ADVANCED PRODUCT INFORMATION
The information provided here is a bit sparse. I expect to have it fully fleshed out by the beginning of March, 2018.
The Modulus-686 circuit boards are currently being manufactured. I expect to have them in stock by the middle of March, 2018. The information provided below is based on the prototype build of the Modulus-686 and is subject to change. You can pre-order your Modulus-686 by clicking the Buy It Now button below.
The Modulus-686 is a balanced composite bridge/parallel amplifier. It uses six LM3886 amplifier ICs to provide nearly 400 W into 4 Ω loads at vanishingly low distortion. With a typical output current capability of 33 A, the Modulus-686 easily drives even the most challenging loads, including loads with impedance dips into the 2 Ω range. The block diagram of the Modulus-686 is shown below.
- Mono construction.
- 4-layer, gold plated, ROHS compatible circuit board. Professionally assembled in Calgary, Canada.
- Output power: 380 W (4 Ω) – 220 W (8 Ω).
- Ultra-low 0.00026 % THD+N (140 W, 8 Ω, 1 kHz).
- Ultra-low 0.00029 % THD+N (260 W, 4 Ω, 1 kHz).
- Gain: +26 dB. Changeable by resistor option. Minimum gain: +20 dB.
- On-board EMI/RFI input filter and ESD protection.
- Power supply agnostic circuit architecture. The Modulus-686 performs identically on an unregulated supply as it does on a well-regulated supply.
The prototype build of the Modulus-686 is shown below.
The Modulus-686 circuit board is available as a fully assembled and tested module and as a DIY-friendly partially assembled option, which has all the surface mounted parts pre-populated. The cost of the additional parts needed to complete the SMD pre-populated board option is approximately $56.
The Modulus-686 circuit boards are professionally assembled in Calgary. My assembly vendor uses a pick-and-place machine for component placement and solders the boards using a 13-zone solder reflow oven. This procedure eliminates the issues with component cracking that you often see from the overseas assembly houses, resulting in a high-quality, high-reliability product.
The preliminary specifications for the Modulus-686 are tabulated below. These were measurements of the prototype and are subject to change.
|Output Power||220 W||8 Ω, < 0.1 % THD+N|
|THD||0.00011 %||1 W, 8 Ω, 1 kHz|
|THD||TBD %||140 W, 8 Ω, 1 kHz|
|THD+N||0.00026 %||140 W, 8 Ω, 1 kHz|
|Output Power||380 W||4 Ω, < 0.1 % THD+N|
|THD||TBD||260 W, 4 Ω, 1 kHz|
|THD+N||0.00029 %||260 W, 4 Ω, 1 kHz|
|IMD: SMPTE 60 Hz + 7 kHz @ 4:1||-103 dB||100 W, 8 Ω|
|IMD: DFD 18 kHz + 19 kHz @ 1:1||-115 dB||100 W, 8 Ω|
|IMD: DFD 917 Hz + 5.5 kHz @ 1:1||-110 dB||1 W, 8 Ω|
|Multi-Tone IMD Residual||< -110 dBV||AP 32-tone, 100 W, 8 Ω|
|Gain||26 dB||Resistor programmable. +20 dB min.|
|Input Sensitivity||2.1 V RMS||220 W, 8 Ω|
|Bandwidth||127 kHz||1 W, -3 dB|
|Slew Rate||16 V/µs||8 Ω || 1 nF load|
|Total Integrated Noise and Residual Mains Hum||25.4 µV RMS||20 Hz – 20 kHz, A-weighted|
|Total Integrated Noise and Residual Mains Hum||32.0 µV RMS||20 Hz – 20 kHz, Unweighted|
|Output DC Offset Voltage||< 2.0 mV||Typical performance|
|Residual Mains Hum||< -120 dBV|
|Dynamic Range (AES17)||> 120 dB||1 kHz|
|Common-Mode Rejection Ratio||TBD dB||1 kHz|
|Common-Mode Rejection Ratio||TBD dB||20 kHz|
|All parameters are measured at a supply voltage of ±36 V unless otherwise noted.|
The THD+N vs output power for 8 Ω and 4 Ω load are shown below. Note that the 8 Ω graph compares the performance of the Modulus-686 for two different power supplies: Linear unregulated supply (Power-86 with an Antek Inc. AN-5225 2×25 VAC 500 VA transformer) and a switching supply (Mean Well SE-600-36). The slightly lower output power of the Modulus-686 with the Power-86 is due to the rail voltage droop of the linear supply.
More plots will be added when the first samples of the professionally assembled boards become available.