Thunderchief vs. Eighteen biasing phase split stage

Started by marino, February 28, 2005, 03:44:59 AM

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marino

Hello everyone!

I just wanna discuss a bit regarding phase split stage in circuits like thunderchief from Runoffgroove or meteor.  I can see that a lot of us, including me have difficulties biasing that stage and getting similar voltages at the specified JFET. I tried a bunch of J201s and BF245As and they are pretty much consistent in a way that they all perform wrong in a same way at this stage.
I get about 1-2 volts at gate, 2-3 volts at source and 4-6 volts at drain and many of us have this readings.
Lets look at the phase stage in Eighteen circuit. Its very much similar to thunderchief stage regarding biasing. Around 10K in the source.
How come that in Eighteen its biased with voltages similar to "wrong" voltages that many people get inThunderchief. Thats 1.6 at gate, 2.2 at source and 6.8 at drain?
I cant see how am i going to get 0; 0.5; 4.5 when even you guys at ROG that come up with great amp sim projects biased phase stage of Eighteen wrong? Or shoud I say wright?
I hope this doesnt sound too confusing. The point is that more or less same thing is biased in two different ways.

By the way, at ROG the best projects around, thats my opinion!

Marin