OPTO "Grinder"

[gyraf]

..and if it's intermittent, wiggle around components one at a time until you find the one with bad soldering/broken pcb trace...

Jakob E.

 

[tuanuibi]

Thanks for the response guys!

Simple silly issue - BD 139 and the vactrol were installed incorrectly.

Sounding great now that they're fixed.

 

[Dontiki]

Hi everyone,

I just finished build this great project but i have some problems.

I have no sound on the output,the signal seems to pass through the unit,and in gr vu mode the compressor acting, but nothing in the input mode of the vu meter.

I read 16.67 + and - v but after 20 second or more ,the vu meter starts to peak in the red all the time,
So i mesure the voltage the positive stay good but the negative oscillate from-16v to -0v.

Also without anything connect in or out.

Thanks

Don

 

[Gustav]

Hi everyone,

I just finished build this great project but i have some problems.

I have no sound on the output,the signal seems to pass through the unit,and in gr vu mode the compressor acting, but nothing in the input mode of the vu meter.

I read 16.67 + and - v but after 20 second or more ,the vu meter starts to peak in the red all the time,
So i mesure the voltage the positive stay good but the negative oscillate from-16v to -0v.

Also without anything connect in or out.

Thanks

Don

Would be good to start with the supply voltages, I guess.

Would you mind sharing a picture of the solder work?

Gustav

 

[ophes]

I am been building a HOL of my own, and initial testing is just around the corner. Yesterday I noticed that there is no "Bypass"-switch for the unit. I might be mistaken though (maybe the meter-switch doubles as a bypass?). My makeshift way of putting one in would be to make a "true bypass" switch (like the ones you find on guitar effects), just do it for both leads of the balanced signal. However, I cant shake the feeling that Im dead wrong and not thinking this through. 

Another thing I was thinking about is that i got a VU-meter with a 12V light built in to it. After looking around a bit, building a voltage divider seems like a reasonable fix for this. The light is just drawing 1.2W so it should be fine I think? Never done a voltage divider before and it took all my googling skills to find that fix. Anyone got a opinion on the matters?

Thanks!!

Isak

 

[Dontiki]

Would be good to start with the supply voltages, I guess.

Would you mind sharing a picture of the solder work?

Gustav

Hi,

Sure

16.66 v for the positive rail

-16.82 v for the negative

and accross the AC Input 20.42 V each

A add a picture of the back of the pcb here and i already join the top on my previous post.

 

[Dontiki]

Hi

I check the ground connections everywhere,test some resistors and caps.

I track the signal with a scope and the signal seems to stop at the NE5534 (i try different ones) of the output section, the voltages on pin 4 and 7 are good ,but nothing go out and i still have the same problem of the negative voltage go to -16 to 0 back and forth after few seconds.

Any Ideas ?

Don

 

[Harpo]

... seems to stop at the NE5534 (i try different ones) of the...

Looking at the schematic, there is no NE5534 on pcb. All seem to be different pinout dual opamps, NE5532 and TL072.

 

[Dontiki]

You're right 

I totally don't pay attention to that point

I use the new revision of the unit all ic's are NE5532 except in the output section (ne5534) and the meter section (TL071)

so i use this schematics https://pcbgrinder.com/download/Hand-of-Light/Hand_of_Light_Schem.pdf

Thanks for your help 

 

[Gustav]

You're right 

I totally don't pay attention to that point

I use the new revision of the unit all ic's are NE5532 except in the output section (ne5534) and the meter section (TL071)

so i use this schematics https://pcbgrinder.com/download/Hand-of-Light/Hand_of_Light_Schem.pdf

Thanks for your help 

Swap IC 3b for a TL072 when you get the unit working (not the cause of your problem, but an improvement)

Remember to add the resistor mentioned in the errata (also not the cause of your problem.


- I would not say voltages are good the way your negative voltage is acting.

- I would start with cutting the jumpers to the supply, check it on its own. If that checks out, try without any ICs inserted.

Did you post a picture of your build?

Gustav

 

[Dontiki]

Swap IC 3b for a TL072 when you get the unit working (not the cause of your problem, but an improvement)

Remember to add the resistor mentioned in the errata (also not the cause of your problem.


- I would not say voltages are good the way your negative voltage is acting.

- I would start with cutting the jumpers to the supply, check it on its own. If that checks out, try without any ICs inserted.

Did you post a picture of your build?

Gustav

Hi ,

I already tried to disconnect the psu from the circuit and that works without the problem.

I add the 22k of the errata and i just check without any ic's and the problem stay the same after
few seconds for the negative voltage.

I add the picture of my first post below.

Thanks Don

 

[Gustav]

Swap IC 3b for a TL072 when you get the unit working (not the cause of your problem, but an improvement)

Remember to add the resistor mentioned in the errata (also not the cause of your problem.


- I would not say voltages are good the way your negative voltage is acting.

- I would start with cutting the jumpers to the supply, check it on its own. If that checks out, try without any ICs inserted.

Did you post a picture of your build?

Gustav

Hi ,

I already tried to disconnect the psu from the circuit and that works without the problem.

I add the 22k of the errata and i just check without any ic's and the problem stay the same after
few seconds for the negative voltage.

I add the picture of my first post below.

Thanks Don

(sorry for being so confused I asked for a picture again, again)

Problem:Negative supply is fluctuating.


What we know

PSU is fine with no load.

No ICs make no difference.

Diode orientation looks good (replace zeners with 1N4148 if you want - won't make a real difference, unless you have pretty high levels in - Harpo made me aware of this misread of the schematic, but 10V is 22dBU reverse voltage, so functionally the same up to 22dBU)

Caps look good.

Good to check

Impossible to make out the connections to the small front panel - double check

Solder work generally looks ok, but I would investigate around the LM337. It looks a little splattered, could be a short. Go over it again, could a few other spots. (For this design, I autorouted a small portion, still not many board under my belt, I didn't notice they were hugging the minimum design rule specs, so a few traces are close to pads etc)

I would probably go ahead and clip the transistors in the output stage to see if the voltage stabilised, but I am a bit of a brute. (And of course, double check orientation of those transistors)

Gustav

 

[Dontiki]

Hi Thanks for all the tips 

I just try to put a heatsink on the LM337 and the problem dissapear,but he is getting hot,don't think it's normal .

I gonna try to change it and see  what it does,and wait to try if i get sound with the ne5534 in place.

Don

 

[Gustav]

Hi Thanks for all the tips 

I just try to put a heatsink on the LM337 and the problem dissapear,but he is getting hot,don't think it's normal .

I gonna try to change it and see  what it does,and wait to try if i get sound with the ne5534 in place.

Don

I am not used to it getting hot in this build, wouldn't expect it to. Did you check any of the items I posted? Like the soldering around the LM337.

Whats your power trafo?

Gustav

 

[Dontiki]

I am not used to it getting hot in this build, wouldn't expect it to. Did you check any of the items I posted? Like the soldering around the LM337.

Whats your power trafo?

Gustav

Yes i check the solder and continuity with a multimeter between components around with the schematic,i have to check again the small front panel connections.

My power transformer is a Talema 2 x 18v but 50 VA cause i already have it in stock , maybe that can be a problem ?

Don

 

[Gustav]

I am not used to it getting hot in this build, wouldn't expect it to. Did you check any of the items I posted? Like the soldering around the LM337.

Whats your power trafo?

Gustav

Yes i check the solder and continuity with a multimeter between components around with the schematic,i have to check again the small front panel connections.

My power transformer is a Talema 2 x 18v but 50 VA cause i already have it in stock , maybe that can be a problem ?

Don

Trafo specs are fine. Your regulators have a bit more work to do, but only a bit. It would not account for the LM337 getting that hot- current draw through the LM337 should also be lower than on the LM317, which is not getting hot, as I understand it.

Did you report back if the stable voltage with the heatsinked LM337 also resulted in passing audio? If not...

Faulty or reversed BD140 is also a great suspect (I mentioned pulling the transistors on the output stage before). It fits the symptoms of signal getting lost at that stage, and I unless I missed something, its the only thing drawing current from the negative supply with all ICs pulled. If its not reversed, clip it, and see if supply is stable/LM337 stops getting hot, check with ICs in place.

Gustav

 

[bio_nick]

I am been building a HOL of my own, and initial testing is just around the corner. Yesterday I noticed that there is no "Bypass"-switch for the unit. I might be mistaken though (maybe the meter-switch doubles as a bypass?). My makeshift way of putting one in would be to make a "true bypass" switch (like the ones you find on guitar effects), just do it for both leads of the balanced signal. However, I cant shake the feeling that Im dead wrong and not thinking this through. 

I did a separate bybass-board to put on the backplate.
If device is turned of the bypass is active..
Photo attached, its the part with the four blue relais.
If you need a ready-to go pcb just give me a sign

edit: there is a true bypass pcb from silent:arts
check here:
http://groupdiy.com/index.php?topic=39570.0

 

[frederickalonso]

Nice build! I'm thinking to remove the transformer in my unit and future build to have less noise.

 

[gyraf]

I'm thinking to remove the transformer in my unit and future build to have less noise.

I wouldn't bother trying that unless you have a real problem that is otherwise unsolveable. And noise problems rarely are.

Jakob E.

 

[frederickalonso]

Thanks Jakob