GRACE DESIGN m501
PRICE ON ENQUIRY
GRACE DESIGN m501 500-series mic preamp and DI: m101 transimpedance circuit, ribbon mode, 75 Hz HPF, 10-75 dB gain. Available in India from Shivansh Electronics, Kolkata, West Bengal, India.
VISUAL GUIDE — See Every Photo, Spec & Setup Step (PDF)
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Gain and distortion
| Gain range, mic input (5 dB steps) | 10‑65 dB |
| Gain range, Hi‑Z input | -10 to 45 dB |
| Output trim | 0 to +10 dB |
| THD+N @ 20 / 40 / 60 dB, +20 dBu out | < 0.00085 / 0.0010 / 0.0050 % |
| IMD @ 40 dB, SMPTE/DIN 4:1 | < 0.0020 % |
| Noise referred to input @ 60 dB, 50 / 150 / 600 Ω | < -130 / -128 / -124 dB |
| CMRR @ 60 dB, 100 Hz / 1 kHz / 10 kHz | > 55 / 75 / 65 dB |
| Phase deviation (HPF off), 50 Hz‑25 kHz @ 40 dB | < 10° |
Frequency response
| Mic input @ 40 dB, -3 dB / -0.5 dB | 3.8 Hz - 288 kHz / 8.35 Hz - 135 kHz |
| Hi‑Z input @ 20 dB, -3 dB / -0.5 dB | 1.7 Hz - 180 kHz / 4 Hz - 72 kHz |
Impedances and levels
| Mic input / ribbon mode | 8.1 kΩ / 20 kΩ |
| Hi‑Z input unbalanced / balanced | 2.5 MΩ / 5 MΩ |
| Balanced / unbalanced output | 300 Ω / 150 Ω |
| Peak LED | Green -12 dBu, red +16 dBu |
| Maximum output (100 kΩ, 0.1 % THD, 1 kHz, in a 500‑series rack) | +27 dBu |
| High‑pass filter | 75 Hz, 12 dB/octave |
General
| Format | Single‑width 500‑series module |
| Power | 120 mA max. from +16 V and -16 V |
| Dimensions (H x W x D) | 13.34 x 3.81 x 16.75 cm (5.25 x 1.5 x 6.6 in) |
| Weight | 316 g (0.7 lb) |
Product overview
The GRACE DESIGN m501 is the 500-series module version of the m101 microphone preamplifier: a balanced, transformerless transimpedance design with 48V phantom power, a 75 Hz HPF, a 1/4" Hi-Z instrument input, ribbon mic mode and 10-75 dB of gain, built in the USA.
The m501 brings the signature transparency and detail of GRACE DESIGN circuits to a 500-series collection. Its natural, musical clarity suits engineers confident in the quality of the source, the microphone and its placement, who want to capture it with as little colouration or distortion as possible. Large diaphragm, vintage ribbon or trusty dynamic: the m501 brings out the very best in any microphone and takes the guesswork out of the input chain.
| Gain with the output trim | 10‑75 dB |
| Noise referred to input, 50 Ω | < -130 dB |
| Mic input response, -3 dB | 3.8 Hz - 288 kHz |
| Single‑width 500‑series module | 316 g |
Key features
- Fast, musical transimpedance architecture; balanced, transformerless mic input
- 12-position gold-plated rotary gain switch and 0.5 % precision metal film resistors
- Ribbon mic mode: relay bypass of the decoupling capacitors, 20 kΩ input impedance and 48V lockout
- Front-panel Hi-Z instrument input switched by a sealed gold contact relay
- 0 to +10 dB conductive plastic output trim: 10-75 dB of gain in total
- 75 Hz, 12 dB/octave high-pass filter optimised for minimum phase shift
- LED indicators for 48V, ribbon mode and HPF; two-colour peak LED
- Enhanced RFI and EMI suppression; no electrolytic capacitors in the signal path
- Laser-etched black anodised front panel; built in the USA
Ribbon mic mode
Pushing the ribbon switch locks out 48V phantom power to protect delicate ribbon microphones, raises the mic input impedance from 8.1 kΩ to 20 kΩ and bypasses the DC blocking capacitors with sealed gold contact relays. With up to 75 dB of gain (gain 65 dB plus trim 10 dB) it suits even the most demanding low-level recordings, and it is also ideal for many dynamic microphones.
Instrument DI on the front panel
Plugging into the 1/4" TRS Hi-Z jack switches the preamp input from the rack's mic input to the front jack. The input impedance of 2.5 MΩ unbalanced and 5 MΩ balanced is ideal for guitars with passive pickups and any high-output instrument; a mono plug grounds the inverting input automatically.
Simple installation
The module slides into any free slot of a 500-series rack and is fixed with the two #4-40 hex head screws and hex wrench supplied; it powers up with the rack. Mic input and balanced XLR output are the rack's rear connectors.
In the box
- m501 module in an anti-static bag
- Two #4-40 hex head screws
- 3/32" hex wrench
GRACE DESIGN m501: frequently asked questions
What do I need to use the m501?
A 500-series rack frame: the module takes its power (120 mA max. from ±16 V) and its mic input and output connectors from the rack.
Is it the same circuit as the m101?
GRACE DESIGN describes the m501 as the 500-series module version of the m101 mic preamplifier.
Can I use it as a DI?
Yes. The front 1/4" Hi-Z input works with instruments and line-level sources.
Is it suitable for ribbon microphones?
Yes. Ribbon mic mode locks out 48V, raises the input impedance to 20 kΩ and bypasses the input capacitors.
Where can I buy the GRACE DESIGN m501 in India?
The GRACE DESIGN m501 is available from Shivansh Electronics, Kolkata, West Bengal, India, with delivery across India.
Workflow 1: Vocal recording in a 500-series rack
Studios building a 500-series input chain.
Connections
| Connect | To |
|---|---|
| Condenser microphone | Rack mic input of the m501 slot |
| Rack output | Interface input |
Setup
- Gain and trim fully anticlockwise; 48V off.
- Connect the microphone, then switch on 48V.
- Raise the gain to the optimum level.
- Ride the level with the trim.
Tip: Always switch 48V off and let it discharge before connecting or disconnecting a microphone.
Workflow 2: Ribbon microphone on guitar cabinet
Engineers using passive ribbon microphones.
Connections
| Connect | To |
|---|---|
| Ribbon microphone | Rack mic input |
Setup
- Switch 48V off.
- Press ribbon: 20 kΩ input, capacitors bypassed.
- Set gain to 65 dB if needed.
- Add up to 10 dB with the trim.
Tip: Ribbon mode waits until 48V has discharged before engaging.
Workflow 3: Bass or guitar DI
Players recording directly.
Connections
| Connect | To |
|---|---|
| Instrument | Front Hi‑Z jack |
| Rack output | Interface |
Setup
- Plug in: the relay switches to Hi-Z.
- Set gain from -10 dB.
- Engage HPF if needed.
- Record.
Tip: A mono plug grounds the inverting input automatically.
Workflow 4: Stereo pair
Studios recording stereo sources.
Connections
| Connect | To |
|---|---|
| Two microphones | Two m501 modules |
Setup
- Fit two modules side by side.
- Set identical gain positions.
- Match levels with the trims.
- Record.
Tip: The 12-position switches make matched settings repeatable.
Workflow 5: Acoustic instruments with rumble control
Recording acoustic guitar or strings.
Connections
| Connect | To |
|---|---|
| Microphone | Rack mic input |
Setup
- Set gain.
- Engage the 75 Hz HPF for rumble or proximity effect.
- Fine-tune with the trim.
- Record.
Tip: The HPF is optimised for minimum phase shift.
Workflow 6: Unbalanced destination
Users feeding an unbalanced 1/4" input.
Connections
| Connect | To |
|---|---|
| Rack XLR output | Unbalanced 1/4" input |
Setup
- Use a cable with pin 2 to hot and pin 1 to ground.
- Leave pin 3 open.
- Set the gain.
- Record.
Tip: The cable diagram is in the owner's manual.
