a couple of questions on the phono ONO

[Stefanoo]

Originally posted by analog_sa



3) Sounds better without cascoding, at least to my ears.

4) Loses a coupling cap in a very sensitive place.

A common cathode FET (paralleled if required), powered by either Jung reg or batteries is very close to the ultimate SS MC stage soundwise. And there is no need for a monstrous coupling cap.

hi analog,

thanks for your partecipation here too.
So you are telling me that in general it's beyyer a circuit without any cascoding? o you are just saying in this case?

I haven't understoond point 4. could you try, if possible to explain it again?

With your last sentence you mean that for the MC stage you would only use the paralleled 2sk170 without the cascoding and supplied by the Jung regulator?
If so i have read on the forum that people tried to eliminate the cascoding (basically making it a Pearl) and the sound was worse, but that could also depend upon personal taste.

[Onvinyl]

Stefano,
if you can, try all three options (without c., bjt, fet).
May I suggest that you reference your ono schematic so we're talking about the same thing?

I would try to design the coupling cap out, as analog_sa said. Not so sure if it's that easy.

Rüdiger

[Stefanoo]

Hi Rudiger

I will try all 3 options and report back as soon as possible.

I am very sorryyy but is till don't get the part as i didn't understand what analog tried to say by Loses a coupling cap in a very sensitive place"

Rudiger: do you mean by "I would try to design the coupling cap out" that you would try to redesign the MC last stage without the coupling cap C37?

[Onvinyl]

Originally posted by Stefanoo


Rudiger: do you mean by "I would try to design the coupling cap out" that you would try to redesign the MC last stage without the coupling cap C37?

Do you mind to reference the schematic? I seem to have a different one.
Rüdiger

[Stefanoo]

sure.
This is the schematic

[Onvinyl]

Ok, thanks.
Yes, C37. I don't see an easy way to get rid of it, though.

The cap multiplier I was referencing to earlier is Q24 that further reduces possible ripple and the like on the supply line.


BTW, do you have a working circuit that performs anywhere near the ono right now? If not, you might not see an urgent urge to experiment that much after you build it

Rüdiger

[Stefanoo]

I was looking at Jung's website and i found an interesting article on RIAA's topology.
So i started to simulate the behavior of the basic RIAA active filtering and connected to at the output the inverse RIAA and run the frequency analysis.
The circuit (look at the attachment here) was simulated using an LF411 and it does simulate fine.

The problem is if i try to use instead of the OP amp i use a differential pair (look at the next post) i don't get the correct result.
I actually don't catch what it could be causing this.

If anybody can give me a tip on this i would really appreciate.

thanks

[Stefanoo]

and this is the schematic with the dual input diff pair

[Onvinyl]

Shouldn't C47 not connect to Q1?
Rüdiger

[Stefanoo]

where is C47 ?
are you referring to the schematic with the op amp or the second with the diff pair?
If, by C47, you mean the 10uF cap (C46) that is connected to the collector of Q1 is just the coupling cap and is just the feedback path from +Vout to -In of the differential stage.
Is it right?