DR-ZEN2 Limiter Build

[LNS]

Hey folks,
I finally came back to to this build and am almost there. My unit is passing audio in bypass, all the LEDs and meters are lit, and I'm getting the correct 28/-28V at the PSU and the 20/-20V on the boards. But when the unit is engaged, it's not passing audio and all I hear is white noise.

Does anyone know what I should be reading at the various test points? Something funky is going on in channel 1 at test points E, F, and G, but without a schematic I'm in the dark. I've triple checked all my components, orientations, wiring, and reflowed my solder points.

Channel 1

• A: 0 V
• B: 12.8 V
• C: 12.8 V
• D: 5 mV
• E: 0.5 V
• F: 0.5 V
• G: 1.15 V

Channel 2

• A: 0 V
• B: 10 V
• C: 10 V
• D: 8 mV
• E: 15 V
• F: 19.7 V
• G: -10 V

I'm in the same position...... finished my build and everything looks good (after replacing the toroidal as the one supplied in the kit had a short), voltages all measure correctly, LEDs and lights all work, my unit also passes audio in bypass, when engaged it still passed audio and the input and output controls work but there's zero compression or movement from the meters

Does anyone have a schematic? I'm struggling with getting much of a response from DIY Racked and getting increasly frustrated I've put so much time and money into something I just can't seem to get up and running. This is the first DIY project I've not got over the line.

 

[lukas]

...some schematics for DRZen2?

 

[MidnightArrakis]

I've just done some more testing as I to try and figure out what the fault is.

I disconnected the PSU board from the toroid and when I turn the power on the toroid buzzes for a split second before blowing the fuse. I'm now using 0.63a slow blow fuse as I've had issues in the past with toroids blowing 0.5a fuse due to the power up spike of inrush current.

I followed DIY Racked's diagram when wiring up the toroid and have just double checked and everything is as it should be, as the fuses are blowing when the only thing connected to the power the toroid is the only thing that could be at fault????

The toroidal is 25v, 50Va and I'm in the uk so supplying it with 240v.

[toroids blowing 0.5a fuse due to the power up spike of inrush current] -- You may want to try and use one of these devices in series with your toroid primary winding wires:

https://www.digikey.com/en/ptm/a/ametherm/inrush-current-limiters-overview
[I'm in the uk so supplying it with 240v] -- Unless your toroid has a means of wiring its primary side in a "Series" configuration, you are supplying 240VAC, from what I see, to a 115VAC transformer!!! See image below:

↓↓↓↓↓↓↓↓↓↓↓


Should this be a -- true -- scenario.....THAT would be a major problem right there!!! >>> POOF!!! <<<

/

 

[LNS]

[toroids blowing 0.5a fuse due to the power up spike of inrush current] -- You may want to try and use one of these devices in series with your toroid primary winding wires:

https://www.digikey.com/en/ptm/a/ametherm/inrush-current-limiters-overview
[I'm in the uk so supplying it with 240v] -- Unless your toroid has a means of wiring its primary side in a "Series" configuration, you are supplying 240VAC, from what I see, to a 115VAC transformer!!! See image below:

↓↓↓↓↓↓↓↓↓↓↓
View attachment 117822

Should this be a -- true -- scenario.....THAT would be a major problem right there!!! >>> POOF!!! <<<

/

The primary was wired up in series for 230v but turns out there was a short which was popping the fuse.

I’ve swapped it out for another toroidal and everything is powering up fine now.

I just wish the unit worked or DIY Racked replied to emails or included a schematic in the build guide

 

[mypantsrblue]

did you ever get this working?

 

[LNS]

did you ever get this working?

Not as it should.

It passes audio in bypass but when the compressor is engaged it rolls off everything below 1k. I’ve been trying to get some support from DIY Racked or a schematic but I’ve heard nothing from them yet.

At the minute my Zen is a real expensive paper weight.

 

[bgrugle]

I'm in the same boat, unfortunately. I'm taking a break before diving back in, but it currently shows all the signs of life but doesn't pass audio in bypass or otherwise. I do think it's some mistake I've made though, not a fault in the design, so that's promising. Just need to do serious troubleshooting.

I also haven't heard back from DIY Racked beyond an initial email!

 

[LNS]

I'm in the same boat, unfortunately. I'm taking a break before diving back in, but it currently shows all the signs of life but doesn't pass audio in bypass or otherwise. I do think it's some mistake I've made though, not a fault in the design, so that's promising. Just need to do serious troubleshooting.

I also haven't heard back from DIY Racked beyond an initial email!

I just need a schematic and then I’ll be able to troubleshoot.

 

[GratefulEight]

I'm also workin on a Dr.Zen2 at the moment. I dug around all over the place until I found what I believe to be the schematic it's based on. I haven't sat down and done a full trace or verified it vs. the boards, so (obviously) use at your own risk...but it might save several folks a whole LOT of looking around for it if it is correct.

 

[LNS]

I'm also workin on a Dr.Zen2 at the moment. I dug around all over the place until I found what I believe to be the schematic it's based on. I haven't sat down and done a full trace or verified it vs. the boards, so (obviously) use at your own risk...but it might save several folks a whole LOT of looking around for it if it is correct.

This could be very helpful, I've tried emailed DIY Racked again today asking for a schematic but I won't hold my breath.

 

[LNS]

I'm now thinking could my diodes be the problem? My first matched pairs were super noisy, I swapped those out for some NOS 1N751A's and now everything below 1k disappears in the audio signal.

I think I need to go back and see if this was also an issue with the noisy diodes, as I didn't do too much testing with them when I heard the noise.

 

[LNS]

ZEN 2 Schematic attached below!

 

[slipperyflax]

I built this unit a couple of years ago but today it hit me that I don't know if I ever calibrated the meters. It's not described in the project documentation as far as I know so is there anyone out there who's done this and cares to share how they did it?