has anyone ever made an attenuator before?

Dave · Post by **Dave** » Mon Feb 17, 2014 5:41 pm

George wrote:if it works and i don't die i'll post the parts list. you can probably get them cheaper elsewhere but i'm not savvy with this stuff really.

Yas plz George!

Brandon W · Post by **Brandon W** » Mon Feb 17, 2014 6:31 pm

I have something similar..I have a cab that has 1 12 in it and my friend put an attenuator with a volume control on the cab. I can run any head or combo out to it and crank the amp but control the volume on the speaker...he said it wasn't hard or expensive to do but i never asked what it entails. It has a good speaker too..celestion gold i think...I think they should all have this. Although my mesa breaks up nice at lower volumes, this makes sense to have on everything. I want the tubes hot but the volume adjustable..if that makes sense. I clean it up on my guitar volume but i like em smoking hot.

Benmurray85 · Post by **Benmurray85** » Mon Feb 17, 2014 6:43 pm

Dave wrote:
George wrote:if it works and i don't die i'll post the parts list. you can probably get them cheaper elsewhere but i'm not savvy with this stuff really.
Yas plz George!

Yes yes plz george

George · Post by **George** » Tue Feb 18, 2014 1:07 pm

does this schematic look good to go with the 3 way switch? i added the red.

this should cover 3 levels of brightness. can i swap the neutral and 4.7uf cap so it goes in order of brightness from bottom to top?

Benmurray85 · Post by **Benmurray85** » Tue Feb 18, 2014 1:27 pm

George where did you source your lpad? I can't find one in the uk. There's some US sellers on eBay but post seems a lot

George · Post by **George** » Tue Feb 18, 2014 1:32 pm

i went with these guys

http://stores.ebay.co.uk/willys-hifi-lo ... d=81735486

i got the 50W 8 ohm because my amp is only rated 30W but i think i got the last one in stock! if you ebay "ohm attenuator" you should get a few options, same as amazon.

just remember:

- ohms absolutely must match
- wattage should ideally be a bit higher than the amp's wattage (but not hugely, if possible)

Benmurray85 · Post by **Benmurray85** » Tue Feb 18, 2014 1:34 pm

Thanks. Some recommended to over egg the wattage rating as much as poss. My amp is 20watts and the LPad I'm currently using is 100W. I'm guessing it just means it's not feeling the strain as much??? Thanks again though and keep me updated. LOVE your idea of the bypass switch!

George · Post by **George** » Tue Feb 18, 2014 1:35 pm

also if you're gonna go for a bright switch, they should be "non polarized electrolytic caps". i read people saying they should be rated at 400V too

George · Post by **George** » Tue Feb 18, 2014 1:37 pm

Benmurray85 wrote:Thanks. Some recommended to over egg the wattage rating as much as poss. My amp is 20watts and the LPad I'm currently using is 100W. I'm guessing it just means it's not feeling the strain as much??? Thanks again though and keep me updated. LOVE your idea of the bypass switch!

well that might be a possibility actually. i might read into that and change my order! it seems people are using 100W attenuators on 100W amps so i think it's probably okay?

i think the main issue would be cooling, so probably worth drilling some ventilation in the enclosure

George · Post by **George** » Tue Feb 18, 2014 1:49 pm

this dude is using a 50W 8ohm L-pad on my exact amp. sounds sweeeeet, and he may still only have the stock garbage tubes and speaker installed

[youtube][/youtube]

NickS · Post by **NickS** » Tue Feb 18, 2014 8:32 pm

AT-60H 100W attenuator at CPC
Range at ESR components, some of the same as CPC more expensive

George · Post by **George** » Wed Feb 19, 2014 9:20 am

NickS wrote:AT-60H 100W attenuator at CPC
Range at ESR components, some of the same as CPC more expensive

damn i got shafted lol. i paid about Â£18. shows what i know

NickS · Post by **NickS** » Wed Feb 19, 2014 12:50 pm

George wrote:can i swap the neutral and 4.7uf cap so it goes in order of brightness from bottom to top?

No. The centre lug is the common. When the switch is in the centre position the centre lug doesn't connect to anything.

George · Post by **George** » Wed Feb 19, 2014 12:52 pm

so the ammended schematic i posted would work though?

NickS · Post by **NickS** » Wed Feb 19, 2014 1:44 pm

George wrote:so the amended schematic i posted would work though?

It would let frequencies starting an octave lower bypass the attenuator. The curious thing is that since the impedance between the centre lug of the attenuator and ground reduces as you turn the volume down, the frequency at which the bypass starts to take effect goes up. When the volume is turned way down, at high frequencies you're connecting the output of the amp to a very low impedance through a capacitor.

Dave · Post by **Dave** » Wed Feb 19, 2014 1:52 pm

I read these kindsa of threads and just go back to my default position of considering it's all done with magic and stardust.

George · Post by **George** » Wed Feb 19, 2014 1:57 pm

hmm i don't really understand any of that lol.

in layman's terms are you saying the more attenuation you add (i.e. the lower you drop the overall volume using the l-pad), the more effect the cap has? i believe this is meant to be the case. apparently the more you attenuate an amp the darker the tone gets, which is why people add a bright switch

the caps are electrolytic and rated for 105 degrees Celsius and 400 volts too if that matters. i don't know what that means either

Benmurray85 · Post by **Benmurray85** » Wed Feb 19, 2014 4:27 pm

Dave wrote:I read these kindsa of threads and just go back to my default position of considering it's all done with magic and stardust.

SAME! Think im just gonna make a basic one.

Bacchus · Post by **Bacchus** » Wed Feb 19, 2014 7:07 pm

Dave wrote:I read these kindsa of threads and just go back to my default position of considering it's all done with magic and stardust.

Never had much of a problem with "loud as fuck."

George · Post by **George** » Thu Feb 20, 2014 2:13 pm

L pad arrived and it has a comically long shaft. Hopefully I can get it at a good height while still fitting in the enclosure.