Supratek Owners Thread

Well Mick sent me a new power supply and it still hums. I tried without umbilical cord and a new tube and it still hums. I am so disappointed because I love the sound of the preamp but the hum is driving me crazy. I can hear it in the speakers and I hear it if real close to the power supply. Any suggestions what I should do?

couger4u
Try disconnecting one component at a time from the pre amp. First the TT then turn everything on. If it still hums reconnect the TT and this time disconnect the DAC then turn everything back on. If it still hums your now down to the amp and pre as the suspects. You could have a ground loop hum. For about a $100 on amazon you can buy the iFi GND Defender, first try it on your amp then next the pre. If that does not get rid of the hum i'm not sure what the issue could be. Good luck.

If you have two different power supplies that hum exactly alike then your issue is either power or grounding related.  Try lifting one at a time the ground on the preamp and the amp. What amp are you using the Supratek with?

@couger4u ,   start with no inputs (no sources plugged  in) and only the output connected to your amp.   If you have a couple shorting plugs you can use on the  'selected' input use them. With the vol. dwn if the amp is quiet and there is no more hum from the speakers (there will always be a tiny bit due to the tubes) then your issues lies a source component and the connection between the pre and that/those components.  If you still have the same hum with the vol down and no inputs connected there is an internal issue somewhere in the circuit.   If it is quiet,  try raising the vol (with no inputs connected).  With a non-terminated (no shorting plug) input you will get some increasing noise with an increase in volume knob,  this is normal (with shorting plugs this would be gone).  You should not hear any loud or disturbing hum though.   Once you have confirmed that it is quiet as described above,  start adding components to the inputs,  1 at a time.  .  Your issue is most likely a grounding issue between the 2.     Any 'mechanical' hum you are hearing from the PS is a completely separate issue.   This can be caused (as mentioned earlier) by wall power or its grounding  or also by the grounding from other components that are connected to the same circuit (breaker).   The PS will always have a little hum.  Nothing you should hear from a seat 8-10 feet away though,  however if you get your ear next to the unit you will hear a little or faint buzzing or hum.  Alot of times this is the rectifier (buzz)  or transformer (hum). Some rectifiers are quieter than others but their perceived noise is also very dependant on the wall power in general as well.   Use the supplied regulators and use a good 5AR4 for the rectifier when testing and listening.   While other tube compliments can work,  it is easy to get some interesting results and subsequent mechanical noise (not from speakers) with other tubes.   Hope this helps a little.  Best,

I have resolved my hum issue by re-routing the umbilical between the power supply and preamp, along with power cords to other equipment and other signal wires. I didn't take a scientific approach to figure out what was causing what. I just fiddled with it until the hum stopped, then "secured" the position of various bits to keep things positioned so the hum was gone.

Hope your efforts are successful.