Here's one for ya Part 2


So,this am the cartridge plays fine.I do have hum but only when I turn the pre up.No hum with a signal.But what I have now is a horrible case of acoustic feedback.So I took the table down and put a heavy patio block on the wall TT shelf.This has always done the trick with other tables.But I still have acoustic feedback.Come to find out I only have acoustic feedback with the clamp on! I tried it loose,tight still feedback.I tried a rubber puck I have also but still feedback.
With no clamp no prob.I have the Delphi level and set up so when I push down on the platter it bounces 3 times then stops.I was told this was correct.
Any thoughts?
I would like to thank Tom for all his help in my return to vinyl.Thanks Tom (aka TWL)
david99

Showing 4 responses by david99

Tom-here's my room/setup
Room 15x20x7.5
At the long end of my room is a area that extends 3 feet longer than the room and is 6 'wide with same ceiling height of 7.5' There are treated windows.
The speakers are 4 feet from each side of the extention and 4 feet from the front wall.
The rack is in the extention as is all my dedicated outlets.The TT wall stand is 4.5 feet up over the stand.The steel support is bolted through my house wall and the nuts are on the outside siding.Every TT I've had I had acoustic feedback but was able to eliminate it with added weight on the TT shelf.3 TT's were non suspention and this is the 2nd suspention TT I've had.
I cant move my rack/stand d/t room setup.
I may need better advice how to set up the Delphi.
I have a ground from the interface box on the back of the delphi to the Creek.I added another ground tonight from the box to the TT steel support and it lowered the hum ~25% more.
Could the 65 gain from the Creek cause the hum?
I have a cheap linestage (tubes) could some better tubes (NOS) lower the hum?Its dead quiet with CD/tuner.
Without the clamp the acoustic feedback is really a non issue.I have to crank it louder than I would normally to get feedback.I would like to figure this out though so I can use the clamp.
Any other tricks to lower the hum with better grounding? Cheater plug maybe?
BTW Tom,The Denon is a special p.u. It reminds me of a Ortofon MC-20 super I once had,only smoother and more transparent.
Sean-Thank you for the information.
The wall the TT shelf is bolted through is load bearing.
The speakers are located 4 feet from the front wall and 2.5 feet from the side walls.
I mentioned the speakers are located 4 feet on each side of the room extention.Not the side walls.
I forgot to mention:
I have a closed stairway on the side of the room that is ~ 3 feet wide by 6 feet long.So ~2/3 of the room is 15' wide and 1/3 is 12' wide.There is a door on the stairs.The right speaker faces the door of the stairs ~ 8 feet away.I have very good imaging and can notice no ill effects from this.
I re-measured the lenght of the room and it is 19 feet long,not 20.
I have bass traps and first reflection point treatment along with corner tunes.
I should have been more precise,Im sorry.
I look forward to you giving me feedback (pun intended) on this information.
Thank you Sean.
Thanks Sean-
I'll see if the suspension can be tuned.
Right now its sounding mighty fine but some tweaking is still in order.
I'll let you know.
Dave