Level Loc DIY - Stereo Unit - Finished

Hi,
Finally finished my DIY Shure Level Loc.

I had this project for a while in my drawer and I finally was able to take the time to build it and test it.

The unit sounds great, I compared it to an original one an couldn't find any relevant diferences.
Sound is like you expect from this unit, dirty , raw and pumping.

I used the original transformers that were in these units as I had a Shure m67 or m68 mixer that had no use so I took the transformers out to use on this project.
The pcb board was from a project that was on the net some years ago called "Sherlock" ,  although it's long gone.
I only had 1 PCB so to do the stereo unit I etched an home board.
The only modification I did was to add a 40dbs PAD at the input so I could use Balanced Line Level signals, the original circuit is for a Mic input only.

Let me say that the transformer outputs are completely useless and the Mic output volume  is really low  (even for the gain of a 70dbs Mic pre) and it's really noisy,  everyone that uses the Level Loc unit or that build the sherlock got to the same conclusion, you need to skip the Balanced Mic out and use the unbalanced Aux Out, then you have a good level and lower noise.
So if anyone is interested in building this unit I advise you to not spend any money in Output transformers you just need the input iron.

here are the pictures of my finished unit:

I will post some documents in case anyone is interested in building a similar unit.

Here it is the schematic and pcb layout:

pcb traces for home etching:

BOM

Build Instructions

Power filter mod to reduce hum

original Shure Manual with schematic

Nice, looks like a very easy project. Would be interested in some sound samples

weiss said:

Nice, looks like a very easy project. Would be interested in some sound samples

Click to expand...

Yes, it's an easy project and it was a lot of fun to do.

I will do some sound samples in the future.

There was a device called the Dynamic Death Ray that was based on this circuit they had some nice samples in the website, I searched for it but it seems the site doesn't existe anymore, I could only find this:

http://shop.atomisonic.com/product.sc?productId=2&categoryId=1

there's some sound samples here:

http://standard-audio.com/level-or.html#

each sample has 3 parts, first it's clean,second part the unit kicks in and the last with distortion I think it's the crunch mode.

The level loc doesn't have the crunch mode, it was a modification of the guys at standard audio, but the second part of each sample it's what it does.

Anyway I can also crunch the sound by not using the PAD, and going Line Out to Mic In

That's great man! I'm going to build this right away!!! What size should the pcb be?
Cheers!

Rémi

remsouille said:

That's great man! I'm going to build this right away!!! What size should the pcb be?
Cheers!

Rémi

Click to expand...

Hello Rémi,
I dont remember and don't have the unit with me at the moment.
What you can do is calculate the pcb size by scaling it from the resistors size.
See this board

Hi again Whoops!
One quick question: what resistor value did you use for the 40db pad? Because it just that, a resistor, right?
Cheers!

It's an U pad 3 resistors,  Attenuates Line level to mic level.

Details here:

http://www.uneeda-audio.com/pads/

Looks like a cool and pretty affordable project!

yes, the Level Loc has a lot of personality.

I advise someone that builds one to ditch the output transformers, the Mic Out is unusable so you dont really need those transformers, then it's even more affordable.

For what it's worth, using better transformers (I experimented with some Lundahls I had lying around) made the box sound "better."  You still had the crunch and grit, but it was more "refined" in it's nastiness.

I've got a pair of original Level-Loc's that I experimented with.  One of them sounds absolutely explosive and I think it's down to the curve of the FET.  I've always meant to trace that FET so I can reproduce that sound.

I also replaced all of the signal caps (1uf? 2uf?) with films.  The original caps were waaaaay gone.

I've toyed with the idea of sticking half of a Fetboy with a transformer off of the aux out to provide sufficient output gain and a balanced signal.

There's also a nice 500 series version of this project:

http://groupdiy.com/index.php?topic=54964.msg701471#msg701471

Nice stuff.

I actually like the sound of the unit with the original Shure transformers.
I like the dirtness and grit

EDIT: And we have a blown transformer! Replaced it, works fine now, I'll try it at the studio tomorrow
I'm having issues making my unit work... Can I use any 1/10 tranformer for the input?  I used one of these:
http://www.monacor.com/en-gb/monacor/products/pa-technology/signal-processing/signal-optimisation/dib-110/

remsouille said:

EDIT: And we have a blown transformer! Replaced it, works fine now, I'll try it at the studio tomorrow
I'm having issues making my unit work... Can I use any 1/10 tranformer for the input?  I used one of these:
http://www.monacor.com/en-gb/monacor/products/pa-technology/signal-processing/signal-optimisation/dib-110/

Click to expand...

Dont really know the specs of the Shure transformer besides it's 10:1, it receives mic levels.
Shure mixer M67, M68 and the reverberator mixer have quite a few of those transformers inside. You can get those mixer for cheap.

What issues are you having in making your unit work?