Just another note,
Ordering 2SK369BL as a pair AND a quad is unnecessary.
If you want to go into pair only mode, simply put S5 in the off position.
Although the first run kits will have collett pins to remove the jfet, it really is not needed to pull out, or replace with another set of JFETs.
aljorden and myself has simply left the jfet in and turned S5 off without any problems.
If I have billed you for both, let me know, and if you understand this - will refund for the pairs.
More on sensitivity settings
Salas Post on switches and stuff in other thread.
Ordering 2SK369BL as a pair AND a quad is unnecessary.
If you want to go into pair only mode, simply put S5 in the off position.
Although the first run kits will have collett pins to remove the jfet, it really is not needed to pull out, or replace with another set of JFETs.
aljorden and myself has simply left the jfet in and turned S5 off without any problems.
If I have billed you for both, let me know, and if you understand this - will refund for the pairs.
More on sensitivity settings
Salas Post on switches and stuff in other thread.
Sorry — one more question. I have a quad of LSK170B at 9.5ma and another pair at 10.2. As long as I’m following the resistor adjustment recommendations for R8/R11 in the BOM, these values should work for a standard build? Just squaring this with the build guide, which still reflects recommendation for Q4 and Q5 under 9ma.
Thanks!
Thanks!
I have done further measurements and listening with Salas guidance of using Jfets outside the original scope of build guide.
I was able to use a test setup of board and able to alter settings settings with R8, R11 to get the appropriate voltage to the JFETS under wider ranges of IDSS.
I have been selling JFETs this way for kits for a number of years without issue or complaint.
Further, I have been able to use 2SK369BL in pair mode with IDSS over 15.5ma without any problems or notable listening issues.
I have used the LSK's in this circuit before as well, and in Q4 sounded particularly notable.
It's no dig on Salas, but I have had to modify values before merely because Salas doesn't run across as many JFETS or parts as I do, as he is running with what he has on hand during initial prototype tests. Sometimes the manufacturers standard variance sits outside of those initial tests.
My recommendation would be Q5 be 9.5ma pair and Q6 10.2 pair, and Q4 ok with either, but probably 9.5ma better.
To correctly use different enough K170 IDSS than noted in any NJFET Riaa thread's example schematic, unfortunately means special preparation trouble*. I prototype with frequent midway IDSS in my stash. That's to help sample chances for others. I have 200 Toshibas no more. When someone picks over and over for a particular narrow bracket of IDSS it's going to eventually deplete though.
*Breadboard the whole section from R7 and beyond. Including R7 but not C4. Substitute R8 with a hundred Ohm rheostat and R11 with a 5k rheostat. B+ should be 34V. Then adjust them rheostats to drop 25V across R10 and 14V across R11. Measure the trim values and use resistors closest to those values in the final assembly along with the same Q4 Q5 Q6 in same positions. Q5 Q6 shouldn't differ more than 1mA between them in the first place, always using the stronger of the two as Q6. All three should not differ to the other channel's K170s.
Q1 Q2 have an IDSS/Rs (R2 R3) look up table of recommendations in the FSP guide and they will work for MC. Beyond 12.5mA IDSS you got to make sure you can still find T.P 4V when with the example R19 R20 values and a logical B+ range for HMC and MM in UFSP.
For someone who bought the previous version, mini kit, fets, and resistors and hasn’t gotten around to collecting the rest of the parts. Getting the mini kit seems like I would be duplicating about half the parts. May just get the updated board if all the parts for the power supply portion of the board are available at Mouser or Digikey. Seems like getting this updated board will work better than trying to use an Ultrabib with the old board.
There are a few things that are not. Private message me and I can discuss that.
No, not sold out. They are not even manufactured yet in quantity. I fixed this. Keep in mind you are are all powerful in editing, proceed with caution.
From original, Q7 and Q3 are different semiconductors, and a few changes in that area. Salas maybe able to explain better.
Newer Schematic Link
Hello, I am following the older thread and this one. I will build this project. But I need your help. I am going crazy...
I have to buy:
1) UFSP Phono pair PCB
2) RAW PSU pcb
If I want also the component, I can add:
1) Big Kit (for UFSP)
2) Raw Kit (for raw pcb)
Then I have to add:
1) 2SK369BL Resistors
2) 2SK170BL
How I have to choose this component? I am using at95e Dual Magnet Cartridge. Thank you
PS: I am sorry for my english, but it's not my native language, and I am doing the best that I can.
I have to buy:
1) UFSP Phono pair PCB
2) RAW PSU pcb
If I want also the component, I can add:
1) Big Kit (for UFSP)
2) Raw Kit (for raw pcb)
Then I have to add:
1) 2SK369BL Resistors
2) 2SK170BL
How I have to choose this component? I am using at95e Dual Magnet Cartridge. Thank you
PS: I am sorry for my english, but it's not my native language, and I am doing the best that I can.
Salas & Tea-Bag:
A couple of questions:
First, I'm clearly getting ahead of myself here, but would it be a mistake in a two-chassis build to include the 1.3s sections with the RAW pcb in a power supply box and leave just the main FSP boards in the phono preamp chassis? Salas seemed to suggest otherwise and I was curious as to why.
Second, I have no real idea how to select C3 and C4, other than by reference to Tony Gee's loudspeaker crossover capacitor test reviews (Humble Homemade Hifi - Cap Test). Is it fair to say that a film capacitor will perform similarly in both a loudspeaker and a phono preamp? If not, can you suggest the qualities that one should look for in film caps for the C3 and C4 positions?
Thank you, by the way, for your generosity with this project!
Regards,
Scott
A couple of questions:
First, I'm clearly getting ahead of myself here, but would it be a mistake in a two-chassis build to include the 1.3s sections with the RAW pcb in a power supply box and leave just the main FSP boards in the phono preamp chassis? Salas seemed to suggest otherwise and I was curious as to why.
Second, I have no real idea how to select C3 and C4, other than by reference to Tony Gee's loudspeaker crossover capacitor test reviews (Humble Homemade Hifi - Cap Test). Is it fair to say that a film capacitor will perform similarly in both a loudspeaker and a phono preamp? If not, can you suggest the qualities that one should look for in film caps for the C3 and C4 positions?
Thank you, by the way, for your generosity with this project!
Regards,
Scott
Hello, I am following the older thread and this one. I will build this project. But I need your help. I am going crazy...
I have to buy:
1) UFSP Phono pair PCB
2) RAW PSU pcb
If I want also the component, I can add:
1) Big Kit (for UFSP)
2) Raw Kit (for raw pcb)
Then I have to add:
1) 2SK369BL Resistors
2) 2SK170BL
How I have to choose this component? I am using at95e Dual Magnet Cartridge. Thank you
PS: I am sorry for my english, but it's not my native language, and I am doing the best that I can.
Yes, you have it right. You could chose the minikit instead of big kit to get the essentials, and order the rest of small parts for board yourself.
The cart you have is moving magnet, 4.0mv gain. It will do fine with 2SK369PR. If you ever wanted to move to low-output moving coil, you could use a quad, and then 'turn off' one of the 2SK369BL by the switch bank. But most pairs (not quads), support most cart gains down to .5mv. I have even used 56db position with .3mv MC with a pre-amp with decent gain.
Ask questions about kit, this is good for thread to flesh it all out.
I will defer to Salas on the chassis question. I am under the impression that the PS 1.3 should be reasonably close to the signal boards. But maybe one could go bezerk and built a three chassis solution. In the previous design, some people built even MC in one chassis, with some good practices and shielding I believe.
On the cap side, I have listened to the CSA and CMR. The CMR clearly outshines the CSA, but mostly in tone. It's soundstaging is remarkably good. The CMR sounds a little less electronic to my ears. Of course, this comes at a price.
I have ordered the Mundorf EVO oil, Supreme EVO, Supreme EVO Oil and the EVO Silver/Gold caps, but the international shipping being the way it is, and delays in production, they are still not at my door. I intend to burn them all in at once and then pop them into the boards one pair or two pair at a time to listen to them. I was hoping to have completed this last month. I think Tony's reviews are excellent, but they do not reflect the impact of the devices in electronics. I have used the EVO oil in my M2 Clone, and it was a huge improvement in clarity and soundstaging compared to the lowly 10uf Elna caps (that are excellent in tone, but not in detail)
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Thank you Tea-bag, you are very kindly. So for my cart I can add only: (this transistor price is not included in any kit, true?)
2SK369BL PR 12-max one per board pr (12€)
If I want use a mc or low voltage output cart, I have to buy:
2Sk369BL Quad (LOMC) 26.00 - max 1 per board pair (26€)
Is it true?
And what about 2SK170BL ?
Thanks in advance for your help
The shunt reg has nice low impedance output over a wide bandwidth that we don't want to spoil by adding the impedance of a between boxes substantial length umbilical DC out cable. That's the technical worry explanation. Keep the shunt regs in the phono box feeding DC to the phono channels with nicely short thick enough DC out cables if possible.
If in another box they should basically work correctly for steady DC rail and no oscillations but if there will also be palpable sonic loss I don't know. They could also pick up interference for instance. Never used the shunts remotely to this phono. Someone has to compare stability noise and sonics between near and remote test schemes to decide. In the previous they were on same board inseparable. In this one they can separate some.
If in another box they should basically work correctly for steady DC rail and no oscillations but if there will also be palpable sonic loss I don't know. They could also pick up interference for instance. Never used the shunts remotely to this phono. Someone has to compare stability noise and sonics between near and remote test schemes to decide. In the previous they were on same board inseparable. In this one they can separate some.
Sorry for replying late but they did something weird in the neighborhood's grid today. We got a long black out and 400VAC for a short while. My old Pioneer DVD/SACD player let out a magic smoke carpet from its tray as spectacularly as an 80s discotheque. Electrolyte all over inside, was pouring out from its corner. Three home network related wall warts died and I am still repairing stuff. 
Salas:
Thanks for the explanation. Your guidance is good enough for me.
Sorry about the smoke. There's no expectation of a repeat performance?
Regards,
Scott