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Old 27th July 2012, 07:49 PM   #6381
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Just for reference: one of the time constants I typed in on the laplace was wrong.
Fixed that, RIAA back on track.
I just see a little bumby behaviour at low frequency that could easily be tweaked.

I was wondering if the 2 13.6mF caps on the signal (the high-pass filter that lowers DC gain) can be replaced with a resistor and if that could still work.

I have simulated it and tweak RIAA values and got the results below.
The only thing is that it looks like I can't push the gain any further up and I obtained 57dB at 1KHz.
Also I don't know if this arrangement can cause problem with DC offset/drift and I am wondering if the Servo can adjust some extra DC drift.

Below the circuit, I wonder if you guys could comment it and let me know what you think.
I just wanted to give my two cents to this wonderful project.


Thanks for your attention and sorry for the intrusion I don't mean to question by any means this wonderful design.
Attached Images
File Type: jpg paradise rev 2-direct couple.JPG (110.6 KB, 304 views)
File Type: jpg paradise rev2 direct couple RIAA precision.JPG (61.0 KB, 295 views)
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Old 27th July 2012, 11:04 PM   #6382
hesener is offline hesener  Germany
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Quote:
Originally Posted by Stefanoo View Post
Just for reference: one of the time constants I typed in on the laplace was wrong.
Fixed that, RIAA back on track.
I just see a little bumby behaviour at low frequency that could easily be tweaked.

I was wondering if the 2 13.6mF caps on the signal (the high-pass filter that lowers DC gain) can be replaced with a resistor and if that could still work.

I have simulated it and tweak RIAA values and got the results below.
The only thing is that it looks like I can't push the gain any further up and I obtained 57dB at 1KHz.
Also I don't know if this arrangement can cause problem with DC offset/drift and I am wondering if the Servo can adjust some extra DC drift.

Below the circuit, I wonder if you guys could comment it and let me know what you think.
I just wanted to give my two cents to this wonderful project.


Thanks for your attention and sorry for the intrusion I don't mean to question by any means this wonderful design.
Thanks a lot Stefanoo, that matches much better with my hearing results ;-))))
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Old 27th July 2012, 11:29 PM   #6383
hesener is offline hesener  Germany
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uhhh, that was exciting.... just started a new thread, and here it is:

Paradise phono stage

The group buy has started, please add your name and we get the ball rolling!
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Old 28th July 2012, 04:12 AM   #6384
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Quote:
Originally Posted by hesener View Post
Thanks a lot Stefanoo, that matches much better with my hearing results ;-))))
I am glad that the simulation helped a little bit.
My question is though, why would we want to have a non-flat response on the bass?
This configuration might offer an unwanted warm sound presentation.

What do you think?
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Old 28th July 2012, 05:03 AM   #6385
MiiB is offline MiiB  Denmark
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Feel free to alter the base response....
The deviation in practical terms is less as the mirror output-impedance is in parallel and it is swamped with parasitic. This here was a deliberate choice not to get on the bright side.. I think about 0.5 dB.
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Old 28th July 2012, 07:38 AM   #6386
RCruz is offline RCruz  Switzerland
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Quote:
Originally Posted by Stefanoo View Post
to make it easier for everybody, in attachment the .ASY and library for LTSPice.
Thank you So much... this will be fun
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Old 28th July 2012, 03:29 PM   #6387
hesener is offline hesener  Germany
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We currently have 18 sets requested for the Paradise R2 group buy (it is called R3 over there, simply to indicate the latest fixes), all of this in less than 24 hours.... looks like this will be huge.....
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Old 28th July 2012, 03:30 PM   #6388
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I am glad I could give my two cents.
Everybody now can play with values and make their own riaa response.

Just a note: make sure to correct the Laplace there is one wrong time constant.
I will post here the correct expression later.
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Old 28th July 2012, 03:37 PM   #6389
hesener is offline hesener  Germany
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Quote:
Originally Posted by Stefanoo View Post
I am glad that the simulation helped a little bit.
My question is though, why would we want to have a non-flat response on the bass?
This configuration might offer an unwanted warm sound presentation.

What do you think?
In fact, the bass I am hearing is very precise and see-through, it does not have warmth to it in my opinion - it is more like a muscular athlete.... this was comparing it to the Paradise R1 (which arguably is just a touch flatter), and the FPS (same thing there), both have just a small tendency of being warmer in the bass, not much though. I was using headphones to compare (K701) so the room played no role in this.

have you tried and increased C8 (in the servo), to see if that changes anything? I also see you are simulating the "old" servo circuit which MiiB calls "funny"... please check the latest schematic (R3) over in the group buy section for how this is done now.

maybe you just want to build and try, eventually measure it (now where is that anti-RIAA again....), and I will try to measure it next week when I am back (currently traveling...)
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Old 28th July 2012, 04:15 PM   #6390
FdW is offline FdW  Netherlands
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Quote:
Originally Posted by Stefanoo View Post
Just for reference: one of the time constants I typed in on the laplace was wrong.
Fixed that, RIAA back on track.
I just see a little bumby behaviour at low frequency that could easily be tweaked.

I was wondering if the 2 13.6mF caps on the signal (the high-pass filter that lowers DC gain) can be replaced with a resistor and if that could still work.

I have simulated it and tweak RIAA values and got the results below.
The only thing is that it looks like I can't push the gain any further up and I obtained 57dB at 1KHz.
Also I don't know if this arrangement can cause problem with DC offset/drift and I am wondering if the Servo can adjust some extra DC drift.

Below the circuit, I wonder if you guys could comment it and let me know what you think.
I just wanted to give my two cents to this wonderful project.


Thanks for your attention and sorry for the intrusion I don't mean to question by any means this wonderful design.
For a more precise replacement of the BC327/337 use the BC807/817-40 that come with LTspice.
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