Gain Pot Bypass..
jakelm
Posts: 4,081
Some of us touched on this subject, in another thread. Just thought I would start a new thread here, for absolutly no reason,..,,,,lol:p
Anyways, some of you know, I am in the process of either bypassing or changing out my gain controls on my B&K amp.
I run my gains at max, so bypassing seems logical (less parts in the signal path), but with no luck, I have tried many different ways to bypass. 3 leads are soldered to the board, per pot, per channel. I have tried connecting, lead, 1/2, 2/3, 1/2/3, 1/3. Not one of those different connections seem to do the trick.
I wanted to get opinions on what you would do. It seems to be a real PITA, to be quick enough to unsolder all 3 leads to get the pot off, to test the value for replacement. I quickly ran out of patience trying to do this.
Would you bypass? If so, how?
Or would you replace?
Jake
Anyways, some of you know, I am in the process of either bypassing or changing out my gain controls on my B&K amp.
I run my gains at max, so bypassing seems logical (less parts in the signal path), but with no luck, I have tried many different ways to bypass. 3 leads are soldered to the board, per pot, per channel. I have tried connecting, lead, 1/2, 2/3, 1/2/3, 1/3. Not one of those different connections seem to do the trick.
I wanted to get opinions on what you would do. It seems to be a real PITA, to be quick enough to unsolder all 3 leads to get the pot off, to test the value for replacement. I quickly ran out of patience trying to do this.
Would you bypass? If so, how?
Or would you replace?
Jake
Monitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek:
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek:
Post edited by jakelm on
Comments
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Turn the volume down to the minimum(mute), and then short out 1/2, 2/3 and 1/3 until the signal reappears as it should.
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Turn the volume down to the minimum(mute), and then short out 1/2, 2/3 and 1/3 until the signal reappears as it should.
I did, it didnt work. I'm thinking it might be because the pot might be so bad , that its shorting out the signal.
I will try again tonight.Monitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek: -
Look closely at the board to determine if there is a trace that connects one leg of each pot together. If yes, this is the ground and ignore it. You want to short the other 2 leads.
The middle lead is guaranteed to be the wiper, or output signal.
Remember that a lot of newer amps can use linear pots and op-amps instead of the usual log pot. You're on your own if this is your case.
Wait a minute, from your initial post, you've already removed the pots? -
Look closely at the board to determine if there is a trace that connects one leg of each pot together. If yes, this is the ground and ignore it. You want to short the other 2 leads.
The middle lead is guaranteed to be the wiper, or output signal.
Remember that a lot of newer amps can use linear pots and op-amps instead of the usual log pot. You're on your own if this is your case.
Wait a minute, from your initial post, you've already removed the pots?
No I have not removed the pots yet.
I'm thinking these pots are looped back to the amp board. Thats maybe why they cant be bypassed in the traditional way.
But what do I know...:oMonitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek: -
Did you say got pot wiseass.
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Without having a schematic to show how they have the pot connected (ie. is it at the input or in the feedback loop of an op amp etc)then I would leave it as is.;)Testing
Testing
Testing -
You need a solder sucker, or solder wick to remove the pot. You will not get all three leads hot enough at the same time to just pull it off. You need to remove the solder.
Here is a page describing the various ways to wire a pot:
http://sound.westhost.com/pots.htm
It should be easy to determine which lead is ground, then it is a matter of connecting the other two leads together. -
You need a solder sucker, or solder wick to remove the pot. You will not get all three leads hot enough at the same time to just pull it off. You need to remove the solder.
Here is a page describing the various ways to wire a pot:
http://sound.westhost.com/pots.htm
It should be easy to determine which lead is ground, then it is a matter of connecting the other two leads together.
Thanks Will.
So a pot will not be looped back to the amp board in mid stride, making bypassing unaccomplishable?Monitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek: -
If the pot still has a sticker on it, look for something like 50kA. The A or B confirms the taper.
Also, see if there is a lead going straight from the input jack to the pot. If yes, this should be a traditional pot and using a jumper will work. -
I'm not sure what you mean by looped back. Usually, there is an "in", an "out", and a ground.The in and out need to be connected together. I have never tried this with the pot still in place.
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Thanks guys I will take another shot at the pot tonight..Monitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek: -
I'm not sure what you mean by looped back. Usually, there is an "in", an "out", and a ground.The in and out need to be connected together. I have never tried this with the pot still in place.
It seems to not work so well with the pot in place. Something wierd is going on when trying to bypass with the pot still there.Monitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek: -
Just an update.
I was able to bypass the pots with the pots removed from the circuit. Bypassing pots with pots on board, failed.
Anyways. I took a couple of shots of the pots, hoping you guys can help me on this.
On the back, reads : A50k 56w
I know now they are 50kohms, but the 56W??? What is that? It cant mean 56 watts, they dont make pots that big.
In my searching for new pots, all I found was 1/2 watt with a rounded bottum. You can see in my pics that the bottum of my pots are square. Any help would be appreciated.Monitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek: -
More..Monitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek: -
Parts express has this, but its tapered and with leads that are round at the bottum. I don think this will work. Its 1/2 watt also, but I dont know if thats the right wattage.
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=023-550Monitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek: -
100w pots do exist, but they are usually variable resistors without the ground lead. The body is usually made of ceramic and can weigh just under 5 pounds. They're not cheap either.
Anyways, I thought you intended to bypass the pots for the sake of quality. Are you trying to replace them now because they were dirty?
Now I can't remember which taper is which. I think 'A' is log or audio taper. Do not replace with a linear taper pot, the sensitivity will be thrown way off. -
I would like to replace eventually, if later I decide to upgrade and sell it, I would like to put it back to spec.
I read Log/Audio = "A" code , which is what is stamped, "A50k"
I thought tapered ment curved bottom? Instead of square like mine?
It looks to be the same size as the 1/2 watt, but there are no marking as to what wattage it is. Just a mark that says "56W", but it cant mean 56 watts?
Parts express says Audio 1/2 watt, I wonder if thats a hint to what is commonly used.Monitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek: -
It does sound great bypassed, but I didn notice signal leakage when amp is turned off. But I think sinse there is no resistance, it is normalMonitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek: -
I get noise on mine with the volume shorted because of the cheap **** source *sigh*.
It is a 1/4w or 1/2 watt model, that's for sure.
Taper refers to how fast the resistance changes when turning the knob. Constant change is a linear taper. Log taper is just that, a logarithmic change with constant motion of the knob.
56W is probably a lot or model number. -
I get noise on mine with the volume shorted because of the cheap **** source *sigh*.
It is a 1/4w or 1/2 watt model, that's for sure.
Taper refers to how fast the resistance changes when turning the knob. Constant change is a linear taper. Log taper is just that, a logarithmic change with constant motion of the knob.
56W is probably a lot or model number.
Thanks Ace, for all of your help.:)Monitor 7b's front
Monitor 4's surround
Frankinpolk Center (2 mw6503's with peerless tweeter)
M10's back surround
Hafler-200 driving patio Daytons
Tempest-X 15" DIY sub w/ Rythmik 350A plate amp
Dayton 12" DVC w/ Rythmik 350a plate amp
Harman/Kardon AVR-635
Oppo 981hd
Denon upconvert DVD player
Jennings Research (vintage and rare)
Mit RPTV WS-55513
Tosh HD-XA1
B&K AV5000
Dont BAN me Bro!!!!:eek: