Vol pot for external speaker

Frank Sprague · From: Custer , Washington, USA

I'd like to add a volume pot to an external speaker that I'm using with my 1969 Fender Deluxe - any suggestions as to ohms or any other concerns ? ?
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Lane Gray · From: Topeka, KS

Adding a pot will monkey with impedance. To tame a speaker, you want an "L pad."
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Frank Sprague · From: Custer , Washington, USA

Thanks Lane - pardon my electronic ignorance , but just what is an "L" pad?
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Stephen Cowell · From: Round Rock, Texas, USA

In order to control an external speaker, you have to do two things:

1.) Keep the load on the amp the same
2.) Vary the signal going to the speaker

The way to do this is to have two controls that are linked... as one is turned up, the other one is turned down. Also, these controls have to be able to hold the power of the amp. For your 20w amp I'd suggest at least a 50w L-pad. Here's a picture of the schematic:

... and here's a link to buy one.

http://www.parts-express.com/cat/speaker-l-pads/306

Note that the L-pad is typically 8ohms... if you parallel one with your current 8ohm speaker, this will be a 4ohm load, no matter what position the control is in. I'm guessing that's what you're trying to do, control the volume of an extension speaker on the other side of the stage.

L-pads can adversely affect your tone... they're resistive, not inductive, like speakers. If you use one in parallel with another speaker the effect will be less... but in any case your volume from your main speaker will go down some due to sharing the power with a non-producing load.
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Dave Campbell · From: Nova Scotia, Canada

an attenuator such as a hot plate or weber mini mass might do the job.

Frank Sprague · From: Custer , Washington, USA

Thanks for the input guys - Stephan you are correct , I have the external speaker on the other side of the stage so our half deaf guitar player can hear me better at low volume gigs ( there is usually the drummer in between ). The speaker cable is run out of the "external" jack of my DR , not in parallel. Both speakers are 8 ohm Telonics . . The 50 watt L-Pad attenuator shown on the Parts Express site looks like the ticket . . Thanks again
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Frank Sprague · From: Custer , Washington, USA

oops - double post
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Stephen Cowell · From: Round Rock, Texas, USA

Frank, the External speaker jack is in parallel with the normal speaker jack, so you're running your Deluxe at 4ohms... which it should handle OK. Good luck!
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Donny Hinson · From: Glen Burnie, Md. U.S.A.

Since there's no amp in the extension speaker cab, you can regulate the volume by where and how you place the cabinet, or by simply covering it up (partially) with a blanket or something else to absorb the sound. In the end, ideally what you want is a way for him to regulate the volume of the speaker near him, not you. Wink

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