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  Dynaco PAS 2 modded and in excellent cond.!
This is an archived listing originally posted on 5/4/2010. (View live listing)





  Description (Dynaco PAS 2)
*Rating is conservative and due mostly to age*

Bear with me here since there's a bit of reading to do. There are a great many things to do to this preamplifier that help out immeasurably. The first is the signal-to-noise ratio of the stock preamp leaves a LOT to be desired. The reason is the volume control is upstream of the tone control amplifiers so the noise of the tone controls is fed wide open to the power amplifier...lots and lots of hiss and hum. The one you see here has the volume control downstream of the tone circuits. This cannot be done unless you lower the gain of the tone control circuit. I'll spare you the details but the tone circuit here uses 12AU7 tubes instead of the 12AX7 high-gain tube. The volume control is the last component in the preamp and so the output is passive. This is no problem at all with six feet or less of high-quality, low capacitance cable to the power amps. The control is a replacement type a fraction of the impedance of the original to widen the bandwidth. This particular one you see here uses the 6189 tube - an industrial version of the 12AU7 in the tone circuit but any 12AU7 tube will work here. Onto the cables inside now... the cheap hookup wire for the audio jacks has been replaced with 100% shielded cable for much quieter audio and better channel separation. With the exception of the phono inputs, all the inputs are now high-level. The low level preamplifier board is set for RIAA equalization. The gain structure of this preamplifier is carefully set so you get plenty of volume with the control set between 10 and 11 o-clock. When the music stops, this preamp is VERY quiet. On the rear of the chassis is a small nut you can loosen with your fingers to attach the ground lead of your turntable, something omitted on the stock preamp. One more thing - this unit has something it should have had all along: a power fuse! The brass front panel has been polished and then sealed with clear will never tarnish on you in this lifetime.