Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › bias voltage of an electrostatic amp
New Posts  All Forums:Forum Nav:

bias voltage of an electrostatic amp

post #1 of 4
4/16/08 at 4:24am
Thread Starter 
I have SRM-727II.
A few days ago me and my friend rewired my amp for 220V (from 117V). After that we measured ~380Vdc before the ballast resisitor (4.7Meg), falling to 318Vdc on the pin (we used a Yokogawa 7532 03 DMM).
In the specifications of 727II the bias voltage shown is 580V. So can anyone explain me the big difference?
Reply
post #2 of 4
4/17/08 at 8:08am
Quote:
Originally Posted by brat View Post
I have SRM-727II.
A few days ago me and my friend rewired my amp for 220V (from 117V). After that we measured ~380Vdc before the ballast resisitor (4.7Meg), falling to 318Vdc on the pin (we used a Yokogawa 7532 03 DMM).
In the specifications of 727II the bias voltage shown is 580V. So can anyone explain me the big difference?
The input impedance of your DMM is probably way to low and is loading down the circuit. You should use a High Voltage probe like the Fluke 40KV probe. I’m sure your 727II is just fine.
Doug
Reply
post #3 of 4
4/17/08 at 10:54am
Thread Starter 
Quote:
Originally Posted by audiod View Post
The input impedance of your DMM is probably way to low and is loading down the circuit.
~260V lower?...
Reply
post #4 of 4
4/17/08 at 5:34pm
Quote:
Originally Posted by brat View Post
~260V lower?...
Yes!!! If you load the circuit down to long you could blow some diodes in the HV supply of the SRM. The Bias supply is normally runing into an almost open load. The input impedence of your DMM is 1meg ohm or 10meg ohm which is way way way to low. The input impedance of my Fluke HV probe is 1000meg ohms.
Doug
Reply
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › bias voltage of an electrostatic amp