TC Electronic Sentry Noise Gate

[nikitasius]

At home, with my guitar, I use a Boss GT-1000 Core as the main brain and feed my Carlsbro GLX80 through the return with my music. :)
The Boss has two noise gates, and they work nicely but are pretty basic. I was googling a bit and found the Sentry — a digital noise gate made by TC Electronic. The price was just €85, so why not? I grabbed it, along with two sets of GHS Boomers for my Jackson.

Measurements taken with my hacked (thanks, EEVblog <3) Siglent. As a signal generator I’m using a 300 mV pk-to-pk signal from my hacked Rigol. Sentry settings are set to 12.

As usual: all photos and screenshots are on my Gdrive: https://drive.google.com/drive/folders/1ASMEk3R2TSroM05pK3R_Hk5Dod5IInEU

• The device has true bypass.
• The device starts draining the battery when you short (i.e., plug in) the INPUT.
• The device draws 83–85 mA from a fresh battery, and around 87–88 mA once the 9 V drops to about 7.7 V.

Device latency is about 2.60 ms, which corresponds to roughly 89 cm of sound in air.

Here is my ref sin wave 1kHz:

Here is the same sine wave after enabling the gate:

It has 1.47–1.56 MHz noise riding inside the sine wave:

Not an issue at all — the Boss or the amp will filter it out just fine.


Here are the two waves; “blue” is the reference:

For the FFT I used a linear sweep from 82.41 Hz to 329.63 Hz in 140 ms.
here is without noise gate:

here are with gate enabled:

Now I limited the bandwidth to 20 MHz to check the power noise:

It measures 3.52 mV at 35.21 kHz, and within that there’s 1.70 mV at 132 kHz. I guess it could be useful to add some extra caps.




Hardware :)

Pedal/Gate is made from metal and feels rock solid:


once opened if have some triggers


HW list:


CPU: Microchip RISC AVR32 AT32UC3B1256
DSP: Analog ADSP-21478
OPAMP: 4558
CAPS: Lelon & "unknown"
some other stuff - enjoy the photos :)

The device is very well made — rock solid, almost military-grade :)
For music, I use it before the Boss to remove noise and string _wizz-wizz_ on distortion. In the Boss, I keep a light noise gate after the preamp.

 

[nikitasius]

the plastic cover inside




PCB without cover, few flux traces




front panel




another side of PCB



DSP without sticker

 

[nikitasius]

Ah, I forgot to add: the signal starts to degrade above 22.2 kHz and remains stable below that, so the sampling rate here is 44.1 kHz.

Is that low? The Boss GX-100 uses 48 kHz, and the Neural DSP Quad Cortex also runs at 48 kHz. It would be nice to have 96 kHz, but almost all modern budget gear (under €2,000) uses 48 kHz. The Boss GT-1000 and GT-1000 Core are exceptions from an older era, running at 96 kHz.

 

[the swede]

This series of TC pedals is very good. The last very good TC pedal series.
Love my Trinity T2 Reverb. Cheesy as fuck sounds and obnoxiously overdone reverb modulations, but it’s super quiet, takes anything into it and makes everything after it sound like the end of the world. Buffer is top notch. Great series of pedals. But ugly as fuck. I hate the lite hump to the sides, looks awful. Bittern old fart rant over but sprinkled with a tiny amount of admiration.