Whistle Rock Audio ML12 preamp BUILD/HELP thread!

[Ricardus]

Build is coming along nicely. I'm in no hurry so I am taking my time with final assembly. I used to geek out and if I had a day off, I would spend 12+ hours glued to my bench working on things, and my neck and back would pay the next morning.

Anyway, because I'm an idiot, when I ordered the panels, I didn't double check the rear panel XLR cutouts, and just assumed they would be Neutrik D-Series which are the ones I like to use (I know, my bad, hence the idiot part). Turns out they were not D-Series, so I just found out my friend Pat bought a small milling machine, and we were able to mill the holes to accept D-Series. So it all turned out well, and nobody would know any better if I didn't tell them.

I was actually out of zip-tie anchors, so I had to order some of those before I can finish this up. Gotta keep the wiring neat.

Anyway, here's that milled panel with some XLRs in, and a couple that aren't so you can see what we did.

 

[Ricardus]

I did some fabrication, and got the AC wired, and the power supply mounted and wired as well. I installed one module and got that going, and it works great. I'll do all 3 other channels tomorrow, and possibly the DI boards. We shall see.

 

[Ricardus]

Almost done.

All 4 channels work great, and the DIs as well. A few more details to square away, as well as making a couple custom support brackets and a shield for the transformer.

 

[Whoops]

Looks pretty good, congrats.

Do you have to photos of the front panel?

It would be great to see how it turned out

 

[Ricardus]

Looks pretty good, congrats.

Do you have to photos of the front panel?

It would be great to see how it turned out

I'm waiting for some good light to take those photos. Several people have requested those, so they will be soon.

Not quite done yet, though.

 

[Ricardus]

With this enclosure, the bottom and top of the enclosure are made of aluminum, and it's not super thick (the sides are steel). In this ML12 build, there are 9 transformers and the weight was making the bottom sag. The enclosure has screw holes in the front and rear middle of the panels in case you wanted to do something to add support, so I made two custom brackets to work with the hardware on each panel to support the bottom. Here are closeups of the rear bracket, and both of them in place (I forgot to take a glamour photo of the front bracket before I mounted it).

 

[sr1200]

Does anyone happen to have the schematic for the preamp still? The links on page 1 are LONG gone.

 

[oran.outan]

Scroll down to the end and you will see Download documents containing all you need !

https://www.diyrecordingequipment.com/pages/ml12-discrete-mic-preamp-pcb-archive

 

[Whoops]

Does anyone happen to have the schematic for the preamp still? The links on page 1 are LONG gone.

No they aren't,
just use Way Back machine website, just search old sites or old links there, can easily access the schematic still as even the original website product page:

https://web.archive.org/web/2016032...cart/documents/ML12/ML12 v3.0 - Schematic.pdf

 

[Ricardus]

Looks pretty good, congrats.

Do you have to photos of the front panel?

It would be great to see how it turned out

OK. Here you go. Front and back.

The front panel isn't done quite yet. The DI in channel 4 needs to be installed. No big deal. Will take about 90 seconds. The only reason I didn't install it yet is because I need to run the 4 indicator LEDs for the 4 power rails on the right, and I need the room to work.

 

[Whoops]

Looks very good, thanks for sharing

 

[Ricardus]

Maybe I'll do this next time. What do you think??

 

[Ricardus]

Really good deal here on relays. Hope there legit I ordered 48. Panasonic Electric Works TQ2-12V
Capi has better deal on op-amp pins than mouser or digi-key as well.

Were the relays legit??

 

[Bobby Baird]

The relay coil impedance checked out against the datasheet. They say Japan on them. I haven't built it yet. Waiting on my transformers to be wound. I have everything else but the power supply chassis and some attunators from capi.

 

[Ricardus]

The relay coil impedance checked out against the datasheet. They say Japan on them. I haven't built it yet. Waiting on my transformers to be wound. I have everything else but the power supply chassis and some attunators from capi.

You using UTC transformers?

 

[Bobby Baird]

Input RE-0887PC & output CM-3301 from cinemag.

 

[sr1200]

Maybe I'll do this next time. What do you think??

Just go 2U and stick 8 in there with a PS like I did. lol

 

[Ricardus]

Just go 2U and stick 8 in there with a PS like I did. lol

I thought about it, but that build looked cramped! I don't think I'd have the patience!

 

[sr1200]

was a lot easier than you'd think. Just start on channel 1 and build your way forward. I added a lot of "extras" too (meters, extra switches, DI switchable since i put the input jacks in the back and have them permenantly wired to my patchbay and normalled to my synths and transformer ratio switch).

 

[Ricardus]

was a lot easier than you'd think. Just start on channel I1 and build your way forward. I added a lot of "extras" too (meters, extra switches, DI switchable since i put the input jacks in the back and have them permenantly wired to my patchbay and normalled to my synths and transformer ratio switch).

Imma stick with my 6 channel with no DIs for now! Maybe I'll be that motivated in the version after that!