• on Audio/Video/Photography
  • Published in issue 12/2000 on page 0
About the article

Valved RIAA Preampfilter

using an ECL86

Valved RIAA Preampfilter
In spite of CDs and digital audio signal processing, there are still people who are devoted to the vinyl phonograph record. And they enjoy their analogue treasures the most in the company of contemporary valve technology.For nearly a century, vinyl phonograph records played an important role as a storage medium for voice and music. Although nowadays the CD has taken over the leading role, analogue records are still widely distributed. Hundreds of millions of records are present in archives and private record cabinets. These include irreplaceable documentary recordings, collectors’ items and many commonplace recordings that reflect the spirit of a particular era and the technology available at that time, as well as recordings that are technically and artistically outstanding. For friends of analogue recordings, there is still a market for phonograph records, in which re-pressings or new pressings can be obtained. Due to the small quantities produced, as well as the high quality, the prices are fairly high.
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Resistors:
(metal film, 0.7 W, 1% tolerance,
MO = 5%, tolerance)
R1 = see text
R2 = 1M? (see text)
R3 = 47k?
R4 = 220k?, MO, 2W
R5,R6 = 1k?5
R7 = 4k?7
R8 = 680k?
R9 = 220k?, MO, 2 W
R10 = 560?
R11 = 1M?2
R12 = 68k?
R13,R14 = 18k?, MO, 4.5 W
R15 = 270?, MO, 2W
R16 = 8k?2
R17 = 10k?
Capacitors:
C1,C2 = see text
C3 = 47µF 35V bipolar
C4 = 47µF 450 V axial
C5 = 2µF2 400V, lead pitch 5mm
C6 = 47µF 450V axial
C7,C8 = 220µF 25V, lead pitch 5mm
C9 = 47µF 450V axial
C10,C11 = 3nF3, 2.5 % polypropylene, min. 100V
C12 = 1nF5, 2.5 %, polypropylene, min. 100V
C13 = 1nF, 2.5 %, polypropylene, min. 100V
Miscellaneous:
V1 (Rö1) = ECL86
1 noval (9-pin) socket, ceramic, for board mounting
1 PCB, epoxy resin strengthened, 70µm copper layer
1 Moving-Coil transformer, type R-110, see text
Solder pins
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