McIntosh MQ 107
Environmental Equalizer, 1990s
Made in the United States of America
McIntosh MQ 107 (about $400 if you know How to Win at eBay). bigger. This all-content, junk-free website's biggest source of support is when you use that or any of these links to approved sources when you get anything, regardless of the country in which you live. Thanks for helping me help you! Ken.
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Introduction top
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This is an equalizer used to optimize loudspeakers to a listening room.
It's made of chrome-plated steel. Its mirror-smooth surfaces make it difficult to photograph. It's chrome, and you'll see the rest of the room reflected in it.
It is intended to be adjusted using a warble-tone or band-limited pink-noise generator and analyzer to optimize loudspeaker installations.
It has variable LOW FREQUENCY COMPENSATION, which is bass boost peaking at 20 Hz, seven programmable bands of semi-parametric EQ, a HIGH FREQUENCY COMPENSATION (treble) control and gain trim for each channel.
Remove the cover to adjust it:
McIntosh MQ 107. bigger.
Replace the cover as shown at the top to prevent anyone from knocking the adjustments afterwards.
A set of capacitors is included and required to program and operate the seven band equalizer. DO NOT BUY one of these without the capacitor kit, as without them you can't program or use any of the seven bands! Of course you could go out and supply your own capacitors.
Included Programming Capacitors. bigger.
The filters are programmed by plugging-in capacitors per this chart. NARROW is third-octave and WIDE is one octave:
Filter Programming Chart. bigger.
McIntosh MQ 107. bigger.
McIntosh MQ 107. bigger.
Internal view, McIntosh MQ 107. bigger. (DO NOT open yours unless you have professional experience in high voltage electronics!)
Internal view of the audio connections. bigger. (DO NOT open yours unless you have professional experience in high voltage electronics!)
Internal view of the power supply end. bigger. (DO NOT open yours unless you have professional experience in high voltage electronics!)
Power supply, McIntosh MQ 107. bigger. (DO NOT open yours unless you have professional experience in high voltage electronics!)
Bottom view, McIntosh MQ 107 with rear cover removed. bigger. (DO NOT open yours unless you have professional experience in high voltage electronics!)
Measurements top
Distortion Noise Power Consumption
These measurements are made with an exotic factory-calibrated Rohde & Schwarz UPL laboratory analyzer. The traces from the Rohde & Schwarz UPL laboratory analyzer are color coded for the Left Channel 1 and for the Right Channel 2. When they don't lie on top of each other, it's due to channel imbalance. When they do lie on top of each other, the trace turns blue.
Unless otherwise specified, all measurements are RMS, fed from a 5Ω source impedance at 1,000 cycles at 1 V and loaded by 200 kΩ.
Gain measurements top
±0.000 dB, EQ OUT (direct passive bypass).
Left: -5.735 dB ~ +3.518 dB.
Right: -5.710 dB ~ +3.497 dB.
Unity gain is at about 1:20 o'clock on the gain controls, not at the marked zeros.
Loaded with 600Ω it's -8.025 dB less than when loaded with 200k Ω as above.
Loaded with 300Ω it's -12.125 dB less than when loaded with 200k Ω as above.
Maximum Output Level measurements top
5.68V @ 0.1% THD no boost or cut.
MOL 5.4V at insane levels of boost.
Max input level about 5.0V with lots of cut.
Frequency Responses measurements top
All controls flat. bigger.
±¼ dB, 16 ~ 20,000 Hz.
Infrasonic Frequency Response, all controls flat. bigger.
-1 dB at 10 Hz, -3 dB at 6.7 Hz.
Ultrasonic Frequency Response, all controls flat. bigger.
-0.5 dB at 30 kHz, -1 dB at 45 kHz and -3 dB at 95 kHz. Perfect.
LOW FREQUENCY COMPENSATION at 1, 1.5, 2, 3, 4, and 5. bigger.
Same as above, expanded vertical scale. The 1.5 setting is a mere 0.5 dB of boost at 20 Hz. bigger.
LOW FREQUENCY COMPENSATION at 1, 1.5, 2, 3, 4, and 5, expanded plot to 10 Hz. bigger.
Not how the maximum boost is deeper at lesser levels of boost.
LOW FREQUENCY COMPENSATION at 5. bigger.
LOW FREQUENCY COMPENSATION at 5. bigger.
Maximum, minimum and zero response with one section set to 16 Hz narrow (1µF CA and 0.56µF CB). bigger.
Maximum, minimum and zero response with one section set to 20 Hz narrow. bigger.
Maximum, minimum and zero response with one section set to 50 Hz narrow. bigger.
Maximum, minimum and zero response with one section set to 100 Hz wide. bigger.
HIGH FREQUENCY COMPENSATION (treble) control set top -5, -4, -3, -2, -1, 0, +1, +2, +3, +4 and +5. bigger.
Distortion measurements top
Noise makes the THD look worst at low levels. Likewise, power supply hum makes the low frequency THD look worse. These curves are showing THD only and at much lower levels than most people measure. These are not simple THD+noise plots, they are filtered THD-only plots.
With 100% being -60 dBV in the 1mV plot, we all know that means 1% of 1 mV (the top of the scale) is -100 dBV, which as we'll see is about the level of power supply hum.
1 mV (-60 dBV). bigger.
10 mV (-40 dBV). bigger.
100 mV (-20 dBV). bigger.
1 V (0 dBV). bigger.
3.162278 V (+10 dBV). bigger.
5 V (+13.98 dBV). bigger.
THD at 1 kHz. bigger.
Noise measurements top
Bypassed
None; it's a hard-wired bypass.
EQ all Flat
-105.0 dBV A-weighted.
-98 dBV unweighted.
(right channel a couple of dB quieter and left a couple of dB less quiet).
All 7 bands at maximum
-88.0, -88.9 dBV A-weighted.
-83.5, -85.5 dBV, unweighted.
All 7 bands at minimum
-91.5/91.5 dBV A-weighted.
-87.5/-87.6 dBV unweighted.
Noise, treble control max
-100 dBV A-weighted.
-95 dBV unweighted.
Noise, treble control min
-105 dBV A-weighted.
-97 dBV unweighted.
Noise Spectra
Noise is mostly power supply hum:
FFT of output when fed from 5Ω source. bigger.
Third-octave analysis of output fed from 5Ω source. bigger.
Power measurements top
Measured power consumption: 3.9 ~ 4.0 W.
Internally it has ±15V DC regulated supplies with 7815/7915 linear regulators.
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