Shure - Level Loc Compressor

Stompboxes circuits published in magazines, books or on DIY electronics websites.
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bow_and_error
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Post by bow_and_error »

denniskrigger wrote: 27 Oct 2021, 04:54 r10 value shound't be 4.7k instead of 47k according to the original schematic?
R9 is 4.7k. The Threshold switch, along with R10/R11/R12 are designed as a voltage divider the delivers the same amount of attenuation as the original "Distance Selector" switch, but with an easier to source 2-pole switch instead of a 4-pole switch.

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Post by bow_and_error »

denniskrigger wrote: 27 Oct 2021, 04:47 Hi, Looks like you just used the Auxout of the circuit. Did you tried using de regular out ? (The E point in the original schematic)
I did try using the original output "E", but it lacked the saturation & grit of the Aux Out. I like that character of the Level-Loc, and wanted to retain it in my build, but you can use either output (you may have to increase the output gain though).

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snk
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Post by snk »

@Bow & Error, thank you so much for your work!
It's been a while i'm eyeballing over the top compressors like the Level-Loc, and I am going to build this one on veroboard!
Your build looks awesome, too :)

@Kizzer, thank you for the veroboard layout!

A couple questions : Did the final ("Level lacquer compressor 3.7") version got a veroboard layout, too? The mods quoted below seem a nice addition, and if it sounds better i'd rather build this one...
I added a hefty power filtering mod from the Drewtronics Sherlock as this circuit is quite prone to noisy power supplies & interference. There are also some small changes including the addition of input & output pulldown resistors + a few values changes.

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Post by snk »

I compared the two schematics (level-loc 2.8 and level lacquer 3.7), and noticed 15 differences :
- 3 values were changed (R13,R44, R45);
- 12 components were added : R46 to 51, C22, C23, CPF1, CPF2, as well as D1 (the 5817 was removed, and replaced by a 4001 in a different place in the circuit) and the output pot.

For the value changes as well as the pulldown resistors, it's easy to modify/add it from the veroboard layout posted above, but the power supply part is a bit more tricky to modify :oops:
Is there any updated veroboard layout featuring the mods?

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Post by snk »

Hi,
I "frankentweaked" the layout to reflect some "Lacquer" mods :
- R13, R44, R45 feature the modified values;
- The VOLUME pot is added, as well as the 220nF cap (C22) going to lug2;
- pulldown resistors added (R46, R48)
- R47 added;
- C23 added;

It's a bit messy and not very elegant (I used an image editor, not DIY layout creator), but the size is the same and only two more cuts are needed.
I am going to try to fit the two 470µF caps and the 3 47R resistors.
I hope it is useful to future builders.
If anyone spot errors or have suggestions, I'm all open :)
Shure Level-Loc Vero  v4 w mods (untested).jpg

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Post by snk »

... and the version with the power supply mods.
It's quite ugly, but hopefully accurate (?)
Please let me know if you find anything :)
Shure Level-Loc Vero  v4,2 w mods untested.jpg

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Post by kizzer »

I just had a quick play around with my layout, so this should be right.

Image
Last edited by kizzer on 07 Nov 2021, 12:45, edited 2 times in total.

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Post by snk »

Awesome!
Thank you!
I see I had made a little mistake on my layout (the 10k resistor column 19, which is on the way of the 10µF to output).

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Post by snk »

Hello,
I am counting only 52 cuts (and I think that the cut in column 29/ row 18 is not needed)?

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Post by kizzer »

snk wrote: 07 Nov 2021, 12:05 Hello,
I am counting only 52 cuts (and I think that the cut in column 29/ row 18 is not needed)?
Yep, good catch! I had moved the Threshold 1 connection and forgotten to take out the cut. I have updated and replaced the Layout to reflect this and included a Cut List down the side.

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Post by snk »

Awesome, thank you so much, Kizzer!

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Post by kizzer »

While I'm at it! By moving a couple of components in the bottom left and adding one more cut you can add the Pad resistors to the board.

Image

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Post by snk »

Hello,
I am building it, and I noticed that I am missing a couple resistors values in my resistor drawer. Quite often, I tend to use the closest value, but in this case, I think some values are crucial to the sound (and some others not so much), so I'd rather ask first :)
- Can use a 12K instead of the 13K resistor going to the THRESHOLD lug 3? Would it change the sound much? Would 15K be better?
- I am also missing the 39ohm resistor (going to Q9) : is this value mandatory, or can I use 33R or 47R (if so, which one would be the best)?

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Post by bow_and_error »

snk wrote: 08 Nov 2021, 17:46 Hello,
I am building it, and I noticed that I am missing a couple resistors values in my resistor drawer. Quite often, I tend to use the closest value, but in this case, I think some values are crucial to the sound (and some others not so much), so I'd rather ask first :)
- Can use a 12K instead of the 13K resistor going to the THRESHOLD lug 3? Would it change the sound much? Would 15K be better?
- I am also missing the 39ohm resistor (going to Q9) : is this value mandatory, or can I use 33R or 47R (if so, which one would be the best)?
- 13k in place of 12k works great, I originally built mine with that value anyway
- 33R will work, but you might hear a change in the Attack/Release time. I originally used 33R and it sounded great.

Nice teamwork on the vero layouts, they look great!

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Post by snk »

Thank you, Bow & Error!

I finished the veroboard yesterday, and used 12k and 33R ;)
With the power supply changes, the 470µF are a bit tight to fit, but it still fit.

I need to do all the wiring in the next days, I will let you know how it goes!

By the way, about the transistors (Q2-Q7), which is best in this circuit : 2N5089 or BC549C?

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Post by bow_and_error »

snk wrote: 15 Nov 2021, 20:29 which is best in this circuit : 2N5089 or BC549C?
Really shouldn't matter, I used BC549C.

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Post by snk »

Thank you. I haven't found the time to finish the build, but hopefully this weekend i'll be able to try that nasty compressor!

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