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(Topic ID: 265033)

Electronics help: How can to quiet chimes and bells with resistors?


By System-J

7 months ago



Topic Stats

  • 40 posts
  • 17 Pinsiders participating
  • Latest reply 6 months ago by System-J
  • Topic is favorited by 1 Pinsider

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#1 7 months ago

Hi!
So I'm isolating in my semi-detached house. I want to play my pins more often but I'm also trying to be courteous to my wife and neighbours (even though my wife doesn't mind too much and I hate my one nutcase neighbour, I still would prefer not to cause any more tensions than we already have--alright, alright, I'll get on with it already):
So, I've heard people refer to the possibility of adding resistors to chimes and bells, but I can't find any specifics. For instance what value of resistor and does it matter what lug it goes on?
So more specifically, and I'm not sure if this matters, but I have a Stern Stars, a Gottlieb Dragon (retrofited with chimes), and a Williams Space Mission. I also have a Black Knight and Grand Lizard I'd like to quiet the bells on.
I've already tried the cloth trick but they're still not quiet enough. I've also added rubber and tape to the bells (and have tried other things) but again would like to try a resistor to find out the effect.
If anyone has advice, I'd love to hear from you. Even if it's just a electronics theory guess.
Thanks ahead of time.

#2 7 months ago

Could always just disconnect the chimes and bells for now.

#3 7 months ago

By cloth trick, do you mean putting an entire hand towel on top of the chimes?

#4 7 months ago

I'm hoping not to have to go that far. Sound is a big part of a game for me. Although I love pinball, I find the sound of a ball rolling around a playfield disappointing.

#5 7 months ago

Ya, I usually use a Terry cloth or something similarly sized. I fold it so it hangs over the chime box a bit and use electrical tape to hold it from sliding off.

#6 7 months ago

A resistor would need very high wattage. A cushion or other thick padded covering is best. you could also try covering the chime box so the sound has no echo.

#7 7 months ago

The chime coil gets quite short pulses, so something like 10 ohm/5 watt resistor could work. But I also think putting some kind of cushioning between plunger and chime bar would be the best solution. Some adhesive felt pads or foam rubber maybe?

With a resistor, there always possibility that the plunger does not hit the chime bar. It is designed so that when activated, the plunger "overshoots" striking the chime and then returning back slightly. Otherwise, if the plunger when energized keeps touching the chime, it would dampen the sound. With a resistor, the overshoot might not happen and plungers just jump up and down without ever reaching the chimes.

#8 7 months ago

Have you contemplated a My Pillow for sound suppression ?pasted_image (resized).png

#9 7 months ago

But seriously folks, Mike Lindell looks great in blue.

#10 7 months ago

I own a My Pillow. Best damn $40 pillow on the market.

#11 7 months ago

Thanks guys for the replies. Very helpful (especially the pillow one ).
So the reason I'd like to find another solution than using tape, rubber, felt and/or towels is because I *think* it might be dampening the sound in a non-ideal way. For instance, when they are not dampened, say in a bar or someones carpeted personal arcade, chimes (and bells) have a sharp PING with a reverberation after. I find using tape and cloth takes this away. Plus the high pitch isn't the sound that travels through wall, it's more of the initial impact (treble vs bass). So, overall, I just want to turn down the volume without losing the sweet PINGS (Besides, putting more flammable things in a pin doesn't seem ideal).
So I want to experiment (safely as possible) on reducing the power of the coil themselves. I found one post from ages ago where someone was recommending a ceramic resistor for a out of control VUK (I think...anyways he was trying to weaken the coil):
https://pinside.com/pinball/forum/topic/how-to-weaken-a-coil
One of the posters recommended trying a 25 watt 4 ohm ceramic resistor. And BigAl touched on this above (thanks BigAl!). What I was hoping for is someone who has already tried something like this to recommend a value and share what the effect was.
I suppose I could look up the ohms of the coil, then get a resistor for however much percentage I want to reduce the sound by.
Looking through my supplies, I only have a 10W680RJ ceramic resistor. I was hoping to try it just to see, but it might be under wattage and too high of ohms. Separately, it seems that 25watts are much less common than 10 watts overall. So does anyone know if 10 watts is too weak, or are people just going overkill with the 25watts? Or even any kind of links to how to calculate what values would be needed?

#12 7 months ago

If you prefer not to mess with the chime unit so the sound is unaltered maybe you could surround it totally/partially with an open ended box lined with foam or whatever, to just reduce the volume... that is if you have room to put it around the unit where the open end is against the side of the cabinet. Sounds like a lot of trouble though. Would be great for the loud-as-hell ringer on BK though, I imagine trying to quiet that would make it sound lousy. Maybe isolate that one from the cabinet by putting a rubber bushing where it mounts, I think it's screwed directly to the cabinet.

#13 7 months ago

I have a number of low ohm high watt resistors from a Radio Shack parts buy out. If you want me to send you some to play with PM me. I have in great number: 50 ohm 10 watts, 10 ohm 10 watts, 1 ohm 10 watt and 8 ohm 20 watts.

#14 7 months ago

I often need to quiet a mechanical pump to prevent interference with acoustically sensitive lab equipment. The solution is placing an enclosure over it, made with some light MDF and lined with sound deadening material. (In the case of the pump, they also put out a LOT of heat so a vent and small fan must be added, but not necessary in this case.)

You can buy inexpensive sound deadening material with adhesive backing to make one. Also, the chime box is bolted to the bottom of the cab, so that must carry some of the initial strike sound, so a rubber mat under the box would help.

Try placing a cardboard box over the chimebox to get the idea what I'm talking about.

#15 7 months ago

While you're experimenting, try to determine what factors make the sounds louder or quieter.
If you strike with a lighter object at the same speed does the volume change?
If you change the size of the striking area does the volume change?
If you strike faster does the volume change?

You might think of other possible solutions if your experiments turn up something unexpected.

#16 7 months ago

Cardboard box. I like that idea. My Pillow is sold in a cardboard box.Neal_ W is on the right track
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#17 7 months ago

How about clamping something, like a small block of wood or several rubber-tipped clamps, to the chime bars or bell?

#18 7 months ago

How about this one - raising the chime bar grommets in tiny increments in their mounts, enough so that by the time the plunger hits it, it has slowed down a little more before it hits the chime and so will be quieter but with same impact sound? Like dialing that in until the plunger hit and the ring are quieter but it's not missing any 'hits' because it was raised a little too high. No idea if or how good it might work, just tossing it out there.

#19 7 months ago

The main sound that is going to travel is all the solenoids hitting their coil stops. There's no way to block this and still play the game. You may not hear this as the "pinball" sound, but people in other rooms do, and that's all they hear.

#20 7 months ago
Quoted from slochar:

The main sound that is going to travel is all the solenoids hitting their coil stops. There's no way to block this and still play the game. You may not hear this as the "pinball" sound, but people in other rooms do, and that's all they hear.

Seems like insulating the whole chime unit from where it's mounted would blunt it a little or a lot depending on how was done. I'd think just the plunger falling back on its coil stop would be barely audible with the door closed if the unit was mounted so there's a good deadener between it and the cabinet. I dunno like felt, or insulating it with rubber grommets at the mount holes, so the unit is only contacting the grommets.

#21 7 months ago

I'm not referring to just the chime unit - I mean all the mechanisms in the machine, that's where the noise is coming from that travels between walls.

#22 7 months ago

1 Record the sounds of the chimes and make them into MP3s.
2 Disconnect the chimes.
3 Install a MP3 trigger sound board with a speaker and a volume control.

Problem solved

#23 7 months ago

frenchmarky @ Ya, I'd rather not mess with them either, but they are way too loud for my house. I've even installed rugs on the walls in some spots and added sound absorbing material (fireproof) in empty spots in the cabinet. It's not enough.
Re: raising grommets. Messing with those things also changes the sound. Williams chimes are a good example. They often sound horrible because the fasteners and washers get worn.

TheWiz: You're awesome to offer and those 8ohm 20watts might work perfect, but I'm up in Canada and shipping up here is more complicated and expensive. I'd pay the shipping but I'd still feel like it would be too much trouble to put you through. But what's your thoughts, theoretically, on what value would be to reduce the force from 30-60%? ...even if it's a guess.

Neal_W : I've heard about and contemplated using a container around the box. It makes sense that it'll work. I've hesitated due to adding any flammable material such as carboard around anything that might arc (I know it sounds paranoid, but I'd rather error on safety. My wife calls me "safety guy"). I'm not ruling out using something less ignitable like mdf, but it seems like a lot more work than soldering on a resistor.

YeOldPinPlayer: You must be a scientist or engineer. This is defiantly the way to approach this. I'll try to brainstorm and think about those things as I go along.

Mikat11: I usually use 2 pillows when I sleep making a "head sandwich". But now you got me thinking I'm doing it all wrong. I'll try placing a box over my head tonight--maybe cut a semicircle hole for around my neck.

jibmums :I'm pretty sure that'll have a similar effect to the towels and reduce/kill the high PING reverb.

slochar: RE:solenoids hitting their coil stops.: Yes, absolutely. I've already done other things such as sound absorbing (fireproof) materials in the box (in empty areas) and rubber feet. You can do only so much for that but the chimes will often still be too loud, they can travel through the house and find thinner wall to go through. On my SS's I have the volume down to under 10% and it's fine. But Pins were made for arcades and the sounds were defaulted at loud to probably attract attention--for some reason they didn't take nostalgic future collectors who have hardwood floors into account. Jerks. Couldn've at least installed a volume knob on chimes and bells.

xsvtoys: My latest project was a BK. Every board had problems! The sound was the last thing I worked on because of parts and going through the game in a methodical manner. The game SUCKS without sound. I would play the PAPA gameplay video when I played it. . Luckily I've got it working now and having Mark Ritchie laugh at me has been my most satisfying Pin repair I've done to date.

#24 7 months ago

Ok, so I've done a bit more coil specific research hoping to make an order for resistors.
So I've able to find the ohms resistance from John Jukes website:
https://www.flippers.com/coil-resistance.html

So the stern stars chimes coils (n-31 2000) are 48.8 ohms
The Gottlieb dragon retrograde chimes (a-17876) are 24 ohms
The bk bell (sm-27 1000) is 10.6

Can anyone give any advice, electronic theory, or website leads on how I would go about figuring out what resistance I should try?
And it seems people recommend a high wattage resistor, how would I find out what wattage is being passed through the coils?

Also, I know some basic electrical theory, and I thought it was that the current actually flows from negative to positive. So, I've seen in other posts saying to connect the resistor to the positive lead. Can anyone confirm this is the correct way to install a resistor?

#25 7 months ago

Doesn't matter where you put the resistor it's going to resist either way.

https://www.easycalculation.com/physics/classical-physics/voltage-drop-across-resistor.php

#26 7 months ago
Quoted from System-J:

Can anyone give any advice, electronic theory, or website leads on how I would go about figuring out what resistance I should try?

http://www.ohmslawcalculator.com/ohms-law-calculator
You can see what effect increasing the resistance will have on the current.
V=I*R is the basic form of Ohm’s Law. Dividing both sides by I gives you V/I=R

Looking at a graph may help you understand the relationship. https://ohmlaw.com/how-slope-of-a-voltage-current-graph-relates-to-resistance/

#27 7 months ago

V=IR will get you a long way!!

As to which way the current flows (DC), well that's a topic of long debate. But in the end it doesn't matter, pick a direction and design around it. The key is that it is going one way, as opposed to back and forth 2 ways like AC. Most of the time when we look at DC circuits we thing about it as going from positive to negative, as per convention that goes back a long time. But its actually going from negative to positive. Probably.

Resistors don't have any +/- orientation, they work the same in either orientation. Capacitors, diodes, and some other stuff, not so much.

There is a ton of cool stuff out there to learn about circuits. The books by Platt are very good I think. Such as Make Electronics 2nd edition

amazon.com link »

There are plenty of others.

#28 7 months ago

In a pinch to get a game working I have put a low ohm power resistor in series with a stronger coil. BSD kickout to left inlane. Worked fine and have left it that way for a few years now.

I had to tinker with the value to get it the strength i wanted. I think i ended up with a few 3w of equal value resistors in parallel.

#29 7 months ago

Thanks for the response guys, great advice! I've been taught and have self-learned ohm's law a few times, now I have to do the tough step and to put it into practice. Looks like I've got some homework to do.

barakandl : you only used 3w resistors? Everyone seems to recommend over 20w that I've seen, are they holding up ok?

#30 7 months ago
Quoted from System-J:

you only used 3w resistors?

Quoted from barakandl:

i ended up with a few 3w of equal value resistors in parallel.

In parallel is the key. Splitting the load between several resistors in this application. BTW https://nvram.weebly.com/ is barakandl ’s site. If you need what he has buy with confidence.

#31 7 months ago

Been watching this thread, interested if this resistor theory will work.
I don’t think you can get the coil weak enough to make a big difference in the sound without the coil being so weak it can’t draw the plunger up from rest.
That made me think that in addition to weakening the coil, I would shim the plungers to have a lot less travel, and that made me think that alone might do what you are trying.
Have you tried just shimming the plunger to only have like 1/2” of travel?
That alone might work.

#32 7 months ago

A resistor can be used but it isn't pretty.
If you know the coil voltage and and the coil resistance then you can determine how much current travels through the coil and how much power it is dissipating while energized.

Using round values for an example: 48V source and a 4 ohm coil -- you have (48V / 4 ohms) or 12 amps.
During the on period - the coil is dissipating (48V * 12A) = 576 watts. That puppy is going to get hot if locked on!

Adding a series resistor will lower the voltage drop across the coil which will reduce the current flow and the power dissipated (and physical power transferred to chime).

Suppose you add a 1 ohm (pretty high value) resistor in series with coil:
(48 volts / (4 ohms + 1 ohm)) = 9.6 amps. You have reduced the coil current and power to 80%.
Power dissipated by both coil and resistor = (48V * 9.6A) = 460 watts. A lot less but still quite a bit.
Power dissipated by coil only = ((9.6A * 9.6A) * 4 ohms) = 368 watts.
Power dissipated by resistor only = (9.6A * 9.6A) * 1 ohm) = 92 watts.
In a locked on coil - it will be a race to see which burns up first - the coil or the resistor (assuming the fuse doesn't blow first).
Theoretically, for the resistor to survive and everything else still burn up - you need a 200W resistor (don't go above 50% rated power).

Thankfully, coils don't lock on very often and are protected by fuses when they do.
The actual wattage of resistor you need depends on how often the coil is pulsed and for how long.
As long as the resistor is allowed to cool between activation cycles then you're covered.

The hard part is figuring out the wattage value for the resistor required for these pulse overloads. There have been studies done on most resistor types for pulse overloads but I have never read them so can't go any further on that one.

Many resistors have a pulse overload test performed by manufacturer. This pulse overload test is typically performed at 4x rated power and typically at 1 second on, 25 seconds off. Coils are typically on for only milliseconds at a time with more than 25x inactive gaps between. My seat of pants guess would be that a 20W part (still a whopping 10x pulse overload) would work in a properly working circuit. Locked coil and all bets are off. I would love to see how many pieces a quarter watt carbon film resistor would burst into if this was tried.

#33 7 months ago

Man, the replies on this post are getting better and better.

@yeold: Ahhh, I get it. Makes sense. Thanks for the heads up with @barakadl. I've heard great things from friends who've dealt with his business.

dno: yes! You're definitely on to something here. I've got some extra rubber sheets, I'm going to cut them and try this out. I can't believe I have seen anyone else recommend that in other posts. If you just thought of that, kudos my man.

@GPE: ...I'm not worthy, I'm not worthy! ... But seriously, thanks so much. This fills in some blanks that would've taken me ages to figure out (if ever) on my own.

#34 7 months ago

Resistor clump is about 4.8 ohm and the coil resistance is 4 ohm for total resistance of 8.8 ohm.

No evidence the resistors have been overheated.

I actually did buy the right coil just never got around to proper fix since it works fine.
20200403_211206 (resized).jpg

Stern Meteor and Stern Seawitch had a power resistor in series with a flipper coil. Probably because an upper flipper so close to drop targets they where getting busted. I can't remember the value Stern used, but it might be included in a wiring diagram.

#35 6 months ago
Quoted from barakandl:

Resistor clump is about 4.8 ohm and the coil resistance is 4 ohm for total resistance of 8.8 ohm.
No evidence the resistors have been overheated.
I actually did buy the right coil just never got around to proper fix since it works fine.
[quoted image]
Stern Meteor and Stern Seawitch had a power resistor in series with a flipper coil. Probably because an upper flipper so close to drop targets they where getting busted. I can't remember the value Stern used, but it might be included in a wiring diagram.

Those are in parallel aren't they? If that's the case the calculations seem quite a bit more complicated (but if it works, it works, right?). I wonder if in parallel (again, if these are in), if the wattage load is dissipated more than it in series.
https://www.dummies.com/programming/electronics/components/electronics-components-combine-resistors-in-series-and-parallel/

I did an experiment with shimming the plungers (thanks for the lead DNO) It definitely made a difference, but not enough to remove the towel for my liking unfortunately. I took some amateur db measurements and I'll post it later.

#36 6 months ago
Quoted from barakandl:

Stern Meteor and Stern Seawitch had a power resistor in series with a flipper coil. Probably because an upper flipper so close to drop targets they where getting busted. I can't remember the value Stern used, but it might be included in a wiring diagram.

My Lightning manual says for games with extra flippers sometimes a 1 ohm 5 watt resistor is used to reduce power.

#37 6 months ago
Quoted from System-J:

Those are in parallel aren't they? If that's the case the calculations seem quite a bit more complicated (but if it works, it works, right?). I wonder if in parallel (again, if these are in), if the wattage load is dissipated more than it in series.
https://www.dummies.com/programming/electronics/components/electronics-components-combine-resistors-in-series-and-parallel/
I did an experiment with shimming the plungers (thanks for the lead DNO) It definitely made a difference, but not enough to remove the towel for my liking unfortunately. I took some amateur db measurements and I'll post it later.

There are multiple resistors of equal value (looks like each resistor is a 27R 3w) parallel to each other. But the resistor clump is in series with the coil.

#38 6 months ago

Here is a nice online calculator tool that you can use to help figure out parallel resistor values. And to think, I used to do this manually in college!

http://www.sengpielaudio.com/calculator-paralresist.htm

#39 6 months ago

The resistors look like 27 ohms to me also (Red-Violet-Black). However I think there are at least 4 of them, and probably 5. It looks like 5 total wires in each clump. You can see one partially hidden behind the front 3. They are wired in parallel which would make their total resistive value nominally 5.4 ohms which is somewhat close to the stated measurement of 4.8 ohms. (assuming 5 resistors, since they are in parallel and all the same value, then the total resistances is 27 divided by 5).

The dissipation of the wattage load isn't directly affected the the parallel resistors. Its the total resistance in the circuit that determines this, along with the current. Total resistance was stated to be 8.8 ohms.

That old standby V=IR always works. Or if you rework it you could say I=V/R. If the voltage is 48V then the current I is about 5.5 amps (divide 48 by 8.8).

The other handy equation is P=IV if you want to know the power (wattage). In this case it is 5.5 x 48 = 264 watts.

If you want to get fancy you can also calculate the power as V squared over R. That would be (48x48) / 8.8 = 262 watts. The minor difference is due to some rounding I did.

Based on all this, as as typical in pinball, this is not a circuit you would leave on for any length of time. The resistors would not handle the power. That is also why typical coils burn out if they are locked on. It is meant to be a transitory circuit. That's why coils that are on most of the time like a Lock relay have a much higher resistance (like 100 ohms), to cut the current down and therefore the power.

Assuming I got everything correct, I am not an electronic engineer, I just play one on the internet.

#40 6 months ago
Quoted from DNO:

Been watching this thread, interested if this resistor theory will work.
I don’t think you can get the coil weak enough to make a big difference in the sound without the coil being so weak it can’t draw the plunger up from rest.
That made me think that in addition to weakening the coil, I would shim the plungers to have a lot less travel, and that made me think that alone might do what you are trying.
Have you tried just shimming the plunger to only have like 1/2” of travel?
That alone might work.

So, a slight lateral movement on this post due to the great lead DNO gave me. I layered rubber under the classic stern plunger coils and took db measurements as I went. It only made a difference of 5db inside the cabinet (from around 70 down to 65) but with the glass on it made a huge difference. So much that I tried taking off the towels but found it again too loud--but in doing this I also found that the high ping reverb was back! I tried using a cardboard box (but fairly crudely) around the chimes unit but the db didn't seem to change. I also noticed that the box was uncomfortably close to some bare wires so I opted not to pursue this too further. But I'm still planning on trying this again on a bell as I know many people have had luck with this method.
A day after and some thought about it I tried layering wood under my Gottlieb Dragon chimes (a paint stir stick was perfect width). I pried up the foam and placed two layers underneath. Again, a huge difference (so much so, that it felt like each stir stick layer was 2-4 volume notches)! It was so quiet that I removed one of the two towels on the chimes and I noticed it sounded much better, yet still had a quieter volume than with just the towels.
So, ideally, I think there's going to be combination of shimming up the plungers and using resistors (I still haven't done my homework to find the ideal values and make an order) for the ideal sound while needed a reduced volume.
I also plan on trying some different towel/fabric options on top of the chimes now that the volume is lower from the shimming. So far the lighter the towel the more of that sweet pinging reverb can be heard.

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