Very confused noob speaker question... Sorry

[mr aize]

I've tried searching on here for a couple of hours but all the speaker topics seem to be for mame cabinets. I've just started building a jamma cab and i'm trying to source some speakers and an amp. (Do I even need an amp for a jamma cab? Can't even find a definite answere on that) The key detail is cheap but decent since it's not gonna be an entertainment center or anything... Found these http://www.maplin.co.uk/4-inch-car-speakers-37982 but can't find an amp to match them. Might be a bit overkill though..

[BobA]

A jamma cab does not usually need an amp as the speaker is usually powered by the game board that is attached to the jamma harness.  Most jamma cabs have a single speaker and were mono.   Neogeo cabs were stereo and use 2 speakers in a modified jamma setup.

[mr aize]

Thanks mate. Don't spose you know how mortal kombat speakers are hooked up? Basically i'm building a jamma cab that's gonna have a multiswitcher in it and mortal kombat, cps2 and neo geo boards. All the pictures i've seen of the mortal kombat ones look like they've got at least 2 speakers. I'd prefer 2 speakers, just for looks if nothing else as they'll be cut into the underside of the marquee display and 1 would look funny. Would the boards be able to handle 2 speakers? If I wired 2 3watt, 8ohm ones in parallel that should be okay I would have thought right?

[matsadona]

According to this (http://www.crazykong.com/pins/MortalKombat.pin.txt) MC has a standard JAMMA speaker setting. I.e one 8ohm speaker.
Two 4ohm speakers in series (don't do them parallel*) makes a total impedance of 8ohm, so that is one way to do it.
You can also go for two 8ohm speakers (higher total impedance is ok. lower total impedance is not), and then be prepared for the MVS setup.

As told before - MVS does not follow JAMMA standards, since it has a stereo output. You have to do some kind of smart switch to be able to change conveniently between the systems.
I'm not sure about CPS2, but doesn't that require an external amplifier?



* Impedance for speakers:
Series: 8 + 8 = 16ohm , 4 + 4 = 8ohm
Parallel: 8 + 8 = 4ohm , 4 + 4 = 2ohm

[Blanka]

We are not dealing with rocket science here. I think all options will work, series, parallel, wrong resistance.... as long as you are expecting classic arcade sound at low volume.
At higher powers these things can become problematic. Speakers in series can be very tricky then as the bounce creates current that flows into the other speaker. It also means that a lot of large (15-30cm) 8 ohm speakers can dip to 2 ohm in low frequencies at high powers, demanding a lot from the amplifier.
If you want better acoustic performance, try a separate amp with some speakers with headroom (50 watt).

[mr aize]

Thanks everyone, that's cleared things up a lot.