Anyone know is SQ fader construction same as QU?

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    Profile photo of log2


    Does anyone know if the general construction of the SQ faders is the same as the QU? I did a few outdoor shows with the QU32 and the dust destroyed the faders on the QU after just 4-5 days. After opening up the QU I see there is no dust shields or protection on the QU faders. The dust falls directly in the slot and on to the resistive surface. Curiously, the faders still mostly work but don’t go to the correct position on a “fader flip”. More strange, it only affects the even faders. Seems if the software waited a few mSec longer for the faders to find position it would be fine.

    I want to buy a SQ. If I can only get a few outdoor gigs before needing $1000 worth of faders it not an option.

    Profile photo of Scott

    I can’t comment on if the Qu/SQ faders are the same or not, but I do know that SQs faders went through some rigorous testing / abuse during development. This is referenced in several of the videos found online about SQ. I can say that I have used my SQs almost exclusively outdoors and have had no issues. I am doing so in a normal outdoor environment, and not anything overly dusty like a motocross track.

    Profile photo of Mike C
    Mike C

    The SQ faders feel and sound different/smoother than the QU faders. By sound I mean the mechanical sound of them moving.

    Profile photo of log2

    Thanks for the reply’s. I did find out the individual faders are not cross-compatible between the QU and SQ.

    Profile photo of KeithJ A&H
    KeithJ A&H


    Interestingly (well, I find it interesting and sounds like you might too!) we spent a really long time developing and testing the faders for the SQ series.

    They’re actually mounted at 90deg compared to ‘normal’ faders and then use an angled arm. You can see this if you remove a fader cap.
    This has a few benefits including:

    • Dust and other ingress does not fall directly onto the tracks and anything that does get in should be brushed off by the fader wipers
    • Less friction means quicker and quieter movement, when switching layers for example

    We worked on the materials used for both the wipers and the tracks to get the optimum balance of wear resistance and conductivity.
    As part of the testing we filled them with all sorts of stuff a fader would hate, including very fine quartz sand and cigarette ash.
    We then had them running through hundreds of thousands of cycles without failure.

    This is all because we know the kind of abuse that motorised faders can take – they’re the most touched, most used and (annoyingly for the QC team) probably the most mechanically complex part of the mixer…

    With regards to your Qu – although it uses a more classic fader design, they are still incredibly resilient and I’d not expect them to fail after just a few days unless it was really REALLY dusty, with worst case being the addition of variable moisture or condensation that could create a nasty fader-killer-mud-dust?!
    The fact that it’s only even faders with the issue is strange however and knowing that the motors on that board are mounted alternately at the top and bottom of the board means there could be something else going on.
    You’d need to have the unit checked over properly by an authorised service centre to know for sure though.


    Profile photo of log2

    Keith, Thanks for the detailed reply.

    Glad to hear you went to the “side mounted pots on the SQ” I’ll be placing an order for a SQ5 right away.

    Regarding my QU; I did have the board looked at by a authorized AH service center. The tech checked the 12v power to the boards and it was ok. He diagnosed it as dirty pots. Before spending the $900 for repair I decided to have a look myself. I was not convinced it was just dirty pots due to the problem happening only on odd faders of the first bank, and even faders on the second bank. Also, “zeroing” each fader when in “fader flip” worked fine on all faders.

    I put the board on the bench yesterday. Here is what I have figured out so far- Any change of page or a “fader flip” works if less than 4 faders need to move in any bank of 8 faders (1-8, 9-15, 16-23, 24-32). I looks like each bank of 8 is globally current limited. This is confirmed by measuring the fader motor voltage. When asked to move 4 or more faders (in that bank of 8) the voltage drops from 5V to aprox 1.5V.

    I am not sure if this is a friction problem, or the current limit is triggering at too low a threshold? Curious it only affects the odd faders on the first 16 and the even on the last 16. I have ruled out noise on the pots with a scope. Its for sure a motor current issue.

    Not sure what my next step will be, as I don’t have a schematic and the 5V circuitry is hidden under the fader pots.

    Any further help would be appreciated.

    Profile photo of log2

    So, I finally had some time to look at the qu-32 again. Turns out the problem was some PTC fuses on the fader boards. Each board has four fuses and they where all damaged. My guess is the dirty faders cuased more current to be pulled through the fuses, combined with hot air temp cuased the fuses to fail. PTC fuses don’t open like a regular fuse they go to a higher resistance. With only one or two faders moving in any bank it could reach position. If three faders needed to move per bank the high resistance of the fuses made the motors move to slow. After cleaning the faders and installing new PTC’s the console works great again.

    Profile photo of log2

    Opps. looks like pics were too large.

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