burning in capacitors for phono stages

I'm in the process of auditioning various capacitors within my phono preamp. It seems burn in is a 'real' issue with caps. In exploring various means to burn in these caps I found the KAB PreconLP, this device converts line level signals to phono level signals. This allows one to use a cd player and burn in disc to burn in phono stages.

I only need substitute various caps in circuit I want to audition. This seems like a huge advantage over any other cap burn in method I've encountered. You are getting the actual signal your cap will see playing lps. Other burn in methods I've seen may or may not have sufficient voltage and/or combo of AC and DC.
I am an Engineer so take this advise which ever way you wish. There is no break-in for a capacitor. A capacitor is simply 2 conductive plates with a dielectric samwiched in between. There is such a thing as formimg a capacitor though. Capacitor forming should be performed on electrolytic capacitors that have not been used in a while. New Capacitors do not have to be formed. If you would like info on forming capactors send me a message as I would be happy to help. Be careful monkeying around with large capacitors as they store a large charge and are a lethal shock hazard.
I know break in of caps is a contentious issue. I only know that many hear changes as capacitors age. The upcoming cap rolling will tell the tale for me.

Thanks, I do understand about caps holding charges, and do discharge them prior to working on equipment.
I suggest you use a variac and charge yr new caps in steps, starting at low voltage to slowly reach their rated level.

I am a music lover and actually listen to my system on a regular basis. I have swapped out caps and they do burn in.

Thank you very much.

Sns,To break in all the caps, solder your caps together in series. Put an RCA on on end, and a 10K ohm resistor on the other end. Run a ground wire from the RCA shell to the other end of the resistor to form a complete circuit. plug this assembly into your pre amp out put. Turn on the Tuner, turn up the volume a third of the way, and go to bed. When you get up in the morning all your caps you soldered together will be broken in and you should be ready to try your experiments.

Don't waste your money on Audio salon caps. all you will need are available from Mouser or Digikey.

As long as you are working on the phono stage, why don't you replace the loading resistors with Vishay S102's? as well as any shunt resistors that are usually located at the output of hte phono stage. They will make as big or bigger difference than the caps.

Happy listening.
Thanks Johnss, I will try that break in procedure for my speaker crossover caps.

As for the cost of boutique caps, I find it rather inexpensive for amount of change I hear. I consider cabling a high cost item for relatively little change. Besides, it is fun listening to all the different caps, and they can always be resold or auditioned in other equipment.

I've thought about changing out resistors, the problem is they are often buried under tons of parts.

Anyway, one thing at a time, its cap auditioning time right now.
Sns- Right you are about the sonic benefits of high quality caps and the fact that the sound changes after the dielectric forms it's charge(commonly referred to as, "burn-in"). I've always purchased mine(and Vishays) from Michael Percy. He will match your components to 1% tolerance(good for channel balance). An excellent selection of polystyrene/polypropylene caps too: (http://www.percyaudio.com/Catalog.pdf)
Here's something else that might interest you: (http://www.geocities.com/rjm003.geo/rjmaudio/diy_rack.html)
Thanks for the info Rodman. I'm using the burn in scheme suggested by Johnss. We'll see how that works.
Sns- There won't be nearly enough voltage to burn the caps in overnight that way(especially with poly-s, poly-p or Teflon caps), but- it would work eventually. Happy experimenting.
Rodman, I'm burning them in for aprox. 150 hours. I've heard in speaker crossovers the V Caps can take 400 or more hours to fully burn in. Eventually, I will get around to building the burn in scheme you suggested. Thanks again.
Just make that capacitor bundle with a male RCA on one end and a female RCA on the other. Plug it into the back of your CD player and run an interconnect between the other end and your preamp. Run the CD player for 100 hours and you've got burn in (200 hours for teflon's). You don't even need the preamp to be turned on at all.

Bob, I would think it would take longer to burn in the cap with that scheme. Wouldn't the cd player be sending out a lower level signal than the preamp?
A typical CD player sends out 2 volts. If you had a passive preamp you would immediately see that the volume full open would be way too loud. Typically a preamp will send out a lower voltage since the volume would be turned down to a "reasonable" level.

Plus, my way you don't need the preamp or amp turned on at all. Just change out the disk 1-2x a day and you've got a pretty easy burn in device. You can even turn the system on once in a while and hear the changes in the caps over time.

I have the preamp volume turned up full.

I like the idea of being able to hear the caps as they burn in using the cd player, think I'll give it a try.
Thanks, Scott
Yes, Bob has a good point, The main thing you want to do is get some time on the new caps, before you install them if your wish is to avoid in system break in.