Hello to all! Retired electrical engineer here with a bit of 70's & 80's era audio gear I'm refurbishing. I came across this forum in my searches for information on the subject and it seemed like a good idea to revive my (very old) membership here.
My background: 40 years of doing failure analysis on integrated circuits (analog, digital and mixed designs). Due to the demands of my job I became somewhat of a generalist so I also know a bit about IC fabrication, chemistry, material science and mechanical engineering. Due to the nature of my job, I'm pretty good at taking things apart but not so good at putting them back together again!
My current refurb projects include an SAE 3CM power amplifier and a Technics SL-120 Mk1 turntable. I'm the second owner of the power amplifier and the previous owner did some ill-advised mods that I'm removing. I also have replaced all the old electrolytic capacitors and swapped out the old phono plugs with decent(er) ones.
I bought the SL-120 new. It currently has a speed regulation problem for both 33-1/3 and 45 RPMs, possibly due to leaky electrolytics (they're slated to be replaced anyway). All the potentiometers will be treated with contact cleaner, and then we shall see how it works.
In addition to old stuff, due to the fact that my old (home-made) phono preamp failed and no replacement parts were to be had, I just finished designing and building a phono preamp. It uses a pair of OPA1651 opamps. The RIAA networks are based on information I found here.
My background: 40 years of doing failure analysis on integrated circuits (analog, digital and mixed designs). Due to the demands of my job I became somewhat of a generalist so I also know a bit about IC fabrication, chemistry, material science and mechanical engineering. Due to the nature of my job, I'm pretty good at taking things apart but not so good at putting them back together again!
My current refurb projects include an SAE 3CM power amplifier and a Technics SL-120 Mk1 turntable. I'm the second owner of the power amplifier and the previous owner did some ill-advised mods that I'm removing. I also have replaced all the old electrolytic capacitors and swapped out the old phono plugs with decent(er) ones.
I bought the SL-120 new. It currently has a speed regulation problem for both 33-1/3 and 45 RPMs, possibly due to leaky electrolytics (they're slated to be replaced anyway). All the potentiometers will be treated with contact cleaner, and then we shall see how it works.
In addition to old stuff, due to the fact that my old (home-made) phono preamp failed and no replacement parts were to be had, I just finished designing and building a phono preamp. It uses a pair of OPA1651 opamps. The RIAA networks are based on information I found here.
Welcome Mark. Can relate to retired engineer. Can relate to FA! Last I did was on a LCD screen backlight failure on a UI at a label printer when I worked at Amazon. I spent some time on it, mostly to the benefit of the OEM who I gladly shared the report with and made phone calls to about it. One of the other guys on the team - all Allen-Bradley PLC programmers - remarked "That's your wheelhouse, isnt it?"
I'm just "up the road" in Olympia.
I'm just "up the road" in Olympia.