Solved: What potentiometer to use

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Hi guys i was reparing my 2.1 PC speaker but i broke the stereo potentiometer so i need help

choosing one. On original broken i see B5 K text wich means 5KOhm stereo so is a little dificult

to find same so i found one in store but is 50KOhm so what will be the different or what is positive

and what is negative of use 50KOhm instead 5KOhm.

 

Thanks for advice.

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Last Edited: Wed. Sep 23, 2020 - 09:27 PM
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Whether or not 50K will work instead of 5K depends entirely on the circuit that uses that potentiometer. We cannot know what that is.

 

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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Thank you Jim it,s a 2.1 PC speaker using 3X TDA2030A and it,s simple stereo volume control potentiometer 

so i drop down the PCB and potentiometer has broke all 6 pins it,s unusaly to broke like that but it did so

i,m not expert about potentiometer and better ask. 

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What you have may be a dual 5K audio taper pot. However, the information given thus far gives us no clue as to what it actually is.

We also have no idea what might look like or how it is actuated. For example:

        Google Images of Stereo Pot

 

I do not have a stereoastrotemporalteliopticon to see what you see.

 

Edit: You may be able to determine the taper of the pot using an ohmmeter to verify its value and whether it is an audio/log taper rather than linear taper.

 

 

 

David

Last Edited: Sat. Sep 19, 2020 - 07:52 PM
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Just out of interest is this about Denon AVR hi-fi or is it about Atmel/Microchip AVR microcontrollers? As they are both "electronics " they can be confused.

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Sorry i upload now photo but i can,t  using an ohmmeter  because pins are broken so i glue the pins to be only for photo and diameter when searching in stores

so this is the original potentiometer on the pictures. 

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No about simple potentiomete what is a difference if original is 5KOhm can i use 50KOhm for volume on 2.1 PC Speakers.

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Linear I guess from this info

 

 

 

A replacement that fits seems unlikely, so this is where hacking occurs.

 

The input impedance of the preamp (where volume is controlled) will tell you if 50k Ohm is OK (probably not).

Last Edited: Sat. Sep 19, 2020 - 09:27 PM
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Ok i figured out that is linear B i was googling so my next question is:

The original is B5KOhms but on the PCB is 50KOhm so it,s hard to

find 5KOhm stereo pot, and what will be different if i use 50KOhm

potentiometer?

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Which picture is the NEW pot?

 

Unless you have a schematic, your search means nothing, since you don't know if it is 5 k in series with a 3 k resistor (then 50k will be horribly out of balance).  Again, without the circuit, you won't be able to say.  If the part is independent (uses no other resistors), then  whether the pot is 2k or 10 k or 75k won't matter much.  Your schematic tells the story.

 

1K 5K 10K 50K, 100K etc are all very very common pot values, so they are telling you a lie if they say it is hard to find.

 

https://www.mouser.com/datasheet...

 

So maybe just install & try it out.  In a few minutes you will know.

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Sat. Sep 19, 2020 - 10:42 PM
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It's not a critical application, so just about any value will 'work'. The worst case outcome would be the volume to turn angle response might be a bit different.

 

If you're worried about the outcome, then you shouldn't be touching the stuff. For those of us who are adventurous, we would've tried it already and found out quickly whether it worked or not.

 

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Thank you man i,m not worried at all i just ask to know if will something change in sound or level 

because i don,t have shematics of this PC 2.1 Spreakers i do build for me amplifiers but only with

shematcs diagram and it,s hard to find shematics for PC speakers it,s DELUX not some high end Brand

or speakers but in my suprise have a very good sound so for one potentiometer i don,t like to throw away

it realy sound good.

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Here you can see where the output is the same regardless of the pot & a simple example where the wrong pot will give a wrong level.

That is why knowing the circuit is critical

 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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The output impedance of whatever provides Vin and input impedance of whatever receives Vout could be important ...

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You should use a 5K pot because very often a technique using a load resistor is deployed to "convert" a linear pot into a logarithmic pot.

 

https://www.electro-tech-online.com/articles/audio-taper-response-from-modified-linear-potentiometer.738/

 

This generally works better than a cheap LOG potentiometer especially for stereo audio where  you need good matching between channels.

 

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The output impedance of whatever provides Vin and input impedance of whatever receives Vout could be important ... 

Hence the word likely...the OP seemed rather entirely lacking any experience with this.  You need the schematic to really know if the pot ohms is important (often just turn it up down more)

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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avrcandies wrote:
Hence the word likely...

Indeed - and hence I said "... could ..."

 

You need the schematic to really know if the pot ohms is important

absolutely.

 

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How old is the amp? From the pictures you posted, the pot looks "too good" to be a 1 cent Chinese piece of junk. It looks more like Japanese to me, or maybe even USA. And, being an audio volume control, it's most likely a log taper, not linear.

 

As for whether or not a 50k will work in place of a 5k... it depends on the circuit. If it's just tapping off a percentage of audio and sending it to a high input impedance amplifier, then yes it will work. If the amplifier as a lower input impedance, or if the pot is part of a gain control loop (negative feedback), then it probably won't work PROPERLY.

 

What may happen is that your volume will be very low through most of the pot rotation range, then the last few degrees of rotation will go from quiet to full blast. Or, the other way around... full volume until turned all the way down, then quiet at the end of rotation.

 

With all that said, I'm sure you can buy a 5k log taper pot from Amazon, Digi-Key, Newark,... lots of places for probably $3 US or less.

 

Gentlemen may prefer Blondes, but Real Men prefer Redheads!

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Hello, 

There are two separate potentiometer units on one shaft in this device.   Yes, both units are 5K ohm and it is a linear pot that is feeding a voltage-controlled amplifier circuit.   Test it with your voltmeter.  There are six pins: three in a row [left:center:right] for both the left and the right channel volume pots.   Between left and right will be 5K ohms, and the center tab (the wiper) will change resistance according to the shaft's turned-to position.    It will probably work fine, and could most-likely be re-mounted into the PCB holes that it came out of.   You could use two ordinary 5K pots, or possibly 1K-10K ohm pots.  Even trim pots or thumb-wheel pots would work.

 

I find it hard to believe that you "broke" this pot.   There appears to be no visible physical damage to the device, and they are nearly indestructible when they are mounted into a circuit.  If the pot is still fine, then something else is wrong.  Is there no sound at all?  no sound on a single channel (L, R, bass)?  distorted sound on all channels?  distorted sound on one channel?

 

Another possiblility would be to replace the whole 3X board with this $9 eBay unit: https://www.ebay.com/itm/TDA2030...

Then you could experiment on the old unit without being very depressed if  you "smoke"(destroy accidentally)  the PC speaker board AND now have no computer sound at all.

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In the old days, you could get pulled over....

    What's that on the dash?

 

Oh, that's my 2K pot, I have a bunch more in the trunk 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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Simonetta wrote:
it is a linear pot

How do you know that?

 

that is feeding a voltage-controlled amplifier circuit.

How do you know that?

 

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avrcandies wrote:
What's that on the dash?

Reminds me of back in the '80s when I was having a design discussion with a colleague over lunch...

We hadn't paid any attention to the officers at the next table until one came over and asked us about the "trimming the pot capacity(sic) & resistance."

 

Fortunately, we had our napkin sketches and ID badges ...

David

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Simonetta wrote:
and they are nearly indestructible

I'll call bollocks on that one. Those cheapo pots break as soon as you look at them. The #1 photo clearly shows a crack in the SRBP.

 

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N.Winterbottom wrote:
The #1 photo clearly shows a crack in the SRBP.

and #6 clearly states that it's been glued together for the photo

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What's the confusion about whether the pot is log or linear? It shows a B 5K in the number.

 

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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It's a linear pot because of the "B" next to the "5K", as indicated by the photo in a previous post.

 

It feeds a VCA because the wiper voltage of a 5000 ohm is not enough to directly drive an output transistor stage of 18 W per channel.  All the images on Google for 3X TDA2030A PCB show three of these ICs on each board design. This is an IC that takes a linear audio input and outputs an 18W max power signal to a room speaker.

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Simonetta wrote:
It feeds a VCA because the wiper voltage of a 5000 ohm is not enough...

It feeds an amplifier, sure - but how do you know specifically that it's a Voltage-Controlled Amplifier (VCA) ?

 

The  TDA2030 is not a VCA - it's just an amplifier.

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I know that but i cannot find circiut diagram because i,t s a PC Speaker not clasic Amlifier and on 

PCB has a mark 50KOhm but on Potentiometer is B5K that i need some advice. :)

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I know that but i cannot find circiut diagram because i,t s a PC Speaker not clasic Amlifier and on 

PCB has a mark 50KOhm but on Potentiometer is B5K that i need some advice. :)

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Thanks a lot man 

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I know that but i cannot find circiut diagram because i,t s a PC Speaker not clasic Amlifier and on 

PCB has a mark 50KOhm but on Potentiometer is B5K that i need some advice. :)

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I know that but i cannot find circiut diagram because i,t s a PC Speaker not clasic Amlifier and on 

PCB has a mark 50KOhm but on Potentiometer is B5K that i need some advice. :)

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Thanks man it, is not clasic Amplifier it,s a 2.1 PC Speaker with TDA2030A 3 of them it takes audio out from PC -Computer out and output is 4,Ohm Speaker 20W Woofer and 2X 4,Ohm 10W Tweeter 

so it,s strange on PCB has mark 50,KOhm and the potentiometer is marked B5K i broke all 6 pin and i have no chance to measure it.

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:) Believe or not i broke this pot. The Power Capacitor whas blown so i change the two same 2200mF 25V and 

because is almost 10 year power ON and is turned OFF only when is power loss so i deside to chage 4 more

capacitors 2X  2,2mF 16V  and 2X 220mF 16V to refresh it and when i asseble the board to the woofer box i

suddenly drop the board and then gues what? The pot was broken so glue the pin to find same pot on store

but they have not in stock so i need to whait so that ehay i ask if i can use 50KOhm pot.

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Using your DMM, you may be able to measure the resistance of what little of the carbon track remains. I'm sure you can tell the difference between 5K and 50K by compensating for the angular distance you can actually measure.

 

This reply has been marked as the solution. 
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I find one original and i fix it so now is working good.

 

Thanks for all who respond to my questions so this tread can be closed now.

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Thanks for feeding back.

 

Please see Tip #5 in my signature, below, for how to properly mark a thread as solved:

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Unfortunately, that pot is a custom part, you may get lucky looking for it on aliexpress, or by contacting the maker of the speaker to see if they sell replacement parts, but the cost maybe more then the speaker system itself.  So most likely you will just need to mark this up to lesson learned, and buy a replacement speaker system.

 

 

(Possum Lodge oath) Quando omni flunkus, moritati.

"I thought growing old would take longer"

 

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Hi ki0bk i foud one like the original first they told me in the shop that is out of stock then we found it on some shell so thanks everyone.

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Sorry i,m new here but i learn quickly :)