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RE: Lafayette Two Tube Preamp

Sell it! Start over, or virtually replace every part in it. The bias is grid leaked because each cathode is grounded. So it is necessary to have those caps on the input grids (.05 and .005 uf shunted with 3M resistors) They are probably ceramic (boo-hiss). We are listening to bad DF capacitors. The power supply is laughable (half wave-only one diode and it is probably selenium which drifts with age. Replace with 4 UF4007 diodes. Using a Shure M3D might be problematic because this was designed for the GE variable reluctance cartridge and the EQ may be off. I could recommend other designs that use the same tube. Dr. Torsten Lousch(AKA Que Yang Wang) has a design on his THUNDERSTONE AUDIO website that I would investigate if I were you. YOU MUST use DC on the filaments if you don't want boo-koo oodles of HUM and the versatility of differing brands of tubes and the Lafayette is using AC filaments (another BOO-HISS). There are many DC filament designs on the web that are simple. One big capacitor (4000uf, 25v) and four UF4007 diodes is all it would take to convert to DC filaments. M.B.
"...the fool doth think he is wise but the wise man knows himself to be nothing but a fool." Will Shakespeare

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