F5X -- the EUVL Approach

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#421
As I mentioned, this is a rare opportunity to have such a large batch of 2SJ74s to match from.
Spencer has already done the hard work for you. Now you have 160 pre-selected FETs.
I can only encourage you to do the 3-point measurement in post # 402 for even better match within each of the 4 groups.


Patrick
 
#426
NicMac said:
Have a look at the Relaixed2 pre-amp/attenuator. Really a great design. I have modified it so that one of the balanced inputs is used as line-out.
Cheers,
Nic
Click to expand...

I just bought this balanced input selector, volume controller and I'm trying a Borbely preamp the the UGS in it. The nice part is it saves a lot of time vs trying a full blown PIC or Amtel build.

I bought it through Taobao, it was about $140 USD. It comes built to your specs (I specified my resistors and display color - blue). PM for more details.
 

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#427
JBdV said:
Spencer has shipped 40 quads matched 70/74 fets to me.
They are grouped in 4 current ranges:


Group K170 J74
1 6.90 6.95 8.10 8.15
2 6.95 7.00 8.15 8.20
3 7.00 7.05 8.20 8.25
4 7.05 7.10 8.25 8.30

He also did a transconductance comparison within the K170 and the J74 groups.

These quads are most likely the best suitable parts he could provide based on his new batch of 2000 J74's for the F5X. (J74 is likely close to becoming obsolete)
K70 is still available in big quantities.

I am happy to offer these for cost to all F5X builders, that have already ordered the cases.
Click to expand...

I´m interested also.
 
#428
JBdV said:
Spencer has shipped 40 quads matched 70/74 fets to me.
They are grouped in 4 current ranges:


Group K170 J74
1 6.90 6.95 8.10 8.15
2 6.95 7.00 8.15 8.20
3 7.00 7.05 8.20 8.25
4 7.05 7.10 8.25 8.30

He also did a transconductance comparison within the K170 and the J74 groups.

These quads are most likely the best suitable parts he could provide based on his new batch of 2000 J74's for the F5X. (J74 is likely close to becoming obsolete)
K70 is still available in big quantities.

I am happy to offer these for cost to all F5X builders, that have already ordered the cases.
Click to expand...

I'm interested, many thanks
 
#430

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#432
JBdV said:
Group K170 J74
1 6.90 6.95 8.10 8.15
2 6.95 7.00 8.15 8.20
3 7.00 7.05 8.20 8.25
4 7.05 7.10 8.25 8.30

I am happy to offer these for cost to all F5X builders, that have already ordered the cases.
Click to expand...

Hi All
Is there a reason for choosing a specific group? There seems very close. How many groups do we need for this FX5? I am happy with any one of the group. How much are these and can it be ship along with any of the other GB? Thanks.
 
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#434
JBdV said:
Spencer has shipped 40 quads matched 70/74 fets to me.
They are grouped in 4 current ranges:


Group K170 J74
1 6.90 6.95 8.10 8.15
2 6.95 7.00 8.15 8.20
3 7.00 7.05 8.20 8.25
4 7.05 7.10 8.25 8.30

He also did a transconductance comparison within the K170 and the J74 groups.

These quads are most likely the best suitable parts he could provide based on his new batch of 2000 J74's for the F5X. (J74 is likely close to becoming obsolete)
K70 is still available in big quantitie
I am happy to offer these for cost to all F5X builders, that have already ordered the cases.[/QUOTE



Hi,
I am interested in a set FETs for a stereo F5X. Please count me in,
Vitali
Click to expand...
 
#435
JBdV said:
Spencer has shipped 40 quads matched 70/74 fets to me.
They are grouped in 4 current ranges:


Group K170 J74
1 6.90 6.95 8.10 8.15
2 6.95 7.00 8.15 8.20
3 7.00 7.05 8.20 8.25
4 7.05 7.10 8.25 8.30

He also did a transconductance comparison within the K170 and the J74 groups.

These quads are most likely the best suitable parts he could provide based on his new batch of 2000 J74's for the F5X. (J74 is likely close to becoming obsolete)
K70 is still available in big quantities.

I am happy to offer these for cost to all F5X builders, that have already ordered the cases.
Click to expand...
 
#438
OK Patrick, sorry for the m*** overhere, my PM box is also crowded ..

thanks Fred.

Please everybody sign up in the spreadsheet:

https://docs.google.com/spreadsheet/...xNdkE&hl=en_US

It will take some time before I can ship.Shipment from Spencer on its way.
I will start with 3 point testing of one group and report the results.
The F5X Case GB members get a higher priority. I hope you don't mind ...

Lets continue the discussion here:

http://www.diyaudio.com/forums/grou...al-other-group-buys-related-euvls-f5x-15.html

Jan
 
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