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Potentiometer Change.

72.220.37.3

I have a MBL 6010D clone or "Clonish" which has surprised me how good it sound stock and even better after some upgrades.

I have had a Left and Right channel balance issue and today I removed the Alps RP168 quad 100K pot and confirmed the issue. So as of right now I can not use any of the Nobles, Audio Note or TKD pots I have on hand cause they are all Stereo pots.

I was going to order a better pot like a GoldPoint Quad as it will barely fit in this preamp. I want to go down to either a 50K or even a 25K quad pot but wonder if this will cause any issues with the IC's oscillating in the stages its between and would likely need some circuit tweaking if so? Or could it be a drop in replacement. I have read that these circuit like the lower 25K and 50K pots in them. The Original 6010D preamp using a very nice/expensive VC Pot of 10K.

The VC is definitely after the First Buffer Stage and Before the Gain Stage. So the stages go like this... Preamp INPUT > First Buffer Stage > VC Pot > Gain Stage > Output Buffer Stage > Preamp Output.

Follow Ups:

RE: Potentiometer Change. - Jonesy 13:13:20 09/08/24 (3)
I'm not familiar with the MBL preamp (though I wish I was!)

Wasn't sure why it has the four channel potentiometer but from what I've read online it wired down to stereo as synchronous channels.

My Counterpoint SA5 does this for it's separate channel balance controls. Threw me for a loop when I couldn't figure out why all three potentiometers were 100k.

Whether it was an engineering decision or clever parts purchase to just buy bulk stereo 100k and wire two stereo 100k in parallel to essentially make dual wiper 50k mono for left and right separate balance controls.

Hope this makes sense and check the wiring in yours. Make sure you also test your's with a multimeter to confirm.

Jonesy

"I know just enough to get into trouble. But not enough to get out of it."
- My Counterpoint preamps... - Cougar 17:36:19 09/08/24 (2)
  the SA-3.1 and SA-1000 both used 100k stereo pots with its balance control..
  
  The MBL 6010D clone measures 100k on all 4 sections per Alps drawing and traced out each output the buffer to the pots. So they are using the 100K for each channel.
  - RE: My Counterpoint preamps... - Jonesy 13:28:01 09/09/24 (1)
    I had an SA3 as well.
    
    Yeah, I guess they are using all 4 decks of the quad potentiometer individually.
    
    I thought maybe they were using 2 decks in parallel for the left channel, and 2 decks in parallel for the right channel for an attempt at overall better tracking tolerance. 2 wipers per channel.
    
    If so, you may have been able to swap out the quad pot and configure one of the stereo ones you had on hand. Just need some math and maybe add/remove resistors.
    
    I should have stated from the beginning.
    
    Sorry I don't know what impact the different quad potentiometer values would have on circuitry in your 6010D.
    
    Jonesy
    
    "I know just enough to get into trouble. But not enough to get out of it."
    - I will just purchase... - Cougar 19:51:28 09/10/24 (0)
      The GoldPoint quad pot either in a 25K or 100K value.

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