Quickie cap upgrade

[aragorn723]

Hi,

Tonight I installed K75-10 russian caps as coupling caps in the Quickie.  They are pretty big, and surprisingly good quality.  I've never seen caps encased in metal before.  Attached are a couple of pics from the install.  Notice the difference between the stock caps and the K75's!  Got a matched pair of these with 5% tolerance on ebay.  Can't wait for them to burn in! 

Dave

[Bonzo]

You'll be pleased, my friend!

Let us know!

Ciao

[Grainger49]

Dave,

You will like these caps.  They are USSR Military Surplus.  My take on it was if you supplied crappy parts to the military you went missing, never to be seen again. 

After about 50 hours you will be almost there on burn in.  Let us know what your impressions are.

[aragorn723]

Grainger,

That's probably true.  I wonder what the original application was?  Seems like they were built to last thru some serious environmental stress.  There wasn't much juice left in the Quickie batteries, so the CDP has been burning them in for the last 13 hours.  They sound pretty relaxed, and have more bass / better midrange clarity than the stock caps.  Does it take the full 50 hours to hear the full potential of these?  Merry Christmas!

Dave

[Grainger49]

Dave,

A very Merry Christmas to you too.

I burn in PIO for 50 hours, film for 100 hours and Teflon for 400 hours.   It is a practice with no scientific proof behind it.

[Paul Joppa]

It's frustrating but educational to listen through the breakin period. Some caps get worse before they get better, for example.

[badman]

I suggest testing the casing for magnetism- if it's steel, it can be removed with a twist-action pipe cutter (about $10 at a hardware store), the type that has a cutting wheel and a thumb screw to apply pressure.  Tighten screw, rotate cap in cutter, repeat 'til the ends pop off (do cut right at the end, btw).

You'll also notice an extraneous solder joint in there- the external leads are different than the internal leads, so you can get rid of that issue as well.  A little heatshrink and hot melt glue and you'll have a cap that works great for hifi, without the performance robbing bullet-proofing aspects. 

[aragorn723]

Has anybody else tried this?  I haven't heard of this before.

Dave

[aragorn723]

Paul,

One interesting aspect of listening to the Quickie during the burn-in period is the voltage drop on the batteries.  While the caps are breaking in and theoretically sounding better, the batteries are wearing down, and the sound is degrading because of that.  My batteries are on the lower side right now-plate voltage was 8v last night, and filament voltage was around 1.2v.  Popping in some fresh batteries would probably give the system a different sound at this point..  Though I figure it couldn't hurt to leave these batteries now to get some juice going thru them and burn in the caps. 

Dave

[Paul Birkeland]

8V on the plate is absolutely dead and nearly not passing sound, I wouldn't call that "low".

-PB

[badman]

Aragorn- do you really mean plate voltage, or are you referring to the voltage across a single 9v battery?  1.2v on the d cells would not be out of line with the 9 volt batteries being at 8v. As c.b. says, 8v on plate is really low and you should replace asap if indeed plate is at 8v

[Grainger49]

Has anybody else tried this?  I haven't heard of this before.

Dave

Dave,

I just tested Polyester, Teflon and PIO KKs.  The POI were ferrous enclosures.  The effect of magnetic fields induced into ferrous leads, end caps (resistors) and bodies of capacitors is subtle in the most revealing of systems.  It is not dramatic.   

I've happily used KK PIO caps in crossovers and as coupling caps for a number of years.  These are directly in the signal path.  I haven't heard any problems but others might hear it.   Of course, it is impossible to know if the ferrous wrap on the cap is the cause till you try the experiment above and listen to nekkid KK PIO caps and shielded caps. 

If you have spares try it and let us know your impressions.

[aragorn723]

Hi Grainger,

I don't have any spares of the caps at this point.  The quickie is basically stock, except for the pjccs, russian coupling caps, copper couplings for microphonics, and westinghouse tubes.  It probably wouldn't be revealing enough at this point to hear a difference, gotta see what happens with these russians once they settle down   To me it seems like the biggest change in sound would come from changing the amp at this point, but that is probably down the road a bit.

Dave

[Grainger49]

I think my brain is beginning to work.  The PIO use the can to hold in oil.  I wouldn't open them. 

I have PIO motor start/run caps in the power supply of my FP 2 that slosh when I shake them.  The KK PIO caps do not slosh.  So I don't know just how much oil is in there.

[aragorn723]

yeah, they probably do..  I wonder if you put enough voltage in them if they spray oil?