Specialized Tools for Electrophysiology and Cell Biology Research

(LPF-8) Low-pass Bessel Filter

Product Summary

A signal conditioner combining an 8-pole low pass Bessel filter with a DC amplifier.


  • Provides greater frequency control for bilayer and oocyte clamps
  • High quality 8-pole Bessel filter
  • 8-Pole low pass filter with cutoff frequencies from 0.1 Hz to 20 kHz
  • Differential amplifier gains to x200
  • Frequency selection with single control
  • Input offset adjustment
  • Digital frequency readout
  • Rack mountable

LPF-8 special features include a digital frequency readout, visual input offset indicator, clipping indicator, and gain telegraph outputs. It is a premier low-pass Bessel filter that provides superior control of analog signal filtering from 0.1 Hz to 20 kHz. The LPF-8 instrument incorporates low-pass signal filtering and output gains from 1 to 200. Dual selectable signal inputs allow the instrument to be configured to operate in normal, inverted or differential modes.

This instrument features an optically encoded circuit which permits frequency selection in two ranges with a single control. Since the set frequency control is not a physical part of the filtering circuit, adjustments to the instrument do not introduce noise artifacts into the output signal. The unique circuit design uses no mechanical switching which insures long-term instrument reliability.

User Conveniences

  • Frequency is dialed up with a single rotary control in 2 ranges. Resolution is 0.1 Hz or 10 Hz, depending on range selected
  • BYPASS switch selects full amplifier bandwidth for comparison of filtered and unfiltered signal
  • The DC Offset / Clipping indicator is a zero center display serving two functions; it is used as a null meter with the offset control and it indicates overload (clipping) conditions
  • Gain telegraph signals are provided for data acquisition systems
Input DC Differential
Input Impedance 1 MΩ each Channel
Common Mode Rejection 80 dB at line frequency
Input Range ± 10 V
Input Offset 2 Ranges, ± 100 mV and ± 1.0 V
variable from zero with 10-turn control
Offset Indicator 20 LED Display
Frequency Ranges Low: 0.1 to 199.9 Hz
High: 10 to 19.99 kHz
Low Range Resolution 0.1 Hz
High Range Resolution 10 Hz
Gains x1, x2, x5, x10, x20, x50, x100 and x200
Gain Telegraph Output 2.5 V to 6.0 V in 0.5 V steps,
x1 Gain = 2.5 V
Output Impedance 50 Ω
Power Requirements 100-130 VAC or 200-250 VAC, 50/60 Hz, 15 VA
Enclosure Rack Mount Cabinet, H xW x D
4.4 x 43.2 x 43.2 cm
(rack hardware included)
Shipping Weight 4.6 kg
Warranty 2 years



  1. Modulation of transient receptor potential vanilloid 4-mediated membrane currents and synaptic transmission by protein kinase C
    Cao DS, Yu SQ, Premkumar LS
    Mol Pain. 2009 Feb 10;5:5
  2. Proton transport through influenza A virus M2 protein reconstituted in vesicles 
    Moffat JC, Vijayvergiya V, Gao PF, Cross TA, Woodbury DJ, Busath DD
    Biophys J. 2008 Jan 15;94(2):434-45. Epub 2007 Sep 7
  3. HCN Pacemaker Channel Activation Is Controlled by Acidic Lipids Downstream of Diacylglycerol Kinase and Phospholipase A2 
    Fogle KJ, Lyashchenko AK, Turbendian HK, Tibbs GR
    J Neurosci. 2007 Mar 14;27(11):2802-14
  4. Regulation of large dense-core vesicle volume and neurotransmitter content mediated by adaptor protein 3
    Chad P. Grabner, Steven D. Price , Anna Lysakowski , Anne L. Cahill, and Aaron P. Fox, 
    PNAS | June 27, 2006 | vol. 103 | no. 26 | 10035-10040
  5. Stable silencing of SNAP-25 in PC12 cells by RNA interference
    Anne L Cahill, Bruce E Herring and Aaron P Fox, 
    BMC Neuroscience 2006, 7:9
  6. NMDA Receptor NR2 Subunit Dependence of the Slow Component of Magnesium Unblock
    Richard J. Clarke, and Jon W. Johnson, 
    The Journal of Neuroscience, May 24, 2006 " 26(21):5825.5834 " 5825
  7. A Cysteine-scanning Mutagenesis Study of Transmembrane Domain 8 of the Electrogenic Sodium/Bicarbonate Cotransporter NBCe1
    Suzanne D. McAlear and Mark O. Bevensee, 
    J. Biol. Chem., Vol. 281, Issue 43, 32417-32427, October 27, 2006
  8. Hydroxylated Xestospongins Block Inositol-1,4,5-trisphosphate-Induced Ca2+ Release and Sensitize Ca2+-Induced Ca2+ Release Mediated by Ryanodine Receptors
    Tram Anh Ta, Wei Feng, Tadeusz F. Molinski, and Isaac N. Pessah, 
    MOLECULAR PHARMACOLOGY Vol. 69, No. 2 69:532-538, 2006
  9. Mapping Conformational Changes of a Type IIb Na/Pi Cotransporter by Voltage Clamp Fluorometry
    Leila V. Virkki1, Heini Murer, and Ian C. Forster, 
    THE JOURNAL OF BIOLOGICAL CHEMISTRY VOL. 281, NO. 39, pp. 28837-28849, September 29, 2006
  10. WNK3, a kinase related to genes mutated in hereditary hypertension with hyperkalaemia, regulates the K+ channel ROMK1 (Kir1.1)
    Qiang Leng, Kristopher T. Kahle, Jesse Rinehart, Gordon G. MacGregor, Frederick H. Wilson, Cecilia M. Canessa, Richard P. Lifton and Steven C. Hebert, 
    The Journal of Physiology Volume 571 Issue 2 Page 275-286 - March 2006
  11. Mouse Chromaffin Cells Have Two Populations of Dense Core Vesicles
    Chad P. Grabner, Steven D. Price, Anna Lysakowski and Aaron P. Fox, 
    J Neurophysiol 94: 2093-2104, 2005. First published June 8, 2005
  12. Glycine Binding Site of the Synaptic NMDA Receptor in Subpostremal NTS Neurons
    Vander Baptista and Wamberto Antonio Varanda, 
    J Neurophysiol 94: 147-152, 2005
  13. Sensitization and translocation of TRPV1 by insulin and IGF-I
    Jeremy J Van Buren1, Satyanarayan Bhat, Rebecca Rotello, Mary E Pauza, and Louis S Premkumar, 
    Molecular Pain 2005, 1:17
  14. Activation of transient receptor potential vanilloid 1 (TRPV1) by resiniferatoxin
    Manish Raisinghani, Reddy M. Pabbidi and Louis S. Premkumar, 
    The Journal of Physiology Volume 567 Issue 3 Page 771Issue 3 - 786 - September 2005
  15. Downregulation of Transient Receptor Potential Melastatin 8 by Protein Kinase C-Mediated Dephosphorylation
    Louis S. Premkumar, Manish Raisinghani, Sandeep C. Pingle, Cheng Long, and Fátima Pimentel, 
    The Journal of Neuroscience, December 7, 2005, 25(49):11322-11329
  16. Sensitization and translocation of TRPV1 by insulin and IGF-I
    Jeremy J Van Buren1, Satyanarayan Bhat1, Rebecca Rotello1, Mary E Pauza2,3, 
    Molecular Pain 2005, 1:17
  17. Phosphorylation-regulated endoplasmic reticulum retention signal in the renal outer-medullary K+ channel (ROMK)
    Anthony D. O'Connell, Qiang Leng, Ke Dong, Gordon G. MacGregor, Gerhard Giebisch, and Steven C. Hebert, 
    PNAS | July 12, 2005 | vol. 102 | no. 28 | 9954-9959
  18. Novel nucleotide-binding sites in ATP-sensitive potassium channels formed at gating interfaces
    Ke Dong, Lie-Qi Tang, Gordon G MacGregor, Qiang Leng and Steven C Hebert, 
    The EMBO Journal (2005) 24, 1318-1329
  19. Gating Reaction Mechanisms for NMDA Receptor Channels,
    Anthony Auerbach and Yu Zhou, 
    The Journal of Neuroscience, August 31, 2005, 25(35):7914-7923
  20. Subunit interactions are critical for proton sensitivity of ROMK: Evidence in support of an intermolecular gating mechanism
    Qiang Leng, Gordon G. MacGregor, Ke Dong, Gerhard Giebisch, and Steven C. Hebert, 
    PNAS | February 7, 2006 | vol. 103 | no. 6 | 1982-1987
  21. Electrophysiological evidence for the presence of NR2C subunits of N-methyl-D-aspartate receptors in rat neurons of the nucleus tractus solitarius
    V. Baptista, W.N. Ogawa, J.F. Aguiar and W.A. Varanda, Braz J Med Biol Res, 
    January 2004, Volume 38 (1) 105-110 (Short Communication)
  22. Electrogenic Na/HCO3 Cotransporter (NBCe1) in Xenopus Oocytes: Functional Comparison and Roles of the AminoVariants Expressed and Carboxy Termini
    Suzanne D. McAlear, Xiaofen Liu, Jennifer B. Williams, Carmel M. McNicholas-Bevensee, and Mark O. Bevensee, 
    The Rockefeller University Press, JGP, Volume 127, Number 6, 639-658
  23. Critical Role of Calcitonin Gene-Related Peptide 1 Receptors in the Amygdala in Synaptic Plasticity and Pain Behavior
    Jeong S. Han, Weidong Li, and Volker Neugebauer, 
    The Journal of Neuroscience, November 16, 2005, 5(46):10717-10728



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Order No. Model No. Product Description USA Price Order
64-0050 LPF-8 Low pass bessel filter, 8-pole, with differential amplifier, 110-240 VAC, 50/60 Hz Login Login
460-7032 BNC-2 BNC to BNC cable, 2 feet (Pomona) Login Login
460-7013 BNC-6 BNC to BNC cable, 6 feet (Pomona) Login Login

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