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DIY Attenuator

Started by Aentons, April 09, 2022, 10:04:30 PM

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Aentons

I put together this attenuator for my AC30 using a Parts Express 16ohm 100w L-pad. This is my first experience with any power soak type stuff.

It was tougher than I thought to get it in a 125B with all the 14 gauge wire. I had to sand the sides of the L-pad to get it to fit. I used a couple layers of thermal paste with an extra aluminum plate between the L-pad and the enclosure face for maximum contact.

After burning it in for a bit on some milder settings, I cranked the AC30 all the way up and put the attenuator dial almost all the way down. It gets pretty hot, but I think it's manageable. It got a little smokey at a couple of points, but I think that's normal for new ones

The left switch is for 2 treble bleed caps. I used a 2.2u and  4.7u. I can't hear a difference with either. I'll prob trade them out later.

jessenator

That's pretty slick!

I've been thinking about making one so I can enjoy an amp a friend built for me and still have hearing at the end of the day. Is 14 the thinnest you'd go for this application? I have a mess of 18 awg, but don't want to risk it if it can't handle it.

Alsa, do you think the heat would be enough to warp something like a 3d-printed enclosure? My amp is ~20 amps so a slim amount less heat than your AC30, I'm guessing.
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Aentons

Quote from: jessenator on April 09, 2022, 11:12:59 PM
That's pretty slick!

I've been thinking about making one so I can enjoy an amp a friend built for me and still have hearing at the end of the day. Is 14 the thinnest you'd go for this application? I have a mess of 18 awg, but don't want to risk it if it can't handle it.

Alsa, do you think the heat would be enough to warp something like a 3d-printed enclosure? My amp is ~20 amps so a slim amount less heat than your AC30, I'm guessing.
Any kind of plastic enclosure would just melt pretty fast. The enclosure acts as a heat sink so you definitely want aluminum.

I went as large as I could on wire because I read up on all the horror stories of wire sleeves and solder joints melting. I'm not sure 18 gauge would handle it.

If you are just doing a little attenuation then the heat is not that bad. It's when you get really low that things start to get hot.

Bio77

That looks cool!  Do you think it'd burn through the floor if I used it with my 60W Deville  ;D

Aentons

Quote from: Bio77 on April 10, 2022, 04:21:49 AM
That looks cool!  Do you think it'd burn through the floor if I used it with my 60W Deville  ;D
Probably, yes