Level Loc DIY - Stereo Unit - Finished

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Hey I have several Shure mixers with the limiters inside that sound great...what is the difference between those and the Level-Locs???
 
supafuzz99 said:
Hey I have several Shure mixers with the limiters inside that sound great...what is the difference between those and the Level-Locs???
It seems they're not much different, except the se-30 has a release knob, which the level Loc lacks. I just got myself a se-30, but it's not working right now, so I haven't had the chance to put it up against my level loc yet....
 
supafuzz99 said:
Hey I have several Shure mixers with the limiters inside that sound great...what is the difference between those and the Level-Locs???

Hi I dont know those Shure mixers with limiters.

Do you have models? photos? links?

thanks,
it would be nice to compare schematics with the Level Loc
 
Hey I know this is reviving an old thread but I’m curious if anyone could help me out with this build. I’m experienced enough to build the circuit, but a bit of a novice in terms of how to get or order the circuit board given what’s here (any places I’ve encountered want a gerber file). Also the pdf with the build instructions seems to have disappeared.

Only other questions I have is the transformers mentioned. I have a chance to get an old shure m68 to part them out from, but I didn’t see them in the parts list, and not sure where they go in the circuit/build (but possibly this was in the build instructions?). Thanks for any help!
 
Hi Vires,
There’s no pcbs available for this project, at least in a standard rack format like I did.
There might be an old project around here for a Level Loc in a 500 series format, I have some recollection of something like that but I don’t remember the name.

Long time ago, before I did this project I bought a PCB of an even older project called the “Sherlock” it was a level loc clone project but it was already dead and buried when I build it. Long story short I was able to buy a PCB of that Sherlock project and as I wanted to do a stereo unit I scanned that PCB and home etched a second one.

So you have 3 options, or you try to find a PCB of the project for the 500 series (if that really existed and it’s not my imagination), or you design your own PCB based on the schematic or you home etch a PCB with scans of an already made pcb (Sherlock)

I’m sure I still have docs somewhere for the Sherlock project. As for the schematics they are easily available and they show where the transformers connect. But if it’s the case that you don’t know how to read a schematic then you should forget doing this there’s no plug and play kit with simple build a puzzle instructions.

The transformers used are 1:10 transformers, you can use any mic input transformer with that ratio. You can also find those transformers in M67 and M68 Shure mixers.
I’m sure I still have a few of those transformers I can spare, let me know if you need them.

You don’t need step down output transformers for this circuit, they’re useless, everyone uses the unbalanced line level output. So just count for input transformer
 
Hi Vires,
There’s no pcbs available for this project, at least in a standard rack format like I did.
There might be an old project around here for a Level Loc in a 500 series format, I have some recollection of something like that but I don’t remember the name.

Long time ago, before I did this project I bought a PCB of an even older project called the “Sherlock” it was a level loc clone project but it was already dead and buried when I build it. Long story short I was able to buy a PCB of that Sherlock project and as I wanted to do a stereo unit I scanned that PCB and home etched a second one.

So you have 3 options, or you try to find a PCB of the project for the 500 series (if that really existed and it’s not my imagination), or you design your own PCB based on the schematic or you home etch a PCB with scans of an already made pcb (Sherlock)

I’m sure I still have docs somewhere for the Sherlock project. As for the schematics they are easily available and they show where the transformers connect. But if it’s the case that you don’t know how to read a schematic then you should forget doing this there’s no plug and play kit with simple build a puzzle instructions.

The transformers used are 1:10 transformers, you can use any mic input transformer with that ratio. You can also find those transformers in M67 and M68 Shure mixers.
I’m sure I still have a few of those transformers I can spare, let me know if you need them.

You don’t need step down output transformers for this circuit, they’re useless, everyone uses the unbalanced line level output. So just count for input transformer
Hi Vires,
There’s no pcbs available for this project, at least in a standard rack format like I did.
There might be an old project around here for a Level Loc in a 500 series format, I have some recollection of something like that but I don’t remember the name.

Long time ago, before I did this project I bought a PCB of an even older project called the “Sherlock” it was a level loc clone project but it was already dead and buried when I build it. Long story short I was able to buy a PCB of that Sherlock project and as I wanted to do a stereo unit I scanned that PCB and home etched a second one.

So you have 3 options, or you try to find a PCB of the project for the 500 series (if that really existed and it’s not my imagination), or you design your own PCB based on the schematic or you home etch a PCB with scans of an already made pcb (Sherlock)

I’m sure I still have docs somewhere for the Sherlock project. As for the schematics they are easily available and they show where the transformers connect. But if it’s the case that you don’t know how to read a schematic then you should forget doing this there’s no plug and play kit with simple build a puzzle instructions.

The transformers used are 1:10 transformers, you can use any mic input transformer with that ratio. You can also find those transformers in M67 and M68 Shure mixers.
I’m sure I still have a few of those transformers I can spare, let me know if you need them.

You don’t need step down output transformers for this circuit, they’re useless, everyone uses the unbalanced line level output. So just count for input transformer
I can figure out the schematic, for something like this anyway. It’s my first rack mount build will be the harder part…

I was already looking into home etching. Seems simple and fun, so I think I’ll try it from the Sherlock if you can share the info/files.

I’ve seen some 500 series versions that look interesting (this one in particular I thought looked cool: Toneloc Level-Loc Compressor Colour
But I don’t have 500 rack, and I didn’t see anything about transformers which I imagine is part of the sound of the original.

I’d be glad to get the transformers from you if you have extras- kind of you to offer :)
 
if you can share the info/files.

All the docs are already shared on this thread.


I’ve seen some 500 series versions that look interesting (this one in particular I thought looked cool: Toneloc Level-Loc Compressor Colour

It’s not that one, that’s just a module, there was an actual 500 series complete unit


I didn’t see anything about transformers which I imagine is part of the sound of the original.

I’m not sure about that, I personally think the sound comes from the actual circuit itself. Limiter characteristics, Attack and Release times and the way it distorts and not from 1 input transformer


I’d be glad to get the transformers from you if you have extras- kind of you to offer :)

I will check that out next time I go to the workshop
 
I worked up a 15x30 stripboard layout of the circuit last year that i got mostly working. Included attack and release controls and could get some cool sounds but I remember having a bit of an issue with the distance control and didnt have the time to pursue it further. Not sure if it was cause i used a rotary switch and messed that up but remember it misbehaving. I will look for it in my notes in a couple days. More DIY than a DIY PCB layout and more room for error but i enjoy the process that way
 
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Lvl loc stripboard.jpg

Here is what I found in my notes. The circled letters are jumper wires, A+ and B+ were from a simple power supply RC network on another board. I used the previously mentioned Shure input transformer for the build. Not sure where the front panel control layout is but it was point to point, using a 470k resistor and 1M pot for release and I believe 1 or 5k pot for attack, referencing a PRR post somewhere on here for how to set it up. On the original schematic it is around point "C." For the PNP transistors (Q6/Q7) I used PN2907, Q9 was a 2N5458, and the rest were good ol 2N5088
 
Hey thanks so much to everyone here. I hope to start working on this within the next couple months. Will probably home etch from the Sherlock design and make minor tweaks to that based on all the info offered here. Excited to dig into this and look forward to sharing my results :)
 
pcb traces for home etching:
Hi there - apologies if I'm being especially dense here, but I can't figure out how to scale the board. I understand the length of resistors depends on the power rating of the resistor, and no where in the parts list does it say what power rating (unless I've missed something obvious). So I'm at a loss - of course being more of a beginner with this stuff I'm sure I've overlooked something, so any help is completely appreciated :)
 
Hi there - apologies if I'm being especially dense here, but I can't figure out how to scale the board. I understand the length of resistors depends on the power rating of the resistor, and no where in the parts list does it say what power rating (unless I've missed something obvious). So I'm at a loss - of course being more of a beginner with this stuff I'm sure I've overlooked something, so any help is completely appreciated :)

Print it in paper at diferent sizes, the dimensions don't need to be exact, just good enough that the components legs are long enough to fit the holes.
So print different sizes , try them out with some resistors and transistors, and choose the size that fits better
 
These are photos of the unit I built many years ago,
you have an inside photo of the PCB so you can visually have a rough idea of the size.
The green PCB is the original one from the ancient Sherlock project and the other PCB was a clone of the Sherlock PCB that I did myself.
Overall it's a simple circuit and easy to build.

Output transformers are useless, don't use them, the supposedly balanced output from those transformers is Mic Level out and it's noisy as hell, this happens in the Clone but it's exactly the same in the original unit. People just use the Unbalanced Line level output on these, that doesn't go through the transformers, so save money and don't use them at all.
I think I removed mine after I built the unit.

fotografia 1.JPGfotografia 3.png
 
Hi!

Does anyone know if this preamp/limiter, inverts the phase of the signal at the line output (Q8) with respect the input signal?
I would say it does not, but the darlington stage (Q1,Q2)after the fet (Q9), makes me doubt!

Jay x
 
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