2010/01/12 PINTEK have finished the improvement on our High Voltage Amplifier, to raised up the Bandwidth.
The difference between NEW specification and old are as the following..
MODEL Item Old Specification New specification
HA-400 Bandwidth  DC-300KHz DC-600KHz
Voltage Gain 0-80 0-90
Output protect --- Micro process protect(option)
HA-405 Bandwidth   DC-500KHz DC-1MHz
Voltage Gain 0-80 0-90
Out put protect --- Micro process protect
HA-800 Bandwidth   DC-50KHz DC-200KHz
Voltage Gain 0-80 0-180
Output Protect --- Micro process protect(option)
HA-805 Bandwidth   DC-50KHz DC-300KHz
Voltage gain 0-80 0-180
Output protect --- Micro process protect
The new specification will be effective since 2010 January.
As the High Voltage Amplifier was a High precision, High precious equipment. To check the specification becomes more important before you purchasing it.
Pintek have provided the selection guide of High Voltage Amplifier. To give the user a more convenience to select the suitable High Voltage Amplifier.。  
HA Selection Guide

Pintek Electronics Co., Ltd.
3F No.32 Tai-pen Rd., Shulin, New Taipei City, Taiwan.
Tel : 886-2-86859562~3    Fax : 886-2-86852081
E-Mail : pintek@pintek.com.tw ; pintek@ms26.hinet.net
Web Site : http://www.pintek.com.tw