GB "long and skinny" FirstWatt J2 clone PCBs

[hifibluedevil]

we can't really know for sure, my J2 was a demo unit so it is possible it is an earlier model where Papa might have used single all BL grade jfets then switched to dual jfets?

 

[Dennis Hui]

Quick update: boards have been ordered.

 

[nashbap]

Hi Jeff,
Can you post a FFT plot of your build?
Thanks. nash

 

[JeffYoung]

Hi Nash,

Here's an FFT from my SPICE simulation. How accurate it is I haven't a clue: I haven't yet tried to figure out how to generate one from the physical article.

Cheers,
Jeff.

 

[carsten.witt]

Hi all,

i have used a small time window and have already written to the EU members, cartons are ordered.

 

[yoaudio]

we can't really know for sure, my J2 was a demo unit so it is possible it is an earlier model where Papa might have used single all BL grade jfets then switched to dual jfets?

Here is my J2, serial number 39XX.

 

[Dr_Strangelove]

I would think this is a later model. Early review pictures clearly showed sj109 style packages on the pcb. And from the moment the J2 went into production, the manual stated it used 2sj109s.

 

[nashbap]

Two 170BL and four 74BL per channel. Thanks for sharing yoaudio.
nash

 

[JeffYoung]

Curiouser and curiouser. Anyone have a close-up picture of one with 2SJ109s?

 

[yoaudio]

Here's one from the net, looks like on the left he used 2- j74's and one 2SJ109. Also 2 170's out of the 3 spaces on the pcb filled.

 

[hifibluedevil]

My serial # is 50xx so it is a later model as well. That implies (but can't be sure) Papa ran out of 109s and used the 74s. The curious thing is that 170s are also BL grade instead being GR grade.

 

[yoaudio]

Another one clearly shown 2- 2SJ109's and 3- 170's

 

[yoaudio]

Mine was a demo from Reno Hifi also.
Great customer service!!!!!!

 

[Dr_Strangelove]

Naah, I don’t think Papa ran out of 109’s. Have you seen his droolworthy stash on youtube?

Just speculation. I think he used the 109’s in the beginning just because he could. The J2 was a huge succes and stayed in production much longer as other amps. As years went by scarcity en prices went up. The advantages of using 109’s instead of good matched 74’s are minimal. So somewhere along the road he decided to switch to 74’s as they are almost just as good in this amp. Saving his stash of precious 109’s for whatever he is cooking up. Again, just speculation.

 

[yoaudio]

My J2 - J74 board, you can not use a 2SJ109's unless you don't use pin 4. No spot on the pcb to solder it on there. He had a few different versions of this pcb, some with 2 170's some with 3 170's.

 

[RustySanwa]

Updating with my location:


North America & RoW
------------
Malvin 1 set
kevinheem 1 set
Soundslave 1 set
mattattnet 2 sets
Myint67 1set
twitchie 1 set
flamethrower1 1 set
necplusultra 1 set
WBS ???
Scott Stansbury - 1 set
nashbap 1set
mlwebb 1 set
Gnub 2 sets
Feds27 1 set (see page 21)
bologna1 1 set
leejh 1 set
AMB4 1 set
thompsontechs 2 sets
RustySanwa 2 sets



EU
------------
pfisla 2 sets
gig 1 set
Dr.Strangelove3 1 set
malisz ???
dieter12 2 sets
pistollero - 2 set
Spades 1 set
Rodeodave 1 set
MEPER 2 sets
iBuell 1 set

 

[Dennis Hui]

Pcbs have been shipped by the board house.

 

[PKI]

Hey guys any chance I can get a stereo set? thanks!

 

[thompsontechs]

Thanks for the update Dennis.

 

[mattattnet]

boards

thanks, Dennis