Valve phono preamp build


Posted on Feb 5, 2014

A stereo valve phono pre built for me by a techie mate. He has the power transformer and all components needed besides the valves which he advised me to source myself based on what would be most suitable to my needs. So, all you experienced DIYers, if you were building a valve phono pre for yourself, what configuration (push pull, single ended) and valves


Valve phono preamp build
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(pentode, triode ) would you use My knowledge of tubes is very limited so feel free to dumb it down! My hifi is not exactly what you`d call high end. Technics SADX 940 amp, a fairly basic Technics SLBD20 TT with Audio Technica cart and a pair of Usher S520s. I listen to a very eclectic mix of tunes from country, jazz to grindcore and drum`n`bass, but I suppose I mostly lean towards "classic rock". Not sure if this would have any bearing on tube choice. Does your mate have a circuit drawn up for this yet If so then your answers we be there. If not then finding an appropriate circuit is a priority - you can`t choose valves without knowing the circuit. Most phono circuits are SE and use triodes, BTW. I can`t read circuit diagrams, but someone here may have the answer to this question. Ask your friend if the 12AX7s are being used as a pair or in sequence. If in sequence, then you need 12AX7s with "matched halves". If being used as a parallel pair for each channel, then you need to ensure that the pair that you buy is a "matched pair". Good suppliers can do this matching for you. There are lots of cheap 12AX7s out there, Chinese and NOS (new old stock). But for a phono amp, I`d be tempted to go for a high-quality specialist hi-fi valve manufacturer. For example Psvane (which would have been Pavane but for a printer`s error in China) make a 12AX7_T hi-fi-quality unit. I bought mine from the US distributor, because they do a much...




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