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Valve Itch phono
Valve Itch phono
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Old 13th September 2018, 01:35 PM   #3101
merlin el mago is offline merlin el mago
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If increase volume increase the hum.
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Old 13th September 2018, 01:46 PM   #3102
Salas is offline Salas  Greece
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Didn't have in the past but it recently developed? If so I would start from tubes swap or screening or moving away if other gear transformer was introduced nearby and the hum went up or undo some sensitive modification
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Old 14th September 2018, 11:02 AM   #3103
merlin el mago is offline merlin el mago
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Thanks for answer Salas, always was the hum. No other gear introduced nearby. I will try swapping tubes if hum not goes away I will try screening the tubes.
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Old 15th September 2018, 02:16 PM   #3104
merlin el mago is offline merlin el mago
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Salas could be the Belton micalex sockets some people said go for teflon? Or the 6SN7 to 7N7 adaptor?

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Old 15th September 2018, 02:48 PM   #3105
Salas is offline Salas  Greece
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If the contacts are clean inside them and they achieve good mechanical lock I would not think that the choice of bases can be a factor for background noise. Adapter maybe can expose more if its barrel is not grounded, but a swap from 7N7 back to 6SN7 direct would tell.
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Old 15th September 2018, 04:27 PM   #3106
merlin el mago is offline merlin el mago
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Hum gone swapping the 7N7 tubes with adapters included

Salas worth the change for teflon sockets to improve SQ?
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Old 15th September 2018, 04:55 PM   #3107
Salas is offline Salas  Greece
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Don't know, haven't used such high quality sockets. Beyond the good insulation material they seem to have very nice machined copper gold plated contacts also and that alone can be a plus when combined with well cleaned and chemicals treated tube pins (Cramolin/Deoxit).
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Old 15th September 2018, 05:06 PM   #3108
merlin el mago is offline merlin el mago
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Thanks again Salas.
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Old 16th September 2018, 09:52 AM   #3109
merlin el mago is offline merlin el mago
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Question Anti RIAA for Itch

Salas could I use this anti-RIAA to measure the Itch RIAA accuracy?

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Component values

Ideal Actual Alternative
R1 883k 909k 910k
R2 75k 78.7k 75k
C1 3.6n 3.3n 3.3n
C2 - 180p 270p
C3 1n 680p 1n
C4 - 270p -
R3 0 1.48k 1 - 1.5k

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Old 16th September 2018, 05:51 PM   #3110
Salas is offline Salas  Greece
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Most of those Anti-Riaa circuits are theoretically accurate but to make a practically accurate one with ready to buy parts I think Bonsai's approach is best: http://hifisonix.com/wordpress/wp-co...verse-RIAA.pdf
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