fini Posted December 19, 2003 Share Posted December 19, 2003 Well, C&S dropped by today and coaxed me into setting up th Fisher 500C I got back from Mike Zucarro a couple of months ago(!). Sounds good with the CD player, but I'm having disapointing results with the vinyl set-up. Nothing to do with the Fisher, but I am getting an extreme amount of, you might say, acoustic feedback. I have the dust cover attached, but that's not the only culprit. Taps on the plinth are very loud, turning up the volume creates a lot of this feedback, too. I don't know if this is a turntable (Kenwood KD-500), tonearm (Infinity Black Widow) or Cartridge (Shure V15 type IV/III) problem, but it makes vinyl playing impossible. I doubt the problem is with the console on which the table is placed. I may try switching back to the Pioneer PL-50, swapping the Grado Black (w/ the Grado dance moves), for the Shure. Do all tube amps/receivers hum to some extent? C&S told me the Fisher's hum was less than his HF-81's, but hearing this hum was initially annoying. The CDs sounded great, though. Quote Link to comment Share on other sites More sharing options...
bkrop Posted December 19, 2003 Share Posted December 19, 2003 Fini, how close are your speakers to the TT? The further the better!Plus, suspect the table/rack/console. Console? Are you using the speakers in the console with the TT on top? YIKES! Quote Link to comment Share on other sites More sharing options...
fini Posted December 19, 2003 Author Share Posted December 19, 2003 The Cornwalls are only about 6 feet apart, center to center, with the custom-built console in-between. The turntable sits on top of the console, next to one of the Cornwalls. Quote Link to comment Share on other sites More sharing options...
bkrop Posted December 19, 2003 Share Posted December 19, 2003 This might be a double post since I typed it once already, Fini move the TT to the center of the console and the max distance from both speakers. If the hum is reduced you will know that you have to spread the speakers or isolate the TT. Hope this helps! Quote Link to comment Share on other sites More sharing options...
Allan Songer Posted December 19, 2003 Share Posted December 19, 2003 My table is about 12" from one of the Cornwalls and I have ZERO problems. ISOLATION. It's pretty simple and you don't have to spend a boatload of cash. Are you sure you don't have some sort of ground loop problem as well? Quote Link to comment Share on other sites More sharing options...
fini Posted December 19, 2003 Author Share Posted December 19, 2003 ---------------- On 12/19/2003 9:33:02 PM Allan Songer wrote: Are you sure you don't have some sort of ground loop problem as well? ---------------- No, not sure. How have you isolated your table, Allan? Could be the way I've routed the cords, too, I suppose (inductive reasoning?). Should the power cord be updated to 3 prong? The 500c chassis is not grounded, otherwise. Should it be? I will do some messing around before taking drastic measures. Mark, Cramwells. I like that! Your isolation technique was indeed suggested by Clipped (who uses it with his Music Hall). I know I have to beef up the floor structure under the equipment, as it's pretty bouncy (1-1/8" plywood over 4X6's on 4' centers). Quote Link to comment Share on other sites More sharing options...
bkrop Posted December 19, 2003 Share Posted December 19, 2003 Fini the TT should have a ground wire to the chassis of the amp! Make sure it has a good contact. BTW, is this hum (bzzz) or feedback (EEEEEEEEEEEEOOOOOOOOOOOO)? Quote Link to comment Share on other sites More sharing options...
3dzapper Posted December 19, 2003 Share Posted December 19, 2003 Fini, Did you try turning the plug around in the recepticle to see if it lessens the hum? I mark the wide slot side on my plugs so I know which is quietest. Rick Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted December 19, 2003 Share Posted December 19, 2003 Mark, That is one good solution. I'd read a post somewhere of something similar, but the guy had made some kind of little corral to hold the balls under the slab.... not too workable. This is a easy and cheap, too. Dee Quote Link to comment Share on other sites More sharing options...
Allan Songer Posted December 19, 2003 Share Posted December 19, 2003 Not only should the chassis of the table be grounded to the amp, but you might also want to run a ground wire from the TONEARM as well! Quote Link to comment Share on other sites More sharing options...
fini Posted December 19, 2003 Author Share Posted December 19, 2003 Yes, the TT chassis AND tonearm are grounded to the Fisher chassis. Does the Fisher need to be grounded, too? Quote Link to comment Share on other sites More sharing options...
fini Posted December 20, 2003 Author Share Posted December 20, 2003 Rotating the plug 180 degrees didn't help with the hum. I'll try plugging it into a UPS. Tomorrow... Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted December 20, 2003 Share Posted December 20, 2003 fini, The feeback caused by extraneous vibrations picked up by the cartridge from that tone arm and table far outweighs the little hum problem with the Fisher 400C, if that little hum is even a problem you can really solve easily. At any rate,they are totally separate issues. My Eico HF-81 had at least the same amount of hum as soon as I got it back from Craig. I think he told me that was normal. That particular hum was inherent in your amp not necessarily any less on aux than phono mode. I think your grounding of the tt was fine. I have a turntable just as close to my Cornwalls as yours, a very similar set up. Cups/Balls/Slab solved it. This system I shall call CBS and maybe give myself a new middle name. I have 4 turntables set up in my living room in one capacity or other. Not one of these arms has anything like the loose play that arm on your Kenwood has. That thing shakes like a big bowl of jelly with hardly any provocation, although I do realize it is close to Christmas. I cannot imagine that this is meant to be exactly like that, although I could be wrong, I guess. Something needs to be tightened up, and the fact that the previous owner was sticking gum in a couple of places seems to indicate a known problem with tobacco. Re: that Infinity Black Widow tone arm, Maybe someone here knows that arm and if it is supposed to have that kind of movement in all directions at the point where the arm connects to the vertical mounting post. Something seems Toulouse to me, although it seems like maybe it is some kind of universal joint that is meant to absorb shock, but still doesn't seem right. All my arms are solid, no play like that, never have I seen an arm with so much play in it and so easily moved. Cartridges pick up the smallest sensations. That is their job, except this sensitivitly is supposed to be focused and isolated on the vinyl grooves. All of the arms on my turtables here are totally solid at that connection. None of them has that kind of play. The other thing is to isolate the table with mdeneen's suggestion. I have done this with every turntable except the Technics which has a good system of its own. When I first got the MM-7 it had worse feedback than your system today, until I got the balls to be under the slab. Its scarry at first but you get used to it, it only hurts for a moment. If your turntable still produces that feedback after you get the handballs and rock slab under it, then you will know that it is the arm. I also needed to remove the cover when I while playing the turntable. This system completely eliminated that feedback and footfall problem. Recipe: 4 Cups, one for each ball. Two cans of balls (two balls per can @ Big 5 in RP) 2 inch thick stone slab large enough to fit under the TT. (most slabs this thick will be plenty heavy) That place up on Petaluma Hill Rd. has a large selection and it is fun to find the right one, the slab meant for you, some are bargains because you only need one, its not like you need enough to do a patio. It is fun looking through the yard ther finding a stone with your name on it so to speak. Scarrrry ....eh kids.....oooooh.... This system works amazingly well and just for kicks I have the Rega Planet on one also. In fact it is so much fun buying that stuff, that I am putting these things under everything here. I use large soccer balls and an enormous slab under the washer and dryer, for example. I even park my cars on them but that takes alot of balls. Put under your bed, you guys will sleep more soundly. Once you get into this, you will find all kinds of applications. -CbS someone must know about the Black Widow tone arm and if it is supposed to have so much play in that connection. Quote Link to comment Share on other sites More sharing options...
fini Posted December 20, 2003 Author Share Posted December 20, 2003 Eh, the wife wouldn't go for any kind of vibration reduction in the bed, if you catch my drift. Quote Link to comment Share on other sites More sharing options...
ironwoods Posted December 20, 2003 Share Posted December 20, 2003 "Something needs to be tightened up, and the fact that the previous owner was sticking gum in a couple of places seems to indicate a known problem with tobacco" Hi, just lurking, but have to ask. What is the gum/tobacco corelation? Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted December 20, 2003 Share Posted December 20, 2003 hi, fini: This has nothing to do with your hum problem (which I hope gets worked out!), but rather with your signature. Are you an artist by any chance? Is the signature one you did yourself? It has that child-like appearance that guys like Picasso, Miro, Paul Klee, and some others liked so much. I like it too! Quote Link to comment Share on other sites More sharing options...
fini Posted December 20, 2003 Author Share Posted December 20, 2003 Eric, I wish!! No, I had to pay a graphic artist the big bucks to come up with that. fini Quote Link to comment Share on other sites More sharing options...
fini Posted December 20, 2003 Author Share Posted December 20, 2003 Well, if my balls don't produce, I may have to send Fisher for a hum job. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted December 20, 2003 Share Posted December 20, 2003 Fini, Read this issue of audio basics. The information about tone arms start on page 5; column 3. Basically Frank says that ideally there would be zero play in tone arm bearings and gives some suggestions for correction: http://www.avahifi.com/root/audio_basics/ab_pdf/ab1982.pdf Rick Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted December 20, 2003 Share Posted December 20, 2003 Yes, I got the idea from you. I had credited you in my post, but in the process of editing the post it got buried and upstaged: "The other thing is to isolate the table with mdeneen's suggestion. I have done this with every turntable except the Technics which has a good system of its own. " I just did exactly what you said when I first had trouble with the Music Hall TT, I liked it so much I did it again and again. It cost under $30 total depending on the marble slab. I had previously purchased some box with an inner tube in it, and did not like it and returned it. Your system is perfect. thanks. C&S Gum/tobacco reference, just some silliness on my part. You know, some guy trying to wean off cigarettes who is nervously chewing alot of gum so he is always sticking it on his turntable arm.....and everywhere else.....I really just meant to say that there was a known problem with the turntable arm before fini got it... Quote Link to comment Share on other sites More sharing options...
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