Seduction hum, buzz and sound quality issues

[Grainger49]

rebbi,

I would go to Radio Shack and buy a pack of "Jumpers."  That is a number of short wires with an insulated alligator clip on each end.  They are great for measuring voltages and resistances as well as shorting the inputs of an amp, preamp or anything else you need it for.

But, yes, you can solder a wire from the center to the RCA jack to the outer conductor.

[Paul Joppa]

My memory is not that good but I do recall that early Foreplays did not have the signal ground attached to the chassis. Making that connection (T13 to T14) reduced hum and buzz in many cases.

I know the earliest Foreplays had 2-wire power cords; I do recommend a 3-wire cord with the ground lead taken to the chassis close to where the power cord comes in. The UL standard is for that ground lead to be the longest, so that if the power cord is ripped out of the preamp by brute force, the ground wire will be the last one to disconnect.

[rebbi]

Well, here it is, November of 2013, and I still haven't sorted out my phono stage hum problems, but now I'm determined to do so!   

I recently completely rearranged my components. My power amps (now a pair of Manley Mahi's) are a fair distance from my preamp (a Manley Shrimp) and my Seduction is on a shelf by itself, well underneath the Shrimp preamp.

The buzz in the phono side is still there.

I noticed that if I touch the top plinth of the turntable, the hum becomes somewhat less loud.

Also (and this seems really weird to me) I have figured out that even with the Seduction plugged in but powered off, whatever preamp input I plug the Seduction into will hum. I tried a number of different Shrimp inputs just to make sure it wasn't the preamp, but no: any input will hum with the powered off Seduction plugged into it.

I still haven't made those grounding plugs but will do so.

[Grainger49]

Do you have a Rega table?  They seem to have a grounding problem brought out by Seductions.  I suppose you have used a pair of Sorting Plugs to see if it goes away.

[rebbi]

Hi, Grainger,
My turntable is a SOTA Sapphire, not a Rega, so that shouldn't be the issue.

[Grainger49]

Hum/buzz is a hard problem to find.  Sometimes inverting the power plug on one device cures it.  Did you try shorting plugs, the above post includes a link?

[saildoctor]

Do you know how shielded your interconnects are?  I was getting a lot of hum from my VPI Classic > Seduction > FPIII with some ICs that had foil shields. I made some diy ones with a heavier braided shield that seem to help quiet down whatever I'm picking up.

[Paul Birkeland]

I'll just mention here that 3 years ago, there was a first step recommended to sort this problem out.  It involves going to a Radio Shack and spending about $10, or placing a parts order online for about the same amount. 

I would start by following through on that advice, then we will actually have the information we need to help you sort this out.

[rebbi]

Okay, I looked on eBay for RCA shorting caps and found a guy selling gold-plated brass ones for about $13 for a four-pack, plus shipping from Hong Kong, which seems ridiculous. So I'm gong to sacrifice two of these plugs (as in the photo) and solder the stripped end of the wire to the outside of the round, metal collar on the plug. That's all I need to do, right? (Sorry for being cautious/dense.)

[vetmed]

Go to Radio Shack or your local discount electronics store. Buy a crappy quality RCA to RCA cable. Amputate one plug, strip the insulation. 2 conductors which you can now short using clip leads.

Robert Lees

[fullheadofnothing]

Butchering cables is a little harder, since they are designed to be thrown away rather than re-soldered

Plugs:
http://www.radioshack.com/product/index.jsp?productId=2103423&retainProdsInSession=1
4 pack, $3.49 ($0.87 each)
Every RadioShack has these in stock. Ask for part number 274-319 if you can't find them.

http://www.ebay.com/itm/RCA-Plug-Solder-Type-Audio-Cable-Connector-device-Intelligent-info-/300861665368?pt=LH_DefaultDomain_2&var=&hash=item460cc0b058

$0.94, free shipping, get at least two.

[rebbi]

Golly, the customer reviews on those Radio Shack plugs are the angriest I've ever seen (as in "this is the cheapest crap I've ever seen") but I guess for my purposes they'd be fine, eh?

[howardnair]

rebbi!-the problem seems to be from your turntable-i won't say that is for certain-but the buzzing changes when you touch that component--  make sure that your ground wire for your turntable is not broken inside the insulation or rt at the terminal  and then have a look at the wires in your headshell

[rebbi]

Howard,

These are good suggestions. The headshell wires look okay; nothing seems to be loose or anything. As for the tonearm cable, what you suggest about a short in the ground wire isn't impossible. The arm (a Linn Basik that I bought, used, in the mid-1980's!) is still using the original cable, so maybe it's gone bad...

[howardnair]

well i wouldn't say the cable  has gone bad -take a ohm meter and connect to the end of the ground wire and the other to the base of the arm you should get some continuity-that is usually the general vicinity of the other end of the ground wire-i am not sure about cking the continuity further up at the headshell -i know you should not put the meter on a  cartridge -