SIT-3

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
The one and only
Joined 2001
Paid Member
Just a tad under 1 cu ft. Mario Yrun made them.

:cheers:
 

Attachments

  • DSC00318.jpg
    DSC00318.jpg
    415.4 KB · Views: 498
While contemplating the simplified diagram of the circuit in the SIT 3 Owners Manual, it made me wonder if it would be possible to adapt the concept to accommodate all of the left over Sony 2SJ28 VFETs out there.

I realize we are talking VFET and not SIT, but would it be possible to find an N channel Mosfet whose Gate voltage is the mirror image of the 2SJ28 and then reverse the voltage to accomplish a similar result?

I'm sure I'm showing my utter ignorance of circuits, but I thought I'd ask anyway. :eek:
 
Member
Joined 2000
Paid Member
VFET and SIT are the same.
http://www.firstwatt.com/pdf/art_sit_intro.pdf

The problem is finding pairs of mosfets and vfets with matching Vgs, like you said.
It's been shown before that reversing the polarity in the circuit when using a P-ch device works. But in this case, wouldn't it be a positive supply? The SIT-3 uses a negative supply. Let me check...it does. Shows it right in the SIT-3 manual.
 
Official Court Jester
Joined 2003
Paid Member
VFET and SIT are the same.
http://www.firstwatt.com/pdf/art_sit_intro.pdf

The problem is finding pairs of mosfets and vfets with matching Vgs, like you said.
It's been shown before that reversing the polarity in the circuit when using a P-ch device works. But in this case, wouldn't it be a positive supply? The SIT-3 uses a negative supply. Let me check...it does. Shows it right in the SIT-3 manual.

ground is state of mind

SIT-3 uses positive supply , but mind is easily fooled (which I'm confirming several times per day)

:clown:
 
Member
Joined 2000
Paid Member
If the lid of the SIT-3 is vented, then yes. Think I read- at least 3" clearance between components.
Surprising amount of heat is generated inside Class A amps; not just from the heat sinks. Heat from the SIT-3 could also heat up the chassis of the HP1.

Good looking couple though. Congrats on the marriage of the two! :)
 
Last edited:
While contemplating the simplified diagram of the circuit in the SIT 3 Owners Manual, it made me wonder if it would be possible to adapt the concept to accommodate all of the leftover Sony 2SJ28 VFETs out there.

I realize we are talking VFET and not SIT, but would it be possible to find an N channel Mosfet whose Gate voltage is the mirror image of the 2SJ28 and then reverse the voltage to accomplish a similar result?

I'm sure I'm showing my utter ignorance of circuits, but I thought I'd ask anyway. :eek:

Hi WBS, that is what I plan to do in the future. I have some quantity of 2SK28s. We can parallel two 2SJ28s. :):)
I am not so knowledged but I think 2SJ28 + IRF240 will do the same work as 2SK82 + IRF9240. If not someone please correct me.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.