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Valve Itch phono
Valve Itch phono
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Old 12th September 2013, 06:27 PM   #1301
merlin el mago is offline merlin el mago
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Swapping the standard 6N2PEV

Left channel 217 V RMS
Right channel 245 V RMS
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Old 12th September 2013, 06:34 PM   #1302
Salas is offline Salas  Greece
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Valve Itch phono
That is just 1dB difference. As the one before.
Now to see about experimental error and changes due to gear, go to 500mV at 0 attenuation so the DMM can catch it better, let it there, then go -40dB (be sure there is no center trim button on the attenuator out of cal position). And measure again.
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Old 12th September 2013, 07:40 PM   #1303
merlin el mago is offline merlin el mago
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502mV 0 attenuation, measured with -40dB attenuation

Left channel 565mV
Right channel 632mV
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Old 12th September 2013, 07:58 PM   #1304
Salas is offline Salas  Greece
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Valve Itch phono
42dB max and 0.97dB difference. When you will have more tubes maybe you will strike a 0.5dB combination or better.

Quote:
Originally Posted by merlin el mago View Post
Swapping the 1578

Left channel 242 V RMS
Right channel 274 V RMS
At the above combination you had hit the 43dB max and ~1dB difference.
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Old 12th September 2013, 08:38 PM   #1305
Salas is offline Salas  Greece
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Valve Itch phono
That is with 192mV at 0dB attenuation as signal from your Leader gen. After -40dB attenuation for Itch input signal, 255-275mV on Itch's output will mean 43dB max gain right on spec and 0.5dB max tolerance.
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Old 12th September 2013, 08:44 PM   #1306
merlin el mago is offline merlin el mago
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Quote:
Originally Posted by merlin el mago View Post
502mV 0 attenuation, measured with -40dB attenuation

Left channel 565mV
Right channel 632mV
Quote:
Originally Posted by Salas View Post
That is with 192mV at 0dB attenuation as signal from your Leader gen. After -40dB attenuation for Itch input signal, 255-275mV on Itch's output will mean 43dB max gain right on spec and 0.5dB max tolerance.

Do you refer to this post Salas?
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Old 12th September 2013, 08:51 PM   #1307
Salas is offline Salas  Greece
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Valve Itch phono
I refer to the combination where you hit 274 using 192 at 0 attn. If you used 502 with that valves combination it will still be the same dB.
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Old 12th September 2013, 09:15 PM   #1308
merlin el mago is offline merlin el mago
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Quote:
Originally Posted by Salas View Post
I refer to the combination where you hit 274 using 192 at 0 attn. If you used 502 with that valves combination it will still be the same dB.
Yes it's the same tube combination only changes 502mV in place of 192mV. I have more 1578 can I try the new tubes, wich position V4 elevated 1578?

Last edited by merlin el mago; 12th September 2013 at 09:28 PM.
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Old 12th September 2013, 09:37 PM   #1309
Salas is offline Salas  Greece
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See post #146
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Old 13th September 2013, 06:03 AM   #1310
stajo is offline stajo  Sweden
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Valve Itch phono
What kind of 6SN7 are you using Merlin?
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