Do you know that even PT will get a pair of EE interconnect for the DV phono? He has never really had a pair of EE in his various systems until the arrival of the DV phono which prompts me to feed it with the best cable.
I always like to solve problem for the fun of strengthening of logical thinking. This is an interesting problem that I would like to share with all of you.
Problem: Hummm noises appear if I switch to Da Vinci phono BUT
(1) It was not there with Zanden 300B Push Pull amp. Only happen
after Wavac 805mk2 was installed.
(2) No problem when Tidal phono
(3) No problem with Zanden 2000p/5000s
(4) If the LCR Driver of the Da Vinci phono is not switched on, then
the humm moises reduced perhaps by 80%. When the LCR
drivers turned on, then the problem re-emerges.
Let's following the reasoning step by step.
For (1), the immediate conclusion is the amp because the problem
was not there with the previous amp.
But if the conclusion is the amp, then why (2) and (3) is ok?
So the logical deduction must be there is so communication problem between (4) and the newly installed Wavac 805mk2.
So we start focusing on (4), and since the problem only happens when the LCR Driver is turned on. We tried to fix this part the first.
What we do is the following:
A. In the power supply section of LCR Driver, we "float up the ground" of the input stage and changed the ground to the next stage in the power supply section. After this, we tried listening again. No ok, the problem is still there.
B. Then, we do the same thing on the power supply of the phono stage. Then we listened again. Bingo!!!!!! Bingo!!!! Bingo!!! All humm noises gone!!!!
Because this is an interesting case so I and Master Wai rethink the whole logic and here is our explanation of the problem in the most loigcal manner.
We explain from (4). Because the source of the humm comes from the phonostage, and as a result, the turn on of the LCR Driver only amplifies the humm noises even more with additional gain stage. It is not the LCR Driver problem as normal logic would otherwise convene.
For (2), why Tidal has no problem is because the phono section is integrated with the linestage sharing a common ground.
For (3), the 2000p/5000s goes directly to the line input section of the Tidal without meddling the phono section at all.
So, it must be the case that the HUMMM problem of the Da Vinci is between the phono section of the Tidal and the Da Vinci phono. If the gound of the input stage of the DV Phono is floated up, and the problems gone immediately, then it must be the case that a GROUND LOOOP WAS THERE between DV and Tidal.
Then the last puzzle was why there is no problem with Zanden and only with Wavac. Based on our numerous listening experiences and technical experiences, our conclusion is Wavac's bandwidth is very very very wide and the input stages are very sensitive.
I previously try to argue against myself that noises level must be higher in the case of 60watt of class A than 18watt of push pull class A especially by the revealing power of the Cessaro Horn. I proved myself wrong on this conventional hypothesis that sounds intuitively correct because when I turn on the volume to 12 o'clock or even 3 o'clock, I HEAR NOTHING. It is extremely quiet.
I think this is a very good case to share with all of us.
(1) The field study of Dso's humm problem led me and master wai
discussed extensiely on this issues
(2) I have to say PTsang's knowledge is very very extensive because
when I first told him the problem, he is certain that it is not the amp
but the phonostage. He is also very sure not because of the LCR
Driver!
Last but not least, I apologize for my very late call to Shanghai bigpiece last night. You are right. I am using United 805 now.
PT, you are most welcome The comment from PTsang and Charles on RCA and United 805 should also be considered and I would love to compare in the future.
I am looking forward to the arrival of my new toys in the next couple of weeks. If you have a business trip to Shanghai in the near future, please let me know.
Comments
Did you run-in the phono? Mr.JLam, Why so silent?
ccn
Very much, just like you, Mr.CCN.
Problem: Hummm noises appear if I switch to Da Vinci phono BUT
(1) It was not there with Zanden 300B Push Pull amp. Only happen
after Wavac 805mk2 was installed.
(2) No problem when Tidal phono
(3) No problem with Zanden 2000p/5000s
(4) If the LCR Driver of the Da Vinci phono is not switched on, then
the humm moises reduced perhaps by 80%. When the LCR
drivers turned on, then the problem re-emerges.
Let's following the reasoning step by step.
For (1), the immediate conclusion is the amp because the problem
was not there with the previous amp.
But if the conclusion is the amp, then why (2) and (3) is ok?
So the logical deduction must be there is so communication problem between (4) and the newly installed Wavac 805mk2.
So we start focusing on (4), and since the problem only happens when the LCR Driver is turned on. We tried to fix this part the first.
What we do is the following:
A. In the power supply section of LCR Driver, we "float up the ground" of the input stage and changed the ground to the next stage in the power supply section. After this, we tried listening again. No ok, the problem is still there.
B. Then, we do the same thing on the power supply of the phono stage. Then we listened again. Bingo!!!!!! Bingo!!!! Bingo!!! All humm noises gone!!!!
Because this is an interesting case so I and Master Wai rethink the whole logic and here is our explanation of the problem in the most loigcal manner.
We explain from (4). Because the source of the humm comes from the phonostage, and as a result, the turn on of the LCR Driver only amplifies the humm noises even more with additional gain stage. It is not the LCR Driver problem as normal logic would otherwise convene.
For (2), why Tidal has no problem is because the phono section is integrated with the linestage sharing a common ground.
For (3), the 2000p/5000s goes directly to the line input section of the Tidal without meddling the phono section at all.
So, it must be the case that the HUMMM problem of the Da Vinci is between the phono section of the Tidal and the Da Vinci phono. If the gound of the input stage of the DV Phono is floated up, and the problems gone immediately, then it must be the case that a GROUND LOOOP WAS THERE between DV and Tidal.
Then the last puzzle was why there is no problem with Zanden and only with Wavac. Based on our numerous listening experiences and technical experiences, our conclusion is Wavac's bandwidth is very very very wide and the input stages are very sensitive.
I previously try to argue against myself that noises level must be higher in the case of 60watt of class A than 18watt of push pull class A especially by the revealing power of the Cessaro Horn. I proved myself wrong on this conventional hypothesis that sounds intuitively correct because when I turn on the volume to 12 o'clock or even 3 o'clock, I HEAR NOTHING. It is extremely quiet.
I think this is a very good case to share with all of us.
(1) The field study of Dso's humm problem led me and master wai
discussed extensiely on this issues
(2) I have to say PTsang's knowledge is very very extensive because
when I first told him the problem, he is certain that it is not the amp
but the phonostage. He is also very sure not because of the LCR
Driver!
Last but not least, I apologize for my very late call to Shanghai bigpiece last night. You are right. I am using United 805 now.
PT
I am looking forward to the arrival of my new toys in the next couple of weeks. If you have a business trip to Shanghai in the near future, please let me know.
Bigpiece