riggler
Well-known member
Hi all,
So I want to mod the attached PSU for ~6.0V heater voltage. I've got a few other questions as well if anybody could chime in. I will be building this from scratch into Sony camera power supply cases for my M50-like mics using the Raytheon 5703WB tube.
Sorry for the large pic, but you can't read it otherwise.
Question components highlighted in red.
1. Gr1 - Diode - Looks like they used two in series here; presumably to up the voltage? So I could use just one 250V rated diode?
2. Gr2 - Bridge Rectifier - Just use 4x IN4007 or something?
3. Gr3 - Zener Diode - Any clue as to the value of this diode? It's used to regulate voltage right? So I want 120V?
4. R5 - ? - Is this a 50k linear trim pot? Sorry to sound stupid but want to make sure.
5. R12 -- Since my mic is fixed-pattern, can I just omit R12, R15, C8, and the pin 6 connection? Do I need to replace R12 with a fixed resistor?
6. Gr4 - Zener Diode - use 6.0V zener for desired 6.0V output? Can tweak with R9, but do I need to change anything else to handle a 6.0V 200mA load from the designed 4V 100mA load?
7. R14 - ? - Another trim pot here? Note the symbol difference with R5... Or wait, this isn't really a pot -- only 2 leads?!
8. TRS1 - AD130 regulator IC - I can still get this part. Any reason I should get something else?
9. Power Transformer: Where in the heck can I find a dual secondary xfo with 210V and 20V? Been looking at the smaller toroidal pieces from the likes of Amveco and not finding anything. I guess I could use 2 separate pieces...
For convenience here is the modified mic schematic to go along with this project. The original mic heater with AC701 tube pulled 100mA at 4V. Sorry for the long post but I tried to organize this the best way I knew how.
Thanks for any ideas guys!
So I want to mod the attached PSU for ~6.0V heater voltage. I've got a few other questions as well if anybody could chime in. I will be building this from scratch into Sony camera power supply cases for my M50-like mics using the Raytheon 5703WB tube.
Sorry for the large pic, but you can't read it otherwise.
Question components highlighted in red.
1. Gr1 - Diode - Looks like they used two in series here; presumably to up the voltage? So I could use just one 250V rated diode?
2. Gr2 - Bridge Rectifier - Just use 4x IN4007 or something?
3. Gr3 - Zener Diode - Any clue as to the value of this diode? It's used to regulate voltage right? So I want 120V?
4. R5 - ? - Is this a 50k linear trim pot? Sorry to sound stupid but want to make sure.
5. R12 -- Since my mic is fixed-pattern, can I just omit R12, R15, C8, and the pin 6 connection? Do I need to replace R12 with a fixed resistor?
6. Gr4 - Zener Diode - use 6.0V zener for desired 6.0V output? Can tweak with R9, but do I need to change anything else to handle a 6.0V 200mA load from the designed 4V 100mA load?
7. R14 - ? - Another trim pot here? Note the symbol difference with R5... Or wait, this isn't really a pot -- only 2 leads?!
8. TRS1 - AD130 regulator IC - I can still get this part. Any reason I should get something else?
9. Power Transformer: Where in the heck can I find a dual secondary xfo with 210V and 20V? Been looking at the smaller toroidal pieces from the likes of Amveco and not finding anything. I guess I could use 2 separate pieces...
For convenience here is the modified mic schematic to go along with this project. The original mic heater with AC701 tube pulled 100mA at 4V. Sorry for the long post but I tried to organize this the best way I knew how.
Thanks for any ideas guys!