An update on my problem with the FX,the humming is on both channels,swapped around the supplied tubes to no avail,the signal path is CD>FX>Amp,there is no hum when the FX is taken out of its path.
There was no power supply,I have used one off a PC monitor,I assume it is of the switching kind,the rating of it is, Input 220-240v~ 50Hz 200mA
Output 12V-1000mA.
I have contacted the seller the reply is.
bestg61 sent you a message about your request:
dear friend so sorry for all trouble Could you plz keep it and then we will refund you 30%as a compensation without return? Could you plz repair it in your local repair shop? Plz do not worry i just want help you and protect your profit. waiting for your repl.
I cannot see how I can fix it,it should be working correct in the first place,unless I have done something wrong.
It could be a ground loop problem rather than a source problem. Does it happen with the CD player disconnected from the FX?
This usually follows a problem related to an AC differential showing up on the ground planes of interconnected components, due to inadequate power supply line isolation somewhere.I have a desktop PC with a very old M Audio analogue soundcard,I've just connected the FX between that and the amp using another power supply still non regulated.
No hum.
Could you please explain a ground loop problem,I understand ground loop issues on a turntable but not digital.
Is your passive a DACT?I had an issue with my unit having a tube fail with a loud cracking noise. I am lucky it didnt take a tweeter out. I have since replaced the tubes with sylvanias and it seems to work fine. At this point i dont have it in the circuit because i am enjoying the passive pre on its own.
Its a tc-754.Is your passive a DACT?
Its a tc-754.
Got my batch of matching November 1985 Voskhod's!
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All four make this distortion buzz/cracking, like dripping at 3 Hz frequency. The loudness of the buzz is independent of the position of volume knob, and is present more or less symmetrically on both channels. Sometimes this distortion escalates to a constant even louder buzz (I could imagine some leak current) that then changes back to "dripping" after 15s or so. Is this something that 'burning the tubes in' will resolve? Or did I get a bad batch?
The original Chinese tubes do not have any issues (anymore), although I remember that very early on there was some (less loud) cracking sounds with them that went away quickly.
Did you buy them on eBay? If so you can get your money back. FWIW I only buy from sellers with high feedback numbers and scores.