Parasound Halo JC 2 Circuit.

[ammel68]

I've seen quite a few favorable reviews of Mr. Curl's Halo JC 2 preamp, but I've not seen anything about the actual circuit itself, either here or anywhere else.

Does anyone, other than Mr. Curl (whom I'm sure isn't going to comment on one of his most successful designs) know anything about the JC 2's circuit, or with this being a current Parasound product does copyright and/or trademark infringements come into play?

Thanks...

 

[kamis]

JC-2 diagram

 

[ammel68]

Wow...thank you for the schematic!

 

[sreten]

Hi,

You can build it for personal use. You can't sell it commercially.

rgds, sreten.

 

[SY]

Why not, as long as you don't use the trademark? Is there something in the circuit that's covered by an unexpired patent?

 

[31697B]

It appears like there are errors in the schematic drawing. ??
Try to sim it first.

THx-RNMarsh

 

[john curl]

Yes, do as SY says: Why buy knowledge when you can copy it? '-)

 

[ammel68]

It appears like there are errors in the schematic drawing. ??
Try to sim it first.

THx-RNMarsh

There could be Mr. Marsh. Hopefully someone here will sim it.

I see several resistors with values that aren't labeled(???).

I'm still trying to figure out what a 2SK247 is.😕
From the schematic it appears to be one of those 2 matched jfets sealed up in one package like the 2SK389, but a Google search turns up some device made by Panasonic.
2SK247 Datasheet(PDF) - Panasonic Semiconductor

 

[SY]

Yes, do as SY says: Why buy knowledge when you can copy it? '-)

Apparently that was Voices-In-John's-Head-SY, rather than the actual one.

 

[kamis]

I think that J-fet is 2sk246 instead of 2sk247 which is complementary to 2sj103. Unlabeled resistors depends on the given idss value of actual J-fets and should be adjusted to give desired output current.

 

[john curl]

Thanks. It was a typo.