Impedance problem...?

[dude]

I have a Crate CR285B SS bass amp head, (mid eighties USA made).

On the back it has two outputs for speakers, one says EXT. the other INT.

150 watts at 4 ohms, (Note:2 ohms min. total load is written pointing to the two output speaker jacks.

I can't find a manual for this head, so I take it a 4 ohm cab produces 150 watts (one 4 ohm or two 8 ohm cabs in parallel).

Two 4 ohms cabs gives 2 ohms impedance for I assume more output wattage.

I have been playing just an 8 ohm cab into the INT. jack, so I assume I'm not getting 150 watts output but more like 75 watts...?

I have another cab that is 4 ohm (one 15, one 10 and a tweeter, cab says 4 ohms on the back). I want to use this cab with the 8 ohm cab which is four 10's.

Everything is parallel.

Can I assume that the back INT and EXT jacks are probably wired in parallel? Which output jacks do I use, for just the 4 ohm cab?

What is the EXT. (I assume external) and INT. internal - Expland what each does...?

Also, how would I hook up the 4 ohm and 8 ohm cabs together into this head? And would that cause an impedance mismatch that would damage the SS head?

Any explanation on how these two outputs jack are to be hooked up?

Also what are the line out and line in jacks?

Thanks as always,
al 

[sluckey]

The two jacks are likely connected in parallel. You don't worry about impedance matching with newer SS amps. BUT DON'T IGNORE THE MINIMUM IMPEDANCE WARNING! Your 4Ω cab paralleled with your 8Ω cab will give a total impedance of 2.67Ω. That's safe for the amp.

Line in/out jacks are just that. You can connect a line level signal source (CD player, guitar preamp, etc.) to the line input and play that thru the amp. You can take a line level sample of the signal passing thru that amp from the line out jack and send it to another power amp, recording system, PA, etc.

[dude]

Thanks,
al

[dude]

What would be the best way to hook-up both cabs, 8 and 4 ohm?

Use INT. jack to one cab, EXT. to other

                or

Use INT. jack to one cab and from that cab to other?


make any difference, probably not...?

[sluckey]

Use INT. jack to one cab, EXT. to other

yes

Use INT. jack to one cab and from that cab to other?

yes, ...IF... doing that puts the cabs parallel to each other. If that's the case, do whichever is more convenient.