Build Thread:MS76

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RSRecords

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I think I figured it out.

I mis interpreted the pcb markings for the molex connectors. Since I used the molex pin numbers on the pcb to wire the control boards, its not an issue for any of them except the blend pot which isn't on a pcb. It was wired backwards.

Also, I was thinking that the input pot should affect the level shown in the VU IN mode. I don't think that is the case.

I am trying to calibrate it now; I'll update if I am successful.
 

Gustav

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Blend pot should be out during calibration. Theres a relay, which will switch it out completely, regardless of the orientation of the  wiring.

VU in is just that - the level coming into the unit.

Hope you get there!

Gustav
 

RSRecords

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Well seems to be working now. I'm not sure what fixed it but I went through and just reflowed most of the pcb and checked all the transistors. Everything tested fine in and out of the circuit.  Who knows! works now and sounds great!
 

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Gustav

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RSRecords said:
Well seems to be working now. I'm not sure what fixed it but I went through and just reflowed most of the pcb and checked all the transistors. Everything tested fine in and out of the circuit.  Who knows! works now and sounds great!

Awsome, and great design!
 

RSRecords

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I kept the front panel layout the same and just changed font and color scheme inspired by the rev a blue stripe.

I've been wanting to try front panel express' print service. It came out pretty good. It's definitely more fragile as you can see some chipping around the chassis screws nothing a washer can't hide but if I were to do it again I'd probably  Hit it with a coat of lacquer or something for extra durability.
 

RSRecords

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One question regarding attack and release:
Is this like an 1176 wherein the fastest setting is clockwise? I haven't had much time to experiment with it yet but I was getting the feeling the release was faster in the counter-clockwise setting.

Thanks!
 

Spex95

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Mar 10, 2018
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Hi,
Can someone tell me the value of the out pot, I must be missing it somewhere?
Is this a linear or log pot?

Thanks!
 

noiro

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Hi Gustav, I'm wondering about a few thing with the MS76, first it seem that the blend pot does not work at all, I disconnect the connector but it doesn't do anything, wondering if there is something wrong with my build. Everything seem to be working just fine. Is there a way to test it. I used a standard  A 10K pot, Am I missing something here? so to resume the MIX knob dry/wet simply does not do anything, the wet is always full on, no dry signal at all, i try disconnect the blend wires but still does not do anything, does not make any sense.
 

Gustav

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noiro said:
Hi Gustav, I'm wondering about a few thing with the MS76, first it seem that the blend pot does not work at all, I disconnect the connector but it doesn't do anything, wondering if there is something wrong with my build. Everything seem to be working just fine. Is there a way to test it. I used a standard  A 10K pot, Am I missing something here? so to resume the MIX knob dry/wet simply does not do anything, the wet is always full on, no dry signal at all, i try disconnect the blend wires but still does not do anything, does not make any sense.

Hi Noiro.

I already replied to the post you made asking me on Gearslut.

https://www.gearslutz.com/board/product-alerts-older-than-2-months/1249677-pcb-grinder-new-units-amp-guides.html

You are welcome to use my mail for future questions!

admin@pcbgrinder.com

 

karloff70

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Hi chaps.....could someone please help me with some Molex issues. I am lacking the 3 way and 6 way cable and connector assemblies meant to be part of the kit, and Gustav is obviously out of this game now, plus his email doesn't respond until June, so.......does anyone have tips on parts numbers, as all I seem to find is separate connector stuff where I need to build the cable myself, which I don't really fancy if I can help it.
 

rtron

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Hi chaps.....could someone please help me with some Molex issues. I am lacking the 3 way and 6 way cable and connector assemblies meant to be part of the kit, and Gustav is obviously out of this game now, plus his email doesn't respond until June, so.......does anyone have tips on parts numbers, as all I seem to find is separate connector stuff where I need to build the cable myself, which I don't really fancy if I can help it.
Hi karloff70, I had a similar issue for the 6way cables and was lazy so I just got 4 of these and then spliced them together to make two cables: Molex Jumper 6 Wire Assembly - PRT-09922 - SparkFun Electronics . I think I had enough 2- and 3-pin wires and headers to make things work (I didn't put 2- or 3-pin headers on the control panel pcbs, I just solder the wires to the boards).

I just finished my unit up and it seems to be working well but I do have a question about grounding... In the build guide pics, it just shows taking the earth line from the power cable to a chassis screw. Is that all that should be done? Seems like it would be good to also run a wire from that chassis screw to the GND on the rectifier/filter board (which is wired to the GND of the main board)? Thanks...
 

Gustav

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Sorry about the missing items - I am cancelling the kits, because I ended up having no time to pack the full kit myself, and having them packed by a third party keeps turning up these errors, which I realise are annoying as hell to the recipient, and also an administrative nightmare to handle.

You can use 2 x 3 way side by side, or 1 x 6 way.

 

Gustav

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Seems like it would be good to also run a wire from that chassis screw to the GND on the rectifier/filter board (which is wired to the GND of the main board)? Thanks...

The routing of the ground works very well on this design - you do not need anything aside from the signal-to-chassis ground established throught he XLR connector.

If you are using a different type of XLR, you could do what you are proposing.

When in doubt, a quick continutiy test with your meter will reveal if you already have the connection made :)

Gustav
 

abbey road d enfer

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Seems like it would be good to also run a wire from that chassis screw to the GND on the rectifier/filter board (which is wired to the GND of the main board)?
That would create a loop that would inject rectification spikes into the audio ground. Is it what you want? (rhetorical question)
 

karloff70

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Thanks for the tip, but not ideal as in the US, I am in the UK. Found two 6 ways from one place and another place has six 3 ways only, but I need 10....aaarghhhh. Search on.
 

karloff70

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F it, found some pricey 3 way ones on ebay, so now all incoming, which hopefully means this thing will finally be finished.
 

rtron

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Mmm, so I do measure continuity between the chassis ground screw and the board ground pins even when there are no xlr cables or power cable connected at the back....that seems confusing. I don't think the plastic xlr connectors can make this happen.... Is it being grounded through some of the wires that connect to the front panel/chassis?
 

Gustav

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Mmm, so I do measure continuity between the chassis ground screw and the board ground pins even when there are no xlr cables or power cable connected at the back....that seems confusing. I don't think the plastic xlr connectors can make this happen.... Is it being grounded through some of the wires that connect to the front panel/chassis?

The XLR I supply have the grund pin connected to the mounting hole, so the screw to mount them makes the connection.

Gustav
 

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