Sunn Coliseum Slave Amp - How do they work? What are they worth?

[pickinatit]

How does a Coliseum slave amp work.  Do you cable your main amp's out-put to the Slave amp's input instead of to the speakers and then the Slave amp's out-put to the speakers?

If I daisy chained two 8 ohm cabs together (4 ohm load) and plugged them into one of the slave amp's speaker outputs.  Then daisy chained two additional 8 ohm cabs (4 ohm load) and plugged it into the other Slave amp speaker output, are they connected in parallel as a 2 ohm load like with other Sunn amps with the two output jacks or does the slave amp regard them as two separate 4 ohm loads?

Or am I just all wet altogether as to how the Slave Amp works? 
Any idea what they have been selling for ?  Don't know exact year, but it has the meter on the front control panel unlike the one that shows in the 1979 brochure on page 11.

[Isaac]

Coliseum Slave amps work just like all other slave amps. They want a line level input, not a speaker level input. Use the Line Out or Preamp Out on your main amp. If you don't have one, use a DI box.

The Coliseum speaker outs are in parallel, so what you describe would indeed result in a 2 ohm load on the amp. It's not stereo, so it sin't going to see any loads as separate.

[pickinatit]

Two of my amps indeed don't have pre-amp out connections (Solarus, 2000S) so I guess I would have to invest in the DI unit you advised (although I know nothing about this and now have a whole new thing to investigate, Oh well these things keep me busy & out of trouble).
The four speaker cabs I have are all 8 ohm,  (Ampeg SVT 115E, Avatar B212 Neo, & two Avatar B210Neo - relatively inefficient compared to the pair of 2 X 15's the 2000S was meant to drive according to info. from another thread on this website)  I am presently only able to run the 15" with either one B212 or one B210  for a 4 ohm load off a 2000S  My idea was that by adding the slave amp to the mix I could run all 4 cabs off the 2000S .  How does a DI fit into all this?  That would be INSTEAD of the slave amp ?  Or with the slave amp?   Will the slave amp / DI  boost the power to the cabs without effecting the tone settings of the 2000S ?

I hope I don't sound too ignorant here.  Please excuse me.  I'm from the era of plug into an amp & play who has just started playing in a band again recently after about a twenty five year break.  I am trying to catch-up/educate myself regarding what is new technology to me (pre-amps, pedals, DI's, slave amps).

In the meantime, I am keeping my eyes open for the old Sunn Cabs and I even have purchased two JBL D140F speakers should I find an empty cab or one without the original speakers.  I really want to end up with the 2000S through a pair of Sunn 2 X 15's  as was meant to be.

Maybe I'll just make do until the cabs show up, but I'm beginning to believe that I will never find two of them in any decent condition.

[Isaac]

DI stands for direct input. There are different kinds. Some go between the instrument and the amp, others between the amp and the speaker. The idea is to create a line level signal which can be sent to a slave amp or mixing board.

If you have a little knowledge of electronics, you can build one yourself. All you'd need is a box, jacks for speaker level input, speaker level output, and line level output. Wires go directly from speaker level input to output. In parallel with this, make a voltage divider to reduce the voltage from that required to drive speakers (around 22vrms for 60 watts into 8 ohms) to a voltage adequate to drive the slave amp (probably 1vrms). Tap off of the voltage divider and run to the line level output jack. Run a shielded cable from the line out to the slave input, and voilá!

[pickinatit]

Voila ?  You lost me when you said ..."if you have a little knowledge of electronics...."  Ha Ha.  I'll talk to a tech guy, although I think I've decided not to spend the money on the slave amp unless it stays under $100.  Then it might be worth looking into.

Thanks,  Isaac.  I appreciate your help & patience.