[gjfim]

Hi all,

I have just completed assembly of GK-1 entry level (with some help
from Hugh- thanks again).  

Hugh points out in an earlier post, that the GK-1 input
capacitor C1 (MMK, Evox-Rifa) passes AC signals better (i.e. with
less distortion), in the presence of “appreciable DC bias”.  

Given that it works this way, would it be advantageous to remove the
output coupling cap in the source (CD player), to allow more DC to
pass into the GK-1 input cap?  If so, what is the range of DC input
for optimum performance of the input cap?

Thanks to all for your comments.

Regards,
Gary

[Malcolm Fear]

I put an Auricap at C1.
Hugh does talk about DC and how an Auricap won't work vwry well here. I spoke to Mr Auricap (Richard Smith) as I was confused. The Auricap at C1 sounded much better than the stock GK-1.

Richard's response
All we have ever heard is that they sound great everywhere. We use an
auricap at the input of our amplifiers and they sound wonderful. Sometimes improving the signal path allows a previously masked problem to be heard.
The problem is then mistakenly blamed on the improvement.

If it sounds good to you don't worry about what someone else says.

Richard
Audience LLC

[EchiDna]

I'm playing Devil's advocate I know, but what else would you expect Richard to say about his own product?

[Malcolm Fear]

Hi Echidna

I did write to Richard, because I heard an improvement using an Auricap at C1 and was confused by what I was supposed to hear. Richard reinforced my own observations.

I do take your point that Richard is going to say nice things about his own product.

[andyr]

Just thought I'd stir the possum here (for all you Yankees in this Forum, that's Aussie-speak for being provocative).

I have replaced the MMK, Evox-Rifa at C1 with a RelCap RTX (bcoz Hugh says they are excellent, sonically ... but please note, the reason he doesn't include them as standard is that they are expensive, so the resulting stock-holding would send him broke!).  Haven't finished my GK-1 yet, so I can't tell y'all how it sounds but I know it's gonna sound a lot better than the old Naim pre-amp which I use at present!

However, I would not use an Auricap for one simple reason ... in my book, the only good wire is a solid-core wire and the Auricaps use multi-stranded leads.  Hence I am replacing the Auricap which Hugh supplies for C21 with a RelCap.

Regards,

Andy

[mb]

Hmm... if you need to dispose of the Auricaps, throw them my way

I believe there are a number of us who are quite happily using Auricaps in place of the Rifa MMKs.  In their price range, they're among the better ones. My speaker crossover had some fairly large MMKs. Replacing them with something like Auricap would have been very expensive, so I just bypassed with 0.1uF Auricaps that I had in stock. The improvement in clarity was very easy to discern. YMMV of course.

[andyr]

Hmm... if you need to dispose of the Auricaps, throw them my way

I believe there are a number of us who are quite happily using Auricaps in place of the Rifa MMKs.  In their price range, they're among the better ones. My speaker crossover had some fairly large MMKs. Replacing them with something like Auricap would have been very expensive, so I just bypassed with 0.1uF Auricaps that I had in stock. The improvement in clarity was very easy to discern. YMMV of course.

Sure, mb and using RTXs is even more expensive.    But, in the search for sonic orgasms, what's an extra buck or two!!??

Regards,

Andy

[AKSA]

Hi Gary,

You wrote:

Given that it works this way, would it be advantageous to remove the output coupling cap in the source (CD player), to allow more DC to
pass into the GK-1 input cap? If so, what is the range of DC input
for optimum performance of the input cap?

Just about all caps work better if they have a few volts across them;  the dielectric has more linear compressive performance (sometimes crudely referred to as 'Young's Modulus') if there is a preload across it.  Caps store their energy as mechanical compression of the dielectric, caused by an attractive electric field across the electrodes, and the preload helps a lot, particularly on electrolytics.

The Evox-Rifa MMK is good sonically, despite low cost, and it takes a VERY expensive cap to better it, such as an Auricap, a Hovland, or an RTX.  Some like the oil-filled Jensens and Vitamin Qs, but in general these caps are used as couplers in tube circuits and like higher voltages.  As a rule, try to match the operating conditions with the spec;  a 200V cap with 1V across it may not sound as good as one with a rating of 50V, all other things being equal, for example.  There are arguments for and against, but this is a good guide.  I have seen it written elsewhere that one should choose the highest possible voltage rating for all circuit situations;  I don't agree with this, and besides, a 470nF cap becomes very large and unwieldy, and if too big, can actually cause oscillation in the AKSA because of positive feedback from the output.  Yes, I've seen this......

The input cap on a SS amp or preamp typically has about 100mV across it.  Very little, and a good chance of damaging the music.  If you are concerned to change C1 on the amp or preamp (or delete the output cap on your CD player) you should do a little comparison with other caps in the market first, so that you actually do extract a performance benefit.  Believe me, it's REAL easy to go backwards!

For myself, I'd be reluctant to replace the output cap on a CD player.  It should be upgraded, perhaps, never removed.  I would try to use a NX Black Gate in this role.  They are good!

Cheers,

Hugh[/quote]

[AKSA]

Hi Gary,

You wrote:

Given that it works this way, would it be advantageous to remove the output coupling cap in the source (CD player), to allow more DC to
pass into the GK-1 input cap? If so, what is the range of DC input
for optimum performance of the input cap?

Just about all caps work better if they have a few volts across them;  the dielectric has more linear compressive performance (sometimes crudely referred to as 'Young's Modulus') if there is a preload across it.  Caps store their energy as mechanical compression of the dielectric, caused by an attractive electric field across the electrodes, and the preload helps a lot, particularly on electrolytics.

The Evox-Rifa MMK is good sonically, despite low cost, and it takes a VERY expensive cap to better it, such as an Auricap, a Hovland, or an RTX.  Some like the oil-filled Jensens and Vitamin Qs, but in general these caps are used as couplers in tube circuits and like higher voltages.  As a rule, try to match the operating conditions with the spec;  a 200V cap with 1V across it may not sound as good as one with a rating of 50V, all other things being equal, for example.  There are arguments for and against, but this is a good guide.  I have seen it written elsewhere that one should choose the highest possible voltage rating for all circuit situations;  I don't agree with this, and besides, a 470nF cap becomes very large and unwieldy, and if too big, can actually cause oscillation in the AKSA because of positive feedback from the output.  Yes, I've seen this......

The input cap on a SS amp or preamp typically has about 100mV across it.  Very little, and a good chance of damaging the music.  If you are concerned to change C1 on the amp or preamp (or delete the output cap on your CD player) you should do a little comparison with other caps in the market first, so that you actually do extract a performance benefit.  Believe me, it's REAL easy to go backwards!

For myself, I'd be reluctant to remove the output cap on a CD player.  It should be upgraded, perhaps, never removed.  To do so would threaten its installation in other people's systems, a move I regard as important to AB testing.  I would try to use a NX Black Gate in this role.  They are good!

Cheers,

Hugh

[Malcolm Fear]

Hugh, you're stuttering again.

[AKSA]

Mal,

Damn!!  If only you could see my weak chin.....  Now I've gone and given myself another bleed, bollocks.....

Cheers,

Hugh