speaker polarity question for Hanabi Hyakkei

[spooner]

I am wiring a stereo l-pad volume control into my Hanabi Hyakkei and have run into a little problem.

I do no know which speaker lead is negative and which is positive. The polarity does not seem to be marked on my speakers or amp. There is a pair of red and white wires that go to each speaker. In my experience, the positive lead would normally be the red wire, but I am not sure if this is the case in Japan.

Is there any way to tell which wire is which using an oscilloscope or a multimeter? Does it mater which is which as long as I am consistent between the two speakers?

Thanks in advance. ~spooner

[gwarzin]

In general it doesn't matter. The only time you could have a problem would be if 1) the case of your L-pad was internally connected to the L-pad's ground pin, AND 2) You mounted the L-pad in such a way that its case touched a grounded metal part in the pachislo.

If you are using the mono L-pad from Parts Express that is so popular among Pachitalk members, that case is NOT grounded. So there should be no issue.

[slotter]

I've done 4 Stereo L-Pad mods now... it doesn't make any difference + or -. (As you said, as long as you are consistent on the wiring.) I did go for black as negative, though. On one machine light brown was considered negative as no black...

[Firewire]

The only issue I have found is that my last install of an L-Pad resulted in min = max volume and vice versa. So that should be your worse case scenario (counterclockwise turns vol. up instead of down).

[slotter]

The only issue I have found is that my last install of an L-Pad resulted in min = max volume and vice versa. So that should be your worse case scenario (counterclockwise turns vol. up instead of down).

David, what caused that again? Did you accidentally use the red as the negative? The last L-Pad I did was on an IGT and they use red and light brown for the speaker wires... I opted to consider red as the positive and it worked fine. I did think of you, though, when doing that one. :wink:

[Firewire]

No, it was on my Giga Fever (Daido). I connected "Red" to position "3" on the L-Pad.

I thought Positive goes to 3, Negative to 2, and 1 on the L-Pad goes to amp Black.

[slotter]

OK... Here's my way of putting the diagram to words. Perhaps, will help someone:

Cut the black speaker wire and connect the speaker side of that cut wire to 2 and the amp side of the cut wire to 3.

Then splice into the red (no need to cut, just splice in) and connect that spliced in wire to 1.

Viola! :wink:

[Firewire]

Yep, I just got 1 & 3 backwards...... :oops:

[slotter]

Yep, I just got 1 & 3 backwards...... :oops:

Well, about 3 minutes with a soldering iron at the switch and you'll have it! :lol:

[spooner]

Thanks for all the great feedback. I will consider red to be positive and white for negative. If I end up being wrong, I will switch them.

Thanks for putting this into words slotter, this is the way I interpreted the diagram as well but it is nice to have confirmation.

Thanks again everyone. This place is great! ~spooner

[Kamehany]

Is this the ideal way to do it - with one for each speaker and ungrounded? Or is there another method (i.e. one that is all-in-one, grounded and covers all speakers as opposed to just one)? If you can't tell from my questions, I'm a total novice when it comes to electronics and wiring.

[gwarzin]

NEVER try to use a single mono L-pad for multiple speakers. This would end up connecting all channels of the amplifier together. Unless the amplifier has very good protection (which it probably doesn't) you will blow the output stages of the amplifier.

The only time this might work is if the pachislo has a single amplifier feeding all the speakers. Many of the better machines have stereo sound, which means they must have at least 2 separate amplifiers.

So, unless you know what you are doing, and can trace back the wiring, and determine with 100% confidence that all the speakers are being fed by one amplifier, you want to always use a separate L-pad for each speaker. It's just not the risk just to save $2.00.

[slotter]

Get a *stereo* L-Pad and you should be in good shape. Even if there is a third speaker in the back, if you regulate the front speakers, you'll probably be satisfied.

[gwarzin]

Stereo L-Pads are great, especially if you are trying to mount the L-pad with the shaft sticking through the side of the cabinet so you can adjust it without opening the door.

But, mono L-pads are usually easier to install. 1) They are smaller so you can more easily find places to mount them right along the speaker wire path. 2) Since you can mount them near the wires, you can usually just cut into the existing wires and won't have to splice in extra wire.

[Firewire]

Another thing is that L-Pads from Partsexpress.com are cheap. Stereo ones are like $4.25 (of course shipping doubles it so buy a couple).

[gwarzin]

I always buy the mono ones and I get them 10 at a time. That puts the price below $2.00.

[spooner]

Thanks for all of the great advice. Here is what I think I will do. I have a 15W stereo l-pad from parts express (I ordered 10 of them). For mounting in the HH machine, I plan to remove the plastic serial number panel on the left hand side of the coin tray (when facing the machine). Then, I will drill a hole for the L-Pad shaft through the plastic where the snap on was so I can mount the L-Pad just above the ashtray.

Yes, I know that I have to be really careful when I drill through the plastic. I think this is a cool place to mount the control for the following reasons:

• 1) i can get to it without opening the door
  2) if i decide to remove or change the type of volume control, all I have to do is remove it and put the plastic snap panel thingy back to cover the hole.
  3) i can leave the necked woman neon sign that i have on top of the machine where it is since the nob will not have to stick out the top.
  4) i have my machines jammed side to side due to lack of space so i cannot mount the control on the side.
  E) the l-pad will be located close to the amp where i plan to tap into the speaker wires.

Now I am ready to hear why this is a bad idea :wink:

Thanks again! ~spooner

[JamesM]

my machines jammed side to side due to lack of space

I wish I had that many :smt108

[Bilko44]

Spooner,

Would you take some pictures of your mod process and post them, here?

Do a before shot, steps in removing parts, fitting and connecting wires, and the after shot. That way you will provide our readers with a great modification project guide.

[spooner]

I wish I had that many

It is not a question of too many machines, but too little space!

Would you take some pictures of your mod process and post them, here?

Will do! All I have done so far is solder the wires to the l-pad. I will take before during and after photos as I go. And post them here when I am done.

It will likely be next week before I get around to actually doing this, but I will take care of it ASAP. The machine is virtually unplayable at the factory volume levels. At least in my book it is.

Thanks for the feedback. ~spooner