Compliments of the Season and Mods to the GK1 Phono Section

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Oz_Audio

  • Jr. Member
  • Posts: 109
To one and all, especially Hugh and Family, Compliments of the Season and a prosperous New Year.

It has been a very long time since I posted on this esteemed forum, but I have a look nearly every day.

Anyway, a number of years ago, I helped Hugh in beta testing the GK1, and to my amasement, my very novice soldering is still OK and it is working perfectly.

I also built a very early version of the phono section and over a number of years kept putting the soldering iron to it make it sound better.  The major improvement was changing the resistors on the musical side to 1% carbon varieties from Jaycar.

A major improvement.  It was like lifting a vial from the music, it became, clean, crisp with an open wide soundstage.

Well it died about 3 years ago, due to too much soldering and I bought a new one from Hugh.  This was built to speck, I changed nothing. And the sound was good, very good, but without the modded versions extra bit of magic.

So after 2 years, moving, unpacking, (still cannot find my multimetre!) I put the soldering iron to the old, pulling out the resistors and the new, putting in the resistors, and presto, the magic is back!!  Big Time!!

I have a Paris head amp, but I wanted to get the basic phono section perfect before changing cartridges from a Denon 160 to a Denon 103R.  I will do this in about 4 weeks because no 1 rugrat, now is interested in vinyl.  He can stuff up the 160 and his records, but not the 103 and my 60's, 70's and 80's classics!

Mark :thumb:

andyr

Re: Compliments of the Season and Mods to the GK1 Phono Section
« Reply #1 on: 22 Dec 2007, 08:19 am »

I also built a very early version of the phono section and over a number of years kept putting the soldering iron to it make it sound better.  The major improvement was changing the resistors on the musical side to 1% carbon varieties from Jaycar.

A major improvement.  It was like lifting a vial from the music, it became, clean, crisp with an open wide soundstage.

Mark :thumb:

Hi Mark,

Greetings to another GK-1 vinyl enthusiast!  :D

Can you tell me which reses in the phono stage you changed?

I also have a "Paris" - a superb head amp IMO - which I use with the phono section of my GK-1 ... but I also have an external phono stage which has more gain, so I don't need to use it with this (for my 0.28mV Benz "Ebony").

Regards,

Andy

Oz_Audio

  • Jr. Member
  • Posts: 109
Re: Compliments of the Season and Mods to the GK1 Phono Section
« Reply #2 on: 22 Dec 2007, 08:31 am »
Hi Andy,

I cannot find my multimeter and cannot read risistor codes so I did not test the values.

From the version 1.0 paperwork values and changes are as follows:

R6 3K3, R5 68K, R4 18K, R2 150R, R3 12K.

On the later versions either R3 or R4 is not used, but on the earlier version they are, so I put them back in.

I also have more gain with the modded version after listening tests today.

Mark

AKSA

Re: Compliments of the Season and Mods to the GK1 Phono Section
« Reply #3 on: 22 Dec 2007, 09:23 am »
Hi Mark,

To you, your wife Helen and children, and the many AKSAphiles out there, I extend a Merry Christmas and Happy New Year also!

Thank you for your email, and thank you for coming back to us.

How is Cairns, do you love the place??  People rave about it!!

Hugh

andyr

Re: Compliments of the Season and Mods to the GK1 Phono Section
« Reply #4 on: 22 Dec 2007, 10:25 am »
Hi Andy,

From the version 1.0 paperwork values and changes are as follows:

R6 3K3, R5 68K, R4 18K, R2 150R, R3 12K.

Mark

Thanks, Mark - verry interesting!  :D

Regards,

Andy

kyrill

Re: Compliments of the Season and Mods to the GK1 Phono Section
« Reply #5 on: 22 Dec 2007, 11:27 am »
 a general question i now have is this universally true enough? Are carbon based R more musical and at the same time transparent enough to enjoy? or is it a matter of taste?

RonR

Re: Compliments of the Season and Mods to the GK1 Phono Section
« Reply #6 on: 22 Dec 2007, 02:34 pm »
Hi Kyrill,

I'm not sure if this applies to all Carbon resistors to the same extent, but here's what Ginger said about Riken Ohms back in 2003:

Quote
The Riken Ohms sound good because they have a voltage dependency.

That is their resistance = R + R x k x V
Where R is its nominal value,
V is the voltage across the resistor
k is some scale factor.

It can be shown mathematically (but I'm not going to bore you with it here) that this introduces Second Harmonic Distortion. Adding second harmonic distortion subjectively adds warmth and makes the bass sound stronger.

Later on, Hugh had this to say:

Quote
I do not believe, having now built up an AKSA redolent with Rikenohms, that too many is good.  It seems these are voltage dependent resistors;  that is, their resistance changes with applied voltage.  This introduces subtle changes in operating points in the AKSA, which in turn fosters creation of H2 and some H3.  (second and third harmonics).  Too much is NOT good;  a balance is necessary.

So it looks like a sprinkling of Carbon resistors in the right places is the way to go here. The $64K question is: Which ones to replace? :scratch:

Cheers,

Ron.

kyrill

Re: Compliments of the Season and Mods to the GK1 Phono Section
« Reply #7 on: 22 Dec 2007, 02:45 pm »
Hi Ron

THIS is NOT what i WANT to hear..

I want to hear YEs YES this brand XX is the best if you favour uncolored transparent and O so, so sweet musical sound
and they are only 18 cents a peice if you take only 1500 or more otherwise
22 cents a piece
Ah well

so other alternatives which are not introducing harmonics but sound musical and transparent?
 the GK1 is introducing already enough harmonics

Oz_Audio

  • Jr. Member
  • Posts: 109
Re: Compliments of the Season and Mods to the GK1 Phono Section
« Reply #8 on: 23 Dec 2007, 12:45 am »
Hi Hugh, yes Cairns is great, better weather and a resort feel to the place because of the number of OS tourists.

kryll, I have not changed to carbon resistors anywhere else in my AKSA's, just the phono section.

IMHO the difference is not a matter of taste, it is dramatic and instant.  The same as going to a GK1 from any other preamp and then going to Siemens Gold Pin valves from the standard ones.

The sound stage is wider, higher, deeper and clearer, more transparent.

Andyr, I hope you try the same, I would love to hear another's opinion.

Mark