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Bakersdozen
01-07-2020, 04:58 PM
So onto the next pedal project. I had such a blast using vero board for the MXR CAE Boost/Buffer, so I settled upon an orange compressor clone. Using this Orange Squeezer layout.

https://uploads.tapatalk-cdn.com/20200701/481d3186fb28441c4a43d49f35c24f60.jpg

Here's the board trimmed down, cuts and links made.

https://uploads.tapatalk-cdn.com/20200701/0dbb3c6a54e322e6c7c23815edcb5e8b.jpg

Bakersdozen
01-07-2020, 05:01 PM
Large sockets, bias trim pot and diode attached.

https://uploads.tapatalk-cdn.com/20200701/f2a1535b65611189bee48882346262ea.jpg

Enclosure drilled and primed.https://uploads.tapatalk-cdn.com/20200701/86e3e3108e0f6497e6cb30a09f0c32ad.jpghttps://uploads.tapatalk-cdn.com/20200701/13da2804111314d2c7b5aeee3419a943.jpg

Great suggestion from DC (via FuzLord) to drill the LED hole 15mm from the centre of the Footswitch hole to solder the leg directly to the 3PDT switch.

JohnH
01-07-2020, 05:35 PM
Cool! Look forward to seeing it when it's all wired up

Bakersdozen
01-07-2020, 05:38 PM
All components fitted.
https://uploads.tapatalk-cdn.com/20200701/00f20a001a2d5a19afd2819d8b720638.jpg

FETs an opamp installed.https://uploads.tapatalk-cdn.com/20200701/002717b2c5c8c396982ba3dd2b491963.jpg

Simon Barden
01-07-2020, 05:45 PM
So you're replacing the fixed 4M7 resistor with another resistor and a trim pot? What values are you using?

Bakersdozen
01-07-2020, 06:00 PM
So you're replacing the fixed 4M7 resistor with another resistor and a trim pot? What values are you using?Whoops, my bad sorry Simon. I uploaded the wrong layout. That one was for the external bias pot. Here is the correct layout for the internal 10k bias pot.

https://uploads.tapatalk-cdn.com/20200701/fe4aa4ebed8420eb8488a465bfc99499.jpg

jugglindan
01-07-2020, 06:04 PM
Ah, the precious precious Ge diode :)

Did you solder that board in the same time spacing as your posts? 40 minutes to populate the board is a radical time. Takes me much longer.

When you get to it, have a look at my Julius Squeezer thread for details on using a multimeter to set the FET bias. I can't recall what voltage I settled on (around 1.3v) but it's got just the right amount of juicy tone and compression.

jugglindan
01-07-2020, 06:09 PM
I am not a fan of the external bias control. There is a very narrow range of voltages at which you get the good sounding compression. All the rest of the adjustment range is either a cleanish boost with no compression, a slightly dirty drive, noisy as hell, or sputteringly silent. Dialing in the adjustment on mine saw me barely pushing on the trimpot at all to change values.

Bakersdozen
01-07-2020, 06:16 PM
Ah, the precious precious Ge diode :)

Did you solder that board in the same time spacing as your posts? 40 minutes to populate the board is a radical time. Takes me much longer.

When you get to it, have a look at my Julius Squeezer thread for details on using a multimeter to set the FET bias. I can't recall what voltage I settled on (around 1.3v) but it's got just the right amount of juicy tone and compression.No, that was kind of a retrospective posting situation DC. I am now up to circuit testing stage next. I have read your Julius Squeezer diary again and will go back and re-study how you dialled in the sweet spot when the time comes.

Bakersdozen
02-07-2020, 09:43 PM
All tested and boxed up.

Had one issue with no sound when testing the circuit and it came down to one link I hadn't tested for continuity. Reflowed some solder in and boom away she went.

I see how sensitive getting that sweet spot to bias will be, but going to go there with a fresh and rested mind. Just happy that it all works.

The decal plan was a COMPLETE fail. 3 goes , mucked them all up. Got them to a good point and then one last little move or manuover ripped something off. Wasn't happy with getting it as smooth as I wanted so I was probably working the decals for too long. Dang oh well. I have a new plan now, but that will take some time to arrive. So i will reveal the concept when that comes to fruition.

I have been enjoying minimising the earth points by using a ring terminal on this and the last build. Looks neater too. Same principal as solder lug terminals, but free cause I already have them and a set of crimps. This build it went under the pot and last build went onto one of the jacks earthing out with the enclosure.https://uploads.tapatalk-cdn.com/20200702/df5d5af2edb183ac503211a57d329787.jpg

JohnH
03-07-2020, 05:31 AM
Very nice and tidy. Sorry you had so much trouble with the decal though

jugglindan
03-07-2020, 06:34 AM
I agree, very tidy! Kudos.

Do you need a bit of insulation between the edge of the board and enclosure? If the board can move at all it's fairly easy to short the traces.

And I feel your decal pain after the struggle I had with the last one. I did look into making silk screens, but was disappointed when I learned that the process permanently sets a screen to one design (or one layer of one design). Great if I wanted to crank out 20 identical pedals, less great for my experimental 1-off designs.

JohnH
03-07-2020, 07:14 AM
...but was disappointed when I learned that the process permanently sets a screen to one design (or one layer of one design). Great if I wanted to crank out 20 identical pedals, less great for my experimental 1-off designs.

No, you can strip it off really easily. That's how I picked up all my fabric screens so cheap - the lady who owned them didn't know she could strip them, so once she was done with her shirt run she sold them for $20 each!

The one thing to note though is that the stripping chemical is often tied to the emulsion you use to set the image - different brands don't usually work with each other*. In cbr, you can coat a screen at Megalo for $5, and strip it for $2 (there are other fees too - hire, etc). If you're doing it at home the stripper I use comes as a powder that makes up a huge amount of liquid when mixed. I don't know how much it would be per screen but it would be $1 or less.

I usually do a few pedals at once, so I can get three or four stencils on the one screen, print them all and then strip it.

*Having said that, there is an ultra-caustic process that will strip anything, so if you find a good second hand screen but don't know what they used to put the image on it is still possible to get it off, it's just gross.

jugglindan
03-07-2020, 07:28 AM
No, you can strip it off really easily. That's how I picked up all my fabric screens so cheap - the lady who owned them didn't know she could strip them, so once she was done with her shirt run she sold them for $20 each!

Good to know. None of the YouTube videos showing the homemade UV exposure method mentioned that part. But it does look fairly easy to make screens from some pine, mesh and a staple gun. I was thinking something A4 sized would be good for pedals. Also hoping I can do it more cheaply than the kits from Eckersleys (https://www.eckersleys.com.au/permaset-aqua-screen-printing-kit) by shopping around on eBay.

JohnH
03-07-2020, 07:32 AM
Yeah, it's a really common complaint, but definitely a very simple and doable process (easier than getting the image on, in fact)

A4 works fine. I normally try to get a screen a bit bigger, as it makes printing easier, so A3 or so. The one I normally use is 50 x 40cm (from memory), but that just means I can get a few designs on and need a good support/bracket system when printing.

The most important thing is the mesh. Honestly, can't stress it enough. Bad mesh= bad prints, every time. You can get away with an awful frame, but the mesh makes the image. A good 70T yellow mesh will do almost anything you'd need, but if you want small details (small font, or halftones) I'd use 100T like this:

https://gjs.co/supplies/p3371/100t-screen-mesh

Bakersdozen
03-07-2020, 07:41 AM
I agree, very tidy! Kudos.

Do you need a bit of insulation between the edge of the board and enclosure? If the board can move at all it's fairly easy to short the traces.



Thanks mate, yeah I will look at that when I get in to do the biasing and make the board a permanent fixture. It's currently sitting in there Blu tacked to the top of a plastic milk bottle for some clearance. Hot glue might be the answer. I just need to get a hot glue gun.

Bakersdozen
07-07-2020, 08:10 PM
So I had a little while to have a play with this tonight. Wow, it is such a sensitive circuit in terms of biasing the transistors hey. Initially my thoughts are it is quite hissy when engaged. The sweep of the trim pot is SUPER sensitive. It seems to react differently to single coils and humbuckers in terms of dialling it in. Humbuckers seem to always have a slight edge of breakup thing going on (not always a bad thing) no matter where the trim pot is. But I'd prefer it to be a clear compressed situation. I'm going to play with it a bit more and possibly try some different op-amps / trannies etc. for a little while until it starts speaking to me. A fun little beast of its own though, which is super fun.

jugglindan
07-07-2020, 09:18 PM
You could try J201s instead, as I have heard of others using them. Mine is using 2N5457s just fine though.

Did you try hooking a multimeter to the gate lead of Q2, then adjusting the bias trimmer until the voltage to ground is between 1.3 to 1.5 volts? That's the method I used. In my build thread I have a photo showing the voltmeter at 1.314v, but I think I actually went a bit closer to 1.35v the next day. To set this you don't need signal, just have the board powered up.

I get good compression (both limiting peaks and boosting low signals) at that setting with both single coils and humbuckers (the DiMarzio PAF in the G&L).

Bakersdozen
07-07-2020, 09:41 PM
You could try J201s instead, as I have heard of others using them. Mine is using 2N5457s just fine though.

Did you try hooking a multimeter to the gate lead of Q2, then adjusting the bias trimmer until the voltage to ground is between 1.3 to 1.5 volts? That's the method I used. In my build thread I have a photo showing the voltmeter at 1.314v, but I think I actually went a bit closer to 1.35v the next day. To set this you don't need signal, just have the board powered up.

I get good compression (both limiting peaks and boosting low signals) at that setting with both single coils and humbuckers (the DiMarzio PAF in the G&L).TBH I've just been doing it by ear. But I will try that approach and see. That was my next step. I do get better performance if the volume is backed down to around 9.

Do you much background hiss when yours is engaged, but not playing?

jugglindan
07-07-2020, 09:48 PM
On my build, volume at 9 is close to unity, so I don't go much above that. Never past 10.

The hiss is typical of a compressor. It's amplifying the noise. This circuit doesn't have a threshold adjustment, and I don't know what level the threshold is. I use a noise gate though, so probably not hearing as much noise.

Sent from my moto g(7) using Tapatalk

Bakersdozen
09-07-2020, 07:53 PM
Second attempt at the artwork on this pedal. It's got the vibe I'm after now. Still having fun dialling this in. The recommended voltage wasn't too far off what I had set it by ear, so that's good that it's lining up with how I hear it working.https://uploads.tapatalk-cdn.com/20200709/baa82ceb1c8ce46f6042c4214cac6a8f.jpg

jugglindan
09-07-2020, 08:51 PM
Is that vinyl? Looks good.

Bakersdozen
09-07-2020, 09:03 PM
Is that vinyl? Looks good.The enclosure is sprayed with some green VHT engine enamal I had lying about. The artwork is vinyl decals.

JohnH
10-07-2020, 05:21 PM
Woah! Came out ace