using a Coliseum Slave (input sensitivity?)

[Pacafeliz]

hey there!

i picked up an old "silverface" coliseum slave amp, but i really don't know how to use it, as i've been an almost 100% tube amp head user.

i've read thru the old threads but nobody mentions the "input sensitivity" pot on the front. what does the 2v, 1v and .5v mean?

can somebody please show me how to connect (and use) this thing? pics would be great, and i'd be very thankful.

rock on!

Pat.

[EdBass]

It has to do with the strength (voltage) of the signal going into the amp. That slave is a power amp only, and the sensitivity control is to help match the slave with whatever preamp you are driving it with; the idea is that whatever the "input sensitivity" is set at should be the amount of input voltage necessary to drive the amp to full output (maximum voltage gain usually measured in dB) before clipping.
Somewhere between 1V and 2V is typical for most audio preamps, but it depends on the preamp so it's certainly not a "given".

[Pacafeliz]

thanks!

and how do i connect this thing?
 

[Isaac]

Inputs in the front, speaker outputs and power cord in the back.

[EdBass]

thanks!

and how do i connect this thing?
 

How do you connect it, or to WHAT do you connect it?
It really wants a pre-amplified signal, so ideally you would power it from a pre-out (maybe labelled "slave" out) of a full Coliseum and use it to power some more speakers. If not another Coliseum, any amp with a preamp out or dedicated free standing preamp should do the trick.
Don't even contemplate the idea of running the output of an integrated amp (pre and power amps together in one unit like the majority of musical instrument amps); it could take out your new slave amp very quickly.

The purpose of slave amps is to get the power of another amp/speaker stack and control it using the controls of the primary amp alone. The slave needs it's own speaker compliment.

[Happy Face]

Back when amps were not so powerful, slaves were a great way to add more power.

And as Ed pointed out, using slaves left the control of tone and master volume on your first head. Easier to control than a bunch of daisy-changed full amps.   

[Pacafeliz]

thanks!

could i also hook it up hendrix-wise? i mean, from the "bridged" 4 inputs of my Sound City head into the Slave?
i've used several tube heads like that before.

rock on!

Pat.

[EdBass]

That will only work if the amps you are bridging to an integrated amp; typical MI amp which is actually a pre amp and power amp together in one unit.
You need to use the "preamp out" on an amp that is so equipped, or use a dedicated pre amp.

[EdBass]

Wait a minute...

You already own this rig, and you don't know how a slave amp operates?

http://sunnforum.ampage.org/index.php/topic,9928.0.html

A Slave amp is just a power amp, just like the pre-amp/power amp rig you have for sale in the classified section.
Am I missing something here Pacafeliz?

[Pacafeliz]

thanks!

i just got the slave amp recently as part of a payment, but so basically a slave and power amp are the same thing?
thanks!

Pat.

[Isaac]

More or less. The term power amp can refer to the power section of a musical instrument amplifier or an integrated amplifier or to a stand alone power amplifier. The term slave refers only to a stand alone.

[EdBass]

Usually the term "slave amp" refers to a situation where the "slave" is a duplicate of the output section of the "master" amp. In the case of your amp, it was intended to be slaved to an integrated Coliseum master and used to power an additional cab(s) effectively doubling the output of the rig. Most "slave" amps were produced in the era before live sound reproduction technology had caught up with the mercurial escalation in venue size of the average rock n' roll show.
In the 1950's and well into the 60's the biggest rock n' roll acts on the planet were playing in small theaters acoustically designed so that the spoken word would travel from stage to the balcony without amplification. It didn't take much backline to be a "loud rock n' roll band" in those venues, high school auditoriums were probably the biggest challenge to SPL they faced.
Case in point; the story of Sunn. In essence the brand we all love was created because Norm Sundholm complained to his brother Conrad about not being able to be heard in some of the larger venues that his band The Kingsmen were playing. Probably the situation that kick started the need for serious sound reinforcement was when the Beatles played Shea Stadium in 1965 and they used the public address horns used to announce sporting events, along with custom built 100 watt Vox amps and with the screaming fans for all intent and purposes the band couldn't be heard at all.

Anyway, as the newborn SR industry was taking shape the MI amplifier manufacturers developed "slave amps" as a way to get the backlines to keep up with the arena and outdoor venues that were fast becoming the norm for major rock shows.
Now days, they are superfluous and as such there is little or no demand. Try to find a current "slave amp" from any manufacturer.
Modern sound systems are so sophisticated that many major acts use ZERO backline; and when they do it very often is only for show as stage props or to satisfy an endorsement contract and they are generally not even being used.

Rambling dissertation aside, your Coliseum Slave performs the exact same function as the "Sunn 200" power amp in your PB-10 rig. Try plugging the PB-10 into your Coliseum slave, should work great!

[Pacafeliz]

thanks!!!