BenchMaster 8  - Versatile 2 channel bench top filter, gain to x500 (+54 dB)   Usually ex-stock

  • 2 Independent Channels each switchable 
    high / low pass
  • Highpass / Lowpass / BandPass / Bandstop and Notch in one instrument
  • 0.01Hz - 99.9kHz filter range
  • Simple front panel operation
  • Input gain to x 500
  • Signal level indication
  • Lowpass/highpass switchable each channel
  • Six switchable filter modifiers
  • Usually ex-stock delivery
     
    BenchMaster 8 pdf data sheet (75 kB)
      Order Now
Kemo BenchMaster 8 versatile dual channel filter

Click image for larger picture (800x480 60kB)

The BenchMaster 8 series of variable filters are now in their 5th generation, two channels of high performance analogue filter, plenty of gain, signal level indication, and flexible input front end all in a compact solid 1U high package. This versatile instrument has set the standards for laboratory and industrial filtering, providing a reliable general purpose filter instrument with a range of filter frequency and characteristic options to suit virtually all applications. BenchMaster 8's use specially manufactured components to ensure close tolerances and good channel matching. The latest version is a complete redesign, giving improvements in signal to noise ratios, overall noise, and a clearer front panel. Modern manufacturing techniques allow us to offer quick deliveries.

Summary Specification
Channels 2
Control Manual front panel all functions
Frequency 0.01 Hz - 99.9 kHz
Gain  x1,2,5,10,20,50,100,200,500 (+54 dB) per channel 
Filters Switchable Hi/Lo - with Butterworth / Pulse / Flat modifiers
Filter Responses - 6 8.03, 8.05, 8.07, 8.09 8.13 8.41
Input Coupling AC / DC / single ended / differential
IEPE Yes 4mA 24V
Size 1U 19"
Power 90 -120 / 180-240 Vac 50/60Hz
Optional 9 - 30 V DC, with AC 'power brick'

The use of the filter response modifiers and the series / parallel mode, give two independent high/lowpass channels, which can be combined to give the following  response types:

+
Lowpass and separate Lowpass
+
Highpass and separate Highpass
+
Lowpass and separate Highpass
+
Highpass and separate Lowpass
 
Highpass and Lowpass in series = Bandpass
 
Lowpass and modified Lowpass in series =  true double strength filtering
 
Highpass and Lowpass in parallel = Bandstop Highpass and Lowpass in parallel = narrow Bandstop (Notch)

All the curves above were measured on a standard BenchMaster 8.03, by using a combination of the series/parallel control and the filter response modifiers.

Frequency Range 0.01Hz to 99.9kHz
The BenchMaster 8 offers a cut-off frequency range of 0.01Hz to 99.9kHz, covered by five three-digit ranges. Frequency is set with three rotary decade switches and a range switch.

Lowpass / Highpass
Each channel can be independently set to high or low pass, over the range 0.01 Hz to 99.9 kHz.

Flexible Input
Single ended or differential input can be set, with overload indication on the input signals. Input signals can be DC or AC coupled, with matched coupling for AC differential input. A 24V DC 4mA source for IEPE transducers is provided, with LED indication of correct operation of the transducer. Green shows correct operation, red shows short circuit, and nothing indicates open circuit.

Input Gain
The BenchMaster 8 has two stages of input gain, x1, 2, 5 (0,+6,+14 dB), as precision differential amplification controlled as one front panel switch, then x 1, 10, 100 (0,+20,+40 dB) as a separate switch control. This combination is easy to use and allows amplification of small signals. This amplification is applied to the signal before the filter stages. The filter stages can be bypassed, so the BenchMaster 8 can be used as a pure amplifier, and in if required the two channels can linked in series to give x 250 000  (+108 dB) gain.

Signal Level Indication
To help optimise the gain settings, the BenchMaster 8 has a 4 level signal indicator. This indicator has a fast rise time and a slow decay, so it can show sharper peaks in the signal.
Signal Level Indication
0 - 2 Volts
2 - 6 Volts
6 - 9.5 Volts
>9.5 Volts

Three Switchable Response Modifiers
Each BenchMaster 8 has 3 filter modifier settings, Butterworth, Flat, and Pulse.
'pulse' modifier, a minimum overshoot response, the normal operating position for the Bessel response 8.07 and 8.09.
'flat' modifier, with a flattened amplitude response up to the cut-off frequency, the normal operating position for responses 8.13 and 8.41.
'but' modifier, provides a -3dB at cut off type response, the normal operating position for the Butterworth response 8.03 and 8.05.
The use of these modifiers makes for a very versatile filter, especially when coupled with the Series/Parallel mode. For Bessel (8.07 and 8.09) and Butterworth filters (8.03 and 8.05) the use of the flat setting allows 2 filters in series to provide correct shape double strength filters. Without these modifiers 2 Butterworth filters in series would have -6dB at cut off, but with one filter in the series, set to 'flat' the correct -3 dB at cutoff is maintained. This allows 96 dB/octave Butterworth filters to be set on a BenchMaster 8.03. 

Frequency Range 0.01Hz to 99.9kHz
The BenchMaster 8 offers a cut-off frequency range of 0.01Hz to 99.9kHz, covered by five three-digit ranges. Frequency is set with three rotary decade switches and a range switch.

Six Models
BenchMaster 8.05 - 4 Pole Butterworth response 24 dB/Octave. ( Data sheet Response 8.05 )
BenchMaster 8.03 - 8 Pole Butterworth response 48dB/Octave. ( Data sheet Response 8.03 )
BenchMaster 8.07 - 4 Pole Bessel response 
BenchMaster 8.09 - 8 Pole Bessel response
BenchMaster 8.41  - General Purpose, very flat to cut off, linear phase.
BenchMaster 8.13  - Sharp Elliptic type filter. -93dB at twice cutoff. ( Data sheet Response 8.13 )

BenchMaster 8 electronic filter amplitude responses   Kemo BenchMaster 8 electronic filter phase responses

            Amplitude     click for larger images      Phase  

Easy Manual Control
The BenchMaster 8 is designed for easy manual operation. 

DC Power (optional)

BenchMaster Dual channel electronic filter with DC power option.

9-30V DC input is available as an option. Power input by 'XLR' type connector, with an AC 'power brick' to power the unit from mains when available. 
Please check our page about DC Power.

Other Features
The BenchMaster 8 is manufactured using the latest surface mount technology, independent linear power supplies for the logic and analogue circuits. The BenchMaster 8 is housed in a solid aluminium case, ready for rack mounting, and with handles which protect the front panel controls. The front panel is laser cut and marked stainless steel, and most of the internal and external fasteners are stainless steel, vibration resistant where possible.
This latest version is a complete redesign, and one that all the staff at Kemo have contributed to, it is a product we feel proud of, and after over 40 years of building filters one that has some expertise built into it.

Ordering Information
Please order as:-
BenchMaster 8.05, 4 pole Butterworth
BenchMaster 8.03, 8 pole Butterworth
BenchMaster 8.09, 4 pole Bessel
BenchMaster 8.07, 8 pole Bessel
BenchMaster 8.13, 8 pole sharp anti-aliasing type filter
BenchMaster 8.41, 8 pole general purpose linear phase filter

SPECIAL NOTE - a BenchMaster 8 can be supplied with any two filters from the above selection, so a unit can be supplied with one 8.03 channel and one 8.41 channel.

Please specify if Optional DC power is required.
 
BenchMaster 8 pdf data sheet (75 kB)        Order Now

Kemo Limited
3 Brook Court,
Blakeney Road,
Beckenham, Kent,
BR3 1HG.
United Kingdom

Tel:  +44 (0)20 8658 3838 
Fax: +44 (0)20 8658 4084
Kemo Inc.
13183 Wexford
Hollow Road North,
Jacksonville,
FL 32224.
U.S.A.

Tel:  (904) 223 0662
Fax: (904) 223 6771