Group Buy for the Through Hole Folded Cascode CEN IV boards

[floyd89gr]

GB3 tentative list :

BRN 2 set boards, no mosfets
ZUM911 2 set boards, no mosfets
barryblue 2 sets boards, 2 sets mosfets
Johnny Canuck, 2 sets boards, no mosfets
BEYoung, 2 sets boards, ?? set mosfets
Hartbigsky, 1 set boards, ?? set mosfets
aljordan, 2 sets boards, 0 set mosfets
Intojazz 1 set boards, 1 set mosfets
floyd89gr 1 set boards, 1 set mosfets
Subbu K, 2 sets boards, no mosfets
manniraj 1 set boards, no mosfets
baswamin 1 set boards, 1 set mosfets
intojazz 1 set boards, 1 set mosfets
av-trouvaille, 1 set mosfets
luchoh 1 set boards, 1 set mosfets

 

[woodturner-fran]

Thanks guys, another bit of tidying up

GB3 tentative list :

BRN 2 set boards, no mosfets
ZUM911 2 set boards, no mosfets
barryblue 2 sets boards, 2 sets mosfets
Johnny Canuck, 2 sets boards, no mosfets
BEYoung, 2 sets boards, ?? set mosfets
Hartbigsky, 1 set boards, ?? set mosfets
aljordan, 2 sets boards, 0 set mosfets
floyd89gr 1 set boards, 1 set mosfets
Subbu K, 2 sets boards, no mosfets
manniraj 1 set boards, no mosfets
baswamin 1 set boards, 1 set mosfets
intojazz 2 set boards, 2 set mosfets
av-trouvaille, 1 set mosfets
luchoh 1 set boards, 1 set mosfets

 

[hartbigsky]

BRN 2 set boards, no mosfets
ZUM911 2 set boards, no mosfets
barryblue 2 sets boards, 2 sets mosfets
Johnny Canuck, 2 sets boards, no mosfets
BEYoung, 2 sets boards, ?? set mosfets
hartbigsky, 1 set boards, YES 1 set mosfets
aljordan, 2 sets boards, 0 set mosfets
floyd89gr 1 set boards, 1 set mosfets
Subbu K, 2 sets boards, no mosfets
manniraj 1 set boards, no mosfets
baswamin 1 set boards, 1 set mosfets
intojazz 2 set boards, 2 set mosfets
av-trouvaille, 1 set mosfets
luchoh 1 set boards, 1 set mosfets

yes for hartbigsky

 

[EUVL]

I counted 9 sets of MOSFETs, so we cannot go and buy 100 pieces of each type for matching.
It will mean a smaller pool to match from, and hence lower yield, which will jack up cost of matched sets.
Maybe by a factor of 2 if we order 50 pairs to get 9 sets.

Just to manage expectations.
If RickRay can supply you all with what he has on hand, maybe he should.
Fran has none left from the last batch, as far as I know.

Shall wait a couple of weeks before ordering MOSFETs, just on case.


Patrick

 

[jimk04]

I have about 30 measured N channel if they are of any use.

 

[EUVL]

No use without P Channel.


Patrick

 

[jimk04]

It saves you buying N channel surely. But they'll just sit here if not wanted.

 

[EUVL]

Fran will decide what to do with the 9 sets.


Patrick

 

[NORTH4]

sign me up for 1 and 1

BRN 2 set boards, no mosfets
ZUM911 2 set boards, no mosfets
barryblue 2 sets boards, 2 sets mosfets
Johnny Canuck, 2 sets boards, no mosfets
BEYoung, 2 sets boards, ?? set mosfets
hartbigsky, 1 set boards, YES 1 set mosfets
aljordan, 2 sets boards, 0 set mosfets
floyd89gr 1 set boards, 1 set mosfets
Subbu K, 2 sets boards, no mosfets
manniraj 1 set boards, no mosfets
baswamin 1 set boards, 1 set mosfets
intojazz 2 set boards, 2 set mosfets
av-trouvaille, 1 set mosfets
luchoh 1 set boards, 1 set mosfets
NORTH4, 1 set board, 1 set mosfets

 

[leejh]

BRN 2 set boards, no mosfets
ZUM911 2 set boards, no mosfets
barryblue 2 sets boards, 2 sets mosfets
Johnny Canuck, 2 sets boards, no mosfets
BEYoung, 2 sets boards, ?? set mosfets
hartbigsky, 1 set boards, YES 1 set mosfets
aljordan, 2 sets boards, 0 set mosfets
floyd89gr 1 set boards, 1 set mosfets
Subbu K, 2 sets boards, no mosfets
manniraj 1 set boards, no mosfets
baswamin 1 set boards, 1 set mosfets
intojazz 2 set boards, 2 set mosfets
av-trouvaille, 1 set mosfets
luchoh 1 set boards, 1 set mosfets
NORTH4, 1 set board, 1 set mosfets
leejh, 2 sets boards, no mosfets

 

[hartbigsky]

[2SK170BL and 2SJ74BL which are available from the diyaudio store. For each channel you will need 2 matched 2SK170 and one matched pair of 2SK170/2SJ74 (for example, one N-channel quad and one NP-quad from the store for a stereo pair @$80-90 plus shipping)]

Are these parts the ones in question? 6-11ma are listed as available. I have a few I would need to match I think I purchased as matched pairs for building basic CEN/SEN I/V which I think this product developed from. I buy a few every now and then to have on hand as I have several Pass components that use them.
How closely do they need to be matched?

regards,
Steve

 

[woodturner-fran]

The short answer here is the closer the better! If you take the diyaudio store as a guide, then match within 0.1mA.

If you get the choice, I would aim for ones ~7-8mA rather than 11 or 12mA

 

[EUVL]

Any mismatch between NJFET and PJFET at the input will result in input DC offset as seen by the DAC i_out.
This cannot be trimmed.

Any mismatch between the two NJFETs at the output will result in output DC offset.
This can be trimmed together with the rest of the circuit, as a whole.


Patrick

 

[hartbigsky]

OK thanks! I would still purchase matched with boards if it works out.

regards,
Steve

 

[woodturner-fran]

Its been a while since I posted and I wanted to give a short update on where we are at with GB3.

I am waiting on board supplier to get back up running after new year celebrations. We have mosfets and R1-R4 sorted for all who have expressed interest. So in about 2-3 weeks I would think paypal invoices will go out, and shipping pretty quickly after that.

Its taken a bit of time to get this up and running, but we are getting closer now....

 

[BRN]

fran,

Thank you for the update and putting this together. Looking forward to trying these boards.

 

[BEYoung]

BRN 2 set boards, no mosfets
ZUM911 2 set boards, no mosfets
barryblue 2 sets boards, 2 sets mosfets
Johnny Canuck, 2 sets boards, no mosfets
BEYoung, 2 sets boards, [mosfets not needed assuming one set RickRay mosfets maps to one set of PCBs]
hartbigsky, 1 set boards, YES 1 set mosfets
aljordan, 2 sets boards, 0 set mosfets
floyd89gr 1 set boards, 1 set mosfets
Subbu K, 2 sets boards, no mosfets
manniraj 1 set boards, no mosfets
baswamin 1 set boards, 1 set mosfets
intojazz 2 set boards, 2 set mosfets
av-trouvaille, 1 set mosfets
luchoh 1 set boards, 1 set mosfets
NORTH4, 1 set board, 1 set mosfets
leejh, 2 sets boards, no mosfets

 

[woodturner-fran]

Thanks everyone - GB3 is now closed. Work is continuing in the background, and I will be back soon as we get through the admin work.

 

[woodturner-fran]

Just a short update - boards are on the way from the manufacturer......

 

[woodturner-fran]

Update:

PCBs have arrived, and I expect mosfets to be here around the middle of next week. So feel free to send on your paypal email, postal address and after everything arrives, I'll start sending paypal requests. If all goes well, I would hope to be starting to post out from 18th onwards.