OPTO "Grinder"

[darkus]

Hi Gustav and other nerds!

Is it possible to make this build with 1176 pushbutton assembly for ratio?

I realize that this opto compressor has 5 ratios as 1176 buttons have the option of 4 and all in but could i leave out the 20:1 some way?

Thanks
Markus

 

[Gustav]

Hi Gustav and other nerds!

Is it possible to make this build with 1176 pushbutton assembly for ratio?

I realize that this opto compressor has 5 ratios as 1176 buttons have the option of 4 and all in but could i leave out the 20:1 some way?

Thanks
Markus

Shouldn't be too hard. I would recommend attaching the control board as usual and wiring the switch from the existing switch connections. All you have to do it route them to the switch bank instead of the Lorlin footprint on the PCB.

If you send me a switch bank, Ill work it out in 5 minutes

Gustav 

 

[darkus]

I was actually going to wire all the pots and mount the pcb with normal standoffs as my idea of the case is a bit different.

I was going to use this ratio switch from hairball audio and leave out thr 20:1 setting.
http://www.hairballaudio.com/shop/product_info.php?cPath=28&products_id=30

Im sure i can find a decent photo out of it to show thr pins etc

 

[Gustav]

I was actually going to wire all the pots and mount the pcb with normal standoffs as my idea of the case is a bit different.

I was going to use this ratio switch from hairball audio and leave out thr 20:1 setting.
http://www.hairballaudio.com/shop/product_info.php?cPath=28&products_id=30

Im sure i can find a decent photo out of it to show thr pins etc

Thats what I meant, but when doing that, I would still mount the control board and draw the wires from the Lorlin mount, rather than direct from the edge connector. It will make the wiring much more obvious.

"Send me a switch" was a bit tongue in cheek, and I meant physically send one. Im sure you can work out he connections with the switch in hand.

Gustav

 

[mastertaenia]

Hi Gustav,
I have a little question when the stereo mode is engaged... Are the controls (ratio, th and gain) of both unit operant?
Thanks 

 

[Gustav]

Hi Gustav,
I have a little question when the stereo mode is engaged... Are the controls (ratio, th and gain) of both unit operant?
Thanks 

The channel with the most gain will drive the other channel, and gain can still be set and shown individually, while compression will be shown commonly.

As you may have noticed, the first version I put out of this board has the stereo link point, the new, easier build does not. Simply linking the two does not yield good results in my experience, and if you are doing it, you should make sure that you are using a dual opto cell for the actual compression and one dual opto cell for the metering in stereo mode. That way, they should be matched.

Gustav

 

[MichaelD]

Just wanted to share. I recently finished building this thing, and I must say this unit is fantastic!
I read others complaining about LA4s not being that great. I don’t know how similar this unit is to an LA4 since I don’t own juan. But I do have a few other compressors - 1176s, LA2A, 160Xs, and this fits nicely into the mix.

I've been putting everything through it with great results! It can be very subtle and smooth, or aggressive. Just love it.
And like other fine analog gear, just going through it with no compression adds goodness!
Seems like such a simple circuit. Vary surprising.
Thanks Gustav for this badass offering, can’t say enough about it.

Michael

 

[weiss]

I'd love to combine this compressor with the tube stage amp! could be some sort of cl1b build for tracking vocals, bass etc.

 

[gyraf]

My thought exactly.

Maybe we can push the good Gustav into an original design like this?

Jakob E.

 

[Gustav]

"the tube stage" being the stage from Jakob's Pultec?

I am juggling a lot of things, finishing up a few plain projects and exploring a few fun ideas right now, but I'll add it to the list.

Gustav

 

[Gustav]

I already have this two channel gain stage up and running.

Sounds great, and theres no noise in the test circuit, but I would like to correct a few things the the grounding that bother me on the prototype "Just because", so I am doing a new revision and can check back.

Gustav

 

[weiss]

Nice to hear that gustav is it difficult to combine the gain stage with the opto grinder? or should i better ask jakob

 

[Gustav]

Nice to hear that gustav is it difficult to combine the gain stage with the opto grinder? or should i better ask jakob

1. Build the tube gain stage.
2. Build the opto comp minus output gain stage.
3. Combine the two.
4. Check for smoke
5. Check for sound.

!?

I would guess that figuring out how to power everything is the first thing to form a strategy for before combining the two stages.

Gustav

 

[weiss]

Nice to hear that gustav is it difficult to combine the gain stage with the opto grinder? or should i better ask jakob

1. Build the tube gain stage.
2. Build the opto comp minus output gain stage.
3. Combine the two.
4. Check for smoke
5. Check for sound.

!?

I would guess that figuring out how to power everything is the first thing to form a strategy for before combining the two stages.

Gustav

i meant on one single pcb

 

[Gustav]

Nice to hear that gustav is it difficult to combine the gain stage with the opto grinder? or should i better ask jakob

1. Build the tube gain stage.
2. Build the opto comp minus output gain stage.
3. Combine the two.
4. Check for smoke
5. Check for sound.

!?

I would guess that figuring out how to power everything is the first thing to form a strategy for before combining the two stages.

Gustav

i meant on one single pcb

The schematics for both are on my site, so you can draw it up and lay out a PCB if you need them on the same board.

Gustav

 

[Jimmy5K]

Hi GroupDIY,
Hi Gustav,

I built this kit and put it into an enclosure.
I followed the assembly guide and the universal wiring guide.

I used the 2x18v trafo  here:
https://pcbgrinder.com/index.php?route=product/product&path=94_97&product_id=103

I am trying to measure the PSU voltages before I solder the 0 ohm resistors in place.

I am getting 22.05V AC between the secondary CT and one end.

At the +18V test point I get +16.72V DC
At the -18V test point I get -16.72V DC


Is the 22.05V AC normal on the output of an 18V trafo?
Is 16.72V a normal range for the 18V test point?

I am currently using a 400mA fuse.
Is there a suggested way to calculate which fuse to use?

Thanks very much for any help anyone can provide.

kind regards,

Jimmy5K

 

[kante1603]

Hi GroupDIY,
Hi Gustav,


Hi Jimmy5K,
welcome to the forum.


I built this kit and put it into an enclosure.
I followed the assembly guide and the universal wiring guide.

I used the 2x18v trafo  here:
https://pcbgrinder.com/index.php?route=product/product&path=94_97&product_id=103

I am trying to measure the PSU voltages before I solder the 0 ohm resistors in place.


O.K.

I am getting 22.05V AC between the secondary CT and one end.

At the +18V test point I get +16.72V DC
At the -18V test point I get -16.72V DC


Is the 22.05V AC normal on the output of an 18V trafo?


Yes,ac voltages on transformers differ as long the secondaries are unloaded,some more,some less,but always higher than specified.


Is 16.72V a normal range for the 18V test point?


Not exactly but well in the range you´re after.If you want it spot-on you might have to change the setting resistors on the regulators,e.g. with a 25-gang trimpot or so.But since both positive and negative voltages are even perfectly balanced you´re good to go and fire it up.
NE5532s and Co. are normally driven at +/-15 to +/- 18 vdc anyway.

I am currently using a 400mA fuse.
Is there a suggested way to calculate which fuse to use?

Looks to be a bit on the high side but will work.You can do a current measurement once fired up and start from there.In most cases I use 315mAs fuses on 30VA transformers.


Thanks very much for any help anyone can provide.

kind regards,

Jimmy5K

 

[Gustav]

Re the slightly lower than 18V voltage.

I ended up turning it down a tad due to the071 in the meter circuit (stupid to use that, but I was so used to bumping into it as a GR drive opamp, I thought there was some special benefit at the time I just wasn't seeing).

So - 17Vish is actually perfect and well within range.

Gustav

 

[Jimmy5K]

Thanks very much for your suggestions kante1603.

I thought the secondary might read high when it wasn't under load.

I will try to measure the current to work out which fuse I require.

 

[Jimmy5K]

Thanks very much for your response Gustav.

I soldered the 0 ohm resistors in place yesterday and did the rough calibration too.


I did some quick tests last night and it's all working as expected.

I still have to work out the front panel artwork but other than that it is all finished.

Thanks.

Jimmy5K