500 series Level-Loc project

[irfrench]

I made some samples the first day it was working, nothing refined, just to hear it in action

Really good to hear another in existence! 

I think I need to try them in a more subtle roll too - maybe paralleled under vocals and bass?  It really seemed to work on the guitar too!  And there I was just beating drumz into a pulp with mine!

Cheers,
Ian

 

[dirtyhanfri]

I think I need to try them in a more subtle roll too - maybe paralleled under vocals and bass?  It really seemed to work on the guitar too!  And there I was just beating drumz into a pulp with mine!

I thought it was the main purpose of this unit, it´s kinda aggressive  and parallel processing is in vogue now.

Also it works specially good on percussive or rhythmic sounds, not so good on sustained sounds for my taste.

I was thinking yesterday in try to add a stereo link to use it with drum room mics or even stereo buses, but maybe it´s not necessary  given it´s not a standard compressor, it´s more a "mojo" unit...

 

[Indecline]

Glad to see some finished 

I'm having trouble with mine.. Fried a couple backwards IC's and I'm not sure my OSA box plays nicely with them. Second time in the LB it oscillated like a baby Moog! (Sounded way cool too!!). I tried it in my buddy's box and it sounds pretty messed up. I think I fired a transistor in there somewhere.

Haven't had much time to finish and try out the second one yet.. I'm hoping for better results

 

[rob_gould]

Done!  I haven't listened to it yet, but everything lights up and there's no smoke so early indications are good...
 
I stupidly forgot to order a switch cap in my last parts order and won't be making another order for a while.  Does anyone happen to have a spare lying around?  Preferably white, but any colour will do...

Cheers,

Rob

 

[dirtyhanfri]

Hi

I've been testing  my two Level-locs in a studio and found them quite noisy (50 Hz noise and some harmonics), just in the limiter circuit. Setting the Mix knob CW (wet setting) the noise is there, independently of the input pot position (see attached image), Bypass and dry gives me some kind of 200Hz-20Khz. bandwidth noise, but it´s about -88 dbu only in fully wet setting, I can live with that.

Or is there another spot I could look at trying to bring down that hum?.

Edit: It wasn't about the V Regulator, the wires going to Comp switch were getting the noise, I trimmed them and the 50Hz noise is about 10dbs lower.

 

[Dr Gris]

In my very limited spare time I finally managed to finish these yesterday.
Nice and easy build. Big thanks to Ian and Marek. Would also like to thank "Indecline" for the Mouser cart
I based my own cart from.

They sound cool when you don't hit them too hard. I find them rather noisy though. I ended up not using
my sleds that I bought, maybe I should to screen them more. Also touching the controls makes a little buzz.
It doesn't ruin the performance, but do anyone have a tip to make them less sensitive and less noisy?

Best regards
//Magnus

 

[rob_gould]

Edit : solved the question about bypass.  Button in is compression circuit disengaged, button out is compression circuit engaged.

I still have the issue where when turning the wet / dry pot to wet, I get a high pitched whining note instead of compressed signal.  The input pot does nothing,  The switches change the volume of the whining noise ever so slightly.

Component values and orientations all appear to check out.

I'm considering changing the J112 but this is just a guess.

 

[rob_gould]

Hi All,

I'm still struggling with this.  The fault is that when the circuit is engaged, a high pitched squeal is heard when turning the mix knob clockwise.  So at 100% wet, I hear my signal going through the unit wit squeal over the top.  What's interesting is that compression seems to be working - I can hear the effect of the compression on the signal and also the compression seems to duck the squeal too.

So far I have :

- verified all component placements three or more times

- checked over and over again for solder bridges / dry joints

- resoldered lots of the components anyway

- replaced the TL074

- replaced the J112 FET with a 2N5457

- removed  all 8 transistors from the circuit, checked their HFE to make sure they're not dead, then put them back in.

I'm pretty much at a loss now because starting to swap the passive components like capacitors just in case they're faulty seems totally barmy to me.

This must be a problem with a solder bridge or dry joint, but I just cannot see where.

Sooooo Frustrating!

Can anyone assist with where to probe to follow the audio through the circuit?  This is the part I'm very bad at and can never tell  whether it's valid that the signal has been lost at any particular junction...

 

[dmp]

This must be a problem with a solder bridge

That's what it turned out to be with mine. I spent quite a bit of time debugging it before I found the problem. I was able to trace the circuit on the scope to narrow down where the problem might be. But it was a bridge I could see once I found it - so if you look over the board carefully, maybe you will see something.
Post a high res picture and maybe someone here will spot a problem?
Also look for bridges in the plating. There were a few in my boards. For people just starting out, I'd recommend checking the board for shorts before any soldering. It's much easier when you can easily use a multimeter.

 

[dirtyhanfri]

(I suppose you could take the signal from the emitter of Q3 and superimpose this,- with or without amplification-, on the control voltage. But if you like the distortion, leave it as it is!)

I'd like to give a try to this

I'm thinking in get the signal between Q3 and R9 and put it before R2, which I think is Control Voltage, but I not sure of this, could someone confirm if I' m right?

Thanks

EDIT: Looks like I was wrong, I got cranking noise at high levels when tried it...

Also I've found this, http://groupdiy.com/index.php?topic=2100.msg458116#msg458116 a simple solution wich seems to be the winner, I will give it a try tomorrow, I don' t have any 470uf cap... ¿Could I use 47uF and 1k resistors? give me the same cutoff freq in the filter calculator...

 

[rob_gould]

Hi dirtyhanfri

Could I ask a favour of you please?

Please could you measure b, c and e voltages at the 8 transistors in this circuit when the unit is engaged but not passing signal? And also the g,s and d of the FET?

I am still really struggling with my unit and I've been advised to compare voltages with a working unit to try to narrow down the issue...

Cheers

Rob

 

[Bassniac]

Hi folks

Another two units completed and working flawlessely. The first one was working directly the second one needed two hours of troubleshooting just to discover my own stupidity.

The fit really nicely in my DIY rack don't you think.

The sound is excellent and just the right thing for parallel drum compressing.

Cheers.

 

[dmp]

That's nice!

The sound is excellent and just the right thing for parallel drum compressing.

They are really cool on parallel compression.  Very dirty. 

 

[rob_gould]

The first one was working directly the second one needed two hours of troubleshooting just to discover my own stupidity.
Cheers.

May I ask what the stupid error was?  What were the symptoms and what was the cause of the problem?

I struggled for so long with the issue weird with mine (outlined above) that I've actually ordered a second unit.  I'm hoping to build this one problem free so I can compare and contrast between the two to see what's up with the first one.

 

[Bassniac]

I messed up the  Transistors positions... Went through all of the soldering joints first to find solder bridges or cold joints. Then I checked all the polarized parts for correct orientation. Then I started to check all the parts fur their correct value... Semiconductors first... There it was.

Now I got two working units that will never again leave my drum chain.

Dirty? I think it's rather difficult to distort them. I rather get really clean drum parallel overcomprwssion. My 1176 are much more on the dirty side.

Perhaps I need to use the more and most comp settings more...

Rob your Problem sounds like a bad Condenser to me. I had a problem like that in one of me preamps. Was a bad Tantalum.

 

[dmp]

Dirty? I think it's rather difficult to distort them. I rather get really clean drum parallel overcomprwssion. My 1176 are much more on the dirty side.

No wrong way to do it if it sounds good. My 1176 are very dirty too in a great way - when setup for it (all buttons in)
I've been doing pretty dirty parallel compression with all my compressors, haven't tried them clean much at all.

 

[Bassniac]

Oh man. I love this DIY thing. For so few bucks you get so pristine things. And all the fun building them.

 

[rob_gould]

Rob your Problem sounds like a bad Condenser to me. I had a problem like that in one of me preamps. Was a bad Tantalum.

Thanks for the input.  I guess you mean capacitor, not condensor?  And your problem made the same kind of squeal?

 

[Bassniac]

Yeah Capacitator, I messed up two languages. Exactly I once had a cap causing HF squeal and another time I had a cap causing LF hum. Furthermore I never had a resistor causing any trouble in a fresh unit.

Cheers.

 

[kank]

Hi guys, here another Lvl_lok builder looking for help. I think it's almost done but it is impossible for me to find the F2UEE switch, not in my city, nor even in my country...  Is it possible to use another kind of switch?
Thank you in advance