Category Archives: Electronics

8-String Flex Upgrade: LTD SC-208

      Custom, Customization, Pickups, XR Series

This LTD SC-208 began life as an entry level 8-string for those interested in dipping their toe in the “deep end”. The stock setup included passive humbuckers, a 3-way selector, master volume and tone control. By converting to a Flex Set the switching options expanded from 3 to 5, the frequency response was greatly extended, and the guitar shed some weight along the way.

The finished guitar sporting an XR-8 based Flex Set and new Hipshot® fixed bridge.

Continue reading

A New Breed of Pickups

      Construction, Electronics, Modula, Pickups, Prototype

What do you get when you cross the Nu and the XR? The Modula. Our new baby: A full-range, semi-modular pickup that can be used for just about any guitar or bass. Yeah, finally the bass! So far, the results of our tests have been very positive. We applied what we learned over the years from the development of the Nu and the XR and the result is no less than outstanding!

Presenting the Modula

  • Modular. Three module types can accommodate all guitars and basses.
  • Aesthetically pleasing, sleek, modern design.
  • Allows arbitrary placement, either straight or angled.
  • Traditional mono or (custom) stereo split configuration.
  • Lo-Z full frequency response. The blank canvas.
  • Tweakable passive tone-blocks emulates all known pickups.
  • Fully balanced, low-noise preamplifier. High headroom Rail-to-Rail output (5v to 18v).
  • Dual-coil humbucking, dual rails design for each module. Quad coils for a single coil (Strat-style) pickup. Octa (8) coils for a full-width (PAF-style) pickup.

I’ll post more information as this project evolves. I value feedback. The Nu and the XR projects started from online forums, fueled by feedback from people all over the world. I invite you to come and join our facebook forum. Be involved in the discussions that will shape Modula’s future design and implementation.

Here are two pictures of an early prototype for a six string guitar. There are two modules for each 3-string group, reminiscent of the Fender precision bass pickup. Click to zoom in.

Continue reading

OPA1692: The perfect Op Amp for low power audio?

      Electronics, Modula, Op Amp

Our Op Amp Shootout page has always been the site’s top post. I’m always on the lookout for new and better Op Amps I can use in our products and I am continually updating the page as new products come along.

I’m never satisfied with the current offerings. Typically, you either have ultra-low noise OR very low power, but not both. Somehow, these are conflicting requirements. See the Shootout link to understand what I am talking about. For benchmark, in terms of low-noise performance, anything close to the 5532 (and its sibling, the 5534), with 5nV/√Hz noise figure (3.5nV/√Hz for the 5534) is wonderful. But the 4mA quiescent current consumption of these audio Op Amps is unacceptable for low power operation, especially when using batteries.

For some background information, I invite you to read the series of articles by Douglas Self (EE Times) Op amps in small-signal audio design (part1part2part3part4).

For applications requiring batteries, like that ubiquitous 9v battery found in typical active guitar electronics, I’m always searching for Op Amps in the 500μA range. My current favorites are 1) NJU77806, from JRC New Japan Radio Co., LTD, with a noise figure of 5.5 nV/√Hz at 1kHz while consuming only 500μA. But the NJU77806 can only go up to 5.5v supply, making it a nonstarter for 9v operation. So, for low power, my other favorite is 2) OPA180 from Texas Instruments, with a quiescent current: of 525 μA (max), but with a noise figure of 10 nV/√Hz at 1kHz. Looking at that spec, it’s not quite at par with the 5532 (or the NJU77806), but in reality, with very low 1/f noise, the 180 performed quite admirably in our noise tests. The 180 can operate from 4.0v to 36v. I’ve always wanted to release a very high headroom preamplifier for our pickups.

Now, there’s this new kid in town: The OPA1692 – SoundPlus Low-Power, Low-Noise, High-Performance Op Amp from Texas Instruments. Hey, Low-Power AND Low-Noise! Have your cake and eat it too?

Features

  • Low Noise: 4.2 nV/√Hz at 1 kHz
  • Low Distortion: 0.000045% at 1 kHz
  • Very Low Quiescent Current: 650 µA per Channel
  • Slew Rate: 21 V/μs
  • Wide Gain Bandwidth: 5.7 MHz
  • Unity-Gain Stable
  • Rail-to-Rail Output
  • Wide Supply Range: ±1.75 V to ±18 V, or 3.5 V to 36 V
  • Dual and Quad Versions Available
  • Small Package Sizes: Dual: SOIC-8, VSSOP-8, SON-8 Quad: SOIC-14 and TSSOP-14

The OPA169x operational amplifiers achieve a new level of performance for low-power amplifiers with a low 4.2-nV/√Hz noise density and distortion of 0.000045% at 1 kHz. These op amps offer rail-to-rail output swing to within 150 mV of the power supplies with a 2-kΩ load, which increases headroom and maximizes dynamic range. These devices also have a high output drive capability of ±50 mA. The OPA169x operational amplifiers operate over a very wide supply range of ±1.75 V to ±18 V, or 3.5 V to 36 V (on only 650 µA of supply current per channel), are unity-gain stable, and provide excellent dynamic behavior over a wide range of load conditions.

The OPA169x family of amplifiers uses a propriety technology to reduce signal distortion that does not increase the power-supply current. The distortion cancellation technique reduces odd-order harmonic distortion, which is produced by the input transistor pair of the amplifier.

I’m getting some samples for testing as soon as they are available!

 

Complete XR Flex Sets 25% Off Starting Father’s Day

      Electronics, Events, Pickups, Store, Support Electronics, XR Series

Beginning Father’s Day, Cycfi Research is pleased to offer a 25% discount on complete systems featuring our XR Flex Series extended-range pickups. The discount applies to the purchase of our pre-configured XR Flex systems including S-S-S (3 XR Dual pickups) or H-H (2 XR Quad Pickups) for 6, 7, and 8 string instruments. In addition to the pickups, systems include a 5-way switch, Active Volume, Blend or Tone Control, Output Jack, 9V battery clip and all necessary cables and hardware. Complete systems with the Resonant Filter are also available.

The new discounted XR Series pickup-system pricing kicks off Sunday June 18, and will continue until new pricing is announced. Come and visit our store.

Continue reading

Nu Update: Roland 13 Pin Adaptor

      Electronics, Nu Series, Release, Support Electronics

You’ve been asking for this for a long time now. A gift to the Roland aficionado. Finally, a Roland 13 Pin Adaptor for the Nu Series Modular Active Pickups.

FPC Receptacles

  1. CH1-4 – Nu Multi Channel 1 to Channel 4 In
  2. CH5-6 – Nu Multi Channel 5 to Channel 6 In
  3. 1 & 2 – 13P FPC Receptacle

6P Male Headers

  1. S1 – Switch 1 Input
  2. S2 – Switch 2 Input
  3. GND – Ground Pin
  4. MONO – Guitar Mono In
  5. GK-VOL – Volume Control
  6. GND – Ground Pin

2×4 Male Power Pins

  1. GND – Ground Pins
  2. 5V – 5V Regulated Power Pins
  3. -VE – (-)7V Power Pins
  4. +VE – (+)7V Power Pins

Dead Bug! Prototyping SMDs

      Construction, Electronics, Hardware, How To, Infinity, Prototype

Gone are the days of DIP (Dual in-line) ICs. Most modern ICs are no longer offered in easy to use 2.54 mm (0.1 inch) pitch packages. The descendants of DIPs, the SOIC (Small Outline IC) and its friends (e.g. the TSOP (Thin Small Outline Package)) are shrunk down to 1.27 mm (0.05″) and even as low as 0.5mm (0.019″).

So how do we prototype using such tiny critters? We do it using the Dead Bug approach: A free-form construction, point-to-point soldering, often with the ICs flipped upside-down with their pins sticking up into the air like dead insects. The components are constructed, ad-hoc, using a bare copper-clad board serving as common ground. This construction technique drastically reduces electrostatic noise compared to other prototyping techniques using perf-boards or bread-boards.

Soldering a tiny TDFN-14 0.5mm package!

Dead-bug constructions are typically ugly beasts! We use a variation of the technique called the Manhattan Dead-bug Style, using small pads punched out of copper-clad board and glued into the main copper base. The pads serve as islands for soldering circuit nodes.

High efficiency Class-D amplifier

I like modular, reusable building blocks. And so we build small modules and connect them together, all on top of another bigger copper clad board. This construction is very favorable to noise sensitive electronics. The module you see here is a high efficiency Class-D amplifier.

 

 

Nu-XR Combo

      Nu Series, XR Series

Some of you asked if it is possible to have the Nu and XR in a common baseplate. It turns out that it is indeed possible. The way to do it is have the Nu Multi, which has a somewhat lower profile, piggyback on the XR’s baseplate. This way, the Nu will still have its own height adjustment independent of the XR. You’d want the Nu capsules as close to the strings as possible (within 1mm to 2mm) to minimize crosstalk. Here’s the idea:

Nexus Update: Programming MCU Module

      How To, Nexus, Support Electronics

The MIDI module includes a small, general purpose 16-bit MCU (Texas Instruments’ MSP430) that converts control voltages (CV) to MIDI. It is designed to be hackable. If you are adventurous enough, you can reprogram the code for your own purposes. The software is Open Source and can be cloned via Github (see Nexus repository). The code is based on the ubiquitous Arduino platform to make it easy to hack into.

You need a programming device to update the MCU Module firmware. There’s a lot of MSP430 programmers available out there, but the question is. “What is the cheapest we can get?”. Answer: the MSP430 launchpad dev board from Texas Instruments. Dev boards from chip manufacturers are often heavily subsidized, making them very inexpensive. The table below shows the price comparison for a few MSP430 programming devices including the MSP430G2 Launchpad Development Board.

Device Price
TI-MSP-EXP430G2 $9.99
Olimex MSP430 – BSL $11.24
Olimex MSP430 JTAG-Tiny-V2 $58.96
FlashPro-430-LB $159.00

What we need:

  1. Nexus MCU Module

  2. MSP430G2 Launchpad dev board
  3. Female-to-female jumper wires
  4. USB Type-B mini cable

Step 1. Remove all header shunts


Carefully remove the shunts highlighted on the dev board. RX/TX pins should also be removed to avoid data collision when programming an external MCU.

 

 


Step 2. Connect the jumper wires to the Launchpad

Follow proper jumper wire color coding indicated in the pictures below.

Step 3. Connect the jumper wires to the MCU Module

Step 4. Connect the USB Cable

Step 5. Install Energia IDE

Follow this link for Mac, Windows and Linux installation guides.

Step 6. Download and clone the firmware

Follow this link. You can download or clone the repository to your local drive.

Step 7. Flash the Firmware

  1. Open the source file using the Energia IDE.
  2. Click upload.
  3. Wait until the app indicate finish upload without errors.

Op Amp Shootout Updated

      Electronics, Op Amp

Time flies! It’s been almost 4 years since I last updated our Op Amp Shootout page. Now It’s 2017, and this page is still our top hitter. I guess that only means that people find this page helpful. And I am always happy to share information. I’ve updated the page to reflect recent developments. I always have a keen eye for new Op Amps and the new additions (shown in light purple) were taken straight from my notebook.

There are some interesting additions such as the OPA188 with a wide supply range of 2V to 18V, and very low 500μA current consumption. I also added a bunch of very Op Amps from Japan with rather respectable specs. Check out the NJ series Op Amps from JRC New Japan Radio Co., LTD. I found out about these cool Op Amps from studying Roland schematics. Have a look at the NJU77806, for example, with a noise figure of 5.5 nV/√Hz at 1kHz while consuming only 500μA.

There are also retirees. For example, the ultra-low noise LME49990 has reached its end of life. But there is certainly a new audio Op Amp king of the hill: the LMH6629 with a super impressive 0.69 nV/√Hz at 1kHz noise figure! The LMH6624 takes second place with very respectable 0.92 nV/√Hz at 1kHz noise figure.

Interesting tidbit: In that page, Mark Norton commented: “I feel sorry for all of you using op amps. Sterile squinching of sound imho.” He’s obviously not a fan, but then I had to reply: “I feel sorry for you believing such myths :-)”. Op Amps: Myths & Facts. The funny thing is, all forms of modern recorded music would have gone through dozens if not hundreds of Op Amps in the signal chain, through the recording process (EQs, compressor, limiters, etc.). If “sterility” means not degrading the purity of the sound (e.g. preamps), then I suppose that is good. But “transparency” is a better term.

Now go and check out the updated Op Amp Shootout page.