VEC-841K Audio Filter Modified for Distortion Measurements, US $820 – Picture 0

VEC-841K Audio Filter Modified for Distortion Measurements, US $820 – Picture 1

VEC-841K Audio Filter Modified for Distortion Measurements, US $820 – Picture 2

Vec-841k Audio Filter Modified For Distortion Measurements

US $820

Trumbull, Connecticut, United States
Jun 9th

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ITEM DESCRIPTION You are bidding on a VEC-841K audio filter that has been modified for measuring and adjusting harmonic distortion in audio equipment using the notch filter that provides approximately 70dB of attenuation. The audio amplifier was replaced with an ultra-low noise Op-Amp (unity amplifier) and the power supply was upgraded with a precision “rail splitter” virtual ground. The filter requires a pure 12 VDC source (battery) for maximum range since it will measure ripple voltage. The noise floor of the unit is 45 uV (microvolts) with a pure DC power source; therefore, it will allow measurement of distortion above that level using a suitable AC millivolt meter. An oscilloscope makes tuning a little easier but is not required. The VEC-841K construction/operating manual with schematic is included as well as an addendum for alignment and use of the modified filter. CONDITION This item is in excellent condition and fully functional. MISCELLANEOUS I have used this device to adjust equipment for minimum total harmonic distortion plus noise (THD+N) and have measured THD+N as low as 0.03% compared to the unfiltered signal. This won’t compete with a high end audio analyzer but it will perform the same basic functions for much less expense. I don’t work on high fidelity equipment any more so I no longer have a use for it. Items are sold "as is" with no warranty other than the item you receive will be as described herein. Happy Bidding. SHIPPING Shipping cost for USA will be based on UPS ground (includes insurance) to the destination address. UPS does not ship to PO Boxes – please contact me prior to payment for shipping cost if you are shipping to a PO Box. Other methods of shipping can be arranged at buyer's discretion/expense. USPS can be cheaper, depending on options selected, but could result in a delay in shipping as it is difficult for me to get to the Post Office before they close.