L-Pad Volume Mod

[Firewire]

This is a 50W stereo L-Pad volume mod from Partsexpress.com installed on a Outlaw.

http://www.pachitalk.com/pachislovol.JPG

http://www.pachitalk.com/L-Pad.jpg

L-Pad part # 260-260 $10.90 w/ knob

[azlew]

You did this for both speakers I assume? Do you have a wide range for the volume ?

[Firewire]

Yeah, I went with the Stereo instead of 2 mono's.

It gives more control than the Potentometer version from Radio Shack, but still only about 33% of the volume works. The rest is just play in the knob.

[arbycoffee]

why on the side ? why not on top, that way you culd put two or more machines next to each other.

than again this could one of my dumb questions, at my age i get to have four a month

:oops:

[Firewire]

why on the side ? why not on top, that way you culd put two or more machines next to each other.

than again this could one of my dumb questions, at my age i get to have four a month

:oops:

So my kids could turn it down too!

[arbycoffee]

see i did ask a dumb one but the end of the month is close, needed to use them up :lol:

[TeeDubya]

Question for anyone who is using L-Pads: Do you notice that the sound is distorted when you reduce the volume?

I decided to put a 50w stereo L-Pad (Parts Express #260-260) on my King Camel tweeters. At full volume, the sound is crystal clear. Reduce the volume and it's distorted. Doesn't seem like it should be doing that. Did I wire this bee-atch wrong or sumpin?

[gwarzin]

I'm not sure that an L-Pad is the right way to control the King Camel tweeters. I think they are a piezoelectric and don't behave like the resistive load of a normal speaker. Thus the normal advantage of an L-pad (keeping the resistance constant) does not apply.

My Camel came with simple variable resistors (the kind that Syscom installs in all their machines) in series with the tweeters. While I have found that these simple resistors don't work as well as L-pads on normal speakers, they do seem to work VERY well on the Sammy piezo tweeters.

[TeeDubya]

Thanks again, Gwarzin. I have seen those variable resistors for sale at the Syscom website, but I didn't know that they were resistors...I thought they were pots. Okay, now I know what to use.

[gwarzin]

Thanks again, Gwarzin. I have seen those variable resistors for sale at the Syscom website, but I didn't know that they were resistors...I thought they were pots. Okay, now I know what to use.

Technically they really are potentiometers (pots) because they have 3 pins. But the way Syscom uses them they have 2 of the pins soldered together. That pretty much turns them into simple variable resistors.

[gwarzin]

BTW, TeeDubya have you noticed that when the forum's spelling checker gets to TeeDubya it suggests "Dead beat" as a the correct spelling? :lol:

[TeeDubya]

:lol: That spell checker is a hateful thing, is it not? I assure you and the rest of the fine users of this forum that nothing could be further from the truth. Deadbeat? I don't think so...

Just the other day, it tried to replace "pachislo" with "patchily." Is that a word???

[Firewire]

TeeDubya,

I have only purchased one of those L-Pads, but I encountered the same thing and chalked it up to me or my specific machine.

Now that I have done the radio shack mod the level of usefullness is even less (about 1/4 turn), but the distortion isn't there.

:smt102

[TeeDubya]

Thanks, David. I ordered a set of 5 variable resistor devices from Syscom yesterday. Maybe I'll do better with those. The distortion from the L-Pad is totally unacceptable. Parts Express is selling these things to people who are into DIY speaker construction? Unbelievable...may as well throw 'em out!

[Ken Layton]

Another way to control the volume is with a rheostat. Atari used a 50 ohm 12 watt rheostat as the volume control for a great many of their classic video arcade games like Pole Position and Centipede to name a few. They designed their audio system so the amplifier was running at FULL VOLUME at all times. The volume was controlled by a rheostat next to the hinge inside the coin door. Drive-in theater speakers also use this system.

The rheostat in Atari games is an Ohmite # RES-50 which you can get at Mouser Electronics (www.mouser.com) as their part number of 588-RES-50 (around $20.). You'd be surprised at how small these rheostats are. They wire just like an L-pad.

[arbycoffee]

Good to have you Ken,
Thanks for the info, Cool Beaners

[Firewire]

Definitely glad to have you here Ken!

This guy is good with Electronics everybody!

[slotter]

I really thought I could live with the sound from my DDK and Cont 4X but my ears are taking a beating. After a BB, the ears literally ring even on the low factory volume setting. Am going to install the stereo L-Pads referenced elseware from PartsExpress. Looked through the various options and think will put the volume control on the outside left side of the cabinet. The partsexpress URL for the stereo pad:

http://www.partsexpress.com/pe/showd...number=260-251

[slotter]

I installed the 15W stereo L-pad from Parts Express today on the Cont XXXX and the sound is good. Not messed up at all. Works like a champ on that machine, anyhow. :lol:

The DDK isn't as loud as the Cont 4X was and am not sure if I really need to install anything on that one.

Which machines does the L-Pad work with and which ones should be regulated with resistors? Which machines have the piezo speakers, in other words. People need to know, so they don't waste time and money doing the wrong mods.

[arbycoffee]

M, If it's loud, I find the switch if it has one (all most all do) put it the softest setting, if still to loud, I cotton ball it.
I got this big bag of cotton balls, maybe 2,000, I just got to use them up.
Think of all them bunnies with out their ballshttp://www.users.qwest.net/~arbycoff...happydance.gif