|A ’59 Bassman LTD (above) and close-up of its input section (below).
Normally, you’d play through the venerable ’59 Bassman either by plugging into one of its two “normal” channel inputs or one of its two “bright” channel inputs, and then off you go. One or the other.
There is yet another option, though, for which there are no extra inputs or switches or anything, that lets you use both channel types together. It involves a simple technique called “jumpering” in which you can combine the ’59 Bassman’s normal and bright channels and blend them to taste.
As described above, the ’59 Bassman is a four-input amp—two normal and two bright. If you plug your guitar into any of the four inputs, you can then run a short cable from that channel’s remaining input to one of the other inputs. That is, if you plug your guitar into one of the amp’s “normal” inputs, you can then run a short cable from the other “normal” input into one of the “bright” inputs (doesn’t matter which one). Similarly, if you plug your guitar into one of the amp’s “bright” inputs, you can then run a short cable from the other “bright” input into one of the “normal” inputs.
Either way, you now have both channels, normal and bright, working simultaneously, and you can use the ’59 Bassman two volume controls to blend them to taste; to determine how much of each channel you want to hear in the overall sound. Pretty cool.
“Jumpering” inputs as described here is often (not always, but often) possible with other multi-input amps; either to another channel of the same amp or from one amp to another.