[Jens]

Yeah, and the caps will have to be changed, too! Anyone know a good source for Nichicon Gold Tune caps?

[RonR]

Jens,

I must have missed this the first time around:
The Nichicon Gold Tunes are on page 8 of the Michael Percy catalogue.

Hugh,

Any news on this mod yet?

Cheers,

Ron.

[Jens]

Thanks Ron,

Not going there right now, but it's certainly nice to know where to source the stuff 

[rabbitz]

Anyone know a good source for Nichicon Gold Tune caps?

Have just received some from here.
http://www.minisemi.com/Nichicon%20Muse%20capacitors.html

I haven't had a reply from Michael Percy on my last 2 emails.... don't know what's going on there.

[AKSA]

Hi Ron,

No further news on the caps mod at this stage, however, watch this space.

If you'd like to buy the 4,700uF 63VW Nichicon Gold Tunes, I have more than 1000 of them at this point but cost is $AUD14.50 each plus shipping, they are quite expensive but REALLY good.

Cheers,

Hugh

[Jens]

Implemented the C2 tweak today - in the form of a Black Gate NX Hi-Q 22 uF cap.

Even though the cap had not been in use at all before, there was something to be had right away; some improvement in bass articulation, and definitely more detail overall.

Well done by such a minuscule cap!!! 

I should mention that C1 and C19 have already been replaced by Sonicap Platinums, as described in the Platinum thread.

I've had good experiences with the BG NXes before, and I wasn't let down this time either. From here this upgrade (fairly cheap, actually) can only be recommended 

[jules]

Going back to an earlier part of this thread ....

With the use of large film caps comes the chance of positive feedback and .... OSCILLATION , particularly if the cap happens to be close to the output wires so ...

* Would shielded output wire be a complete solution to this problem?

and

* I know this a a bit "how long is a piece of string" but is there a "safe distance here"?

Totally unrelated to the above ... I'm considering using a sub at some time in the future. In this situation it would seem to be clever to use a smaller cap at C21, so if we are looking at say 70-90 Hz for the sub xover, what would be an appropriate value for C21?

edit: maybe I should expand a bit on the "C21" thing. With a sub or other low frequency drivers, a decent C1 is going to be important to give low base but while the sub-out comes from the ss stage [before C21] the main speakers come from the tube stage after C21. So a smaller C21 won't reduce the bass from sub but it could provide a useful roll-off from the mains albeit gentle. Have I got it right here 

jules

[andyr]

Implemented the C2 tweak today - in the form of a Black Gate NX Hi-Q 22 uF cap.

Even though the cap had not been in use at all before, there was something to be had right away; some improvement in bass articulation, and definitely more detail overall.

I should mention that C1 and C19 have already been replaced by Sonicap Platinums, as described in the Platinum thread.

Hi Jens,

Yes, I used the BG 22uF/6.3v 'NX' at C2 also.

In addition, BG 10uF 'NX' for C1.

Regards,

Andy

[Jens]

Going back to an earlier part of this thread ....

With the use of large film caps comes the chance of positive feedback and .... OSCILLATION , particularly if the cap happens to be close to the output wires so ...

* Would shielded output wire be a complete solution to this problem?

and

* I know this a a bit "how long is a piece of string" but is there a "safe distance here"?

Totally unrelated to the above ... I'm considering using a sub at some time in the future. In this situation it would seem to be clever to use a smaller cap at C21, so if we are looking at say 70-90 Hz for the sub xover, what would be an appropriate value for C21?

edit: maybe I should expand a bit on the "C21" thing. With a sub or other low frequency drivers, a decent C1 is going to be important to give low base but while the sub-out comes from the ss stage [before C21] the main speakers come from the tube stage after C21. So a smaller C21 won't reduce the bass from sub but it could provide a useful roll-off from the mains albeit gentle. Have I got it right here 

jules

Hi Jules,

Just a word of caution: Lowering the C21 cap value caused hum problems in my GK-1. I had the same thought as you, i.e. to implement the roll-off via the output cap, so I changed the output cap value to .047 uF instead of 1 uF. It turned out that because of this, hum found its way in through the interconnects between the GK-1 and the LF55. Granted, these interconnects are unshielded, but I'm not sure that shielding them would solve the problem.

In other words, it seems that "hum rejection" becomes too low if the output cap value is lowered too much.

However, it could be that in your setup, it would not create a problem, it's difficult to be sure about these things. I should tell you that great effort has been taken in my system to ground everything properly, both on the signal side and the AC side, as a result of which my system is very silent.

If you succeed with lowering the cap value, please let us know. It's fairly easy to try out and return things to normal, if it doesn't work out.

In my system, I'll probably implement the rolloff in another way. I'll get back with details when it has been tried out

[jules]

Jens,

sorry, I was a bit slow to pick up on your response but that's very useful information thanks. I certainly won't experiment with a range of V caps at C21 

As for the other problem of possible oscillation [signal out wires close to C1] I think I'll use some judicious shielding, along with a slight re-route first up.

jules

[RonR]

A simple (and relatively cheap!) tweak to report.

In the Power Supplies of the GK-1 solid state section, replace:
C15 + C16 470uF
C10, C11, C12 + C14 100uF
with equivalent Nichicon KZs.

The effect is quite subtle, but the Nichicons give rise to an effortless presentation which is similar in character to the Lifeforce.
These caps replaced Black Gate STDs in these positions. I prefer the KZs. And what's more, burn-in was over in a just a few hours. They are roughly the same size as the BGs, so may be a bit of a squeeze on the GK-1 analogue board.



Cheers,

Ron.

[gerado]

Hi all,

I oftern visit and follow the topics but this is my first post!

I finally did the C1 and C19 mods to my GK1 with Platinum sonicaps 22nf and 0.47uf. Initially I thought I ordered the wrong C1, it is huge compaired to what it replaces.
I was not prepaired for the difference in sound. Its only 3 days now with less than 15hours burn in but all my friends think there is another reason for the constant smile on my face
The base and top end is probably better than I was expecting having read the threads and speaking with Hugh. What I did not expect was in the midrange area. I have always been irritated by midrange edginess on my system, but this is now much much smoother. I also noticed that there is a certain quietness, the music has more meat to it and the imaging/sound stage is considerably better.
I hope there is a technical explanation and Im not just talking myself into hearing whats not there

I cannot imagine what its going to sound like after the 100+hours of burn in required  that  has been mentioned here.

Today I also changed to a stepepd attenuator(no buffer or op amp yet) and though the difference is not as pronounced , the top end particularly sounds cleaner.


Question
Does replacing the coupling cap C21 with a better quality cap make significant sonic improvements. The DIY manual implies this is such a crutial cap to the sonics of the GK. What can be considered here and is it worth it?


T


modified 38/6/2007

[kyrill]

hi

Congrats with yr better sound
22uF for C1?
Are you sure? sonicaps doesnt have a 22uF listed for gen II at least not at soniccraft.com?
not that 22uf will not do, i think
and .47uF for C19? i thought .01uF was the default value?

[gerado]

Ahh not a good start
well spoted

22nf and 0.47uf got my n's and u's mixed up

and double checking my order was the platinums, must have felt  rich that day.

[stvnharr]

Ahh not a good start
well spoted

22nf and 0.47uf got my n's and u's mixed up

I hope you used the .47uf in C1 position and 22nf in C19.  C19 only requires .01uf, but.................
You get the biggest bang with Platinum in C1!!!  The C21 output coupler, in a Platinum, won't give nearly as much improvement, and it does need a 1uf cap.  You could try Dynamicap there.  But it's not good value to put Platinum there.

Steve

[gerado]

Thanks Steve
did use them in the right spots. Was unsure if they were directional , but do not seem to be. Nothing smoking so far!
Will try the dynamicap as well, thank you for the advice.

[DSK]

Hey Steve, did you soften the lighting and let your GK-1 Platinum have its way with your LF55 Platinum yet? Was it good for them ... and you?

[stvnharr]

Hey Steve, did you soften the lighting and let your GK-1 Platinum have its way with your LF55 Platinum yet? Was it good for them ... and you?

Darren,
The Gk-1 is at my wife's in Ballarat.
I am currently in my American phase, in Wyoming, and have the LF here.
Everything will get together upon my return.
That will be good in many many ways!!!

Steve

[stvnharr]

Thanks Steve
did use them in the right spots. Was unsure if they were directional , but do not seem to be. Nothing smoking so far!
Will try the dynamicap as well, thank you for the advice.

The caps aren't directional, but there is a shield.  I used them each way and never noticed a difference, so I wouldn't really worry about it.