Philharmonic Record Scratch Suppressor Circuit - EH Scott Radio Enthusiasts2024-03-29T04:37:17Zhttps://ehscott.ning.com/forum/topics/philharmonic-record-scratch-suppressor-circuit?feed=yes&xn_auth=noThis is good information guys…tag:ehscott.ning.com,2015-03-29:3925821:Comment:477012015-03-29T23:37:09.823ZScott Seickelhttps://ehscott.ning.com/profile/ScottSeickel
<p>This is good information guys... Thanks for posting.</p>
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<p>This is good information guys... Thanks for posting.</p>
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<p></p> Norm,
In addition to this dis…tag:ehscott.ning.com,2015-03-25:3925821:Comment:471602015-03-25T00:09:23.076ZBill Liershttps://ehscott.ning.com/profile/BillLiers
<p>Norm,</p>
<p>In addition to this discussion, I'd like to suggest to those restoring one of these Scotts, that there are often either "ruggedized" or low microphonic audio specific versions of many pentodes. These include:</p>
<p>using 1612 for a 6L7, or using a 1620 for a 6J7. For 6K7s and 6B8s you might be better off with the mil version if you can find them; VT-86 or VT-93 respectively. Of course, many std grade tubes work fine, but often you will find poorer noise performance and…</p>
<p>Norm,</p>
<p>In addition to this discussion, I'd like to suggest to those restoring one of these Scotts, that there are often either "ruggedized" or low microphonic audio specific versions of many pentodes. These include:</p>
<p>using 1612 for a 6L7, or using a 1620 for a 6J7. For 6K7s and 6B8s you might be better off with the mil version if you can find them; VT-86 or VT-93 respectively. Of course, many std grade tubes work fine, but often you will find poorer noise performance and microphonics in the later pentodes.I especially like to use the 1612 tubes in the expander circuit. Typically very quiet and easy to match. As far as the differences in RF pentodes made after it was fashionable to use them in audio circuits ('37-'38), I cannot say for sure if the tubes were designed differently, possibly many of the test constraints that applied to audio were then simply overlooked.</p>