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Old 16th March 2013, 05:42 AM   #21
AKSA is offline AKSA  Australia
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Jens,

The TKD pots are a revelation. You will immediately notice improve clarity and resolution (maybe these are the same, no?)

I was very suspicious when I fitted one to a Lifeforce. After I heard it, before and after, I realised what audiophiles were raving about. The very high cost does delivers the pinnacle of performance, but of course using these uber-expensive gadgets in retail product are very hard to justify. I have also being eyeing the IC resistor arrays (PGA series from TI) which deliver attenuation duties, but they also include a full on opamp and I am concerned about sonic qualities just yet.....

Cheers,

Hugh
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Last edited by AKSA; 16th March 2013 at 05:46 AM.
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Old 16th March 2013, 11:31 AM   #22
Jens A. is offline Jens A.  Denmark
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Quote:
Originally Posted by AKSA View Post
Jens,

The TKD pots are a revelation. You will immediately notice improve clarity and resolution (maybe these are the same, no?)

I was very suspicious when I fitted one to a Lifeforce. After I heard it, before and after, I realised what audiophiles were raving about. The very high cost does delivers the pinnacle of performance, but of course using these uber-expensive gadgets in retail product are very hard to justify. I have also being eyeing the IC resistor arrays (PGA series from TI) which deliver attenuation duties, but they also include a full on opamp and I am concerned about sonic qualities just yet.....

Cheers,

Hugh
Hi Hugh,

Well - what can I say? Except that the GK-2 definitely deserves the best pot possible?

Cheers,

Jens
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Old 16th March 2013, 12:12 PM   #23
AndrewT is offline AndrewT  Scotland
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I rarely see this section but came to my attention today.

Having read that twin bipolar electrolytics connected back to back & in series offer a very low distortion audio coupling with DC blocking, would it be sensible to consider such for the sub out of the GK2?

A pair of 15uF or 22uF would give a big increase in coupling capacitance over the 1uF.
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Old 16th March 2013, 11:59 PM   #24
AKSA is offline AKSA  Australia
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Hi Andrew,

Back to back quality electros are OK, there is a small improvement but it's marginal IMHO.

As for 15-22uF is probably too much because you are not trying to reproduce signal of 2Hz. Very should not go too late, less that 15Hz is not needed, because firstly there is no recorded information at that frequency, and secondly at around 16Hz the ear does not musical tone - they are perceived as 'seismic' noises.

There is again a good reason not high value of coupling cap this playing vinyl. Rumble. Arghhhh.......

Cheers,

Hugh
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Old 18th March 2013, 10:29 PM   #25
Jens A. is offline Jens A.  Denmark
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The TKD motor pot arrived from Michael Percy today very well packaged and in perfect condition.

I hope to get it installed one of the next few days and will report back on sound when I have had a bit of a listen

Cheers,

Jens
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Old 18th March 2013, 11:29 PM   #26
andyr is offline andyr  Australia
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Quote:
Originally Posted by AndrewT View Post
Having read that twin bipolar electrolytics connected back to back & in series offer a very low distortion audio coupling with DC blocking, would it be sensible to consider such for the sub out of the GK2?

A pair of 15uF or 22uF would give a big increase in coupling capacitance over the 1uF.
Haha - exactly what I am going to do - but not using such big values!

I happen to have a stash of 1uF BG NPs, so I will use 4 for each channel in their back-to-back "Super E" configuration.


Regards,

Andy
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Old 19th March 2013, 09:20 AM   #27
AndrewT is offline AndrewT  Scotland
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That is exactly what I would not do.

I'd used a suitable single film cap for a 1uF coupling cap.
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Old 20th March 2013, 04:02 AM   #28
andyr is offline andyr  Australia
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Quote:
Originally Posted by AndrewT View Post

That is exactly what I would not do.
Can you explain why (you would not do this)?

Quote:
Originally Posted by AndrewT View Post

I'd use a suitable single film cap for a 1uF coupling cap.
While I have a single 1uF cap on the tube out, using a 2.2uF film cap would give a lower CR roll-off than 1uF - which is very important IMO for "Sub Out". (But, yes, maybe 4uF is a bit OTT. )

But any "good" cap of 2.2uF is physically large ... and difficult to fit - hence the attraction of using the BG NPs. And the "refinement" which the big film caps provide for the tube out ... is not needed for Sub out.

Regards,

Andy
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Old 20th March 2013, 11:09 AM   #29
AndrewT is offline AndrewT  Scotland
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In post26 you said "that is exactly what I would do" and you quoted my post showing twin bipolar in series for an effective halving of the coupling capacitance.
You then followed up with "stash of 1uF". I will use 4.
To me this implied since you were doing "exactly" twin bipolar in series, that you were going to parallel a second twin series bipolar to bring the effective coupling capacitance back to 1uF.
That is what I would not do.

If you meant something else, then your post did not convey that message.
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Old 20th March 2013, 09:45 PM   #30
andyr is offline andyr  Australia
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Quote:
Originally Posted by AndrewT View Post
In post26 you said "that is exactly what I would do" and you quoted my post showing twin bipolar in series for an effective halving of the coupling capacitance.
You then followed up with "stash of 1uF". I will use 4.
To me this implied since you were doing "exactly" twin bipolar in series, that you were going to parallel a second twin series bipolar to bring the effective coupling capacitance back to 1uF.
That is what I would not do.

If you meant something else, then your post did not convey that message.
Haha - I am having a similar difficulty understanding what you are saying, likewise.

Let's start off by agreeing that a "Super E" configuration of BG Ns/NPs is a parallel pair of them, arranged so that the '+' leg on one connects to the '-' leg of the other. Because they are NPs, you can safely do that.

What I originally was thinking off doing was using 4 x 1uF NPs, arranged so that 2 '+' legs were connected to 2 '-' legs. This is a "double Super E", giving a total capacitance of 4uF.

However, I am subsequently thinking that it's not a good idea to go this high ... and a standard "Super E" pair - giving a total of 2uFs - is fine.


Regards,

Andy
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