And this list for the Buffer board and Parts
emyeuoi (x1)
PET-240 x1 + 1 set JFETS + 1 set Susumu
Myint67x1
Juancho x2
Stijn001 x1
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
PCB= 17
Parts= 6
emyeuoi (x1)
PET-240 x1 + 1 set JFETS + 1 set Susumu
Myint67x1
Juancho x2
Stijn001 x1
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
PCB= 17
Parts= 6
Mk57, I don't see your name in the GB for the buffer. Which JFETs you are referring to? The only JFETS that are available from carlsor are the ones relevant to the buffer circuit.
Regards,
Enrico
And this list for the Buffer board and Parts
emyeuoi (x1)
PET-240 x1 + 1 set JFETS + 1 set Susumu
Myint67x1
Juancho x2
Stijn001 x1 + 1 set JFETS + 1 set Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
PCB= 18
Parts= 7
emyeuoi (x1)
PET-240 x1 + 1 set JFETS + 1 set Susumu
Myint67x1
Juancho x2
Stijn001 x1 + 1 set JFETS + 1 set Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
PCB= 18
Parts= 7
And this list for the Buffer board and Parts
emyeuoi (x1)
PET-240 x1 + 1 set JFETS + 1 set Susumu
Myint67x1
Juancho x2
Stijn001 x1 + 1 set JFETS + 1 set Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
PCB= 18
Parts= 7
JanGr. (x1)
emyeuoi (x1)
PET-240 x1 + 1 set JFETS + 1 set Susumu
Myint67x1
Juancho x2
Stijn001 x1 + 1 set JFETS + 1 set Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
PCB= 18
Parts= 7
JanGr. (x1)
emyeuoi (x1)
PET-240 x2 + 2 set JFETS + 2 set Susumu
Myint67x1
Juancho x2
Stijn001 x1 + 1 set JFETS + 1 set Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
JanGr. (x1)
PCB= 19
Parts= 8
PET-240 x2 + 2 set JFETS + 2 set Susumu
Myint67x1
Juancho x2
Stijn001 x1 + 1 set JFETS + 1 set Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
JanGr. (x1)
PCB= 19
Parts= 8
Multiple DAC Board CCS Adjustment Idea
I just thought of another way to deal with the problem of adjusting each CCS circuit board current for multiple stacked DAC boards that need to be tied together to one set of Rload resistors on the Main Board.
In order to install CCS circuit boards the multiple DAC stacks need to be taken apart anyway. I suggest installing four cheap 1% 133 ohm resisters on each DAC board as follows for both the left and right sides:
A-pos/B-neg to Rload Common
A-neg/B-pos to Rload Common
A DAC board would be added to the stack one at a time. All vertical connection wires would be soldered to each DAC board except for the A, B and Rload Common points which would remain isolated to each DAC board with the 133 ohm resistors. Power up the DAC and adjust the CCS trimmer pot to get 2.7V across each of the 133 ohm resistors.
After the top DAC board is installed and its CCS trimmer pots adjusted, the 133 ohm resistors would be removed and the vertical connection wires be installed through all the A, B and Rload Common points down to the Main Board.
I just thought of another way to deal with the problem of adjusting each CCS circuit board current for multiple stacked DAC boards that need to be tied together to one set of Rload resistors on the Main Board.
In order to install CCS circuit boards the multiple DAC stacks need to be taken apart anyway. I suggest installing four cheap 1% 133 ohm resisters on each DAC board as follows for both the left and right sides:
A-pos/B-neg to Rload Common
A-neg/B-pos to Rload Common
A DAC board would be added to the stack one at a time. All vertical connection wires would be soldered to each DAC board except for the A, B and Rload Common points which would remain isolated to each DAC board with the 133 ohm resistors. Power up the DAC and adjust the CCS trimmer pot to get 2.7V across each of the 133 ohm resistors.
After the top DAC board is installed and its CCS trimmer pots adjusted, the 133 ohm resistors would be removed and the vertical connection wires be installed through all the A, B and Rload Common points down to the Main Board.
CCS JFETS
As long as I am testing and matching BF862 JFETs for the Buffer it would be little extra trouble to test 2SK208"O" JFETs to determine what resistor value is needed to operate at 0.40ma from a 2.4V voltage source. I can then recommend what fixed value resistor and trimmer pot that would work for each set of 2SK208's.
I recommend a set of three (3) 2SK208s for each pair of CCS boards in case one gets destroyed or pops out of the mounting tweezers never to be seen again. I would charge $4 for each set of three that are shipped with Buffer SMD components. If I happen to have the desired SMD resistor in my parts supply, I can make them available for $0.50ea. For orders without the Buffer parts, shipping by envelope should be only $3-4 for most destinations around Europe. Just add "parts" to your entry in the CCS GB list if desired.
Mouser no longer stocks the 2SK208"O" JFETs, but Digikey has over 13,000 of these in stock.
As long as I am testing and matching BF862 JFETs for the Buffer it would be little extra trouble to test 2SK208"O" JFETs to determine what resistor value is needed to operate at 0.40ma from a 2.4V voltage source. I can then recommend what fixed value resistor and trimmer pot that would work for each set of 2SK208's.
I recommend a set of three (3) 2SK208s for each pair of CCS boards in case one gets destroyed or pops out of the mounting tweezers never to be seen again. I would charge $4 for each set of three that are shipped with Buffer SMD components. If I happen to have the desired SMD resistor in my parts supply, I can make them available for $0.50ea. For orders without the Buffer parts, shipping by envelope should be only $3-4 for most destinations around Europe. Just add "parts" to your entry in the CCS GB list if desired.
Mouser no longer stocks the 2SK208"O" JFETs, but Digikey has over 13,000 of these in stock.
emyeuoi (x1)
PET-240 x2 + 2 set JFETS + 2 set Susumu
Myint67x1
Juancho x2
Stijn001 x1 + 1 set JFETS + 1 set Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
JanGr. (x1)
ed linssen x1 + set JFETS + 1 set Susumu
PCB= 20
Parts= 9
PET-240 x2 + 2 set JFETS + 2 set Susumu
Myint67x1
Juancho x2
Stijn001 x1 + 1 set JFETS + 1 set Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
JanGr. (x1)
ed linssen x1 + set JFETS + 1 set Susumu
PCB= 20
Parts= 9
CCS
Hi Carlsor,
Why not replace the trimmer AND fix resistor together after having determined the replacement value for one single resistor?
Besides, a good placement for the litlle CCS board could be underneath the boards, on the 6K spot? What do you think?
regards,
Ed
Hi Carlsor,
Why not replace the trimmer AND fix resistor together after having determined the replacement value for one single resistor?
Besides, a good placement for the litlle CCS board could be underneath the boards, on the 6K spot? What do you think?
regards,
Ed
Last edited:
CCS Questions
Ed,
The trimmer pot and fixed resistor can be replaced with the exact resistance needed after the adjustment to 2.7V RLoad voltage is made. It is much easier to find two resistors in series that add up to a desired resistance than to find one resistor that matches from the limited choices available. I wouldn't deviate more than 1 ohm from the "exact" resistance needed. There shouldn't be any loss in sq from using 2 Susumu RG resistors in series instead of one.
The CCS mini-board would work just as well mounted under the DAC board at the 6K location. It would be harder to adjust or remove in this location for a single DAC board setup. It may be easier to adjust for multiple DAC setups.
Ed,
The trimmer pot and fixed resistor can be replaced with the exact resistance needed after the adjustment to 2.7V RLoad voltage is made. It is much easier to find two resistors in series that add up to a desired resistance than to find one resistor that matches from the limited choices available. I wouldn't deviate more than 1 ohm from the "exact" resistance needed. There shouldn't be any loss in sq from using 2 Susumu RG resistors in series instead of one.
The CCS mini-board would work just as well mounted under the DAC board at the 6K location. It would be harder to adjust or remove in this location for a single DAC board setup. It may be easier to adjust for multiple DAC setups.
emyeuoi (x1)
PET-240 x2 + 2 set JFETS + 2 set Susumu
Myint67x1
Juancho x2 + 2 sets JFETS + 2 sets Susumu
Stijn001 x1 + 1 set JFETS + 1 set Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
JanGr. (x1)
ed linssen x1 + 1set JFETS + 1 set Susumu
PCB= 20
Parts= 11
PET-240 x2 + 2 set JFETS + 2 set Susumu
Myint67x1
Juancho x2 + 2 sets JFETS + 2 sets Susumu
Stijn001 x1 + 1 set JFETS + 1 set Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x2
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x1
SimonJ x1 + 1 set JFETS + 1 set Susumu
JanGr. (x1)
ed linssen x1 + 1set JFETS + 1 set Susumu
PCB= 20
Parts= 11