Putting Amps Together

Ibanez Bassist · #1 03-23-2011, 06:29 AM

I have a Fender Rumble 100 and there are two out puts on the front one is a Pre amp out FX send and the other is a balanced XLR line out with a volume control.. I wanted to drop another passive or active monitor on the floor but the rumble is a 4 Ohm and most all ( If not all ) of the external speakers/monitors are 8 Ohm.. will this be a problem ?
Thanks Scott

ddhm · #2 03-23-2011, 09:07 AM

Scott,
Would I be safe in guessing that you don't know much about this kind of thing? Frankenstiening an amp can quickly lead to it's death if you don't know what you are doing.

a little info here: Series Vs. Parallel Wiring

The rumble is a 100 watt amp and just doesn't have much in the way of power. Adding a speaker probably won't give you what you want. It sounds to me like you are in need of more power.

If you have a powered monitor, use the XLR output. If you do not, it is time for a bigger amp.

Ibanez Bassist · #3 03-23-2011, 09:25 AM

I know as much as I need to know I guess for now.. I wasn't looking to put two bass amps together as one.. I was looking to distribute sound to different locations.. example: My Rumble is out in front of me at this particular place so I wanted a monitor ( which people do use I believe) powered or not to distribute the sound to myself and the drummer.. not looking for a boost of power I have enough volume, thing is, it needs to be re directed a little.. more power will only send more volume to the place its already going and its not necessary.. I do have powered monitors/speakers both 12" and 15" so I will try coming from the volume controlled XLR to one of these active monitors and see what that does... the thing that I wasn't sure of and a lot of people dont answer directly was if my rumble is 4 Ohms can you run that to a passive 8 Ohm speaker.. I wasn't sure about something like that.. I know there are formulas for such a thing, and I guess I could make this all go away by using an active monitor but do I really need that, there much more expensive and if im not looking for more power just distribution why couldn't I use a passive monitor..

ddhm · #4 03-23-2011, 09:44 AM

What is this "mon-i-tor" that you speak of??? lol j/k Yes, folks use monitors, they just have enough power to push them. However, a 100 watt amp might have trouble doing that. If you add a speaker, you cut the wattage that is going to your internal speaker. Also, by adding a speaker to the combo, you change the ohm load resulting in a probable wattage loss as well. That's why I suggest more power.... or more specifically enough wattage to run more cabinets.

Be sure to use a balanced input of your powered monitor then. If it doesn't have one, you'll have to psuedo-balance the cable (putting pins 1&3 of the XLR together on the sleeve of the 1/4 inch) or you'll suffer a 12db (or is it 6db?) loss between your output of your combo and the input of your powered monitor.

Ibanez Bassist · #5 03-23-2011, 09:59 AM

There are actually Balanced inputs or 1 balanced input on the back of the active monitor/speaker.. well then I guess I should do that then and if at some point I happen to need a little more I guess I will have it because of it being a powered monitor ( instead of cutting it ) with a Passive.. makes sense I will try that.. Thanks..