Ampeg BA112: defective? silent after switching inputs

[lmichaels]

Hi everyone,

I recently got my self a refurbished Ampeg BA112. Happy about it, but wanted to check with someone more experienced if the following is typical or a sign of some sort of electronic problem:

This amp has two instrument inputs (0db for passive basses and 15db for active ones). If I switch the amp on, plug a bass first into the 15db input jack and then decide to use the 0db input jack instead, then the amp farts and goes silent. Only by plugging it off and then back on does it go back to working. Basically, if I want to change from one input jack to the other (in particular, from the 15db to the 0db one) I need to switch off for it to work.

Is this normal? I have never had an amp before with two inputs and need to know if I should return it by Wednesday.

Thanks!
~l

[RickenBoogie]

That is not normal, but there's no reason to use the -15dB input anyway. Just use the normal input, and if the input gain is too high, lower the control marked gain. (that's all the input pad does anyway). So, just use the normal input and play away.

[5port]

I own the Ampeg BA110. Similar amp with 30W and 1X10. It does not happen when I switch inputs with the power on. Sounds like you have a cracked solder joint or wire connection problem. Time for a tech.

[lmichaels]

Many thanks for your terrific help.
~l

[dog1]

Originally Posted by RickenBoogie

That is not normal, but there's no reason to use the -15dB input anyway. Just use the normal input, and if the input gain is too high, lower the control marked gain. (that's all the input pad does anyway). So, just use the normal input and play away.

+1. I play both active and passive basses, and always just use the "normal" input. Of course the active bass is louder then the passive at the same volume setting.

BTW, if using just the one input solves your problem, I would not waste any money having the amp serviced. Repair costs could be close to the resale value of the amp.

[BurningSkies]

Sounds like the padded input is shorting and causing the amp to shut down to protect itself. I'd just pretend that input isn't there. I've never had much use for one on an amp with an adjustable preamp gain stage.