Dual-Mono Construction
Dual-mono construction separates the left and right audio channels into largely independent circuits. The equipment still plays stereo.
The extent of separation depends on the design: check which power supplies and ground connections remain shared. The aim is to reduce interaction between channels. Crosstalk means unwanted signal leakage from one channel into the other; dual mono guarantees neither zero crosstalk nor better sound.
Dual-Mono Construction — Power Amp
For this power-amplifier specification, dual mono requires separate channel supplies; two amplifier boards sharing one supply are insufficient. One transformer can feed separate secondary windings and separate channel supply circuits. These windings are electrically separate coils within the transformer.
Separating supplies can reduce one speaker channel’s power demands affecting the other. Check rated watts at the stated speaker load; the label gives no wattage. A stereo dual-mono amplifier is not a single-channel monoblock. Bridging combines amplifier outputs to drive one speaker and needs explicit manufacturer support. Follow the manual for ground connections.
Sources
- A1: channel power supplies and specifications (pp. 3, 7) — Musical Fidelity
- AHB2: stereo, mono and ground connections — Benchmark Media Systems
Dual-Mono Construction — Optical Equalizer
An optical equalizer processes an optical cartridge’s left and right signals and supplies power to the cartridge. Dual-mono separation can include its audio circuits and the supplies serving each light detector. Check whether the cartridge’s LED supply is shared or separate too; the label alone does not describe every supply.
This is different from driving loudspeakers: the additional supply powers the cartridge’s light source. Use an equalizer explicitly compatible with your optical cartridge. A dual-mono MM/MC stage cannot substitute: optical cartridges need their own powering and different equalization.
Sources
Dual-Mono Construction — Phono Preamp
A phono preamp amplifies the small signals from a magnetic cartridge. Separating its channels aims to reduce unwanted leakage while those signals are amplified. Dual-mono circuitry can operate from one external adapter, with separate circuits inside.
Match gain (amplification) and electrical loading to the cartridge, and retain the required RIAA frequency correction for records. Dual mono does not require balanced connections or cure hum caused by wiring. Follow the manual’s grounding instructions, including the turntable ground wire where specified. Compare noise figures at the stated gain; channel construction alone cannot establish how quiet the stage is.
Sources
- Tube Box S2: circuitry, supply and noise specifications — Pro-Ject Audio Systems
- Phono Box DS3 B: cartridge settings and grounding (pp. 2–4) — Pro-Ject Audio Systems