DS Audio's all-tube equalizer for optical cartridges: the low noise and clarity of optical playback with the warmth, openness and natural voices of a valve circuit.
Every DS Audio optical cartridge needs an equalizer to power its LEDs and equalize the photodetector signal. The TB-100 does all of its amplification with tubes. Each channel uses two quad-matched ECC82 (12AU7) tubes, one for voltage gain and one as a low-impedance cathode-follower output buffer. The tubes are matched to within 1% (0.1 dB). A wideband input transformer converts the photodetector's current signal to voltage while keeping the channels in phase. DS Audio quotes response within −1 dB from 10 Hz to 70 kHz. The construction is twin mono, with a fully independent ground and power transformer for each channel. A separate low-noise regulated supply powers the cartridge.
Hi-Fi News described the TB-100 as warmer and more romantic than DS Audio's cool, precise solid-state equalizers. It sounded more open, separated voices more clearly and made vocals more natural. DS Audio's solid-state Master 1 equalizer had a bit more attack and bass slam on hard rock. The reviewer framed the choice as a matter of tube or solid-state taste and said he would buy one without hesitation. Two RCA outputs are provided. Output 1 is standard RIAA and Output 2 adds a 20 Hz subsonic filter, and a toggle selects a 30 Hz or 50 Hz bass roll-off. There are no balanced outputs, so plan on an RCA connection to your preamp. It works with any DS Audio optical cartridge.
| Type | All-tube equalizer and power supply for DS Audio optical cartridges, twin mono |
| Tubes | 4 × ECC82 (12AU7), quad-matched to within 1% |
| Rated output | 500 mV at 1 kHz |
| Output impedance | Approx. 700 Ω |
| Frequency response | 10 Hz – 70 kHz, −1 dB (manufacturer) |
| Inputs | 1 pair RCA |
| Outputs | 2 pairs RCA (Output 2 adds 20 Hz subsonic filter); no XLR |
| Low-cut filter | 30 Hz or 50 Hz, switchable |
| Power supply | Separate power transformer per channel; dedicated regulated cartridge supply |
| Dimensions (W × H × D) | 17.3 × 5.9 × 19.0 in (440 × 150 × 482 mm), including terminals |
| Weight | 41.2 lb (18.7 kg) |
Pearl Audio is an authorized DS Audio dealer. Call or visit our Portland showroom to talk about matching a phono stage to your cartridge.
