Hi guys,
I am a complete valve noobie. I've always wanted to convert one of my TDA1541 cd players to valve output like Lampizator does.
The stock kit I 've had for a while has 470r resistors for the cathode but lampizator recommends 150r. The service manual for 6N2 states 2.25 +- 0.45MA
I read a forum that I copied the cicruit diagram from but doesnt mention anything about the resistor. Its the exact same circuit as mine. In that forum is not being used as I/V
This link below from lampizator states for 6n2p use 150r. "150-250 Ohms for 6H2P". I have also attached the document.
http://www.lampizator.eu/lampizator/photogallery/STEPS/Lampizator.doc
The circuit diagram is missing the grid to plate connection. I also measured the B+ voltage on my supply its 288v DC across the power capacitor.
Am I being paranoid in worrying about an expert like Lampizator or is he wrong? I understand if the bias is too high it can damage the valves and too low won't sound right.
Any input would be greatly appreciated
I am a complete valve noobie. I've always wanted to convert one of my TDA1541 cd players to valve output like Lampizator does.
The stock kit I 've had for a while has 470r resistors for the cathode but lampizator recommends 150r. The service manual for 6N2 states 2.25 +- 0.45MA
I read a forum that I copied the cicruit diagram from but doesnt mention anything about the resistor. Its the exact same circuit as mine. In that forum is not being used as I/V
This link below from lampizator states for 6n2p use 150r. "150-250 Ohms for 6H2P". I have also attached the document.
http://www.lampizator.eu/lampizator/photogallery/STEPS/Lampizator.doc
The circuit diagram is missing the grid to plate connection. I also measured the B+ voltage on my supply its 288v DC across the power capacitor.
Am I being paranoid in worrying about an expert like Lampizator or is he wrong? I understand if the bias is too high it can damage the valves and too low won't sound right.
Any input would be greatly appreciated
Attachments
Hi!
The value 2.3+/- 0.9mA is the nominal anode current, at 250V anode voltage, with -1.5V grid bias. This is how the tube is measured by the manufacturer. Typically though, the 6N2P is biased for 1mA in many circuits, which were designed for a 12AX7.
Using a 150 ohms resistor results in ~2.5mA, less than 400mW anode dissipation. Remember here every triode handles approximately half of B+, not B+. You are safe with 150 ohms.
Regards,
Jose
From the Russian datasheet, the maximum cathode current for the 6N2P is 10mA. Assuming no grid current, this equals to the maximum anode current. The maximum power dissipated by the anode is 1W.
The value 2.3+/- 0.9mA is the nominal anode current, at 250V anode voltage, with -1.5V grid bias. This is how the tube is measured by the manufacturer. Typically though, the 6N2P is biased for 1mA in many circuits, which were designed for a 12AX7.
Using a 150 ohms resistor results in ~2.5mA, less than 400mW anode dissipation. Remember here every triode handles approximately half of B+, not B+. You are safe with 150 ohms.
Regards,
Jose
Hi Jose,
Thank you for taking the time to explain this. I can somewhat technically understand what you are saying. I can finally move forward with testing. Thanks again.
Thank you for taking the time to explain this. I can somewhat technically understand what you are saying. I can finally move forward with testing. Thanks again.