Turntable as tuner?
Do you have a tuner connected to your preamp/integrated amp, as well? If so, it is common enough ... you are experiencing bleed through. I have noticed this with a vintage Marantz receiver that I have. If I have the selector set to AUX and turn the volume way up, I can hear the radio very faintly. To my knowledge, there is no servicing that is required. Regards, Rich |
Yes, actually it's a preamp/tuner. The funny thing is that no other devices exhibit this behavior no matter how high I turn up the volume. Why only the phono? BTW, I've switched the phono stage to other inputs (the B&K has 5 identical inputs plus tape in/out) and the same thing happens, but when I plug a CD player into the same place -- lovely silence. I've also tried switching out the interconnects one by one (no effect). I _have_ discovered that if I power off the phono stage the noise goes away, while turning off the TT doesn't get rid of it. |
Does the station you hear change when you tune the tuner? If not, then bleed through is not the issue. You are receiving RFI frm the station. The high gain required for the phono board acts much like an RF preamplifier and he input stage of the preamp is acting like a detector. Try som clamp on RFI filters from Radio Shack. Also try some better interconnects between turntable and preamp and preamp to your line stage. Could also be a damaged ground in your tone arm. In any case, sounds more like RFI than bleedthrough since bleed through should be just as bad with a CD playing through the same set of inputs. sensorman |
I agree with the RFI diagnosis. I had a similar problem in a previous (high RFI) location and the problem had to do with direct sight lines coming through the windows. Things you can try (those blockers did nothing for me): 1.try rotating the pre-tuner 90 degrees 2.hold up a piece of steel (baking sheet?) between the pre/tuner and the windows and see if that affects the RFI 3.if it turns out that #2 does affect the RFI beneficially, but steel between the source of the problem and the pre/tuner is not an option, you might consider relocating the components to a completely different location - I had to literally have my system one floor down (which was under street level) with only the speakers above - to really eliminate the RFI Good luck! It's a tough problem! |
I'm tending to think that it's an RFI problem, too. Further experimentation: late last night I tried an old Kimber IC I have and the problem worsened dramatically, I think because of the lack of shielding. The cables I have right now are AQ Diamondbacks, which are decently shielded, I think -- one reason I was a little unwilling to accept that they might be acting as antennae ;-). Also, I stuck a HighWire anti-RFI coil on the TT's power cable, which did help some: I can still hear the radio, but it's much quieter now. Moving things around is a good idea, but I just spent a day moving the system for improved WAV (and to help remote usage) so I not real excited about moving again :-). On the other hand, this problem didn't exist (or at least I didn't notice it) until after the move. I tried the cake pan thing, no improvement; also tried rotating the phono stage (it's small), no improvement. I guess I'll try the ferrite clamps next, and maybe some All Clear coils. |
RFI unbound: when I was a kid so many decades ago, I had a friend that lived across the road from a fifty thousand watt broadcast am transmitter. When I went to his bathroom, his house radiators worked like a tuner. And the copper played the radio out of the sink. No kidding. Leaping from '69 to '99, I was listening to my cd when orders came from the boss to go to the store for milk. So I get in the car im my garage and the radio comes on. At first I think, how weird, I was just listening to 'El Cant de la Sibilla' in the house as I realized how stupid I was for thinking even for a second that would be on my radio. On the other hand maybe it is bleed through. Do the above mentioned test. |
Finally fixed the problem with a pair of AudioQuest RF Blockers (RS wanted $21/4, the AQs wee only $4 more and seemed to be much higher quality) on each cable and a pair of All Clears on the TT phono stage cable. Nothing less seemed to work. Thanks to everyone for the help! P.S. The rest of my system sounds better now, too, esp. bass. Synergy... |
Well, I _thought_ that the ferrite things had fixed the problem, but I was mistaken. It turns out that (although the interconnects were a part of the problem), the real culprit was the cable on the wall-wart that powers my Project Phono Box. Wrapped it around a couple of the AQ RF Blockers and Presto! no more noise. BTW, during all this I decided to try shielded coax interconnects from Blue Jeans Cable (http://www.bluejeanscable.com) & love them! Cheap & tasty is best... |
