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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bow_and_error
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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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snk
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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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snk
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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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kizzer
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Post by kizzer »

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

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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.

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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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Post by dwrockdoctor »

Just for anyone having trouble getting this working from the last vero layout on this page, theres a cut on row 4, hole 13 that shouldn't be there that is stopping the IC from getting voltage to it. Once I fixed that cut the circuit is working as expected, thanks everyone for all the hard work and making this crazy compression effect available outside of spending crazy money on an original or a clone.

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Post by kizzer »

dwrockdoctor wrote: 10 Jun 2022, 00:06 Just for anyone having trouble getting this working from the last vero layout on this page, theres a cut on row 4, hole 13 that shouldn't be there that is stopping the IC from getting voltage to it. Once I fixed that cut the circuit is working as expected, thanks everyone for all the hard work and making this crazy compression effect available outside of spending crazy money on an original or a clone.
Good Catch! Missed this when I modified my previous layout. Cheers!

Image
Last edited by kizzer on 11 Jun 2022, 09:49, edited 1 time in total.

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Post by dwrockdoctor »

kizzer wrote: 10 Jun 2022, 12:00
dwrockdoctor wrote: 10 Jun 2022, 00:06 Just for anyone having trouble getting this working from the last vero layout on this page, theres a cut on row 4, hole 13 that shouldn't be there that is stopping the IC from getting voltage to it. Once I fixed that cut the circuit is working as expected, thanks everyone for all the hard work and making this crazy compression effect available outside of spending crazy money on an original or a clone.
Good Catch! Missed this when I modified my previous layout. Cheers!

Image
Oh, and is there meant to be a cut beneath the 13k resistor that goes to the threshold switch? I built it off board on the DPDT toggle but I'm guessing it needs a cut on the Vero to work properly?

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