CD100E extension speaker question

[Doughbroz]

Need to install two exterior mono speakers, either on 70v with transformers, or on the 8 ohm taps, makes no difference to me as the wire run is very short.  Already has interior stereo pair on the 8 ohm stereo taps.  Need volume controls on the exterior pair.  Problem is I once blew an amp by following the instructions that came with an L-pad to run mono to a pair using the mono hookup on the 8 ohm strip.  I know the solution was simple, but I just can't remember how it had to be done.  The amp was not overloaded, the hookup was just not the same as running it from something other than a jukebox.  Any ideas appreciated.

[lilshawn]

l-pads aren't really compatible with these amps. the speaker load must be maintained on these amps...when you switch an L-pad from one volume setting to the next, it often disconnects and reconnects the speakers through another transformer to simulate an extra resistive load. this is super hard on the switching transistors of the amp. you need to maintain a 4 ohm load MINIMUM on the amp per channel. depending on how your speakers are wired, disconnecting an externally connected L-pad speaker load could dip your load WAY down.

get yourself a dual volume control (or another control) and hook it up in stereo volume mode (but with 2 separate volume controls, not a ganged control.)

then you can separate your inside and outside speakers to the left and right halves of the amp for separate control. for instance have your juke speakers and your inside speakers on the left channel and your outside speakers on the right.

if you post up the actual ohm rating of the speakers you have (get a meter and measure) and those that you would like to connect up... i can let you know how to wire it correctly.

for instance "two 8 ohm inside with the jukebox speakers and four 6 ohm speakers outside."


FYI, the juke manual information regarding speakers is WRONG. don't bother following it. it is about 50 years out of date and they can't be bothered to update it so they just copy paste it into every manual.  we now understand impedance load is the issue not watt rating.

[Doughbroz]

I finally found a Rowe diagram for splitting the channels as you describe.  I assume the first thing I need is a dual channel remote volume control.  All four speakers will be 8 ohm.  The inside pair is currently wired for stereo.  Since they will now be mono, if I want them running at about 10 watts each, I should wire them in parallel to a tap that provides around 20 watts?  And the same for the two exterior speakers on the other channel?  thanks for the help

[lilshawn]

yes, you will need a dual volume control (or 2 single volume controls)

see, that's the thing, it doesn't matter how many watts.

all that matters is the load on the amp.

the speaker taps are in parallel with each other, so if you add speakers on different taps, it's the same a putting them in parallel.

Two 8 ohm speakers outside on one channel and four 8 ohm speakers and the juke speakers on the other?

this is how you would like to do this? (assuming real 8 ohms) also i will draw a bad MSpaint picture for you.

it's a little bit complicated but to get a proper load... but in a nutshell you want to "series parallel" your 8 ohm inside speakers and then series that with the jukebox. if you parallel it with the jukebox, (the speaker taps act as a parallel connection to the amp) your load will be under 2 ohms and will blow the output.

the outsides will daisy chain together so from the amp+ and -  into a speaker + and - ...then back out again to the next. easy.

this will give you a about a 11 ohm load on the inside and a 4 ohm load on the outside (within safe range of load for this type of amp) but most of your power will go to your 4 extra speakers with about 75% of the channels power going there.

if your outside speakers are too loud (or you want to limit how loud it gets outside at max volume, just place the + on a lower numbered tap.

like so:

[Doughbroz]

Thanks for the help, I truly appreciate it.  One more question, the inside speakers are a pair of 8 ohm, not four 4 ohm, so I assume that if I just slice off the bottom pair on your diagram, that would be the same thing.  Oh for the good old days when speaker wiring was simple. 

[lilshawn]

no, those are @ 8 ohms.

you need to pair up two 8 ohm speakers to get 16 ohms.... then two sets of those to bring it back down to 8 again (so 4 total.)