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For sale Maxon AF-9 Auto Filter (Envelope Filter) MIJ

Sold
$320.00 $300.00
Location
Franklin Tennessee, United States
Status
This item has been sold and is no longer available!
Status
1 member is watching this classified ad

Details

$325.00 shipped CONUS. Venmo or PayPal preferred. No interest in trades at this time.

Recently discontinued, this pedal gives you the classic Mu-Tron sound, with all the options. This is the original version with sliders for the sensitivity and peak controls, made in Japan. The pedal is in very good cosmetic and working condition. There are a few small marks on the case, which I've tried to capture in the photos. Ships with the original box and manual. No Velcro.

From Maxon:

The AF-9 is Maxon’s version of the venerable Mu-Tron III envelope filter circuit (original version, not HAZ reissue). The biggest difference between the two circuits is that the AF-9 runs on a single 9V supply while the Mu-Tron ran at 18V.

In addition, the III had a Gain pot which controlled the output level of the pedal as well as the Threshold of the Filter – this was an awkward design, as it prevented increasing the filter sensitivity without raising the output volume of the pedal.

These items aside, the basic structures of the two circuits are very similar. The AF9 starts with a unity gain buffer Op Amp and then splits the signal into control and effected circuits. The control circuit is shaped by the Sensitivity pot and amplified by an Op Amp. This control signal then travels to a series of two photocouplers.

The effected portion of the circuit split goes into a three Op Amp filter network that is almost identical to the Mu-Tron’s, right down to the Low Pass, Band Pass, and High Pass switch that selects which portion of the filter network is used. These filters are triggered by the CdS cell side of the previously mentioned photocouplers.

The AF-9’s Range is selected by changing the gain structure of the filters. After the filter network the signal is run through a unity gain buffer to provide a low impedance output.

The AF-9 features Mechanical True Bypass switching via a Fujisoku 4PDT switch.

Input Impedance: 500K Ohms

Input Jack: 1/4 inch standard phone jack

Output Impedance: 10K Ohms

Output Jack: 1/4 inch standard phone jack

Output: 1

Residual Noise: -95 dB or less (input shorted IHF-A weighted)

Filter Frequency: 100 Hz 2 KHz (Low) / 200 Hz 4 KHz (High)

Controls: Sensitivity, Peak

Switch: Normal/Effect (true bypass configuration), Filter LP/BP/HP, Drive Up/Down, Range High/Low

Power Supply: 9V Manganese dry cell battery (6F22) or special AC adaptor

Power Voltage: DC9 V (Battery) / DC10 V (AC-adaptor)

Current Consumption: 17 mA (9 V) / 19 mA (10 V)

AC Adaptor: AC210N (option) Input: AC120V Output: DC9V/200 mA Center - / Sleeve +)

Dimensions (whole): 74 mm (W) x 124 mm (D) x 54 mm (H)

Weight: 580 g

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Comments

winston

Gold Supporting Member
May 2, 2000
3,714
2,972
East Bay, CA
www.olokunmusic.com
I've had 2 of these and they're great for classic analog filtering!
Only reason I sold 'em is I got an Ibanez UE303B multi-fx from the '80s that has an AF-9 plus a compressor and stereo chorus/flanger.

GLWTS!
 

Classified ad information

Posted by
Charley Umbria
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For Sale: Effects and Pedals
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Location
Franklin, TN, USA