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Microelectrode AC Amplifier Model 1800

The Model 1800 includes:

  • Operator's manual
  • Rack mount hardware
Note: For proper operation, the purchase of two Model 1800-compatible headstages (Catalog#: 700500) is required. Two Model 1800 headstages will be automatically added when you add a Model 1800 to cart.

Please note that A-M Systems instruments are not approved for use with human subjects in either a clinical or research environment.

Catalog # Description Price Quantity
700000 Model 1800 2-Channel Microelectrode AC Amplifier, 110 V, 60 Hz $1,450.00 
Quantity:
700005 Model 1800 2-Channel Microelectrode AC Amplifier, 220 V, 50 Hz $1,450.00 
Quantity:
700500 Model 1800 Headstage $325.00 
Quantity:
749918 Extended Warranty, 2 Year, Model 1800 with two headstages $225.00 
Quantity: 



Summary

The Model 1800 Microelectrode AC Amplifier is a two-channel, differential amplifier designed for two headstage probes and is intended for extracellular recording and/or stimulating with high impedance metal microelectrodes in research and teaching applications. Extracellular neurophysiological recordings with high impedance microelectrodes can easily be done from excitable tissues such as nerve and muscle. The instrument is not intended for clinical measurements in human subjects.

Special Features

Mode Selection: This switch allows the user to select one of three Modes for each channel of the amplifier: Impedance Check (IMP), Record (REC), or Stimulate (STIM). During Impedance Check, an internal 1 kHz oscillator automatically applies a calibrated current through the electrode and the amplifier monitors the voltage in order to check impedance.

Capacity: This control is used to neutralize the capacitance during electrode impedance check. In record mode, the instrument amplifies the differential input signal by an amount selected by the Gain switch. In the Stimulate mode, a stimulus is applied directly to the electrode through the Stimulus connector, and the amplifier monitors the current passing throught the electrode.

Gain Selection: In the Record mode, the gain of each amplifier may be independently set by adjusting the Gain switch to x100, x1000, or x10,000.

Headstage

The headstage for the Model 1800 is small and convenient. It is 0.535 inches (1.395 cm) in diameter and 4 inches (10.2 cm) long. It includes a 0.187 inch (4.7 mm) diameter mounting rod and 5 feet (1.5 m) of Superflex silicone jacketed cable which resists mild alkalis, acids and solvents. It has 0.062 inch female pin connectors to attach to your sensors.

Warranty

Includes standard 3 year warranty.

Note: For proper operation, the purchase of two Model 1800 compatible headstages (Catalog# 700500) is required.

Specifications

  • Amplifier for metal microelectrodes
  • Two amplifiers in one instrument
  • Recording gain options: x100, x1000, x10 000
  • Low noise (1.0 µV p-p typical, 10 Hz–10 kHz)
  • High common-mode rejection ratio (100 dB at 60 Hz)
  • High line frequency rejection with notch filter (>110 dB at 60 Hz) (50 Hz notch filter optional)
  • High input impedance (100 000 MΩ)
  • Low input bias current (±3 pA typical; ±20 pA maximum)
  • Adjustable low and high frequency filters
  • Power supply may be set for 110 VAC at 60 Hz or 220 VAC at 50 Hz

FAQ

The following is a list of commonly asked questions regarding this product. If you have any additional questions, please feel free to contact us at 800-426-1306 for further information.

  • Can I get a replacement Instruction Manual for this instrument?
  • Is it possible to have a Model 1800 amplifier customized for my preferred gain and filter settings?
  • Do you sell extension cables for your headstages?
  • What are the major differences between the Model 1700 Differential Amplifier and the Model 1800 Microelectrode Amplifier?
  • My Model 1800 is not working, but our university has an excellent electronics facility. Can we repair the unit ourselves?
  • Should I purchase a Model 1800 or a Model 3000?
  • What is the impedance mode?
  • Can I use this instrument outside of the United States?
  • What are the proper operating and storage conditions for my Model 1800?
  • Can I get a replacement Instruction Manual for this instrument?

    Additional Operator's Manuals are available for download by clicking on the 'Downloads' section from the menu bar at the top of this web page.

    Is it possible to have a Model 1800 amplifier customized for my preferred gain and filter settings?

    Yes, in most circumstances, we can easily customize at our factory any of our amplifiers' filter and/or gain settings. Please contact technical support (800-426-1306, or tech@a-msystems.com for more information.

    Do you sell extension cables for your headstages?

    We do not sell extensions, however we do sell new headstages with longer cables (for a small customization charge). The maximum length is usually 12 feet. Typically, the main amplifier needs to be returned to us for calibration with the new longer headstage cables.

    What are the major differences between the Model 1700 Differential Amplifier and the Model 1800 Microelectrode Amplifier?

    The 1700 has 4 channels and the 1800 has two. The 1800 comes with preamplifiers (probes, headstages) while the 1700 does not. Thus, while the 1700 and 1800 will work equally well in recording if you have electrodes that are 1M-ohm or less, recording with high impedance electrodes will require the headstage probe provided with the 1800. The Headstage eliminates signal losses due to long cables and the capacitance they generate. The 1800 can monitor an external stimulus being delivered through the recording electrode, while the 1700 can not. The 1800 has a built-in impedance measuring circuit, while the 1700 does not.

    My Model 1800 is not working, but our university has an excellent electronics facility. Can we repair the unit ourselves?

    It is recommended that A-M Systems perform the needed repairs as we are the most familiar with the units. However, if you are confident in your electronic technician's skills, you can always purchase the schematics for the Model 1800 from us (Cat#703000) and attempt them yourself. Please note that any user-attempted repairs during the warranty period may invalidate the warranty, and might invoke additional charges to correct them if A-M Systems is required to make repairs at a later date.

    Should I purchase a Model 1800 or a Model 3000?

    Both instruments are designed for low noise differential recording of physiological signals. The Model 1800 is a true AC amplifier. In contrast, the Model 3000 has a DC front end, which also enables the researcher to record DC offsets that would otherwise be eliminated by a full AC amplifier, like the Model 1800.

    The Model 1800 uses capacity compensation during impedance measurements only, while the Model 3000 also uses capacity compensation during recording as well as impedance measurement, while .

    The Model 1800 has lower noise than the Model 3000, but both instruments have acceptable noise levels for high quality recordings.

    The Model 3000 can fit within a Faraday cage, as its power input is DC from the remote power supply.

    The Model 1800 has two channels, and two headstages are included. In contrast, the Model 3000 has only a single channel, and headstages are options available for an additional charge.

    What is the impedance mode?

    When the Model 1800 is in impedance mode, a 100nA 1kHz sine wave is injected into the electrode. With the capacity compensation control fully counter-clockwise, the resulting amplitude on the output is proportional to the impedance (Z=V output / I injected). For an electrode with 1M impedance at 1kHz, you would get 100mV on the output. The capacity compensation knob will charge up the capacitance of the electrode to eliminate it from the measurement leaving only the resistance of the electrode. So as you turn the capacity compensation clockwise the capacitance of the electrode will be eliminated and the amplitude of the sine wave will increase. When the sine wave starts to get noisy and approach high frequency oscillations, you will have compensated for almost all of the capacitance of the electrode.

    If you would like more information on electrodes, we suggest a book titled: "Electrodes and the measurement of bioelectric events." by L.A. Geddes.

    Can I use this instrument outside of the United States?

    All of A-M Systems instruments can be modified to work outside of the United States. Typically, this modification is made at the factory (at no additional cost) prior to shipping to our customers. Just inform the customer service department where the instrument will be used, so our technicians can prepare the proper power supply modifications.

    What are the proper operating and storage conditions for my Model 1800?

    The Model 1800 is designed to be used under laboratory conditions. Operate in a clean, dry environment only. Do not operate in a damp environment. Temperatures for storage and operation should be between 5 °C and 40 °C. Storage should be indoors in a cool dry place.

    Headstage

    The headstage for the Model 1800 is small and convenient. It is 0.535 inches (1.395 cm) in diameter and 4 inches (10.2 cm) long. It includes a 0.187 inch (4.7 mm) diameter mounting rod and 5 feet (1.5 m) of Superflex silicone jacketed cable which resists mild alkalis, acids and solvents. It has 0.062 inch female pin connectors to attach to your sensors.

    Current Model 1800 Headstages are furnished with short interconnects designed to mate with any metal electrodes that terminates in Cooper/Wire-Pro/Amphenol style Reliatac 220-P02 connectors, including all of A-M Systems metal electrodes. To use glass micropipette electrodes with the Model 1800 headstage, a compatible microelectrode holder should be purchased. Any pipette holder with a 2 mm pin can mate directly with the headstage without the use of the interconnect. Older Model 1800 headstages (sold prior to March 2013) accept slightly smaller pins, and can mate directly to our 1.6 mm pin holders.

    Options & Accessories

    Downloads