Thread: Valve preamp.
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Old 18th Jun 2019, 8:30 am   #46
Craig Sawyers
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Join Date: Nov 2010
Location: Oxford, UK.
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Default Re: Valve preamp.

Originally Posted by Electronpusher0 View Post
Hi Andy,
I put the pre-amp on the bench as promised. I attached a modified schematic,
Just put the RIAA values (without tolerances) from the schematic into TINA. The response deviates quite a lot (+/-0.8dB), with a big hump at low frequency. From 100Hz to 20kHz it is +/-0.15dB.

However, keeping the 330k fixed, take out the 560p and just use 2.2n. Change the 39k to 48.1k (E192 standard value) and the cap in series with that becomes 5.6n//1n (for 6.6n).

That gives +/-0.13dB from 20Hz to 20kHz assuming perfect values

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