[PSP]

I am considering replacing the input cap of my GK-1R with wire (I think Kyrill has been doing this for some time).  This cap blocks DC into the GK-1, but if I turn equipment on in proper sequence (I use a Belkin PF-60 for this purpose) I should not have a problem.  Correct???

In addition, the GK-1 has an interstage coupling cap (C-19) and an output cap.  All of my amps (LifeForce or AKSA) have input caps.  So, it seems to me that the risk of blowing my Orions is very low. 

Am I missing something?  If you think this is dumb, I'd really like to hear your POV.

Many thanks,
Peter

[AKSA]

Folks,

As a rule I take the ultra conservative approach here, and never encourage audio sex without a prophylactic....  however, Peter is quite right, and we've spoken on this, and he is canvassing opinion, which is only prudent.

Any DC applied to the input transistor base because of a bypassed cap will manifest at the output of the SS section.  It will NOT get through to the tube, however, since there is a small 10nF grid cap blocking it.  However, any small DC voltage, even as little as 15mV, will be impressed upon the volume pot, and will create serious static when the level is changed.  This can be extremely irritating, but it's not fatal for any of the components....

If you have dispensed with C1 on the GK1, can we hear your opinions?

Cheers,

Hugh

[jules]

ok ... so as a temporary test, would it be ok to bridge C1 with a wire link [without removing C1]?

Would a soldered link be safest?

jules

[AKSA]

Yes, Jules, here we go dancing with wolves, that would do it!! 

Hugh

[kyrill]

ah as a designer statistics moves its ugly head.
I cannot advise as a retailer to my customers to remove caps from the signal path
as they are there for safety reasons. As i am bound to induce in my population of end users
problem cases if I would advice it.

but as an enduser myself you have a very small chance actually close to zero
if you know what you are doing. replace them beginning at the source and measure DC at the output of the preamp. Then work your way up with replacing caps to the poweramp. Measure between steps with all interconnects in place except to the power amp. if no dc enters the poweramp, delete inputcaps in the poweramp. Dont use it with other equipment!! glue a sticker with a skull symbol on the input (backside) of the amp
Just keep DC out of the signal path from source to speakers.
If you see how extreme good sounding capacitors may costs hundreds of  dollars even close to 1000 $ and they all sound worse than a bridge of wire.. you can imagine how much you "earn" with every cap removed.

example The USBdac has   end caps. the preamp has input caps and output caps, the amp has input caps.
to replace them with o so musical   teflon wil cost you 8 caps! the newest Aura-T teflon will cost you 367 dollars per cap for 1uF. But end cap and the next inputcap are in series and halving their value. if you therefore take 3uF the price will go to 960 dollar per cap. So you need to pay 8x 367dollar to be on the cheap side..

these caps sound less however than the wire bridge. So i remove the endcaps of the USB dac, remove the inputcaps of the preamp, replace one pair of outputcaps in the preamp and delete the input caps in the power amp. price 732 dollar instead of close to 3000 $

If you take run of the mill 20 or 30 dollar caps, the quality differences with the bridge of wire becomes even huge
For the sake of argument i took the 600V Aura-T teflons
you can choose for silver and teflon: Audionote 2.2000 uF    600V     Silver Foil     $1,122.00 a piece
still less than a very short piece of wire

[jules]

15mV is horribly small  .

I appreciate the method you're applying there kyrill but I guess the prob. could be that a raw mains supply isn't either perfect or constant, so there's always the chance of some errant DC dropping in for a visit.

The PSP plan looks like a reasonably daring compromise. Perhaps any Platinum caps from C1 could be moved on to C21 [is that the right descriptor for the output cap ?].

Hmm ... wonder if DC/AC inverters have any residual/inherent DC? Must check up on it.

jules

[kyrill]

as i  understand it you dont have to make the whole chain DC free .Dc will destroy tweeters and don't belong in the speaker set at all. but (some) dc in the preamp signal path is no problem. if without end caps the dac produces many volts of dc at its output, i would hesitate to let that enter the preamp even with caps at its output. But the burson audio buffer does not have input or output caps and does no harm to itself by amplifying dc .

[stvnharr]

I am considering replacing the input cap of my GK-1R with wire (I think Kyrill has been doing this for some time).  This cap blocks DC into the GK-1, but if I turn equipment on in proper sequence (I use a Belkin PF-60 for this purpose) I should not have a problem.  Correct???

In addition, the GK-1 has an interstage coupling cap (C-19) and an output cap.  All of my amps (LifeForce or AKSA) have input caps.  So, it seems to me that the risk of blowing my Orions is very low. 

Am I missing something?  If you think this is dumb, I'd really like to hear your POV.

Many thanks,
Peter

Peter,
As I recall from your posts, you have a SonicCap Gen.I at C-1.  Following the dictum that the best capacitor is no capacitor, then a wire link should be a very noticeable improvement.  Of course you are then not protected from anything coming in from the source, but Hugh says preamp will be okay.  C-19 is very small cap.
Then you have the Orion crossover followed by the 6 amplifier channels that are direct coupled to the speaker drivers. 
I would think that at the very least the preamp input cap and the output cap on the tweeter amp positions should have something as insurance.  The amp cap is only a .1uf cap, and is not overly costly, especially compared to the cost of the Millenium tweeter. The preamp teflon cap can be a .47uf cap, and does cost a little.

Nonetheless, be sure to post when you give things a go.

Steve

[PSP]

Hi Steve,
My apologies, I've been "down periscope" for several days.  You are correct... I'm still using the 2.2uf Sonicap Gen I at GK-1 C1.

My plan is to set GK-1 C1 = wire link, but to keep the GK-1 output cap and the input cap for all AKSA and LF amps driving the Orion.  Before connecting the amps, I will check for DC at the output of the GK-1 and at the Orion ASP outputs.  That seems safe to me...

I will post my findings, but my conclusions will be blurred to some degree by the sudden loss in late December of my modded Philips 963SA CDP... it suddenly just went dark.  I have sent the 963 back to Scott Quick (he  did the mods two years ago) to see if he can fix it.  Meanwhile I am using an open box Denon DVD/SACD/CDP I picked up cheap at Best Buy and--after  couple of weeks break in--it sounds reasonably good but misses some of the instrumental timbre and texture that the 963 rendered quite well.  In addition, I have recently set the Orion ASP input impedance to 36k ohms (vs. 10.2k stock) to make it easier for the GK-1R to drive (this was originally MikeC's idea, and a good one too!!  ).  This change improved dynamics, clarity, bass extension, and removed a bit of congestion I sometimes heard at high volumes with the stock ASP Zin = 10.2k.  So.... I've made a lot of changes recently. 

More news to come!!

Peter

[stvnharr]

Hi Steve,
My apologies, I've been "down periscope" for several days.  You are correct... I'm still using the 2.2uf Sonicap Gen I at GK-1 C1.

My plan is to set GK-1 C1 = wire link, but to keep the GK-1 output cap and the input cap for all AKSA and LF amps driving the Orion.  Before connecting the amps, I will check for DC at the output of the GK-1 and at the Orion ASP outputs.  That seems safe to me...

I will post my findings, but my conclusions will be blurred to some degree by the sudden loss in late December of my modded Philips 963SA CDP... it suddenly just went dark.  I have sent the 963 back to Scott Quick (he  did the mods two years ago) to see if he can fix it.  Meanwhile I am using an open box Denon DVD/SACD/CDP I picked up cheap at Best Buy and--after  couple of weeks break in--it sounds reasonably good but misses some of the instrumental timbre and texture that the 963 rendered quite well.  In addition, I have recently set the Orion ASP input impedance to 36k ohms (vs. 10.2k stock) to make it easier for the GK-1R to drive (this was originally MikeC's idea, and a good one too!!  ).  This change improved dynamics, clarity, bass extension, and removed a bit of congestion I sometimes heard at high volumes with the stock ASP Zin = 10.2k.  So.... I've made a lot of changes recently. 

More news to come!!

Peter

Peter,
Well, good luck is all I can really say.
If you ever get a spare couple hundred, a pair of Platinum caps on the preamp input is a good bargain.  I'm not game enough to try the "best cap is no cap" there, even if I were to bypass the BGNX coupling cap on my Marantz with a small teflon.
Orions are nice!

Steve

[PSP]

I've had 3-4 nights now to listen to my modded GK-1 (details below).
 
I took MikeC's suggestion (seconded by Hugh) to increase the Orion ASP (analog XO and signal processor) input impedance from 10k2 to 36k to make life easier for the GK-1.  IMO, changing to 36k was a big success... looking back, I can see/hear how the GK-1 might have been straining a bit under the 10k2 load and how much more clarity and dynamics I heard when I moved to 24k2.  When I changed to 36k I have not (so far) noticed more dynamics but I did hear more clarity, resolution, and microdynamics.  I would characterize the GK-1 driving 36k as "relaxed, capable, no sense of strain whatsoever".

A few days later, I did the following mods to my GK-1R (all at once, because my GK-1R build makes it very painful to work on the analog board).

The GK-1 mods:
C1:  was 2.2uf Sonicap Gen I bypassed with 0.022uf Audiocap teflon (TFT),
now = 24awg Cat5 wire

C19:  was 0.047uf Audiocap teflon (TFT),
now = 0.022uf Sonicap Platinum

Cout:  was 1.0uf Auricap bypassed with 0.01uf Audiocap teflon (TFT),
now = 2.2uf Mundorf Silver/Gold (a huge cap mounted el-wacko)
 
The Mundorfs had been used extensively in one of my 100N+ amps so they were well burned in.  The 0.022uf Platinums that I put into the interstage coupling spot are brand new.
 
Before connecting the amps, I measured very little DC from the GK-1 normal (tube) output with all sources connected and the CDP playing music. 

After these changes (in combination with the ASP changes) the word that came immediately to mind was "natural".  So far, I've listened to Eva Cassiday, the Minnesota Orchestra Reference Recording of Pictures at an Exhibition, Sharon Bazaly playing Mozart flute concertos(SACD on BIS), and a live recording of a very good local choral group. 

I have always been frustrated with good choral recordings by a layer of sonic complexity/richness that is apparent in concert but which sounds like light fuzz/distortion when played back through my system.  Last night, the choir sounded much, much closer to the live performance, and the occasional cough and titter from the audience, the sound of a large venue that is heard even in silence () were real enough to run shivers down my back.

Last night I listened to Otto Klemperer conduct Beethoven's 9th Symphony (recorded live at the Proms: http://www.amazon.com/Beethoven-Symphony-No-9-Choral/dp/B00002MXTT/ref=sr_1_6?ie=UTF8&s=music&qid=1202321116&sr=1-6) .  I have had this recording for several years, but for the first time I understand what is so exciting about this concert and recording.  Reminiscent of vinyl, the music was dynamic, immediate, and exciting (detail, clarity, dynamics, spatial information, and the orchestra, instruments, and vocalists sound "right").  I'm busy tonight, but I'm definitely going to treat myself again tomorrow night!!

At this point, I've sewed up the GK-1... no more reasonable mods in sight, except for eventually implementing AndyR's output buffer for the GK-1 sub out.  This will allow me to add a second Orion ASP for bass driven by the GK-1 Sub out.

edit:  BTW, I'm still using (and happy with) the original stock tubes.  It's been maybe 3(?) years and I listen for 3-4 hours, 3-4 nights a week.  Doing rough arithmetic, that's ~ 2000 hours, I guess.

Peter

[jules]

Very interesting observations Peter,

Replacing a Gen 1 [they aren't platinum, correct?] with wire might not be quite as dramatic as replacing a platinum cap with wire but the results lead in the same direction as other C1 improvements don't they?

I'm interested in your comments on the Klemperer recording. Might I ask what tubes you use in your GK1?

I've noticed the same thing with good quality older recordings converted from analogue to digital and been very surprised that it was possible to extract the essence from what I'd come to give up on as flat and lifeless.

I'm using a Burson Buffer between my CDP and the GK1 with a Platinum cap at C1 but I also think the tubes have a lot to do with the improvement on older material with this being a strong point for the 6es8s although it also works with the 6dj8s.

jules

[kyrill]

hi Jules have you looked at the output caps of the cdp?they are primarily responsible for the MAX quality of the whole chain ( cap wise)

[jules]

kyrill, I did briefly lift the lid on my cdp while thinking "upgrades" but I hastily put it back on again when I saw how incomprehensible the whole thing was 

jules

[kyrill]

it may not be that incomprehensible
neglect 99% of what you see ( too incomprehensible 
Focus only on the relevant 1% ( easy not at all incomprehensible 
The last output cap ( coupling cap) is mostly
also the last component before the rca chassis posts
if you follow with yr focus where the wire goes from the rca chassis to the pcb and then try to follow the path from there,  to the very first cap you encounter on that path.
You see the pcb from the wrong side ( component side) in order to follow the signal path on the solder side)

but the chance is  that the nearest/closest cap you can see from component side is the one.
worst are the small electrolytics, better a wima like rectangular film cap.
you have to find a way to prepare to loose the whole pcb so you can look at the trace side.

but the first look is  a nice way to see what kind of quality caps are close to the rca wires.
if you cannot find any BIG caps the better jump in listening quality you will make when replacing the caps for a wire bridge

the difference will be like instead of listening to the GK-1 you listen  now ( before the mod) to a Philips preamp
Unless you have a famous good sounding expensive CDP than you listen now to a good Yamaha

I mean it will be worth the trouble and multiply  the effects of your GK-1 mods

[PSP]

Jules,

Replacing a Gen 1 [they aren't platinum, correct?] with wire might not be quite as dramatic as replacing a platinum cap with wire but the results lead in the same direction as other C1 improvements don't they?

Yes, I had a Sonicap Gen1 at C1.  Certainly replacing a Platinum with wire would have given a much smaller improvement.  Although Kyrill made good arguments long ago regarding replacement of coupling caps with wire, the guy who convinced me to go ahead and set C1 = wire was Jeff Glowacki, the guru at Sonic Craft.

Might I ask what tubes you use in your GK1?

I'm using the stock tubes that Hugh sent with the kit.  I will check when I get home and see if I can find more information.

Peter

[jules]

Yes Kyrill, you are quite correct and a little disciplined examination should make things clear  . I'll have a go. One of the reasons I held back was that I wasn't sure what value cap I should use as a replacement on the CDP. The logic escapes me in that the blackgate C1 cap on a GK1 is nominally many uF [haven't got the figure in front of me] while the replacement platinum cap is "only" 1Uf or so [despite its immensity]. With wire, the size isn't an issue though is it 

Peter ... thanks for the cap report. On tubes, I've been trying a range of 6ES8s and 6DJ8s lately and for the most part [except perhaps for vinyl and analogue to digital remasterings] I think the latter [inc 6992, ECC8, E88CC] are better but I'll post a long review here shortly on those I've tried.

One of the stock 6es8 tubes Hugh supplies in a plain brown paper bag, is actually a Mullard/Amperex, Heerlen Holland, A frame dimple getter tube. It's not nearly as  ordinary as is normally assumed.

jules