Connecting exterior speakers to a AMI Rowe Star

[rhaskell53]

I have an 1989 AMI Rowe Star Model R93 Jukebox.  I wish to connect two exterior speakers (audio source LS one) with a power capacity of 40W maximum and 8 OHMS.  Which connections do I use in the Jukebox to connect these speakers?  There is a left and right bank with seven screw heads for each bank.  Thank you for your reply.
Rick

[kingstontom]

Hey there. The Rowe boxes are quite particular about extension speakers. An improper load can blow the output devices, so be mindful of this. I'd recommend referencing a manual, because that has an entire section about attaching extension speakers and any deviation that you want to make from what I repeat from the manual below will also be following Rowe's specs.

Here's a conservative setup that would give you stereophonic sound from your extension speakers: According to my r-94 manual (same sound specs), using taps E1 (black) and E5 left (violet) and E5 right (pink) will dedicate 28 watts of the amplifier's power to the speakers in the jukebox. You could then attach your left extension speaker to left E1 and E5 and your right extension speaker to right E1 and E5. This will dedicate 14 watts for each extension speaker (combined 28 watts), which is nicely balanced with what the speakers inside the jukebox are drawing from the amp. Wiring the extension speakers will be as follows then: Left channel negative goes to left E5 and positive goes to left E1. Right channel negative goes to right E1 and right channel positive goes to right E5. The left channel and right channel  extension speakers' polarity are reversed when compared to each other because the output phase has already been reversed on the output transformer assembly by design.

Polarity is important on this, so follow the hookups above closely, and the extension speakers should produce the desired sound level relative to the sound level of the speakers on the jukebox, hence the equal amount of wattage for everything.

Tom

[rhaskell53]

Thank you very much Tom for the information.
Rick

[ami-man]

Hi Rick,

I would be inclined to connect your extension speakers across  E1 to E4  on each channel or even to E3 if you need a softer sound.

The Output Package (Ami call this the Output Transformer Package) is great for blancing the overall sound if the jukebox & extension speakers are in the same room, you can raise or lower the jukebox speakers or the extension speakers, they do however do not want to be be on the same tappings as suggested, this would in effect reduce the impeadence on the speakers by wiring them in parallel.
The amplifier speaker outputs must not be lower than 4 ohms, lower than this is what puts the amplifier in overload and it can blow the output transistors.

Regards
Alan

Alan Hood
ami-man
UK

[lilshawn]

I've covered the proper impedance matching for the rowe 250 watt amp jukeboxes here:

http://forum.arcadecontrols.com/index.php/topic,106586.msg1129388.html#msg1129388

in a nutshell, the suggested calculations and worksheets to figure out speaker loads in the jukebox manual are archaic and out of date and not in the least relevant to modern understanding of the impedance requirements of class a/b amplifiers.