effects of changing this pot from 10K to 100K ?
- Thread starter elnaldo
- Start date
petehall347
the brandy coffee man
does it work and sound ok ?
p.s hide an attenuator inside ..dj.s always seem to turn things up way too high .
p.s hide an attenuator inside ..dj.s always seem to turn things up way too high .
I need to know who/what is driving the pot. This is limited by the drive capability of the circuit driving the pot.
Don't laugh thinking that is never a problem. A friend of mine brought over his priced CD player that is supposed to be audiophile quality. He plug into my preamp that has a 50K volume pot at the input. It sounded like crap. He had opamp AD821 or something, it's supposed to be good. Finally I gave him one of my LM4562 to replace his, the sound came alive!!! His original opamp just could not drive the 50K pot.
So post the driving circuit to see.
Don't laugh thinking that is never a problem. A friend of mine brought over his priced CD player that is supposed to be audiophile quality. He plug into my preamp that has a 50K volume pot at the input. It sounded like crap. He had opamp AD821 or something, it's supposed to be good. Finally I gave him one of my LM4562 to replace his, the sound came alive!!! His original opamp just could not drive the 50K pot.
So post the driving circuit to see.
usually drive issues are related to shifting to a lower value pot, not a higher one. Basically not enough current capacity on the source to drive into it. Going from a 10K pot to a 100K would make the driver have a much easier life.
Where you *might* run into problems is with Miller effect. I seriously doubt it, but its not impossible that you will get some high frequency roll-off at partial volume levels. It depends on the input capacitance and gain of the next stage. Basically it forms an RC low pass filter, and the higher the value of the pot, the lower that pass point is. Frankly this is probably not much of a concern but its not totally impossible either.
Where you *might* run into problems is with Miller effect. I seriously doubt it, but its not impossible that you will get some high frequency roll-off at partial volume levels. It depends on the input capacitance and gain of the next stage. Basically it forms an RC low pass filter, and the higher the value of the pot, the lower that pass point is. Frankly this is probably not much of a concern but its not totally impossible either.
elnaldo
Lunatic Member
Gadget73 is right, somebody changed to 100K, the pots are scratchy so I was thinking to replace them again, but getting parts down here is difficult, so I wonder if should I go back to 10K or get whatever I can, and fit 100K again. Of course the A plan is to get 10K, but since I see other resistors in this RC network I wonder about the effects of having this pots changed.
But I don't want to waste your time, if you don't see anything obvious, I'll try to find something between 10 and 100K.
The owner says the phono inputs have too much gain compared to other mixers, (I've read the specs and it shouldn't have that problem, cartridge output is perfectly within the device specs). I don't know if this pot could make such a difference.
Complete circuit is page 15 of this PDF document: https://www.manualslib.com/manual/1102190/Roland-Dj-2000.html
But I don't want to waste your time, if you don't see anything obvious, I'll try to find something between 10 and 100K.
The owner says the phono inputs have too much gain compared to other mixers, (I've read the specs and it shouldn't have that problem, cartridge output is perfectly within the device specs). I don't know if this pot could make such a difference.
Complete circuit is page 15 of this PDF document: https://www.manualslib.com/manual/1102190/Roland-Dj-2000.html
The higher value pot would cause a bit less loading, so you may get extra signal output as a result. Turning it down some should compensate though.
as a test you could try strapping a 10K (or 12K if you have one) resistor across the 100k pot to get close to the original loading. If it doesn't make any real difference, the pot isn't the problem. Of course the pot won't work right this way, you'd have to turn it all the way up.
as a test you could try strapping a 10K (or 12K if you have one) resistor across the 100k pot to get close to the original loading. If it doesn't make any real difference, the pot isn't the problem. Of course the pot won't work right this way, you'd have to turn it all the way up.
petehall347
the brandy coffee man
make sure his record decks dont have amplifiers built in .
I looked at the schematic, having 100K pot would not make the phono stage louder. The pot is after the tone control, the tone control is after the selector circuit. Whatever the problem is, it's not related to the pot.
One question I am confused, does it have 4 individual board for 4 channels and they all have the same circuits like you show?
elnaldo
Lunatic Member
Channels 2 to 5 are similar. (Channel 1 is only mic) (channel 2 has line 1 and line 2 selector, channels 3 4 5 have line-phono selector) all the channels are at the same board. Schematic shows channel 1 & 2.
BTW 10k pots are on the way. What I didn't find yet is the 100K for the mic channel.
BTW 10k pots are on the way. What I didn't find yet is the 100K for the mic channel.
