Pad location in drake pre

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insideout

Active member
Joined
May 12, 2006
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37
Location
Auckland, NZ
[quote author="PRR"]http://twin-x.com/groupdiy/albums/userpics/pd7017.pdf

Gain-range 40dB-80dB is rather frightening for rock-n-roll.

Input iron is connected 1:5. NE5534 feedback minimum gain is 5. Total gain 25 minimum. Rails are +/-12V, peak output say 10V, 7V RMS. 7/25= 280mV maximum input at 5534 clip (I dunno if the iron will take 280mV heavy bass). It will be widely useful, but for all-purpose use you want a 20dB pad in front of the transformer. [/quote]

I'd like to clarify whether that pad should be before the input or output tx. If it goes before the input transformer, won't I be padding down a perfectly good signal and then amplifying that, which would not be an optimal signal/noise ratio throughout the chain?

Would I achieve better results padding down before the output transformer?
 
did not look @ scheme but pad are generally the first thing the signal sees--quote 40-80 dB gain, 20db pad makes it 20-60. yes s:n compromise. but thats anywhere you put a pad. better a small s:n loss than a hard clip of input amp/ overdrive input tranformer.

look @ schemes from other mic pres. there is a generic input scheme @ jensens applications page; how to pad, polarity, phntm.
 
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