JVC Turntable QL-A7

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MaxCast

Re: JVC Turntable QL-A7
« Reply #20 on: 10 Aug 2011, 09:03 pm »
Well, it works  :) but I'm getting a nasty hum which I didn't have with two other tables connected.
JVC > Vista Audio phono pre > Maple Tree preamp.  Hum fluctuates with volume.  Ground connected.  The I/C ends were a bit bent but straightened easily (would really like to replace the ends someday).  Any ideas on how to eliminate before I go searching will be appreciated.

I took the weight off (it just pulled off the back of the arm) and I don't remember what number it was on  :duh:     Got some reading to do on dialing it in.

neobop

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Re: JVC Turntable QL-A7
« Reply #21 on: 10 Aug 2011, 09:56 pm »
If one of your other arms has an SME type headshell like that, try it and see what happens. You might be replacing those ends or cables a little sooner than you planned.
neo

S Clark

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Re: JVC Turntable QL-A7
« Reply #22 on: 10 Aug 2011, 10:00 pm »
Did you clean the IC's  before hooking it up?

MaxCast

Re: JVC Turntable QL-A7
« Reply #23 on: 11 Aug 2011, 12:23 am »
I sprayed the connectors with pro gold, stuffed the end of a rag around the center pin and twisted it around then hooked her up.

I'll replace the ic ends first.  Why would changing the SME headshell eliminate a hum?

S Clark

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Re: JVC Turntable QL-A7
« Reply #24 on: 11 Aug 2011, 12:33 am »
I sprayed the connectors with pro gold, stuffed the end of a rag around the center pin and twisted it around then hooked her up.

I'll replace the ic ends first.  Why would changing the SME headshell eliminate a hum?
Try moving the wire around at the connectors.  The IC may have broken wires, especially if it had been bent and roughly handled.

bastlnut

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Re: JVC Turntable QL-A7
« Reply #25 on: 11 Aug 2011, 08:12 am »
hallo,

die cinch connectors are press fit and i always immediately replace these out of hand.
the leads are not bad but replacing these for some of better quality and ensuring a better direct connection to the tonearm wires bring real benefits.
get an acrylic mat because the felt one does not give you the isolation and more direct interface to the heavy platter for the best sound.
a record clamp also improves things.

regards,
bas

dlaloum

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Re: JVC Turntable QL-A7
« Reply #26 on: 11 Aug 2011, 08:42 am »
Hi Bas

you reckon the Acrylic is better than a rubber or other elastomer based mat?

I would have thought that an acrylic mat would provide insufficient damping of the platter...
Unless you also do some damping of the underside of the platter with elastomers..... in which case maybe acrylic on top would provide a better interface between damped platter and vinyl....

I would have chosen a Herbies elastomer based mat as my first choice for a replacement...

(my QL-Y5F has the original mat, and I have not tried to mess with it.... yet...)

bastlnut

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Re: JVC Turntable QL-A7
« Reply #27 on: 11 Aug 2011, 09:08 am »
hallo,

i don't like the soft rubber or elastomer mats.
they damp too much for my liking, softens the leading edges.
thin acrylic does not damp enough, so you have a point there.
a 5mm or thicker acrylic mat does offers the right amount of damping for me without softening the sound.
on a Rega with glass platter a 3mm is enough but i like the cork mat i make even better.
the cork mat i make is from small cork granules and not sanded flat, so the surface is a bit uneven. the material thickness here is ≠ 2mm.

a lot depends on the tonearm as well.
if the tonearm is highly damped.....might be lightly damped in your eyes while i prefer only light damping if any at all....then the higher damping of the cork or a harder rubber mat (can be softer but then must be thicker) can provide the better result.
the UA 5045 tonearm is damped a bit and the acrylic mat offers the best balance for me.
i have a very revealing system that is not analytical sounding by any means,
so i hear the micro information that i find so important for me.
it is all about digging all the information out of the source and not with an analytically balanced system, or overly neutral and dry sounding one.

with your QL-Y5F, you can set the damping which restricts the movement at the bearings and not armwand damping, so a harder/thicker material for the mat may let you use the JVC tonearm damping to greater effect.

regards,
bas

neobop

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Re: JVC Turntable QL-A7
« Reply #28 on: 11 Aug 2011, 07:01 pm »
I sprayed the connectors with pro gold, stuffed the end of a rag around the center pin and twisted it around then hooked her up.

I'll replace the ic ends first.  Why would changing the SME headshell eliminate a hum?

If you had another headshell already set-up you could just substitute it to eliminate or identify any of those connections. Hopefully a new set of plugs will fix it.
neo

MaxCast

Re: JVC Turntable QL-A7
« Reply #29 on: 20 Aug 2011, 01:12 am »
Spinning vinyl, got rid of the hummer by replacing the RCAs.  :thumb:
Listened to 2112 and breakfast in America.

Two things. I hear things between songs and loss of dynamics. I expected vibist of loss of dynamics but not the song between the songs. Any ideas?
Opps got to flip the record....
Gotta remember to turn the wolume down when queing.  :o
Anyway is the song between the songs the quality of the record or something else?

jimdgoulding

Re: JVC Turntable QL-A7
« Reply #30 on: 20 Aug 2011, 01:24 am »
Max- Could that be pre-echo?  Anybody ever heard of a song on the other side leaking thru?

S Clark

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Re: JVC Turntable QL-A7
« Reply #31 on: 20 Aug 2011, 06:00 am »
I have heard that before. I believe it to be an echo from the imprint of one lap from the master tape on the adjacent layer down- the result of using a thinner mil tape or one that has been stored for a long time.  It is heard between cuts on records in which faulty master tapes were used.  I can't imagine that it is possible for the flip side of a record to impact the other side. 

MaxCast

Re: JVC Turntable QL-A7
« Reply #32 on: 20 Aug 2011, 12:52 pm »
It happened to all albums I listened to.  It was the next song that you can hear.   :scratch:
I believe it was happening throughout the record as I think I heard during a quiet passage.  Like there was another low amped needle 1/2" ahead of the main needle.

neobop

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Re: JVC Turntable QL-A7
« Reply #33 on: 20 Aug 2011, 02:04 pm »
It is possible to hear the adjacent groove sometimes, usually as an (pre) echo as described. Is this the cart that came with the table? Maybe VTF is excessive or it needs a new stylus. Improper anti-skate setting could make it worse. This will happen on occasion with mass produced records, but no way should it happen consistently.
neo