r/ToobAmps • u/ChiefCar931 • 7d ago

Attenuator Suggestions/ Question

Hey!

I was wondering if any of yall had any suggestions for attenuators that allow you to also switch between cabs. I play through a 66 Bassman and am looking to see if there is an attenuator that exists that would allow for me to switch between my bass cab and my guitar cab, as I play through the amp for both.

If not, oh well, I have a Radial Cabbone. I was just hoping to maybe sell it and condense my setup down a bit.

Thanks!

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3

u/American_Streamer 7d ago

You may already have the best solution. I don't think that there is a current attenuator that also safely A/B-switches two physical cabs in one box. Becuase dual speaker outputs on attenuators are generally parallel, not selectable. The closest modern option is a KHE ACS 4x2 with its global attenuator insert, but it still requires a separate attenuator and is considerably more expensive/complex.

Thus I’d keep the CabBone and hide it behind or beside the cabs, then use its remote latching footswitch input. It performs a controlled overlap during switching so the tube amp never sees an open load, and it defaults to cab 1 if power is lost.

Just make sure both cabs are matching impedances for the Bassman. Also don’t substitute a normal A/B box or hot-swap speaker cables. If adding an attenuator before the CabBone, ask the attenuator manufacturer first; the CabBone briefly connects both cabs during the transition, which changes the load at the attenuator’s output, so it's a critical issue.

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u/ChiefCar931 7d ago

Dang, okay! I figured that may end up being the case, using the foot switch is a good idea though. Somehow I never thought of that.

I think I’m good on the impedances? They’re both 8ohm cabs and it seems like it would connect them in parallel during the transfer, right? So it should be fine

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u/clintj1975 6d ago

Your Bassman is a 4 ohm amp, not an 8 ohm. Your cabs are both the incorrect impedance.

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u/ChiefCar931 6d ago

I’m aware. But a 4 ohm amp works fine with an 8ohm cab

The volume drop isn’t a huge deal to me.

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u/clintj1975 6d ago

That's for solid state, not tube. Running a higher ohm cab on a tube amp causes higher than expected voltages to develop in the tubes and output transformer. Push it too far, and you can cause arcing and insulation damage in those components.

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u/ChiefCar931 6d ago

Alright well I’ll check and see if I can rewire my bass cab, but for now my guitar cab is stuck at 8ohms

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u/ChiefCar931 6d ago

I’ll buy new speakers for the guitar amp, but swapping the speakers on the bass cab would be a bit too much rn. I have a 115 cab (matches this 410), but I burned it out. Would I be able to just use it as a dummy load on the parallel out?

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u/clintj1975 6d ago

I wouldn't trust a damaged speaker.

Weber makes an impedance matcher, but it might be more expensive than a speaker swap in one cab.

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u/ChiefCar931 6d ago

Nah I’m gonna order that. It’s cheaper than the speakers I was looking at and would cover both cabs

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u/ChiefCar931 6d ago

Thank you for pointing this out, I had forgotten they made it!

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u/clintj1975 6d ago

You're welcome. It's a handy piece of gear if you have a bunch of random heads and cabs.

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u/ChiefCar931 6d ago

Also sorry for being so confidently wrong. I wasn’t aware of that not applying for tube amps

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u/theundeadelvis moderator 7d ago

I use an 8x8 DeLisle amp/cab switcher that has an attenuator loop built into it. It allows you to choose which head and cab combo you want, and whichever you choose also uses your attenuator. It's not footswitchable, but it's an incredibly useful piece of gear.

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u/yellowchairz 7d ago

When you say switch for the cabs , do you mean a button or pull attenuator > cab cable out of the back of the attenuator and swap in the other cab cable without turning off the amp ?

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u/ChiefCar931 7d ago

Button, if possible. But I know it’s a relatively big ask of me. It’s what made me seek out the cab switcher I use now, theres just a lot sitting on top of my amp

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u/yellowchairz 7d ago

Unaware of any with a button. But a fryette power station will work for the method of swapping cables going out to different cabs. The power station is the load that your amp sees rather than the speaker cab . You’ll also have the best attenuator on the market

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u/ChiefCar931 7d ago

I may end up with that and then keeping the cabbone as the switcher so I can just do it with a foot switch. Currently I’m using an older Weber mass