, but since it was put together when it was turned on or off there was a crackling sound
that faded out after a few seconds . But it didn't have any effect on the sound , just annoying
and I figured it was a tube .
I finally decided to try different tubes and Since I would have it apart to change out the tubes
and rectifier , and not being able to leave things alone , I figure I would upgrade the caps while
I was in there . Easy enough .
Since they were on sale and I didn’t want to go way too expensive I decided to going
to go with the Jenson Copper and oil after reading alot of reviews , but they only had
one of them so I bought the Dueland’s instead , at unfortunatly alot more $$ .
Here is where it gets puzzling . After just changing the caps and nothing else there is a
low hum coming from the speakers both channels equally . ( It was dead quiet originally
) I changed out the tubes ( three sets ) and rectifier tube (2 different ones ) and there was no
change in the hum doing that in any configuration ( the original crackling noise is gone
though ) . It will hum on either set of output caps the new ones and the old Mundorfs .
And it gets louder as you go up with the volumn . It’s not a real loud hum, you don’t
notice it from a couple feet away or when the music is playing . but is annoying since it
was so quiet before the change .
Also it only hums on when the selector is set to Phono , Aux 1 or Aux 2 , it is quiet on
CD or Tuner , and it gets a little louder on phono setting when the PH15 is on than when
I thought it might be because the caps are so big and where I had them mounted they
were too close to the wireing that they might be causing the hum from that ( see the
pictures below ). I originally soldered them in without removing the board so as not to
disturb anything so I didn’t think I hurt any of the wiring . But after double checking
everything I decided to listen to it for a little while and see what happened .
Its hard for me to describe but I’ll try my best . Other than the hum on first impression
right off the lows - base was a little tighter smoother not much of a change but it’s there
. The vocals were the most improved , on a couple of recordings ( blues & rock ) it
sounded like they were in the room singing ! very natural sounding . But the highs which
they were supposed to be best at reproducing sounded harsh and brassy , not good at all ,
at first dissapointing . But after about ten hours or so they have smoothed out very
noticably and and sound alot more natural and right now probobly not even fully broken
in , they are to my ears they are better sounding all around than the Mundorf S/O ‘s .
So over all better sounding , and worse at the same time ?
I decided to take it back apart and move the new caps away from the wires and double
check the soldering and wires . The solder looked good but I re-flowed it just to be sure
the wireing looks undamaged , but after doing this no change it still hums .
I did not unsolder the original caps , I just snipped the leads near the board and soldered
the new ones in the second set of holes I didn't want to chance damaging the traces . Could
this be a problem?
Any suggestions of things to check ? Am I missing somethging obvoius ? Keep in mind
I’m not real experienced in troubleshooting , I’m still learing .
Original build page http://dynacotubeaudio.forumotion.com/t1224-my-sp14-build