Sherlock Level-Loc Clone Troubleshooting

[JimiB]

can i power both channels with the one included wallwart supply? wouldn't that split the voltage in half or is there a way around this?

you can definetly power 2 units with one power supply - no issues there.
If you are going to make PCB's you should make a few extras. I made some but I did the layout myself (tons of work) based on the original schematic http://www.freeinfosociety.com/electronics/schematics/audio/shurem62v.pdf

The sherlock used DPDT switches but the distance and power switches only need to be SPDT actually the power could be SPST

 

[Whoops]

Hi Jimi,
does your unit works as it's supose to do nowadays?

Did you solve your problem?

thanks

 

[JimiB]

I think so - not having anything to compare it to makes is difficult. I have 3 more PCB's though as I wanted to build 2 in a rack.

 

[Whoops]

Hi,
I recently acquired a Drew Sherlock kit, that was built.

It's a mono kit, and I would like to do a 2 channel / stereo version.

Do you know where could I buy those transformers that Drew was providing in the Kit?

I need 2 more for the second channel. They look like standard cheap 10:1 transformers, but I dont know where to get them.
I also read about buying a Shure M67 mixer and scavenge the trannies. They are cheap on ebay but if you add shipping costs to Europe and Duty fees, they will not be cheap anymore, and as I already have 2 Drew Transformers, my best option is to just get 2 more.

Thanks

 

[JimiB]

No but I have some - I also have some PCB's that I made up for this - lemme see how many I have. Feel like taking some really good Hi-Rez pics of yours? That will help me double check a few things. I believe mine is working correctly but its hard to know when you are cloning somthing old that is being intentionally abused/misused for it bizarre effect.  ;D

 

[Whoops]

Here are the pictures of the Sherlock transformers.
Are they the same as the ones you have?

sent you a PM with my email

 

[JimiB]

yes those are the same. I meant pics of the sherlock  ;D

 

[phishman13]

[quote author= link=topic=2100.msg70197#msg70197 date=1109273722]
My Sherlock is up and running, and I've got a low level coming out (yes, I'm running it into a pre!), but otherwise it's working the way I expect.  EXCEPT that when it compresses it adds a distinct BUZZ to the audio - sounds almost like a fret buzz on a high E string on the guitar.  I wrote Drew and send an MP3 file and here's what he wrote back:


" install the power filter mod - just a lowpass filter on the power
line using 3 100-ohm resistors and 2 470 or 680uF capacitors!

      Some people have experienced this, some not, it's a strange
phenomenon, hopefully this will fix it.

      Also make sure you're not hitting it too hard, it has a very low
threshold "

Unfortunately, this "power filter mod" doesn't make much sense to a newbie like myself.  I'm posting it here incase anyone else is having the same problem.  And I'm hoping someone could clarify what he means

This is only on the XLR out.  I haven't tried the aux out.  Hopefully I'll get around to it tonight.
[/quote]

I am having this same problem with mine.  Except its the lower hum.  I am also getting a hellacious hum to both aux and main outputs.  Its above 60hz, maybe 120, and when I touch the front panel or any other metal it adds in a lower octave. 

Does anyone have that power filtering schematic that was mentioned in the post above?  Or at least a working grounding schematic to make it not so ridiculous?  I know it might be there faintly in the end, but it is louder than the main signal at this point.  Other than that, I can tell it is working fine!  So its annoying knowing that I have it working, but can't use it due to the hum.

Any ideas?

Thanks!

 

[JimiB]

" install the power filter mod - just a lowpass filter on the power
line using 3 100-ohm resistors and 2 470 or 680uF capacitors!

dont need a schematic - on the other side of the 9v connection before it feeds the unit power add a 100ohm resistor then a 470uf cap to ground then another 100ohm resistor then a 470uf cap to ground then another 100ohm resistor then feed the circuit power.
Did you do your grounds per the schematic?

 

[phishman13]

OK, that power filter mod makes perfect sense now.  I will try that.

I have my unit grounded where every ground point comes together at a star ground  (not sure if that is as per schematic, i just see the ground markings on the schem, not how to tie together).  Now that includes my power ground.  It seems to get way worse when the power ground is tied in, but I just don't know where else to tie it that is separate that will make it work.  I'm being thrown off by wiring mains and having 2 leads go to the psu circuit, and one get tied to chassis.  How do you deal with tying power for just a 9v DC input?

Maybe all I need is the power filter mod.  JimiB, how did you route your grounds for that stuff?  Maybe I can try that if its different to see what happens!

Thanks for the info!

 

[pH]

Is the Sherlock a direct clone of the Level Loc? I'm trying to troubleshoot an original and wondering if I can go by the voltage chart posted here.

Cheers,
Paul

 

[Whoops]

I'm also finishing my sherlock stereo unit right now.
Nice to see a bit of life in this thread.

althought I still haven't tried mine, I can tell you that the original unit is really really noisy.
We have the Shure level loc at the studio, and:

1) XLR output is unusable, really low signal and a lot of noise

2) the Aux out is the only output we can use, the signal is much stronger, but there's also quite a bit of noise.


makes me think if there's a need for a output tranie at all, since everyone seems to be using the unbalanced out (aux) instead of the balanced out

 

[Whoops]

Is the Sherlock a direct clone of the Level Loc? I'm trying to troubleshoot an original and wondering if I can go by the voltage chart posted here.

Cheers,
Paul

I think it's a direct clone.

Anyway I can give you some documents I have, including schematic of the Shure Level loc, and Sherlock shematic and you could compare both circuits.

Would that help?

 

[pH]

Thanks Whoops, a Sherlock schematic would help (already have one for the Shure). PM'd you...

 

[Whoops]

Email sent,

hope that helps Paul.

 

[JimiB]

All the grounds including the -9v tie together and then to a 10ohm resistor which is tied to the chassis. I do think this is a noisy bothersome unit - its just that it squishes so hard and does really killer things to drums - almost like reverb.

 

[phishman13]

Alright,

Followed your instructions JimiB.  Did the power filter mod, but only had 1000uF caps laying around so I used those instead.  Star grounded everything and then tied it to the chassis via a 10ohm resisitor.  Let me say, FIXED!

It pretty much doesn't even hum at all, i have to crank the input of my console to hear the hum.  The hiss and noise is definitely below a workable threshold.  With a moderate level source, the noise would be below the level of annoying.  Now this is using the aux out, not the mic level out.  Haven't tried that one yet, will get to it tomorrow.  I will record some drums tomorrow to see how it works.  Although I only have 1 channel wired up.  Need to get the other done now.

Thanks for the help!

 

[Whoops]

Alright,

Followed your instructions JimiB.  Did the power filter mod, but only had 1000uF caps laying around so I used those instead.  Star grounded everything and then tied it to the chassis via a 10ohm resisitor.  Let me say, FIXED!

That's great,
can you show some pictures of your project?

you should try the Mic output also to see if it was improved.
If so, you would be the first one to be able to use that output.

 

[JimiB]

yeah the aux out is where its at.  ;D

 

[phishman13]

That's what I'm finding!

Go here to check out my JUST finished and tested unit:

http://www.groupdiy.com/index.php?topic=37263.0