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Capacitance

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Graham Slee View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 2016 at 4:26pm
Strikes me that the capacitance is too low, not too high. Allowing 25 pf for arm wiring you'd need a 75pf cable. The 100 - 220 pf input capacitance most phono sections use will then give you 200 - 320 pf, which is in the region Ortofon suggest.

I'll restate that MM manufacturers know there is a resonant hump and design their cartridges to be flat with it. By reducing capacitance as you have with the 12.2pf cable, you are extending the response but at a lower level. Without any capacitance at all, a 0.7H cartridge will be -3dB (half power) at 11kHz and then the output will fall of at a rate of 6dB per octave (halving the output in voltage terms per doubling of frequency).

By the looks of it you're somewhere in-between.


Not simple enough for Google-Bot to understand...
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Paul H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Paul H Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 2016 at 4:37pm
Don't tell me that, Graham: I just spent £70 on that cable!

Seriously, I have two lengths of cable available to me: 2 foot and 3 foot. I can swap my 2 footer for a 3 footer which will add in another 12pF but really, is that going to make much of a difference? Failing that, I can add my mono switch back in which requires two runs of cable. That will increase the capacitance of the cable to roughly 60pF plus whatever the switch adds but it seems better to me to have that switch in or after any pre-amp rather than in front of it.

Thinking out loud: I wonder what capacitance ProJect's TT cable is?
ProJect 1Xpression Carbon UKX w/ Ortofon 2M Black; Arcam Alpha 7 CD player; Graham Slee Revelation M pre; Denon PMA 355UK amp; Epos K1 speakers; Blue Jeans LC-1 interconnects. Room: 2.9m x 3.1m.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DaveG Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 2016 at 4:37pm
Hi Paul

My thoughts are similar to Andrew's - once you get a really good phono stage in between your TT and amp I would expect the particular problem to disappear. It only affects vinyl right? your TT is a good 'un if reputation is anything to go by. Ortofon's likewise. I don't know your cable but that is an extremely low capacitance figure and as Graham said, Denon are unlikely to be doing anything peculiar. So with my Inspector Clouseau hat on, I deduce ze Integrated phono stage is ze culprit! Perhaps the room interaction doesn't help matters, but that would be the same for all sources. The EGV you are getting on loan will confirm it in seconds. I reckon you'll be very pleasantly surprised.
Dave

Michell Gorbe + HR PSU -> Cadenza Bronze -> SME V -> Elevator -> Accession -> Proprius -> B&W CM6 s2 | Cusat 50 & Spatia cables ->
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Paul H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Paul H Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 2016 at 4:40pm
Hi Dave,

I was recommended that cable by folks at the Steve Hoffman music forum who were aghast at how much capacitance I had in my system. Half the problem is that it's hard getting specs off anyone. For example, if Project's own cable has a higher cap (which I suspect it does) I can easily pop it back into the chain but then I have no idea what cap I'm actually generating.

You're right though, trying out another amp will confirm one way or another.
ProJect 1Xpression Carbon UKX w/ Ortofon 2M Black; Arcam Alpha 7 CD player; Graham Slee Revelation M pre; Denon PMA 355UK amp; Epos K1 speakers; Blue Jeans LC-1 interconnects. Room: 2.9m x 3.1m.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Drewan77 Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 2016 at 4:42pm
So a 1.5metre Lautus interconnect @55pf/m should fit the bill nicely - maybe Paul should add this to his loan items? Wink
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DaveG Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 2016 at 5:04pm
I just had a look at Blue Jeans website. A 75 ohm coax, double-screened, low capacitance cable is the best for audio according to the blurb. Now where have I seen such things for sale elsewhere . I've never tried any of their products, but they do have a no nonsense vibe that I like. I'd guess it's a decent cable.

Myself, although high capacitance can be bad I don't worry about it overmuch, other than I like to keep it low-ish. Cusat fits the bill for me
Dave

Michell Gorbe + HR PSU -> Cadenza Bronze -> SME V -> Elevator -> Accession -> Proprius -> B&W CM6 s2 | Cusat 50 & Spatia cables ->
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 2016 at 5:15pm
With all due respects to the good people over at Steve Hoffman, they might not have my 43 years turntable user and electronics design experience, and I doubt any can match Denon's 106 years!

And I have also heard of the "all capacitors are evil" witch hunt.

You can doubt me as much as you want at me suggesting you've insufficient capacitance but the capacitance is there for a reason.

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