I have been away a couple days, so I answer with delay to your comments.
1) Could you please post a sketch of your idea of shielding the Servo? I am sorry I don't understand exactly what you meant and I want to make sure I get your idea right as I am sensing it is a sensible idea.
2) For the RIAA caps, could you tell me what capacitors are you recommending and say they sound better than AuraT capacitor? I will get those and try them out. However as far as impact of the RIAA capacitors my findings are different from yours. I found the RIAA capacitors toimpact significantly the sound also, and I am talking on the paradise, the ELCAP makes a huge difference. I just ran 2 different type of capacitors, same vale, and even my wife jumped out of the counter asking me what I changed.
This is a wonderful idea.
Having more output current helps driving RIAA at high frequency.
observation: if you unbalance the mirror, how can it still work since the base current of the two halves connected together will be different?
I mean it works, but I tried that yesterday on the modified paradise and there are issue for the servo to try to zero out the voltage.
so I am trying to find the cause and a possible fix to that.
EDIT: Simulation wise it works, but There is something that doesn't pen out in my head for some reason when trying to unbalance the mirror.
True, but I only had 3dB more.
What I want to try to audition is less BJTs in parallel just to understand if I can get a more "enjoyable" sound out of it.
It is already pretty nice, but in my set up and with my type of music, IMHO it still needs tweaking to get it to my liking.
I want to see if halving the BJTs, although paying in terms of more noise, can have an overall improvement or not.
Also I want to revisit Supply Voltage and current bias and perhaps input device.
I want to, in other words get familiar with this structure and see if BJTs can get to sound as colourful as JFETs, maybe not, maybe yes...I want to try...
Thanks to Joachim, we are back with this thread.
Here is the initial draft proposed by Master J and also a proposition for the Servo controller.
The idea is to utilize the super FET IF3602 and explore possibility of a fully balance phono stage.
I was wondering if anybody can point me out as far as getting LTSpice Model for the OPA1632 so that I can start simulating.
Here is the initial draft proposed by Master J and also a proposition for the Servo controller.
The idea is to utilize the super FET IF3602 and explore possibility of a fully balance phono stage.
I was wondering if anybody can point me out as far as getting LTSpice Model for the OPA1632 so that I can start simulating.
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What I usually do and correct me if this is wrong, I do the other way around i.e. I get standard cap and trim resistor if it can help.
Sometime, like in Paradise, you need no matter what a custom cap.
I would like to avoid using a custom cap.
What if in this approach we split high freq cut after first stage and then the other two time constants as shunt feedback?
soes this sound stupid?
I know that by doing this there is a loss with the passive low pass filter at the input.
I trust your experience and my little one says that too, passive RIAA will bring a lot of problem with overload margins and distortion at high frequency however it can sound pretty good too.
So if your recommendation is to go 100% active feedback, let's do it that way then.
I am just concerned that if we don't split caps then we will be limited to use parallel of capacitors and really not high quality parts.
I hope that people will soon receive V-Caps and will post their honest opinion but if it is like I think, they will be blown away and maybe at that point you will be more convinced of the importance of using this super caps on this masterpiece
If that will ever happen, then to use V-Caps we need to have standard values as Custom caps will definitely not be viable since we wouild need to go through a group buy and I am sure that due to the final price of this thing there won't be so many people who will want to build this, plus long lead time and so on....too much for me to deal with again
!!Any take on this?
if you make an active Riaa, exotic parts has more merit as they actually pass the signal, on the current RiAA like the Paradise, the influence is a lot less. So there the exotic parts play no role or a role that to me is insignificant compared to a lot of other issues like a good build, shielding, grounding ect.
When it comes to Teflon I have quite some hesitation, reason is that while Teflon is a very good dielectric, it also has a lot of drawbacks when it comes to making good caps. So while it's good a one specific area, it's really lousy at most others.
When it comes to Teflon I have quite some hesitation, reason is that while Teflon is a very good dielectric, it also has a lot of drawbacks when it comes to making good caps. So while it's good a one specific area, it's really lousy at most others.
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Yes I generally agree with you are saying, shielding, good build, making sure circuit doesn't oscillate etc...comes first!
Also Caps on Active RIAA play a more important role.
Anyhow, and this is my experience, I perceived clear and significant difference just switching from custom Aura T to custom V-Caps CuTFT.
I can't imagine changing from Rifa or Wima to CuTFT.
That is like I said my experience, with my set up and everything.
I am really curious to see what the other over 15 people think about the change on their stock Paradise Board, that might be a more useful and objective evaluation of the influence of caps on the Current/Trans-Z RIAA's style.
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