$500.00 AUD


 The HP400 is an ideal millivolt meter to set up audio equipment. Robust, well made, easy scales to read, long lived and easily updated / recapped / calibrated. Nagravox buys batches of these from time to time specifically with the intention offering them to our customers who want to embark on the final journey of setting up and calibrating their tape machines. 

HP produced a lot of different models of precision AC voltmeters for almost 65 years. Starting with vacuum tube models through to digital. The HP400 was introduced mid 60’s and were available into the 80's in a number of different versions /   guises.

The 400 series is a solid-state (transistors) AC Voltmeter for measuring AC voltages on voltage and Db scales covering a flat frequency range from 20 Hz to 4 MHz or 10 hz to 10 Mhz and 0.5 - 4% accuracy depending on model and range. The input impedance is 10 Mohm, One of the main advantages of this millivolt meter is the taut band technology and superb robust workmanship of its meter movement.

 Dual Scales either log or lin can be in:

  • Db 12 Db log or linear decade scale in 14 ranges from –72 Dbm to +52Dbm.
  • Volts 100 divisions in log or lin decade scale in 14 ranges 100 uVs to 300V.

The meter can indicate both voltage and dB in a variety of linear or log configurations depending on model. Type EL, FL and GL have the Db scale linear and the voltage scale logarithmic. Type E and F versions have the voltage scale linear and the Db scale logarithmic. Generally we use the Db scale in setting up a tape recorder and there are advantages and disadvantages to having the Db scale linear or logarithmic (see picture in gallery for reasoning).

 The build quality is excellent in these meters as are the precision components used.

RECAP KIT.  Some of the tantalum and electrolytic capacitors are starting to get a bit long in the tooth at 30+ years and should be replaced. Nagravox offers recap kits for these meters and a calibration reference with its digital signal generators should you wish to check or set the calibration.  We also supply as part of the recap kit depending on model, 1 or 2 BNC chassis mounted sockets with a switch so you can convert to BNC (F and G models that dont have BNC) or add a 2nd channel input. The idea is that you can have the option of switched dual channel BNC input capability which is useful and relevant to setting up stereo tape machines. 

NEW!  Our recap kits also include a specially made new meter face transfer so you can have a new looking meter face as many 'crumble' and look tatty. 

The 5 different models are:

HP400E     10 hz - 10 Mhz logarithmic Db scale -10 to +2Db

HP400EL   10 hz - 10 Mhz linear Db scale -10 to +2Db

HP400 F     20 hz - 4 Mhz logarithmic Db scale -10 to +2Db

HP400 FL   20 hz - 4 Mhz linear Db scale -10 to +2Db

HP400GL   20 hz - 4 Mhz linear Db scale -20 to +0Db

 The different models are offered in 3 variations:

  • 2nd hand meter tested and working complete with a full diy recap kit.
  • Fully refurbished, recapped and calibrated as a single channel instrument
  • Fully refurbished, recapped and calibrated as a switched dual channel instrument

Please note that we do not supply a mains lead as each country has a different plug. You will need to get an inexpensive widely available mains lead  (IEC C13) used for most computers, kettles and other appliances and available in different lengths. On some models a proprietary HP mains input socket is fitted that is difficult to get plugs or leads for.  So we supply a C14 Male Chassis Mount Socket with EMI Filter with our recap kits. This makes the instrument  IEC C13 compliant /  compatible.


HP400E stock limited.

The  overhauled are special order so there may be a delay involved which we will inform you of after purchase. (usually 3 - 6 weeks)

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