11-04-2016 Post does not mapped to Knowledge Tree lampes Posts 3 Joined on 11-05-2016 Post #: 26 Post ID: 22832 Reply to: 21587 6e5p SRPP bias fiogf49gjkf0d Hi to everyone years of reading but never subscribe and post to forum I see that Zarathustra circuit and i m very interested on the first SRPP stage Can someone point out how to implement Melq Gas Bias on that SRPP circuit? I would like to implement a line lever preamp with low output impedance use that tube Thanks in advance Thanos

11-15-2016 Post does not mapped to Knowledge Tree shannon Posts 23 Joined on 08-08-2014 Post #: 27 Post ID: 22849 Reply to: 22832 Not really possible fiogf49gjkf0d thee srp in Zarathustra is cathode bias, melq is grid bias.  If gas biased the srpp it would no longer be the circuit in zarathustra. what would this do to sound i have no idea.  The function of the gas tubes in melq are not only for providing bias.  Most importantly they absorb garbage and shape the sound. They need to be in the location and circuit to do what they do. But if you wanted to do what you are thinking.  The back to back reveresed gas tubes output  the few volts of bias needed. so say one is 149v one 151v you get 2 volts.  so the 270ohm cathode resistor in zarithustra would be some how replaced with that few volts.  Not sure if this is possible or correct I never experimented with srpp.  I'm sure someone on that russian forum could tell you exactly how to do it. they may have already did it. Why not try ,did myself, single ended gassed 6e5p like in melq for preamp.  It can work but nothing interesting to me.

11-17-2016 Post does not mapped to Knowledge Tree lampes Posts 3 Joined on 11-05-2016 Post #: 28 Post ID: 22852 Reply to: 22849 Gas Bias SRPP 6e5p fiogf49gjkf0d Hi Shannon I think that Romy have it already on his pre-assembled Zarathustra on this topic's pictures: http://www.goodsoundclub.com/Forums/ShowPost.aspx?PageIndex=1&postID=4121#4121 and also here: on post #8 http://www.goodsoundclub.com/Forums/ShowPost.aspx?PageIndex=1&postID=1029#1029 As you see there are two 6e5p and two Reg tubes on the circuits If Romy likes to share will be good Thanks

11-17-2016 Post does not mapped to Knowledge Tree shannon Posts 23 Joined on 08-08-2014 Post #: 29 Post ID: 22853 Reply to: 22852 Yes fiogf49gjkf0d I Forgot they did this.  I only have experience with se driver stage. You would remove r3 and c1. change r2 to 10k and put the bias voltage from the gas tubes across it.  I would try just regualar zaruthstra srpp circuit first.  Like do you know it will benifit your playback?  Dima said difference from regular to gassed is small. It is lot's of expensive parts to experiment.  Unless you have the transformers and chokes and sockets and high power resistors and gas tubes all just sitting there.

11-24-2016 Post does not mapped to Knowledge Tree lampes Posts 3 Joined on 11-05-2016 Post #: 30 Post ID: 22864 Reply to: 22853 Gas Bias SRPP fiogf49gjkf0d Hi Shannon and thanks for the answer I guess i have to try it when i m able to build it Regards Tom