Hi Frans
From the graphs 2SK170 is left most is that a beater choice and the others in order?
From the graphs 2SK170 is left most is that a beater choice and the others in order?
The choices are placed in order, 2SK170 best, to J310 worst, 🙁 But the J113 will do just as good as the 2SK170.
No, the bigger the degeneration the better the regulation so the J113 is a better choice.
It is a so called " short gate " J-Fet.
You see that in the value of the source resistor, it is higher.
For performance of the total shunt circuit it does not make a big difference though.
It is a so called " short gate " J-Fet.
You see that in the value of the source resistor, it is higher.
For performance of the total shunt circuit it does not make a big difference though.
The 2SK170 is optimized for low voltage noise and the J113 is optimized for high output impedances at low current. Study the straightness of the idle visa drain-source voltage at the chosen current. It is similar to early voltage in BJTs.
It is allways the bl or the v, that are in demand never the gr, for that reason it could be more available🙂
Yes, GR is easier to get.
Problem with GR is that they have less Gm but the same input capacitance as the BL or V parts.
That is what John Curl told me. Actually i never verified this.
I learned that high Gm parts are just paralleling on many smaller transistors inside the chip. Following that logic a lower Gm part should also have lower input capacitance.
Problem with GR is that they have less Gm but the same input capacitance as the BL or V parts.
That is what John Curl told me. Actually i never verified this.
I learned that high Gm parts are just paralleling on many smaller transistors inside the chip. Following that logic a lower Gm part should also have lower input capacitance.
To much heat?
Originally Posted by Benedetto
@J.G.;
nothing fooled yet.
But in some Friends builds, there are some
issues that make them think....
Like heat !
Originally Posted by Joachim Gerhard
too much heat of the cooling fins ?
On the other hand running the cooling fins on lower heat would provoke a plethora of responses that a shunt works best driven HOT.
That comes from too much input voltage.
When the semis get hot there is a chance of oscillation.
Originally Posted by Joachim Gerhard
too much heat of the cooling fins ?
On the other hand running the cooling fins on lower heat would provoke a plethora of responses that a shunt works best driven HOT.
That comes from too much input voltage.
When the semis get hot there is a chance of oscillation.
Originally Posted by Joachim Gerhard
too much heat of the cooling fins ?
On the other hand running the cooling fins on lower heat would provoke a plethora of responses that a shunt works best driven HOT.
That comes from too much input voltage.
When the semis get hot there is a chance of oscillation.
Tanks Peter
Today I have measured the heatsink temperature from both boards .
After a half hour 50 Degree C constat, by 24 Volt input. Output 18 Volt
steady and I can adjust + - 0,5 Volt. ( see Benedettos Fotos my boards ) 🙂
Is that OK Frans 😕
All the best from the green Island
Originally Posted by Benedetto
@J.G.;
nothing fooled yet.
But in some Friends builds, there are some
issues that make them think....
Like heat !
Originally Posted by Joachim Gerhard
too much heat of the cooling fins ?
On the other hand running the cooling fins on lower heat would provoke a plethora of responses that a shunt works best driven HOT.
That comes from too much input voltage.
When the semis get hot there is a chance of oscillation.
Originally Posted by Joachim Gerhard
too much heat of the cooling fins ?
On the other hand running the cooling fins on lower heat would provoke a plethora of responses that a shunt works best driven HOT.
That comes from too much input voltage.
When the semis get hot there is a chance of oscillation.
Originally Posted by Joachim Gerhard
too much heat of the cooling fins ?
On the other hand running the cooling fins on lower heat would provoke a plethora of responses that a shunt works best driven HOT.
That comes from too much input voltage.
When the semis get hot there is a chance of oscillation.
Tanks Peter
Today I have measured the heatsink temperature from both boards .
After a half hour 50 Degree C constat, by 24 Volt input. Output 18 Volt
steady and I can adjust + - 0,5 Volt. ( see Benedettos Fotos my boards ) 🙂
Is that OK Frans 😕
All the best from the green Island
Well said, I am available. I am afraid there is no easy means to detect oscillation of the PSU other than with a scope - the shunt is so good that detecting it with a DMM is difficult. I have yet to get my hands on a Paradise R3 "amplifier" that oscillates......
Good morning all
Just for clarity
Is Q107 R108
and Q207 R208 that need changing?
I got a stash of 2SK107BL from Mouser from time to time they do get same so place your order and eventually they will arrive.
I am going to try those this morning, if SHE lets me, I don't have the J113 but I will get same for the R3 boards.
Just for clarity
Is Q107 R108
and Q207 R208 that need changing?
I got a stash of 2SK107BL from Mouser from time to time they do get same so place your order and eventually they will arrive.
I am going to try those this morning, if SHE lets me, I don't have the J113 but I will get same for the R3 boards.
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Yeah I remember early days when same XXXX could not get the thing to work and started to rip thing apart.
I have been re-reading the build guide
Quote from Paradise R3 Assembly and trubleshooting guide .
My
recommendation would be to use values around 400 for both N and P for the input stage, whereas
the other parts of the circuit can use higher gains (but please make sure you have those decoupling
caps in place on the bottom side of the PCB).
It sems to contradict recent posts...
I believe that Joachim mentioned advantages to be had if the Imput stage has hi Hfe is this correct?
I have NPN up to 550 and PNP over 600
http://www.diyaudio.com/forums/swap-meet/226166-paradise-bcxxx-40-a.html
Quote from Paradise R3 Assembly and trubleshooting guide .
My
recommendation would be to use values around 400 for both N and P for the input stage, whereas
the other parts of the circuit can use higher gains (but please make sure you have those decoupling
caps in place on the bottom side of the PCB).
It sems to contradict recent posts...
I believe that Joachim mentioned advantages to be had if the Imput stage has hi Hfe is this correct?
I have NPN up to 550 and PNP over 600
http://www.diyaudio.com/forums/swap-meet/226166-paradise-bcxxx-40-a.html
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The advantage of higher Hfe in the input stage is less base current so less DC into the cartridge. On the other hand we have an offset trim in the R3.
In the beginning we thought that very high Hfe in the input stage can provoke oscillation.
As far as i know that is not the case.
In the beginning we thought that very high Hfe in the input stage can provoke oscillation.
As far as i know that is not the case.
Sorry I don't I do not use the simulator much maybe Riccardo
But I be happy to send you a few 2SK170BL if you need them
But I be happy to send you a few 2SK170BL if you need them