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Old 16th September 2013, 04:43 AM   #11
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or may an out-board cheap phono-stage be your easy solution
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Old 16th September 2013, 05:16 AM   #12
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Any chance at all you may be running a MM cart into a MC loaded input?
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Old 16th September 2013, 06:09 AM   #13
Leeds is offline Leeds  Singapore
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Quote:
Originally Posted by bicefalo View Post
have you tried with another pickup ?
No! I have only one turntable. I tried adding a earth connection to the Nytech (there is no earth connection for the Nytech) to the turntable earth connection. The problem still persist.
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Old 16th September 2013, 06:11 AM   #14
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Originally Posted by analog_sa View Post
Any chance at all you may be running a MM cart into a MC loaded input?
It is a MM board and my cartridge is MM too. The phono stage was working fine the last time.
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Old 16th September 2013, 06:13 AM   #15
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Quote:
Originally Posted by bicefalo View Post
or may an out-board cheap phono-stage be your easy solution
The Nytech has one of the best sounding phono stage. If replacing some caps could solve the problem, I would prefer this option.
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Old 16th September 2013, 06:26 AM   #16
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If both channels are affected then only the PSU is common to both. It all looks single ended AC coupled. The big cap will be rail decoupling for the phono stage. Is the rail voltage OK ? You have to start somewhere

A cap failure in one channel wouldn't affect the other. The tantalum caps are prone to failure but all I have said before still applies.

The definitive test is to put a scope and signal generator on the phone stage (with an inverse RIAA network) and see what the response actually is.
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Old 16th September 2013, 06:43 AM   #17
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Quote:
Originally Posted by Mooly View Post
If both channels are affected then only the PSU is common to both. It all looks single ended AC coupled. The big cap will be rail decoupling for the phono stage. Is the rail voltage OK ? You have to start somewhere

A cap failure in one channel wouldn't affect the other. The tantalum caps are prone to failure but all I have said before still applies.

The definitive test is to put a scope and signal generator on the phone stage (with an inverse RIAA network) and see what the response actually is.
When I connect to an external CD player and playing the tuner, there is no such problem. So the problem must be with the phono stage which goes to the preamp. Since playing CD does not have the problem, it is not likely the preamp or the power amp sections are at fault.

Are you referring to the power supply unit (PSU)? Can the PSU be at fault and yet playing CD does not have the problem?

I am not trained in electronics so may have problem and knowhow using the scope. If the problem could be the faulty capacitors; the two smaller caps (47 uf 16v) and the bigger single cap (1000 uf 10v) on the phono card as shown, I could get them replaced. The point is I have no confidence that the caps are the cause of the problem.
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Old 16th September 2013, 07:13 AM   #18
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The phono preamp is really a separate item. It is a high gain preamp in its own right. A failure of one cap on one channel on that phono board would mean that the other channel still played OK. A problem with the PSU (meaning the PSU local to the phono board, in other words the phono boards supply derived from the main PSU) would affect both channels of just the phono stage but would most likely just cause distortion rather than a change in response.

A starting point might be to measure the voltage across that large 10 volt cap. That looks like the supply (although a 10 volt supply is really low by todays standards). Could it be a shared feedback return cap for both channels for economy ? That's a strange possibility. Measure the voltage as a starting point.

Do you have a scope ????
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Old 16th September 2013, 08:21 AM   #19
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was the soft and muddy sound while playing turntable occurred suddenly or rather gradually with the progress of time ??
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Old 16th September 2013, 08:49 AM   #20
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Quote:
Originally Posted by tiefbassuebertr View Post
was the soft and muddy sound while playing turntable occurred suddenly or rather gradually with the progress of time ??
The problem occurs gradually over a period of time.
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