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Old 26th June 2012, 08:10 PM   #701
Salas is online now Salas  Greece
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It shows more ground lines for not mixing return currents from different loops.
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Old 27th June 2012, 07:44 AM   #702
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Thanks Salas. So no short cuts, do the job properly. My bread board build sounds great now so don't want to wreck it through careless build now. Anyone found good cable/cable shield available in uk? I would prefer nice metal shielding. Seems to only be sold by the reel.
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Old 2nd August 2012, 04:39 PM   #703
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Finally arrived the Belton sockets (attached pic), I have several questions before starting the Salas Valve Itch Rev.1.1:

-B+ PSU: can I use 200uF / 350V instead 220uF/450V for C3-C4?
-Heaters PSU: can I use 33uF/16V or 47uF/50V instead 22uF/25V for C8-C9?
-For insterstage cap: can I use 47nF/200V instead 47nF/250V for C4?
-I'm sorry my ignorance, how have to measure 1.36mA & 3.5mA: between the junction & cathode using a 1R or 10R resistor?
-All resistors 1/4W except R2 82K 2W & R10 33K 2W?
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Old 2nd August 2012, 04:50 PM   #704
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-350V sounds marginal for mains variations
-Yes
-Marginal
-See Vdrops on R3 & R11 and divide with each one value
-Yes
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Old 2nd August 2012, 05:11 PM   #705
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Thanks Salas,

-For instersatge cap could I use Russian FT3 100nF 600V?

OK I will use 220uF 450V for mains caps PSU B+

If don't measure 1.36mA & 3.5mA could I change the resistors accordingly to reach the mA necesary?
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Old 2nd August 2012, 05:21 PM   #706
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-Yes if 100nF will not sound too full in big speakers

-OK

No, you measure for ballpark value so to know its about right. Each valve biases differently so you try match valves by seeing those numbers close enough between channels.
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Old 2nd August 2012, 05:28 PM   #707
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Thanks for the input Salas

For 6N2PEV can try with different valves but for 6H8C it's a little bit more complicate if supplier can't sell real matched pairs.

Last edited by merlin el mago; 2nd August 2012 at 05:32 PM.
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Old 3rd August 2012, 07:00 PM   #708
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I believe 6H8C is pin compatible with 6SN7?
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Old 3rd August 2012, 08:01 PM   #709
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Same tubes.
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Old 3rd August 2012, 08:02 PM   #710
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Are you elevating heaters to 150V?
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