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GB "long and skinny" FirstWatt J2 clone PCBs

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M

mattattnet

Member
Joined 2004
Adding a second pair

Hi,

Friend wants a pair, too, please add a second pair of boards to my buy request.

Matt
North America & RoW
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Malvin 1 set
kevinheem 1 set
Soundslave 2 set
mattattnet 1 set
Myint67 1set
twitchie 1 set
flamethrower1 1 set
necplusultra 1 set
vvs07 2 sets
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



EU
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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


Unknown
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RustySanwa 2 sets
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D

Dennis Hui

Member
Joined 2002
Paid Member
North America & RoW
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Malvin 1 set
kevinheem 1 set
Soundslave 2 set
mattattnet 2 sets
Myint67 1set
twitchie 1 set
flamethrower1 1 set
necplusultra 1 set
vvs07 2 sets
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



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


Unknown
------------
RustySanwa 2 sets
 
S

soundslave

Member
Joined 2010
North America & RoW
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Malvin 1 set
kevinheem 1 set
Soundslave 1 set
mattattnet 2 sets
Myint67 1set
twitchie 1 set
flamethrower1 1 set
necplusultra 1 set
vvs07 2 sets
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



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


Unknown
------------
RustySanwa 2 sets

Somehow my request for 1 set was changed to 2
 
V

vvs07

Member
Joined 2011
Paid Member
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



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


Unknown
------------
RustySanwa 2 sets


----

I removed myself from the list. Will be building the Babelfish version.

Thank you, Jeff!
 
N

nashbap

Member
Joined 2012
JeffYoung said:
The J2 (by my reckoning) needs 2SK170GR, rather than BL.

Still, that's a great price from AmpsLab. I ordered 20... I think I see a Wayne's BA2018 line stage in my future....
Click to expand...


If you have received your order just wondering whether you have measured the Idss of them. Are they clustered around a certain Idss or all over the place? Thinking of ordering so I ask.
Thanks. nash
 
JeffYoung

JeffYoung

Member
Joined 2017
@nashbap, I have received them although I haven't measured them yet. I'll put that on today's TODO list....

hifibluedevil sent me pics of his K170s, and there's no doubt they're BL. You could get to the stated 8ma - 12mA range with a pair of them at the very bottom of the range, but only just. I'm not sure what to do with this data....
 
G

gary s

Member
Joined 2002
I ordered 20 of the Toshiba 2SK170GR grade and after testing I got 5 selected pairs to give a total Idss of 8.49mA to 8.69mA to feed the 2SJ109BL LTP. They measured individually from around 3.4 to 5.00 mA, the other 10 all measured over 5.5mA each, so adding 2 together gives an LTP current of over 11 mA. So in general they tested at the higher end of the 2.6mA to 6.5mA GR grade ranking.
 
Last edited:
JeffYoung

JeffYoung

Member
Joined 2017
My 170BLs (from AmpsLab) all tested in the lower half of the BL range (6mA - 12mA):

5.9
6.1
6.4
6.5 6.5
6.6
6.7 6.7
6.9
7.0 7.0
7.2
7.9 7.9
8.0
8.2
8.5
8.6 8.6
8.8

Gary, did you have any at the very top end (6.4/6.5)? I'd be happy to trade a couple of 5.9/6.0/6.1 for a couple of 6.4/6.5 (in either direction).

Cheers,
Jeff.
 
G

gary s

Member
Joined 2002
I totally agree Jeff, based on their rarity now and the price one has to pay. When I got the last ones from B&D Ent, they showed 40 in stock, but when I placed my order for all 40, they came back and said there were only actually 21 left in the bin - so I got all of those. Maybe if they had the 40 then more of a chance to get a better spread, and more matched pairs as required by some circuits or in the case of the J2 current source, selected pairs to give the 8.5mA LTP current total.

Maybe you can also use one off BL grade in the J2 CCS position that measures close to the design 8.5mA LTP Idss current - what do you think? Not sure why NP used two 2SK170 in that position, unless of course he has dropped a clue somewhere about that.
 
JeffYoung

JeffYoung

Member
Joined 2017
He he... sounds like B&D hadn't updated their stock count from the ones I bought. ;)

I have also wondered about using a single JFET. Using a pair I think slightly reduces noise, but the question then becomes is that reduction worth more or less than not being in the sweet spot current-wise?
 
A

AMB4

Member
Joined 2017
Hello
please add me to the buy. i would like 1 set
thanks

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


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


Unknown
------------
RustySanwa 2 sets
 
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