Multi-band equalizers, EQ preamps and small line mixers for home and car audio.
Douk Audio T8PRO 7-Band EQ Tube Preamp — read reviewLine preamp with a genuine 7-band equalizer (50Hz-16kHz), balanced XLR and RCA inputs and outputs, a balance control and a pluggable Soviet 6H1N-BN tube stage for warm, rollable tube tone.
Douk Audio D5 4-Way Switcher 5-Band EQ — read reviewA 4-in-1-out switcher and 1-in-4-out splitter with a 5-band equalizer from 80Hz to 10kHz, EQ bypass, a built-in headphone amp and a large analog VU meter with 6-level backlight.
Douk Audio EQ5 Mini 5-Band EQ Preamp — read reviewA pocket-sized 5-band equalizer at $64.99 built on five JRC4558 op-amps, one per band, with a bypass button for untouched sound, gold-plated I/O and USB-C power for home or car use.
Douk Audio EQ7 7-Band Equalizer Preamp — read reviewA 7-band stereo equalizer and preamp spanning 32Hz to 10kHz with +/-10dB per band, true balanced XLR output converted from RCA, dual VU meters and a volume knob.
Douk Audio EQ5-TONE EQ Equalizer Bluetooth — read reviewA 5-band stereo equalizer and preamp with bands at 75Hz through 10kHz, each processed by its own op-amp, plus Bluetooth 5.0 streaming and twin 45mm VU meters. A bypass switch takes the EQ out of the signal path entirely.
Douk Audio T7 7-Band Equalizer Preamp — read reviewA desktop 7-band stereo equalizer and preamp with true balanced XLR and single-ended RCA inputs and outputs, 64Hz-8kHz band control, and a bypass mode for comparing processed and original sound.
Douk Audio MC5-BX 4-Channel Audio Mixer — read reviewA pocket line mixer with four 3.5mm inputs and one 3.5mm output, each channel with its own level knob. Run it in passive mode with no power at all, or active over USB-C for a stronger, amplified mix.
Douk Audio MX5 4-Channel Audio Mixer — read reviewA compact 4-channel line mixer with per-channel mono/stereo switching, individual volume knobs, and dual-color LED level meters, powered from DC5V.
Nobsound EQ9 9-Band Stereo EQ Preamp — read reviewA 9-band analog equalizer preamp with ±6dB per band, dual RCA in/out pairs, a bypass switch, and a balance control, in a shielded aluminum case.
All nine reviews here come from one store, Douk Audio's store at doukaudio.com (eight Douk Audio and one Nobsound), at $33.29 to $123.49 as priced on October 23, 2026. Seven are equalizers and two are mixers, which do different jobs: an equalizer boosts or cuts bands of frequency in one line-level signal, while a mixer (the MC5-BX and MX5) blends four sources into one output. Compare the bands first. Three list 5 bands (the D5, EQ5 and EQ5-TONE), three list 7 (EQ7, T7 and T8PRO) and the Nobsound EQ9 lists 9, from 20Hz to 16kHz at plus or minus 6dB; the EQ5 and EQ7 list plus or minus 10dB. These are fixed graphic equalizers with set center frequencies that differ by model, and the EQ7 review notes there is no parametric control, meaning no adjustable center frequencies. Three models (EQ7, T7 and T8PRO) have balanced XLR as well as RCA.
None of them drives speakers: the T7 and EQ9 reviews say an amplifier or active speakers are still required, and only the D5 (a built-in headphone amplifier) and the MX5 (support for 16-200 ohm headphones) mention headphones. The noise figures are the store's own and differ: the EQ9 lists THD 0.001% and SNR of 111dB or better, the EQ5-TONE and T7 list THD 0.003% (the T7 with SNR of 104dB or better), and the tube-based T8PRO lists 0.01% and 98dB or better. Wiring quirks matter. On the EQ5 and EQ5-TONE the RCA and 3.5mm inputs are wired in parallel, so connect one at a time. On the D5 the 3.5mm Priority jack mutes the RCA ports. On the MX5 the 3.5mm output disconnects the 6.35mm output. On the EQ7 and T7 the XLR and RCA outputs always carry the same signal, the EQ7 has no true bypass switch and the T7 has no volume knob.
Douk Audio's store applies the same terms to every listing: shipping in 2-8 business days with duties, taxes and customs included in the checkout price unless noted; returns requested within 30 days of delivery and approved by Douk first, shipped back within 7 days of approval, with original shipping fees and duties not refunded; and a 24-month warranty for manufacturing defects, although an older policy page still says 1 year. None of the reviews gives a shipping fee or says who pays the return shipping.
Check power before ordering. The EQ5, EQ5-TONE, MC5-BX and MX5 list no adapter, and the makers warn against powering the EQ5, EQ5-TONE or MC5-BX from a computer USB port or a supply shared with the audio source. The D5 includes a 5V/2A adapter, the T7 a 12V one (1.5A or more) and the T8PRO's packing list a 12V one (2A or more). The EQ5's bypass works without power, but its EQ section needs 5V. The MC5-BX has a passive mode that needs no power, with slightly attenuated output, and an active mode on 5V. Both mixers take line-level signals only, so no phono turntable or microphone.
| Review | Price | EQ bands | I/O |
|---|---|---|---|
| Douk Audio T8PRO 7-Band EQ Tube Preamp | $123.49 | 7 bands: 50Hz / 125Hz / 315Hz / 750Hz / 2kHz / 6kHz / 16kHz | — |
| Douk Audio D5 4-Way Switcher 5-Band EQ | $109.99 | 5 bands at 80Hz, 330Hz, 1kHz, 3.3kHz and 10kHz, with EQ bypass | In: 3 RCA groups + 3.5mm AUX; out: 3 RCA groups + 3.5mm jack |
| Douk Audio EQ5 Mini 5-Band EQ Preamp | $64.99 | 100Hz, 400Hz, 800Hz, 4kHz, 10kHz | Stereo RCA and 3.5mm AUX in and out, gold-plated |
| Douk Audio EQ7 7-Band Equalizer Preamp | $119.99 | 7 bands from 32Hz to 10kHz, +/-10dB adjustment | RCA and XLR inputs; simultaneous RCA and XLR outputs |
| Douk Audio EQ5-TONE EQ Equalizer Bluetooth | $89.99 | 75Hz / 400Hz / 800Hz / 4kHz / 10kHz | Bluetooth 5.0 / stereo RCA / 3.5mm AUX |
| Douk Audio T7 7-Band Equalizer Preamp | $99.99 | 7 bands: 64Hz / 125Hz / 250Hz / 500Hz / 2kHz / 4kHz / 8kHz | Balanced XLR and single-ended RCA in and out |
| Douk Audio MC5-BX 4-Channel Audio Mixer | $33.29 | — | 4 groups of 3.5mm AUX |
| Douk Audio MX5 4-Channel Audio Mixer | $64.99 | — | 4 groups of 6.35mm / 3.5mm jacks |
| Nobsound EQ9 9-Band Stereo EQ Preamp | $49.99 | 9 (20Hz–16kHz), ±6dB each | 2 groups of stereo RCA in and out |
The listings give 5 bands (D5, EQ5, EQ5-TONE), 7 (EQ7, T7, T8PRO) or 9 (EQ9). More bands let you adjust narrower slices, but the center frequencies differ: the EQ5 uses 100Hz, 400Hz, 800Hz, 4kHz and 10kHz, the EQ7 runs from 32Hz to 10kHz, and the EQ9 covers 20Hz to 16kHz. Compare where each model's bands fall with the frequencies you want to change.
An equalizer shapes the tone of a signal by boosting or cutting frequency bands. A mixer combines several sources into one output with a level control for each. The MC5-BX ($33.29) and MX5 ($64.99) each blend four sources, and the MX5 lists headphone support of 16-200 ohms. The D5 switches four inputs but has no per-channel volume, so its review says it cannot be used as a mixer.
No. They process a line-level signal and pass it on, so you still need an amplifier or active speakers; the T7 and EQ9 reviews say so directly. The D5 adds a built-in headphone amplifier, and the MX5 lists support for 16-200 ohm headphones. The T7 has no volume knob and outputs its rated level, so level control has to come from the source or amplifier.
Yes, and four do not include one. The EQ5, EQ5-TONE, MC5-BX (in active mode) and MX5 take 5V and list no adapter. The D5 comes with a 5V/2A adapter, the T7 with a 12V adapter and the T8PRO's packing list includes a 12V one. The EQ5, EQ5-TONE and MC5-BX makers warn against a computer USB port or a supply shared with the audio source.
Three: the EQ7 ($119.99), T7 ($99.99) and T8PRO ($123.49). The EQ7 does an active true-balanced conversion and takes RCA or XLR in. The T7 and T8PRO list balanced XLR and single-ended RCA both in and out. On the EQ7 and T7 the XLR and RCA outputs are always active together, so you cannot switch between them.
Douk Audio's store allows a return request within 30 days of delivery. Douk must approve it first, the item goes back within 7 days of approval, and original shipping fees and duties aren't refunded. The warranty is 24 months from purchase for manufacturing defects, with free repair or replacement, although an older policy page still says 1 year.