Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Ledzepp007 on June 08, 2018, 06:39:30 pm
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Hello. I recently purchased a UA Ox Amp Top Box. It's nice sounding and required where I'm moving (city). However, it's kind of a pain in the ass to hook up different amps to it on the fly.
Thus, I was thinking of building an amp selector that would allow me to quickly select between amps on the fly.
I attached a layout. Each of the three amps I typically use has an 8 ohm output. The selector box is for three amps. The two amps that aren't selected are meant to see an 8 ohm load (so that they don't self-destruct). The amp that's selected obviously gets sent on to the Ox.
Thanks for looking it over.
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As drawn, the dummy-load is 32 Ohms, not 8 Ohms.
The small 3P3T are usually rated 50ma, 0.050 Amps. Your "8" Ohm 100W loads suggest 3.5 Amps is possible. If switched while the amplifiers are wailing, the switch may melt.
The switching seems unnecessarily complicated.
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I see-- the complex switching avoids a 3rd power resistor.
I'm still too lazy to check your configuration.
Unless you truly need 100W beasts, _I_ would trade another few bucks for much less brain-pain.
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As drawn, the dummy-load is 32 Ohms, not 8 Ohms.
The small 3P3T are usually rated 50ma, 0.050 Amps. Your "8" Ohm 100W loads suggest 3.5 Amps is possible. If switched while the amplifiers are wailing, the switch may melt.
The switching seems unnecessarily complicated.
Crap, I had originally drawn them in parallel, and forgot to change the resistors to 4 ohm. Good catch.
I do want to maintain the capability to handle 100 Watts.
Here’s the switch I was considering:
https://www.mouser.com/ProductDetail/CK/A30305RNZQ?qs=sGAEpiMZZMvNbjZ2WlReYqS7wnWG8l9OaX%252b%252b8H70EBI%3d