• Why create a company dedicated to vintage API gear? Why not Neve, SSL, etc.?
• Will we ever see ClassicAPI kits in a 1RU rack format, instead of 500-series?
• Why does old API gear sound so good when it’s specs are so bad?
• The sonically stunning Gar2520 discrete opamp.
• Jeff’s new, two-stage preamp design, the VP28.
• How Jeff tried to cram a full API console strip into one 500-series slot.
• “Inventory management is a bitch.”
• How DIY gear is beginning to penetrate the big-budget recording world.
• Are we seeing a return to the early days of recording when many engineers built their own custom gear?

Download the mp3 file.

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To learn more about the Lola, check out my conversation with the designer Mike Mabie. If you’d rather not leave things to fate, you can buy Lola kits today at hairballaudio.com/lola.

Bonus Second Place Prize: The second winner will receive a sharp new Hairball Audio hoodie. The winner can choose their size. They can also choose any color they want, as long as it’s black!

Topics discussed:

• How Scott developed the Alice Microphone
• The brilliant Mic Builders Yahoo group.
• The Transound TBS-165A condenser capsule
• What happened when Scott swapped electrolytic for film capacitors in the Alice circuit.
• Tips for DIY mic bodies and headbaskets. The McMaster-Carr store is your friend.
• What to look for in a headbasket mesh material.
• “Somewhere between sculpture and audio.”
• Scott’s most recent project: a linear microphone array for piano.

In the 90′s Dane Tate sold his unique Optical De-esser #31 to a small number of raving fans in the pro audio world. The #31 has since been retired and reborn as the XQP 531 for the 500-series, but Dane has graciously offered his remaining inventory to the DIY community. There are an extremely limited number of products available: 12 PCBs and 5 chassis. I wish there were enough for everyone, but unfortunately this is it! You can order directly from Dane via the PayPal button below.

For more info on the #31, see the XQP Audio website.

PCB features:

• All components are standard and currently available
• Includes on-board power supply and power transformer
• Fits in a 1RU, half-rack size chassis

Chassis features:

• 1RU, half-rack size
• Two different color schemes: Green on anodized silver and gold on green. Sorry, no choosing–you get what you get!
• Serial number engraved on back panel (duplicates of commercially sold units)
• PCB slide-in slot
• May have minor paint-fill issues
• Includes a blank panel and mounting bracket to fill the space next to the de-esser

Beginners be warned! While the #31 is not a very complicated circuit, there will be no assembly guide or support offered for this project. Dane will supply the PCB/front panel and a schematic/bill of materials only.

Order PCB and/or front panel (Payments go directly to Dane Tate)

Options

PCB & chassis $95.00 USD PCB only $20.00 USD

Audio Samples:
The following are samples of the 545 Optical Disruptor processing various instruments. Just as Dane says in the interview, this thing is great at making synths more lifelike. All of the samples are in the order of: 1) Clean, original audio 2) Medium disruption 3) All the way up!

So, I’ve got the itch to make my own DAW controller. Great! Right now that’s about all I’ve got. I know next-to-nothing about MIDI (or anything digital for that matter), and the MIDIbox website makes about as much sense as Greek Alphabet soup after a couple hours of browsing. I do know, however, that I’ve been through this before–I couldn’t have told you whether audio signals were AC or DC when I built my first preamp. This time around, I’m going to document every step of my climb up the MIDI learning curve in hopes that it will take some of the mystery out of building your own DAW controller for those standing on the sidelines.

The Grand Vision

Since this is my first foray into MIDI, I’m planning on doing something fairly simple that would nonetheless break me out of the box for most of my mixing needs. There are 16 channels with pan, volume, mute, solo, and two aux sends each. That’s 64 potentiometers total (16 slide + 48 rotary) and 32 switches.

I’m still debating whether to use motorized or normal faders. It would be great to bring up a session in my DAW and have all of the faders snap to the corresponding positions. But motor faders are at least 5x more expensive than the normal ones. At this point, I’m leaning towards regular faders to keep the cost low. What do you think, will I regret this down the road? I’ve never mixed a project on a console or control surface without motorized faders before, is it a huge workflow problem not to be able to see where your levels are by looking at the faders?

Choosing a MIDI Interface

After a bit of research, the two MIDI platforms I’m looking at are Doepfer “Pocket Electronic,” Doepfer USB64, MIDIbox 64, and MIDIbox LC.

Doepfer MIDI Interfaces

The Doepfer products are appealing because they come as assembled, pre-programmed analog/MIDI interfaces. The Pocket Electronic puts out up to 16 channels via MIDI jack, while the USB64 can do up to 64 via USB. The Pocket Electronic seems like a great solution for a simple 8 faders + pan pots setup, but is decidedly short on channels for what I want to do. The USB64 offers enough channels and the option for digital inputs, which can be used for solo/mute switches. However, as far as I can tell, the USB64 can operate only in digital or analog mode, not both. Meaning I can have pots or switches, but not pots and switches. So, while the Doepfer units look very appealing from a digital newbie’s perspective, they’re not quite right for what I want to achieve.

The MIDIbox Platform

MIDIbox is an open source, modular MIDI platform that, while it’s pretty confusing to me still, appears to be extremely flexible and scalable. Basically, there is a core “brain” circuit board that takes inputs from different modules (analog input module, digital input module, etc.) and turns them into MIDI I/O. People configure these modules in all sorts of ways with different firmware to create things like sequencers, DJ control stations, synth controllers, and of course DAW controllers. I’m sure that is a gross simplification of the MIDIbox system, but it’s what I’ve been able to figure out so far. (Please feel free to correct or englighten me in the comments.) Circuit board layouts and firmware downloads are available at ucapps.de, and PCBs/kits are available from the MIDIbox shop.

Of the many MIDIbox permutaions available, those that seem most applicable are the MIDIbox LC and the MIDIbox 64. The LC emulates the performance of the Logic Control / Mackie Control surfaces. If I were building the Ultimate DAW Controller, I would probably go with this as it allows for motorized faders, but since it uses the LC (or MCU) format, I’m not sure it’s compatible with my DAW of choice, Reaper

MIDIbox 64 is an older project, which appears to have been replaced by the MIDIO128, but since the Midibox Store stocks only the 64 PCBs at the moment I think I’ll go with that. The 64 allows for up to 64 pots/faders, 64 switches, and 64 LEDs. More than enough to realize my “Grand Vision.” There is also support for an LC-display and other stuff, but I’m going to ignore those for this project in the interest of keeping things simple.

What’s Next

Right now I’m leaning towards the MIDIbox 64, but I’m going to continue reading about the MIDIbox platform until I start involuntarily piecing together interfaces in my head as a I fall asleep (usually a good sign I’ve reached a critical level of obsessiveness with a project). Once I settle on a configuration, I should be able to assemble a rough bill of materials and price out the project in Part 2. Until then, if you have any experience with MIDI DAW controllers, I’d love to get your feedback on which/how many controls you feel are essential for mixing, especially how you work with or without motorized faders.

This month, I’m glad to be able to offer an exclusive DIY kit from ribbon mic designer Artur Fisher of DIY Audio Components (DIYAC). The kit is for Artur’s RM-5 microphone, which I reviewed here and Jordan Reynolds reviewed for RecordingHacks. The RM-5 is a great mic, and I’m thrilled that Artur is offering it as a kit to the DIY community. However, he’s only doing one run of kits and closing the pre-order on April 5th. You can order directly from DIYAC through the PayPal button below.

Some words on the kit from Artur:

While RM-5 Ribbon Mic usually sells for €265, Artur will be offering basic kits for €99, including the mic body and hand-assembled ribbon motor. This kit includes everything needed to build an RM-5 ribbon mic, except for the output transformer. The Edcor RMX-1 output transformer and a custom shock mount are also available as add-ons to the basic kit. Worldwide shipping is free!

Again, this is a one time offer. The pre-order will end on April 5th or when Artur runs out of kits, whichever happens first!

Kits will ship from Artur’s lab in Latvia by mid-April.

More details about the RM-5 can be found at diyaudiocomponents.com:

• The RM-5 product page
• DIY ribbon design notes

Feel free to contact Artur directly if You have any questions: info (at) diyaudiocomponents.com.

The Lola’s fully differential design is derived from the “Double Balanced” mic pre design of Graeme Cohen. There’s a lot of good stuff about Cohen and his preamp design at Leon Audio’s website.

Full and partial kits for the Lola will be available from Hairball Audio’s website.

Many thanks to Mike for granting me this interview!

August 2011: Researching Reamping

My original goals for the LINE2AMP were that it should:

1. Perform as well as any commercially available unit
2. Cost less than $50 to build
3. Be simple enough for newbies to build successfully.

I starting looking around at other reamping designs available on the internet and found three popular schematics: Jensen, Recording Mag (Scott Dorsey), and NYDave. Looking at schematics the schematics, I realized that all of them shared the same essential topology:

I ordered a couple of transformers from Edcor USA to start experimenting with circuits.

September 2011: Prototyping

Four weeks later transformers arrived and I started soldering. 30 minutes later I had a working reamping box. Huzzah! Goal #3 was in the bag. My first prototype hewed almost exactly to NYDave’s design: I used the Edcor PC10k/150 transformer with a volume pot and 200 Ohm terminating resistor. The only variation was that I used a 1M Ohm variable resistor to test different output impedances. Testing the prototype with a variety of amps, pedals, and DIs revealed a few things:

1. The unit was dead quiet and imparted practically nothing on the tone. At first, I had been skeptical about how the unshielded Edcor would perform, as both the Jensen schematic and the Reamp use shielded transformers. While a shielded trafo would certainly be better on paper, in practice the Edcor added no noticeable noise, even when run via DI into a clean preamp.
2. The impedance resistor had no noticeable effect on the sound until it was cranked beyond about 200k Ohms, after which the signal started to lose some high frequencies and become distorted in the bass.
3. In almost all cases, there was less noise when the connection from ground pin of the input jack to the case was disconnected. Only with some pedals did it sound better connected.

Overall, I was really happy with how the circuit worked. I didn’t have a commercial reamping box on hand to shoot it out against, but it did everything a reamping box should and without any noise or sonic artifacts of its own. In fact, I was pretty blown away by the transparency of the Edcor transformer. In a blind test between A) a signal sent first to the reamping box, then the DI input of my Hamptone preamps and B) a signal sent right from my interface to the line input of the Hamptones, I couldn’t make any conclusive distinction between the reamped and non-reamped signal.

Paring Down to Essentials

After playing around with my prototype, I realized that the LINE2AMP could be made even simpler than any of the other reamping designs and do the job just as well. The first thing to go was the impedance knob. From one perspective, it makes sense to have a range of output impedance available to emulate the source impedances of different guitars (typically between 10k-50k Ohms) and pedals (as little as 200 Ohms with a buffered output). However, in testing there was no audible change in tone until about 200k Ohms<. From a technical perspective, this makes sense as any source impedance below 100k or so would be easily bridged by most guitar amp and pedal inputs. So, au revour to the impedance pot.

Next to go was the volume knob. In theory, it's nice to have a tactile way to control the volume going to the amp. In practice, I found myself using the output control in my DAW instead as it allowed me to recall levels exactly when switching between different amps and pedals. Additionally, since the 8.2:1 transformer shaves off a good amount of signal before the volume pot, I rarely found myself wanting less volume before an amp or pedal. And finally, I was happy to be rid of the carbon pot in my signal path.

What’s left is the bare essentials of a reamping device: a transformer for impedance/voltage conversion and ground isolation, and a resistor to set the input/output impedances. That’s it!

Please leave your contributions in the comments section. Thank you to Justin Boland for getting us started.

*Indicates that this was the original transformer used for this purpose.