I built another gar2520 opamp for my 3rd #500SeriesAPIClone . Prototype no. 1. The one that lives in my lab to test mics with. I don't know why I only ordered parts for 2 opamps the first time around, but I remedied that. I have a ton of opamps of other designs, so I had been using it with a spare, but now it's as it should be.

I also changed out the inductors in the 2 FET847 boards to the smaller ones they didn't have in stock when I originally ordered the parts.

#FET847MicBuild

Got the dryer power cord all sorted, and now I have a fully functioning washer/dryer pair.

This weekend I'll finish prototype #3 of the API preamp project, and if all goes well I'll finish up the KM84 based LDC mic.

I also have been in contact with a friend on a preamp project from the Amek M2500 console. I've worked on a variety of Amek consoles over the years including the 9098i, Mozart, Angela, and Big, but don't have any Amek mic preamps in my locker.

#500SeriesAPIClone
#FET847MicBuild

OK, I finished prototype number 2 of the 500 series API preamp. I'll post pics some other time. I'm taking my time this weekend, and I'm taking a lot of breaks and chatting with the band who is tracking their new album in our studio.

I also got some parts needed to finish the FET847 mic which I'll hopefully be able to work on next weekend.

#500SeriesAPIClone
#FET847MicBuild

Did quite a bit of work to the preamps today. I didn't end up finishing either because I was taking my time. Should have at least one finished tomorrow.

#500SeriesAPIClone

Need to relocate some mounting holes on the PCBs since I'm still working with REV1 prototype boards, then solder the transformers. Shortly after that I should have 2 more working API prototypes for the 500 series.

I'll work on that this weekend.

Then if I get lucky, next weekend, I might be able to finish one of those FET847 mics, which is the Neumann KM84 amplifier circuit modded for large diaphragm capsules. They're kinda like inexpensive mini U87i's.

#500SeriesAPIClone
#FET847MicBuild

Did some metal fabrication to the L-Brackets that help provide stiffness to the PCBs on this project. The PCB holds two transformers, and the L-Bracket helps strengthen the PCB to be able to support all that weight.

The Brackets come with a solid flat face, and I used the blue front panel as a template for where to drill and file. You can kinda see the evolution here.

#500SeriesAPIClone

@stevensrmiller

Going to be working on two more prototypes of my 500 series API build today. Gotta do some metal fabrication to the L-Brackets to get all kinds of holes (for pots and switches) to line up.

#500SeriesAPIClone

Also on the upcoming build agenda is making two more of my 500 series API clones with the Rev1 boards. I already populated the boards and bought two more panels, so I need to finish those. Then all future builds will be with the Rev2 boards which hopefully fixed all the bugs from the Rev1 boards.

#500SeriesAPIClone

Re-introduction:

In terms of classic recording equipment clones that I've built, I have a bunch of SSL, API, and Neve mic preamps, and I'm developing my own API clone with a friend for the 500 Series. Here are some hashtags:

#500SeriesAPIClone #500Series #ML12Build #Neve1073Build #MP573Build #SSL9kBuild #SSLBusComp

A proper desoldering gun is one of the most useful specialty tools an electronics maker can have. Sometimes a month goes by without needing it, but when you need it, a good one saves potentially hours of time and definitely keeps your PCBs from being damaged.

I ended up having to use mine on prototype No. 1 of the #500SeriesAPIClone yesterday because two diodes were silkscreened on the PCB top in the wrong direction. Manual solder suckers and solder wick just wouldn't have gotten the job done.

Then I realized I had a short between the 48 volt rail and ground. When I was modding these REV1 boards I had to drill a hole to move a PCB standoff and got too close to the 48v line. It was shorting to the ground plane right there. I was able to isolate the short out of the circuit and solder a jumper around it to get the phantom power rail working again.

After that it worked exactly as expected. YAY!

Super thrilled.

Not the best photo. I'll get better shots, soon.

2/2

#500SeriesAPIClone

Then I realized I had a short between the 48 volt rail and ground. When I was modding these REV1 boards I had to drill a hole to move a PCB standoff and got too close to the 48v line. It was shorting to the ground plane right there. I was able to isolate the short out of the circuit and solder a jumper around it to get the phantom power rail working again.

After that it worked exactly as expected. YAY!

Super thrilled.

2/2

#500SeriesAPIClone

Got prototype #1 of the #500SeriesAPIClone done. When I powered it up, it didn't. The PSU warned me that something was wrong, but I didn't know what exactly. Immediately I noticed that the two power rail input protection diodes were in backwards. How I didn't notice this sooner is beyond me, but I didn't. But this would only keeping current from flowing. It would keep the circuit from working, but shouldn't have made the PSU kick up an error.

1/2

#500SeriesAPIClone

Welp, many months work should come to fruition tomorrow. Since I got the REV1 #500SeriesAPIClone panels in the other day, that means I can now do final assembly on prototype #1 and see if it doesn't splode when I power it up.

I suspect it will be fine, but we'll know more tomorrow by mid afternoon.

Can't wait to play.

#500SeriesAPIClone

REV1 of my custom panels for the #500SeriesAPIClone project that I am working on with a friend, came today. These panels will work with the REV1 PCBs, but not any future PCBs. Reason being we moved a few components on the REV2 PCBs. So anyway, I have 3 prototypes under construction right now with REV1 boards, so I got 3 REV1 panels in. I'd say my panel guy did a great job.

#500SeriesAPIClone

Just got the update that my #500SeriesAPIClone panels will come tomorrow. Can't wait to see how everything looks with the knobs I have chosen.

I went with very plain-ish knobs (round silver) on this line of preamps for a reason.

I'm also curious to see how everything lines up with the PCB. It should be exact. The wood panel cutout I did on our laser cutter seemed to have it pretty perfect, but my metal guy can hold tighter tolerances, so hopefully it will be even better.

#500SeriesAPIClone

@havoc

#D87Build
#TubePreBuild
#PMillettBuild
#ActiveDIBuild
#CAPI500Build
#CP5Build
#SSL4000GBuild
#SSL9kBuild
#1176Build
#LoudLifterBuild
#TubeHiFiPreampBuild
#ClassDAmpBuild
#RibbonMicBuild
#SSLBusComp
#CAPIVP25Build
#ML12Build
#MP573Build
#Neve1073Build
#LevelLocBuild
#RatPedalBuild
#Mackie1202Upgrade
#BalancedOutputBox
#LowFiMicBuild
#CarbonMicBuild
#500SeriesAPIClone
#KM84CloneBuild
#FET847MicBuild

Looks like the panels for my #500SeriesAPIClone build will be delivered Monday. I was hoping they'd come today so I could finish prototype no. 1, but I'll do it next week I guess.

#500SeriesAPIClone

OK, I think REV2 of the #500SeriesAPIClone board is done. But what this means is the 3 prototype panels I ordered, and which will be here any day now, won't work with REV2 of the PCBs, since some components moved a bit. No worries. REV2 is production ready and even though I ordered 20 of the slightly flawed REV1 boards, they still work, and I'll just use the prototype panels with those until I do an order of the REV2 boards. It's all part of the process.

#500SeriesAPIClone

OK, REV2 of the #500SeriesAPIClone PCB is done. Components were moved. This means I had to move the holes on the front panel design.

The good news is computers make this easy.

#500SeriesAPIClone