CC-CCS-X-BZLS: It's alive!

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Well i have some pictures of my 90% finished pre-amp has taken a long time to get this far but it powers up and no smoke. Just needs the inputs/outputs installed and then wiring for the digital pot.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.
 
I know that with the Loveltech JFETs you could make
the small power amp, but wondered about noise level?
Would a more conventional JFETs such as 2SK170's
be quiter for line stage only use?
Or how about several paralled 2SK170's? Would you need
individual coscodes for each device or a single large
MOSFET or Bipolar?
 
Although I love my creation, it can, and has been, bettered. It could be modified to work with the Lovoltech power JFET's, but your idea about moving to cascoded 2SK170's is the better approach. I suggest you look at the "Pumpkin" thread by Zen Mod, who has followed that exact design approach.

Cheers, Terry
 
I don't think the Pumpkin would be what I want to do either,
Terry. It looks like the JFETs are used for voltage gain only
and then passes through MOSFETs anyway for current gain.
I was just thinking of a whole bunch of 2SK170BL or similar
in place of your Q1-Q2. Like 2 or 4 paralelled in each Q1 and
Q2 position. Would that give me sufficient output current
capability? Would I need separate coscodes for each or would
a single coscode per side handle 4 or so JFETs in those Q1, Q2
positions?
 
I was just thinking of a whole bunch of 2SK170BL or similarin place of your Q1-Q2. Like 2 or 4 paralelled in each Q1 and
Q2 position. Would that give me sufficient output current
capability?

You really don't need all the current capability, especially if you are using CC-jfets-X. You don't even need CCS for it to sound really, really good. (I listened to it for a long time with and without CCS).

Gain is another thing, but I think a single 2sk170 has plenty of gain for this app.

If you have a 10mA Idss jfets, just set your total current to 18mA or so and you are good.

JJ
 
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