[Fredly]

Hi everyone, my system consists of a Nirvana’d TLP and the AKSA 55W Nirvana +. I am VERY pleased with the performance of this setup, and as of late have been ready many stellar reviews regarding the Chris V OIMP (Oil Impregnated Metallized Polypropylene) V-caps. (http://v-cap.com/oilcapacitors.html).

I’m seriously thinking about upgrading the Auricap Coupling Caps in the TLP to these caps, but would like a bit of advice on the size of cap best suited for this upgrade.

If I’m not mistaken, originally in the TLP the coupling cap was a .47uF, this got upgraded to a 1uF 200V cap in the Nirvana upgrade. Should I just order a 1uF 250V V-cap and be done with it OR is there a sonic advantage in increasing this cap size to say a 2uF or 3.3uF 250V? What about upgrading to a 1uf 600V cap, any sonic benefits in upgrading to a high voltage rating?

Any guidance someone could give me would be TRULY appreciated, since this is a relatively expensive upgrade and one I want to ensure I do correctly.

In the grand scheme of things, if I like what I hear with this upgrade, I plan to do a similar upgrade in the AKSA 55W as well.

Oh, and one last thing……break-in time.

I upgraded the TLP and the AKSA 55W to the Plus about 8 weeks ago. I admit that with summer being here I haven’t been listening to my Stereo nearly as much as I would during winter, BUT I would say I’ve put a good 200hrs or more on it since the upgrade. During load/bass intensive passages, I continue to hear an unpleasant “distortion”.

Is this simply caused by the Blackgates breaking in? I understand they really need 400+ hrs to fully settle, so I’m hoping this is the case. I’m questioning whether an incorrect offset voltage or some other problem would be causing this to happen.

Again any comments regarding this would be very much appreciated.

Thanx much in advance, Fred in Canada.

[PSP]

Hi Fred,
My 55N+ rounded the big sonic curve at around 80 hours (but I had been using the N+ caps in the power supply from day one) and after that I heard only minor changes.  I never heard anything that could remotely be called "distortion" during burn in.  The sound evolved and generally improved, but it was pleasant listening from intitial switch-on.

I'm not sure what's causing your distortion, but I've had at least two cases of distortion (not subtle, either) that immeadiately followed tweaking sessions.  Close inspection of my work with an illuminated magnifying glass showed solder joints that looked a little sketchy.  When these bad joints were re-heated and flowed with a little fresh solder (once I had to desolder with wick, then add fresh solder) the distortion went away.

BTW, if I remember correctly, Hugh auditioned a lot of coupling caps for the TLP-N before he settled on the Auricap.  If you do go ahead and try a bunch of caps in this position, be sure you let them settle in before drawing conclusions and let us know what you learn.  I still have my TLP playing every night in my bedroom system.

Good luck,
Peter

[AKSA]

Hi Fred,

I believe Peter is right;  there could be something else wrong here.  You shouldn't have distortion at any time;  check the bias figures, all the vital signs of the amp; in particular there should be even voltage drop across R1 and the 82K feedback resistor;  they should be equal, around 200mV.

Then check the voltage across T3 base/emitter, the voltage amp - it should be 600-630mV.  And check offset voltage wrt ground;  it should be no more than +/-30mV.

If all these things check out, then the fault very likely is a defective solder joint, so running over existing joints which look a bit dull with a good quality resin core solder should fix it.

Be sure to clean up the board after this because you don't want flux left on the board over long periods;  in hot weather this can actually cause corrosion.

Concerning teflon Venhaus caps, I have tried them and my one concern is a perceived lack of bass.  In some situations, active systems for example, this can be an advantage, but in a full range amp it could be an issue.  It's difficult to try before you buy, but I'd go for around 2.2uF rather than 1uF on the input to offset the bass issue.  Otherwise, teflon (I've tried the RelCap offering) is very, very good with great refinement and accuracy.  Keep this cap physically remote from the inductor underneath;  one of the problems with large foil caps is their susceptibility to fields, and if close to the output inductor it can cause positive feedback leading to destructive oscillation.  Often better to put this cap nearer the input RCA than actually on the module pcb.

Hope this is helpful, that you get to the bottom of it.  While you are at it, don't discount the woofer;  it might have a poling voice coil, broken surround or loose mounting, worth a look.

Cheers,

Hugh

[Fredly]

Hugh/Peter, thank you very much for your input.

Hugh, when ordering the Chris V teflon caps, I'll get the slight larger 2.2uF as per your recommendation, and report back with my findings.

As for the "distortion" I was experiencing during loud/bass intensive passages.....well I think I've found my problem.

In my rig, I use the JR filters for everything except the amplifier, which is plugged directly into the wall outlet. It appears that this filter, when powering my ART DAC, TLP preamp and modded 3950 transport simultaneously, is the "distortion" culprit.

I confirmed this by changing the plug configuration and playing the same passage over and over, until the "distortion" has all but disappeared.

In addition, I believe the sonic resolution I am now getting with TLP/55W  combo, is making me VERY aware of the slightest imperfection, whether it be a bad recording, vibration, DAC or transport limitations etc.

Anyhoo, once again thanx for your input/feedback, Fred in Canada.