2408 vol control bad?
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Discussion related to installation, configuration and use of MOTU hardware such as MIDI interfaces, audio interfaces, etc. for Mac OSX
Discussion related to installation, configuration and use of MOTU hardware such as MIDI interfaces, audio interfaces, etc. for Mac OSX
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stephen1212b
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2408 vol control bad?
I have been having trouble with the volume control on my 2408 mk3. It seems to jump to full volume on one channel and off on the other. I opened up the box and discovered that the control is mounted to the board with no nearby support so the whole board flexes. Unfortunately after checking all the traces it seems like the problem is the construction of the pot itself. It is separating into layers. Does anyone know of a better replacement pot with the same footprint for soldering into the board?
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diavi
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Me too
I'm having the EXACT same problem. It started about 2 months after I bought it. I can sometimes make it go away by tapping or playing with the volume control...but lately nothing makes it better. I also opened mine up and saw nothing obviously wrong. So, I tend to agree with you that it's something fundamentally wrong with the parts/construction.
I sent MOTU emails about this from the very beginning and they will not answer my emails or offer any help what so ever. I'm extrememely dissapointed.
I sent MOTU emails about this from the very beginning and they will not answer my emails or offer any help what so ever. I'm extrememely dissapointed.
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stephen1212b
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diavi
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Interesting
Thanks for the info...I may try that too! If you find a suitable replacement, please let me know...and if I find an alternate solution I'll le you know. 
Just out of curiosity...what channel (left or right) is having the problem?
Just out of curiosity...what channel (left or right) is having the problem?
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stephen1212b
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diavi
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Stephen, that is unbelievable! That is exactly what mine is doing...I mean, word for word. I happen to work at a Pro Audio shop and I had my friend in repair take a look at it because I'm right in the middle of a session and couldn't afford to be without it. In typical repair situation fashion, he plug it in...and it works just fine. We couldn't recreate the problem...even though it's been happening non-stop for last month (and intermitten ever since I bought it).
Anyway...he went ahead and touched up all the solder points on the volume pot just to be safe (since he had it open and right in front of him). I just got it back yesterday and have been working with it non-stop ever since! It seems to be OK now. I do notice a VERY slight bleed through to my powered speakers...but it's so slight that I don't even care! Anyway...that's something to consider...have someone (if you don't feel comfortable yourself) touch up the solder points.
For what it's worth, I contacted MOTU tech support and they were nice and all...tried to help me by charging me $80 USD to replace the part (since I had a long email chain saved from back when I first bought it). So, if that's an option for you...you may want to pursue it. I just couldn't afford to be without it right now. It going nuts has already cost me enough time (equating to cash).
Anyway...best of luck to you man. Definitely keep me (and the rest of us) up to date as to how you resolve this issue.
Later,
David
Diavi Production Team
Anyway...he went ahead and touched up all the solder points on the volume pot just to be safe (since he had it open and right in front of him). I just got it back yesterday and have been working with it non-stop ever since! It seems to be OK now. I do notice a VERY slight bleed through to my powered speakers...but it's so slight that I don't even care! Anyway...that's something to consider...have someone (if you don't feel comfortable yourself) touch up the solder points.
For what it's worth, I contacted MOTU tech support and they were nice and all...tried to help me by charging me $80 USD to replace the part (since I had a long email chain saved from back when I first bought it). So, if that's an option for you...you may want to pursue it. I just couldn't afford to be without it right now. It going nuts has already cost me enough time (equating to cash).
Anyway...best of luck to you man. Definitely keep me (and the rest of us) up to date as to how you resolve this issue.
Later,
David
Diavi Production Team
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diavi
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UPDATE
Well,
The previously mentioned touching up of solder joints was a temporary fix...the problem is back with avengence. I was lucky enough to have reported this problem to MOTU back when my unit was only a few weeks old...so they say they'll replace it for a fee.
Two problems I would have believed as an amazing coincidence. But, with radd saying he's having the exact same problem...I'm getting really pissed, as it's starting to look like this is a problem MOTU probably knows about. You know, I didn't buy a cheap ass product like M-Audio or something for a reason! I spent the extra bucks on a MOTU for a reason!
Needless to say, I share in your frustration. I've had to go out of outputs 1 and 2, into my powered Genelecs and adjust the volume on those instead...which is (1) not very accurate (2) Inconvenient when needing to adjust monitoring levels (3) Unprofessional as hell when a client is looking over my shoulder and (4) Completely unacceptable.
The previously mentioned touching up of solder joints was a temporary fix...the problem is back with avengence. I was lucky enough to have reported this problem to MOTU back when my unit was only a few weeks old...so they say they'll replace it for a fee.
Two problems I would have believed as an amazing coincidence. But, with radd saying he's having the exact same problem...I'm getting really pissed, as it's starting to look like this is a problem MOTU probably knows about. You know, I didn't buy a cheap ass product like M-Audio or something for a reason! I spent the extra bucks on a MOTU for a reason!
Needless to say, I share in your frustration. I've had to go out of outputs 1 and 2, into my powered Genelecs and adjust the volume on those instead...which is (1) not very accurate (2) Inconvenient when needing to adjust monitoring levels (3) Unprofessional as hell when a client is looking over my shoulder and (4) Completely unacceptable.
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stephen1212b
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Ok after completely loosing the right ch I finally had to do something.
If you choose to replace the volume pot you will need a dual 10K linear. Do not use an audio taper pot as this is not an attenuator, but actually changes the feedback and thus the gain of the output driver.
The stock pot has the shaft directly connected to the wipers so when you bump, play or simply use the volume control you are damaging it. A really poor choice of part. The only way to effectively remove the offending pot is to destroy it completely by rocking it gently back and fourth until it breaks free and then clean up the mess.
There are 7 connections to the board. Facing the front of the unit pin 1 (farthest to the left) connects to the low side of ch 1. pin 2 connects the low side of ch 2. Pin 3 is the wiper of ch 2. Pin 4 is the wiper of ch1. Pin 5 is the high side of ch2. Pin 6 is the high side of ch1. There is no connection to pin 7 although you may want to attach a wire from ground to the case of the new pot.
The hardest part was mounting the new pot as the hole is large enough for the knob to pass. I cut some plastic sheet and mounted the pot to that. I also chose a pot with detents so I can recreate the same listening volumes at different sessions. A good quality pot or at least conductive plastic sounds better, but most good quality ones are too large to mount in the same hole.
The final result is better more repeatable sound that will likely last far longer than the original part.
If you choose to replace the volume pot you will need a dual 10K linear. Do not use an audio taper pot as this is not an attenuator, but actually changes the feedback and thus the gain of the output driver.
The stock pot has the shaft directly connected to the wipers so when you bump, play or simply use the volume control you are damaging it. A really poor choice of part. The only way to effectively remove the offending pot is to destroy it completely by rocking it gently back and fourth until it breaks free and then clean up the mess.
There are 7 connections to the board. Facing the front of the unit pin 1 (farthest to the left) connects to the low side of ch 1. pin 2 connects the low side of ch 2. Pin 3 is the wiper of ch 2. Pin 4 is the wiper of ch1. Pin 5 is the high side of ch2. Pin 6 is the high side of ch1. There is no connection to pin 7 although you may want to attach a wire from ground to the case of the new pot.
The hardest part was mounting the new pot as the hole is large enough for the knob to pass. I cut some plastic sheet and mounted the pot to that. I also chose a pot with detents so I can recreate the same listening volumes at different sessions. A good quality pot or at least conductive plastic sounds better, but most good quality ones are too large to mount in the same hole.
The final result is better more repeatable sound that will likely last far longer than the original part.
Congrats on the fix and good luck with that.
I'm gonna keep it in mind for the future.
I just sent my rack unit (only) to motu. They are going to replace the whole rack for $79.95. I bought mine used for like $536.00 or $560.00, I forget, so it's not a bad deal for me to get a brand new one.
Motu did say that this happens some times.
I wonder if the unit has been slightly redesigned for that purpose since mine was first released. Someone on this forum told me that mine was one of the first revisions of this model after asking about a click or pop sound when powering off.
I'm gonna keep it in mind for the future.
I just sent my rack unit (only) to motu. They are going to replace the whole rack for $79.95. I bought mine used for like $536.00 or $560.00, I forget, so it's not a bad deal for me to get a brand new one.
Motu did say that this happens some times.
I wonder if the unit has been slightly redesigned for that purpose since mine was first released. Someone on this forum told me that mine was one of the first revisions of this model after asking about a click or pop sound when powering off.
Stephen,
I really appreciate all the info on the mk3 guts. There's probably a bunch of us here that do.
That sucks about the linears. I had considered that, but figured since I thought I had heard some of the classic "pot crunch" from mine, that they were regular pots tied into the signal. I guess that wouldn't make much sense for something we're using for our monitors.
I've got bags of mono linears and audios here for something else, as well as various dual audios, but a dual linear is sort of a rare breed. I don't understand enough of it to get this, but it seems like with a linked control, setting some digital value for a DtoA circuit, you could use the same output value from the pot for more than one channel, and the audio signals would still be separate (same way that our software maps single fader remote messages to the DAW's stereo channels and busses). I guess there's a reason that it doesn't work like that.
Mine's not as bad as most of the complaints in here, so thanks to you, I may not rip it up unless it gets worse. I'm running Mackie 824's at a closer than normal distance, and the mk3 is on around a 3 to 5 setting most of the time. I'm not sure me or the speakers would recover too quickly from a sudden burst of full output. What I really need to do is just put a clean, passive attenuator on the mains, maybe with a nice long 100mm fader or something. The rack unit here isn't really at a convenient location anyway.
Radd, I think something was revised in the 424 too (before the G5). I think they said they were all the same, but mine has two small jumper wires glued to the board, which ride almost the full distance across. It has a distinct "post production" look to it, and I hadn't seen that on others. It may just have been a faulty connection on mine which got repaired.
-George
I really appreciate all the info on the mk3 guts. There's probably a bunch of us here that do.
That sucks about the linears. I had considered that, but figured since I thought I had heard some of the classic "pot crunch" from mine, that they were regular pots tied into the signal. I guess that wouldn't make much sense for something we're using for our monitors.
I've got bags of mono linears and audios here for something else, as well as various dual audios, but a dual linear is sort of a rare breed. I don't understand enough of it to get this, but it seems like with a linked control, setting some digital value for a DtoA circuit, you could use the same output value from the pot for more than one channel, and the audio signals would still be separate (same way that our software maps single fader remote messages to the DAW's stereo channels and busses). I guess there's a reason that it doesn't work like that.
Mine's not as bad as most of the complaints in here, so thanks to you, I may not rip it up unless it gets worse. I'm running Mackie 824's at a closer than normal distance, and the mk3 is on around a 3 to 5 setting most of the time. I'm not sure me or the speakers would recover too quickly from a sudden burst of full output. What I really need to do is just put a clean, passive attenuator on the mains, maybe with a nice long 100mm fader or something. The rack unit here isn't really at a convenient location anyway.
Radd, I think something was revised in the 424 too (before the G5). I think they said they were all the same, but mine has two small jumper wires glued to the board, which ride almost the full distance across. It has a distinct "post production" look to it, and I hadn't seen that on others. It may just have been a faulty connection on mine which got repaired.
-George
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diavi
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Self Repair
In light of Stephen's info...I decided to call MOTU and ask them if my replacement unit (and all new versions of the 2408 MK3) have better volume pots. I was told "No, we use the same parts. You're the only one with this problem". I replied with "Actually, no. I'm not. I've met several others that have the EXACT same problem, that manifests itself in the EXACT same way". His reply? "Well, we've had this problem with a few people...but out of the thousands we sell...that's not bad enough to warrant a part substitute". I said "Well, I guess when you're charging us all $80.00 for a replacement unit...when the problem is really only a $15.00 part, I can see why you're not in a hurry to correct the problem. However, some of us (like myself) actually work for retailers and will remember this when asked for our professional opinion of your product".
I'm just not comfortable getting a replacement unit that was returned for god knows what...when I at least know exactly what is wrong with the one I have and know how to fix it. So, I will also be replacing my own volume pot. I'll let you guys know how it turns out!
Good luck to you all!
I'm just not comfortable getting a replacement unit that was returned for god knows what...when I at least know exactly what is wrong with the one I have and know how to fix it. So, I will also be replacing my own volume pot. I'll let you guys know how it turns out!
Good luck to you all!
WOW! That's kinds F'd up but yet somehow not so unexpected either.
I wonder if that guy was BS'ing you about the "same parts" because he really did'nt even know and decided to give you that answer at the spur of the moment. (Wishful thinking on my part)
I also wonder how many "a few" are.
Thanks for sharing this info diavi and yes, let us know how it turns out.
I wonder if that guy was BS'ing you about the "same parts" because he really did'nt even know and decided to give you that answer at the spur of the moment. (Wishful thinking on my part)
I also wonder how many "a few" are.
Thanks for sharing this info diavi and yes, let us know how it turns out.