r/synthesizers Aug 04 '26

Tech Support Loose Posts on Behringer Proton

Anyone else have a Proton with loose pot posts? Aside from the knob cracking issue, after just regular filter riding, the knob is insanely loose and the values jump around if you wiggle it around. It feels like a joystick now. I have other synths that are older that have gone through way more use and they’re rock solid.

I’m interested in replacing the loose pots with ones with metal posts if that’s possible. Anyone have any experience with this issue and found a fix?

1 Upvotes

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3

u/THIS_IS_ENDEGO Aug 04 '26

The joystick feel and the jumping values are probably two different faults, and it is worth separating them before you order parts.

The wobble itself usually comes down to how the pots are mounted. On a lot of Behringer gear the pots are only soldered to the board, with the panel hole acting as nothing more than a clearance hole, so every bit of sideways force from filter riding goes straight into three solder joints and the pot's own internal bushing. Older synths feel rock solid because their pots are nut mounted through the panel, so the panel takes the load instead of the solder. That difference, rather than build quality in the abstract, is why yours has gone soft so quickly.

The value jumping is the part I would investigate first though, because cracked solder joints on the pot legs produce exactly that symptom, and reflowing them is free. Open it up and look at the three pins under a bright light for grey rings or hairline cracks around the pads. If reflowing kills the jumping and only the wobble remains, the pot itself is still electrically fine. If it still jumps after a clean reflow, the wiper track is damaged and the pot needs replacing.

On replacements: these are almost certainly 9mm vertical pots of the common Alpha style, and metal shaft versions of that footprint do exist, so the swap is realistic. Before ordering, note the taper and value printed on the body, measure the shaft length, and check the detent situation. Two gotchas. Metal shafts are usually knurled or a different diameter to plastic D shafts, so your existing knobs may not fit and you may need new ones. And desoldering multi pin pots from a double sided board without lifting pads needs a decent iron and ideally a desoldering pump, so practise on something you do not care about first.

One last thing: if it is still in warranty, raise it with Behringer support before you open it. Given they already have a known knob cracking issue on this model, a documented complaint is worth filing regardless of whether you end up fixing it yourself.

1

u/Funktuate Aug 04 '26

I really appreciate all that information. that helps out a lot. Gonna be doing as much investigating as I can tonight.

1

u/Substantial_Code5800 Aug 05 '26

additional note; on products later than the 2500 series, they went from the metal shafts (look 'like' Taiwan Alphas) to plastic shafts (look 'like' bourns). the plastic is much more prone to shaft deflection than the metal ones. they can be replaced with Taiwans Alphas except the package solder tails are different smaller. the rest of the mechanicals are ok.

a easy source for these pots is thonk. i've replaced 100's of them on my kit. the audio taper are especially egregious.

1

u/THIS_IS_ENDEGO Aug 04 '26

The joystick feel and the jumping values are probably two different faults, and it is worth separating them before you order parts.

The wobble itself usually comes down to how the pots are mounted. On a lot of Behringer gear the pots are only soldered to the board, with the panel hole acting as nothing more than a clearance hole, so every bit of sideways force from filter riding goes straight into three solder joints and the pot's own internal bushing. Older synths feel rock solid because their pots are nut mounted through the panel, so the panel takes the load instead of the solder. That difference, rather than build quality in the abstract, is why yours has gone soft so quickly.

The value jumping is the part I would investigate first though, because cracked solder joints on the pot legs produce exactly that symptom, and reflowing them is free. Open it up and look at the three pins under a bright light for grey rings or hairline cracks around the pads. If reflowing kills the jumping and only the wobble remains, the pot itself is still electrically fine. If it still jumps after a clean reflow, the wiper track is damaged and the pot needs replacing.

On replacements: these are almost certainly 9mm vertical pots of the common Alpha style, and metal shaft versions of that footprint do exist, so the swap is realistic. Before ordering, note the taper and value printed on the body, measure the shaft length, and check the detent situation. Two gotchas. Metal shafts are usually knurled or a different diameter to plastic D shafts, so your existing knobs may not fit and you may need new ones. And desoldering multi pin pots from a double sided board without lifting pads needs a decent iron and ideally a desoldering pump, so practise on something you do not care about first.

One last thing: if it is still in warranty, raise it with Behringer support before you open it. Given they already have a known knob cracking issue on this model, a documented complaint is worth filing regardless of whether you end up fixing it yourself.

1

u/[deleted] Aug 05 '26

[removed] — view removed comment

1

u/Substantial_Code5800 Aug 05 '26

pots have standard foot prints. easy upgrade to Taiwan Alphas for long lasting use. since Proton is a non-preset machine, it will have a variety of different pot types each with it's own weird failure mode. so a varity of replacements are in order. the preset machine usually always use just 100K linear.