucket.com/albums/y318/jpparlier/Dummy%20load/IMG_4000_zps5d17a6ae.jpg) (http://s1025.photobucket.com/user/jpparlier/media/Dummy%20load/IMG_4000_zps5d17a6ae.jpg.html)

(http://i1025.photobucket.com/albums/y318/jpparlier/Dummy%20load/IMG_3999_zpsb67f5cd7.jpg) (http://s1025.photobucket.com/user/jpparlier/media/Dummy%20load/IMG_3999_zpsb67f5cd7.jpg.html)

Title: Re: BIG DUMMY
Post by: jubal81 on February 10, 2014, 01:43:43 AM
Now THAT's heavy-duty. Great work.
Title: Re: BIG DUMMY
Post by: rullywowr on February 10, 2014, 02:05:43 AM
That's killer. Really nice and useful tools when doing any amp repair.  Sweet.
Title: Re: BIG DUMMY
Post by: danwelsh on February 10, 2014, 02:38:19 AM
totally wicked man :)
Title: Re: BIG DUMMY
Post by: pickdropper on February 10, 2014, 04:17:06 AM
Fred Sanford approves.

(http://soullinedance.files.wordpress.com/2011/11/fred-sanford.jpg%3Fw%3D242%26h%3D300)

I'm not so sure about Aunt Esther.
Title: Re: BIG DUMMY
Post by: lincolnic on February 10, 2014, 04:27:48 AM
Captain Beefheart approves too.



Love the look of those giant resistors.
Title: Re: BIG DUMMY
Post by: AntKnee on February 10, 2014, 04:33:23 AM
Is that for simulating the load of speakers so you can get the amp running hot?
(Forgive me, I've never worked on an amp.)
Title: Re: BIG DUMMY
Post by: pryde on February 10, 2014, 04:47:51 AM
Quote from: AntKnee on February 10, 2014, 04:33:23 AM
Is that for simulating the load of speakers so you can get the amp running hot?
(Forgive me, I've never worked on an amp.)

Yes it loads the amp for testing various functions including output power/headroom distortion if you want to see that. I find it more useful for fault-finding/troubleshooting using a scope


Title: Re: BIG DUMMY
Post by: stevie1556 on February 10, 2014, 10:26:58 AM
That's awesome!

Sent from my thumbs using Tapatalk!

Title: Re: BIG DUMMY
Post by: muddyfox on February 10, 2014, 11:11:24 AM

Wow P.!

Tube amps scare the living daylights out of me. In my book, anyone working on them has gotta have these and then some...

(http://farm1.static.flickr.com/253/521907607_77de5f9232.jpg)
Title: Re: BIG DUMMY
Post by: GrindCustoms on February 10, 2014, 12:37:38 PM
That's really neat, makes a while that i need to build one of those load box.