OTL Asylum OTL, Output Transformerless Amplifier User Group.

---

[ Follow Ups ] Thread: [ Display  All  Email ] [ OTL Asylum ]

---

[ Alert Moderator ]

---

Re: 6SL7 STRESS TEST CONCLUSION

Posted by Al Sekela (A) on May 30, 2002 at 13:30:42

In Reply to: Re: 6SL7 STRESS TEST CONCLUSION posted by Lew on May 30, 2002 at 13:09:43:

The CCS tube has its grid voltage fixed by the Zener diode stack. The bottom of its cathode resistor is at the negative rail. The difference between the CCS tube grid voltage and the negative rail, less the [positive in the case of 6SL7, negative in the case of 6SN7] grid-to-cathode bias required by the CCS tube to maintain the current, appears across the cathode resistor. The only influence the CCS tube has on its cathode current is through changes in the grid-to-cathode bias necessary to maintain the current. If the tube were to try to run away, all it could do is increase its cathode current very slightly by reducing the required grid-to-cathode bias. This would not change the cathode current by much, but would reduce the power input to the grid.

This is why I believe the CCS circuit is immune to thermal runaway from positive grid current in the CCS tube. Sorry to belabor this point if I've misunderstood your questions.

This post is made possible by the generous support of people like you and our sponsors:

Schiit Audio

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---