Led is best. Lower impedance by far, comparable noise to the resistor, its Vf much less dependant to the stability of the jfet source underneath. Its just I wanted it flexible for the 3 phono builders. Else if it was for one Vout, I would go Leds hands down. Zeners can be good if Tc compensated. Alas it proved much easier for a particularly bad zener to find its way in a build as it happend to RCruz than a for a particularly good zener series to be found in a store sold 1 by 1.
I don't think so. V2 is much more technically advanced as a coherent system. Its I just add one little thing once in a while and listen to it enough if the application is there, don't forget that it is for the phono and must adhere to the least possible components and not away from its original tone as a combo concept. That is why I did not post it here as a tech advance. Iko has shown many much stronger possible advances here. Its V1.1 in my mind.
Everything can be adopted to anywhere if will not oscillate or interact detrimentally. More psrr and higher level signal can obscure some advance evident on phono though. Its a system thing. Maybe remote sensing could do the same subjectively for example.
Still Leds sound more robust to me than resistors. Have seen that in DCB1S. In the particular var one so to jump phono versions with just one shunt, trimmer was adequate. Don't create rules in your mind. I tried a ccs for the follower's load for instance, and even if the background went blacker, the dynamics squashed. I would think that it was bad idea for the emitter follower as a whole if I did not go through the resistor loaded first. Easy to dismiss. That is why I go one step at a time. Also I don't know if it will sound untoward out of my system. You must experiment yourselfs too. Iko has given so many ideas, its a goldmine. Try.
Still Leds sound more robust to me than resistors. Have seen that in DCB1S. In the particular var one so to jump phono versions with just one shunt, trimmer was adequate. Don't create rules in your mind. I tried a ccs for the follower's load for instance, and even if the background went blacker, the dynamics squashed. I would think that it was bad idea for the emitter follower as a whole if I did not go through the resistor loaded first. Easy to dismiss. That is why I go one step at a time. Also I don't know if it will sound untoward out of my system. You must experiment yourselfs too. Iko has given so many ideas, its a goldmine. Try.
Thanks salas 
What I meant to say is that it turns out John Curl has been using the jfet+resistor||capacitor voltage reference trick for a while. So, for those that are not afraid of tweaking, this is a really nice solution for replacing the zener. I have been using this in my experiments for some time, it turns out salas too, and then the other day I found that John Curl has been using it for a much longer time. When someone of his caliber uses it, I pay attention. He mentioned the j203 jfet, I happened to use j201. So, there we go, I think this might become the recommended choice; it is for me. It measures great as far as low noise is concerned.
What I meant to say is that it turns out John Curl has been using the jfet+resistor||capacitor voltage reference trick for a while. So, for those that are not afraid of tweaking, this is a really nice solution for replacing the zener. I have been using this in my experiments for some time, it turns out salas too, and then the other day I found that John Curl has been using it for a much longer time. When someone of his caliber uses it, I pay attention. He mentioned the j203 jfet, I happened to use j201. So, there we go, I think this might become the recommended choice; it is for me. It measures great as far as low noise is concerned.
Jameshill had asked about it for a long time now, early in the thread, and told him that he may vary with a trimmer but it sounds softer to me than led. JC is using it for ages, that is why I once wrote, ''first there were electrons''. The Vref decoupling capacitors subjective choice becomes more of an issue with the resistor. Also whatever stability the jfet ccs has, it directly translates to the resistor, when leds are much more stiff to it. Experiment subjectively too, all of you I just say. Don't expect steadfast solutions. And that's the core joy of diy. Just my 2c.
With regards to the impedance thing. I would distinguish between AC impedance and DC impedance. By lower impedance we refer to the DC impedance only, not AC. AC impedance is provided by the bypass capacitor, as its impedance is much lower.
So the problem may be that with a zener or a string of LEDs DC might be kept more stable by the 2SK170 CCS (or not?). But this may not affect the AC performance of the circuit.
For most circuits, the absolute rail DC voltage is usually less important. It is the AC behavior that is more important.
So if the DC impedance does not affect AC, and if the resistor gives less noise, using a resistor may have advantage.
Correct me if I am wrong.
Since the resistor + trimport > 2k5, a 1uF MKP would have a -3dB point of 63Hz. In other words, if we parallel an electrolytic capacitor of 100uF (-3dB at 0.63Hz) with a 1uF capacitor, above 100Hz, the film capacitor plays are more dominant role. This would provide much better sonic than a single electrolytic capacitor, something a zener / string of LEDs can not do. And this is a very conservative figure.
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My experience says that you never know sonics before you listen. For long in different systems, secures conclusions. All well with foreconclusions, but I still consider everything as ''wishful thinking'' until I solder something, won't smoke for 2 days power on, and enough people say its a plus in enough systems. Even if I have a good score in planning I am still reserved. Have experienced many akward things. Because there is aways that something that maybe lurking and manifests after. Of course with the benefit of hindsight all is very explainable. Many film over electrolytic bypasses are a disaster for instance. Just ask the GC snubber crowd.
I agree. Usually bypass inappropriately causes more problems than it can resolve. This happens more on rail bypass where higher inductance cause ringing in the RLC circuits. In the C2 position, however, I can not see much issue. Even in rail, in my tube preamp, the sonic improved dramatically after I bypass the 300uF/450V electrolytic with a 20uF/630V MKP.
Then try it. It looks like it will be better. But I just can't say before. I only talk certain or recommend things that I have made and used. That's my rule. Imagine the long film and bulk and legs and boosted BW of the film one picking and adding RF noise directly on the Vref for instance. Can foresay?
I have just got Spencer's note that 100 x 2SK170 was sent today and would arrive within 2 weeks.
While Futurlec sent me a cancellation note last week, and they even gave the transaction ID with which they credited my credit card, no money has been deposited into my credit card, and today a parcel from Futurlec arrived!
In that order, I had only 18 x 2SK170.
I was going to do the Idss tests using the method recommended, but I could not pull out the lead plug from my DMM after 4 years without doing current measurements (I always did voltage measurements to work out currents), even with heavy machine tools. So I connected 14VDC in series with a 100R resistor and then the JFET (g connected to s). Measuring the voltage across the 100R and dividing the number by 100 give the current. Let me know if this method is not good.
I got the following readings converted to mA:
(1) 7.34
(2) 7.51
(3) 8.05
(4) 8.17
(5) 8.39
(6) 8.44
(7) 8.58
(8) 9.14
(9) 9.88
(10) 9.92
The rest are not good, reading from as low as 3mA-6mA and as high as 10mA-18mA.
I read that they should be 7-8mA. So I have only two that are qualified. For +/-13V rails,
can I use (1) for CCS+, (2) for the CCS -, (3), (4) for shunt+, (5) and (6) for shunt-?
Or perhaps I should use (5) for CCS+, (6) for the CCS-, (1), (2) for shunt+, (3) and (4) for shunt-?
If so, I won't wait for the batch from Spencer and can get it done once I get the remaining a few parts.
Regards and thanks,
Bill
While Futurlec sent me a cancellation note last week, and they even gave the transaction ID with which they credited my credit card, no money has been deposited into my credit card, and today a parcel from Futurlec arrived!
In that order, I had only 18 x 2SK170.
I was going to do the Idss tests using the method recommended, but I could not pull out the lead plug from my DMM after 4 years without doing current measurements (I always did voltage measurements to work out currents), even with heavy machine tools. So I connected 14VDC in series with a 100R resistor and then the JFET (g connected to s). Measuring the voltage across the 100R and dividing the number by 100 give the current. Let me know if this method is not good.
I got the following readings converted to mA:
(1) 7.34
(2) 7.51
(3) 8.05
(4) 8.17
(5) 8.39
(6) 8.44
(7) 8.58
(8) 9.14
(9) 9.88
(10) 9.92
The rest are not good, reading from as low as 3mA-6mA and as high as 10mA-18mA.
I read that they should be 7-8mA. So I have only two that are qualified. For +/-13V rails,
can I use (1) for CCS+, (2) for the CCS -, (3), (4) for shunt+, (5) and (6) for shunt-?
Or perhaps I should use (5) for CCS+, (6) for the CCS-, (1), (2) for shunt+, (3) and (4) for shunt-?
If so, I won't wait for the batch from Spencer and can get it done once I get the remaining a few parts.
Regards and thanks,
Bill
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if you add a 1k pot (or maybe a 500r pot) in series with the 100r current measuring resistor, you can adjust your fixed 14Vdc supply to give Vds of 10V. That lets you test to the manufacturers specified voltage.
The pot should be set to vary between 200ohm and 400ohms to drop the extra ~3.1V that you need to achieve that 10Vds.
You will reduce slightly the power dissipated in the FET and thus reduce it's temperature. This will help move the FET temperature towards the Tc=25degC specification temperature.
You will find only a small difference in your Idss values and I think your will find that most will remain in the same order of ranking.
The pot should be set to vary between 200ohm and 400ohms to drop the extra ~3.1V that you need to achieve that 10Vds.
You will reduce slightly the power dissipated in the FET and thus reduce it's temperature. This will help move the FET temperature towards the Tc=25degC specification temperature.
You will find only a small difference in your Idss values and I think your will find that most will remain in the same order of ranking.
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