True but I don't understand why you are not keeping in consideration the solution I suggested.
That will work for sure and calibrating the impedance of the current source it can have a high precision RIAA using same caps used on Paradise and noise down to 0.55uV/rtHz which I believe is as low as the paradise.
Diffderence on the CCS will deeply impac noise performance and DC and also low frequency response of the gainstage.
Well how about the 5LP01C, which is slightly higher power at 0.25W. It's ZTC is about 22ma, so that a couple of current sources in parallel could provide 45ma. Just run the input FETs a bit harder and you're there. You still need to cascode the 5LP01Cm to limit the voltage across them to stay within the power limit, which starts getting a bit more complicated.
http://www.onsemi.com/pub_link/Collateral/EN6619-D.PDF
---Gary
yeah the concept is correct.
I was going to do it but I got caught like I said by other things and then I was too tired to do that.
I mean have you tried with the simple cascoded IRF9610 CCS? It might not be as bad as we think and you should be able to get 61dB of gain out of the thing.
If you will try that I will consider sending you on private email the circuit with the values for evaluation and if it works it can be posted as well.
Just let me know.
A little something off record.
Maybe someone has an idea as how to fix it.
Yesterday I was listening to the modified version of the paradise without Elcap and bass response improved noteacebly and due to that I can now hear some very low frequency buzz. Probably on the 25-30 Hz range.
I thought at first it was the air pump broken or something transmitting vibration to the needle.
So I turned it off and nothing changed (I can still track a quite track for noise evaluation).
It sounds like vibration picked up from the motor or soemthing.
Any idea as how to fix it?
Thanks
Maybe someone has an idea as how to fix it.
Yesterday I was listening to the modified version of the paradise without Elcap and bass response improved noteacebly and due to that I can now hear some very low frequency buzz. Probably on the 25-30 Hz range.
I thought at first it was the air pump broken or something transmitting vibration to the needle.
So I turned it off and nothing changed (I can still track a quite track for noise evaluation).
It sounds like vibration picked up from the motor or soemthing.
Any idea as how to fix it?
Thanks
no I didn't use trans-diodes in place of the cap I used the simplest resistor.
The noise I hear disappears if I lifr the pick up from the record so IMHO has nothing to do with the phono.
Increased noise is only a wite distribution with higher density noise.
why would you think thhink that the Temp-Co would be only half of the story?
Regarding Tempco what I think is that cancelling Tempco on the CCS still doesn't completely solve the non zero tempco of the Jfet (unless the If3601 have a temp-co point).
I mean ideally when the CCS pumps a fixed amount of current indipendent from the Temperature, the temperature contribute of the input device should be negligeble.
However I think that in practice even the jfet swill give a wide contribute to the Thermal drifting.
I also noticed that using the opamp solution to compensate for the CCS increases output spectra noise quite a bit.
Basically anything done to the CCS will deeply affect noise performance as well so that will be the culprit for stability noise and gain.
Regarding Tempco what I think is that cancelling Tempco on the CCS still doesn't completely solve the non zero tempco of the Jfet (unless the If3601 have a temp-co point).
I mean ideally when the CCS pumps a fixed amount of current indipendent from the Temperature, the temperature contribute of the input device should be negligeble.
However I think that in practice even the jfet swill give a wide contribute to the Thermal drifting.
I also noticed that using the opamp solution to compensate for the CCS increases output spectra noise quite a bit.
Basically anything done to the CCS will deeply affect noise performance as well so that will be the culprit for stability noise and gain.
well with resistor you loose about 15 dB.
You have to compensate adjusting other parameters on the circuit.
It is not trivial but not impossible.
With proper adjustments you get 61dB of gain out.
Noise rises I think by a factor of 6dB if my calaculation are right.
Said that and connecting to a comment of JC, this noise level would stil lbe acceptable on the "phono's market" and as a matter of fact you can easily listen to it and get all the microdetails as well.
Obviously more silence will be even a step further.
This solution clearly helps low level listening that before was fatiguing and now gets pretty easy and liquid.
Definitely definition of bass response and more extended and natural highs.
I get more the feeling that every vinyl sounds different, while before it was pretty monotone compared to this one.
What we need is a stable DC at the output node including drift compensation of the input stage. I got that working but the gain i got is not high enough so we also need high impedance at that node. Then we need low noise, something i think is solvable becsaue the higher the output impedance of the CCS, the more it gives gain in certain limits.
That is then limited by the output impedance of the input stage. We can not make that infinite so the Signal-Noise has a theoretical limit that we can not circumvent.
I agree 0.5nV/Q Hz would be very acceptable although with other concepts we can get a few dB lower. I still would accept that because i agree with Stefano in principle that super low noise is not everything.Then the CCS should have low output capacitance up to high frequencies. Did i forget anything ?
That is then limited by the output impedance of the input stage. We can not make that infinite so the Signal-Noise has a theoretical limit that we can not circumvent.
I agree 0.5nV/Q Hz would be very acceptable although with other concepts we can get a few dB lower. I still would accept that because i agree with Stefano in principle that super low noise is not everything.Then the CCS should have low output capacitance up to high frequencies. Did i forget anything ?
Stefano i do not want to nit pick but i see an inconsistence in your argument chain about the electrolytics. First you say that you reduced the values and that sounded better.
That broke loose a discussion about the reason and not only Salas jumped in arguing that it may be a good idea to truncate the deep bass because of subsonic rumble. MiiB and i gave in at the end. Honest, we felt even a bit cornered but i kept the original values.
Now you DC couple and that sounds even better ! I find that a contradiction.
That broke loose a discussion about the reason and not only Salas jumped in arguing that it may be a good idea to truncate the deep bass because of subsonic rumble. MiiB and i gave in at the end. Honest, we felt even a bit cornered but i kept the original values.
Now you DC couple and that sounds even better ! I find that a contradiction.
No pick din't worry i don't take it personal.
You have probably mis-understood my explanation.
This is the thing, with 4.7uF you obtain the best compromise between natural sound and bass extension.
Bass with 10m or more on the el cap is not deeper it is just slower. It might look a bit more extended on instrument but that is not all.
There is less articulation and the highs are damed by a color typical of the electrolytic.
When you re-adjust the circuit taking the elcap off the bass is even more articulate which makes it feel even deeper.
If you have experience with a high end gears you will agree with me that the most important thing on the bass response is its articulation or it will mask mid and highs thus causing loss of resolution.
Right now with this set up I can ensure you that music at low level is much more enjoyable and that alone tells you a lot on the gain quality.
High volume listening just confirms a finer sound with more depth and width and more extnsion on both ends or I would have to say more articulation on the bass and highs more natural.
The only thing that I am missing from the other configuration is the quieter background.
With this possible hopefully new design IMHO can have the dead quite residual noise plus a very refined presentation. Time will tell.
As for the rumble noise I was getting, it turned out to be the motor. I tighten up the screws of the pulley and the noise drop down significantly.
You have probably mis-understood my explanation.
This is the thing, with 4.7uF you obtain the best compromise between natural sound and bass extension.
Bass with 10m or more on the el cap is not deeper it is just slower. It might look a bit more extended on instrument but that is not all.
There is less articulation and the highs are damed by a color typical of the electrolytic.
When you re-adjust the circuit taking the elcap off the bass is even more articulate which makes it feel even deeper.
If you have experience with a high end gears you will agree with me that the most important thing on the bass response is its articulation or it will mask mid and highs thus causing loss of resolution.
Right now with this set up I can ensure you that music at low level is much more enjoyable and that alone tells you a lot on the gain quality.
High volume listening just confirms a finer sound with more depth and width and more extnsion on both ends or I would have to say more articulation on the bass and highs more natural.
The only thing that I am missing from the other configuration is the quieter background.
With this possible hopefully new design IMHO can have the dead quite residual noise plus a very refined presentation. Time will tell.
As for the rumble noise I was getting, it turned out to be the motor. I tighten up the screws of the pulley and the noise drop down significantly.
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One of the leading, and also very old and famous, CD shops is closing its doors. Plato, in Rotterdam, but also Plato in Den Haag are closing the shop forever. That in itself is not very shocking, but the comment that was made, on television, by one of the competitors was enlighten he did say, something like, They are going out of business due to not serving the market, the market is moving to vinyl, and Plato was selling CD’s only. Makes you wonder… where is this going…
3voor12 - Home
And some perspective http://www.smh.com.au/digital-life/hometech/vinyl-gets-its-groove-back-20120606-1zuv7.html
he did say, something like, They are going out of business due to not serving the market, the market is moving to vinyl, and Plato was selling CD’s only. Makes you wonder… where is this going…3voor12 - Home
And some perspective http://www.smh.com.au/digital-life/hometech/vinyl-gets-its-groove-back-20120606-1zuv7.html
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I see the trend when going to Audio shows, vinyls is growing,. Think the future will be a split between analogue and bandwidth limited analogue (digital) streaming... The good news is that regardless speakers are needed.. for me the fact that vinyl is increasing s a sign that the audiofile hobby is growing and that the hobbyists like the ritual of the LP... The streaming and unlimited access removes the value of the music, it becomes a given, always present, but not of value, analogue restores the value, the adjustments, the tweaking and our influence on the result, makes the hobby grow and lures the users into the very best addiction..
for me the fact that vinyl is increasing s a sign that the audiofile hobby is growing and that the hobbyists like the ritual of the LP... The streaming and unlimited access removes the value of the music, it becomes a given, always present, but not of value, analogue restores the value, the adjustments, the tweaking and our influence on the result, makes the hobby grow and lures the users into the very best addiction..