Tube Amp Output Question

[kcaithness93]

Hello all, my name's Kyle, and I'm joining ya here on Basschat over from Canada, mainly because I've bought a bass from a guy on this site. I had a question regarding my setup, and was hoping someone could help me shed some light on it?

I've read on the internet that running a tube amp (I own an Ampeg SVT-2Pro, all tubes) without speakers plugged in to it is bad for it, and can cause serious problems like fire. My amp has two 1/4" output jacks, and my cab has two output jacks as well (I own a Peavey 1810 cab, one 18" Black Widow and two 10" Scorpion drivers), and with the cab one jack goes to the 18", the other to the 10"s. I have a second amplifier, and also own a Rickenbacker 4003, and I want to experiment with the "Rick-O-Sound" feature, splitting the signal so that one pickup goes to one amp, and the other to the other. Basically, my question boils down to this: do both jacks on the tube amp have to be connected in order to prevent any damage to the amplifier? Or is it enough to plug in a single jack from that amplifier to a single jack on the cab, and a similar setup on the second amp?

I hope this makes some slight modicum of sense, and hope that someone on here can give me a helpful answer! Thanks in advance.

Cheers,


Kyle

[Grissle]

Only one jack has to be used on the amp so that it sees a load.

[~tl]

In most cases (but not all!) the speaker jacks on the back of the amp are connected in parallel. You only need to make one connection between the amp and a speaker cabinet. The second jack is there to connect a second speaker cabinet.

However, from your question, it sounds like you want to connect TWO amps to ONE speaker cabinet using the two jacks on the back of the cabinet. This is a bad idea, as you will directly connect the output stages of the two amplifiers which risks damaging one or both of the amps.

To utilise the "Ric-O-Sound" feature you need two amps with their own, separate, cabinets.

[Mr. Foxen]

That cabinet is two cabinets in one, the 10s are high passed. That also means you should high pass into them if biamping. They probably can't take more than 30w or so of full range, you can't just treat them like a 2x10. Bear in mind each set of speakers has its own jack, and there should be a full range jack with a crossover that splits the signal once it reaches the cab, need to make sure you use the right ones.

[kcaithness93]

Thanks for the answers everyone! Much appreciated.

[Mikey R]

Valve amps have switchable impedance.

If, for example, you are used to plugging two 16 ohm cabs into the amp, then the amp should be set for 8 ohms. If you only plug the one cab in, then you should switch the impedance selector to 16 ohms.