Audio Cap Thetas

[Bob from Florida]

I was placing a Parts Express order a couple of weeks ago and needed a few bucks to get "free shipping". So, I discovered they carried Theta caps - polyprop tin foil caps with gold plated copper leads - and ordered some .1 uf 600 volt caps with the intention of using them in guitar amp phase inverters. The cost was $6.50 each - about double the cost of the Sozo mylar / tin foil caps I usually use - not a bad price for doing something "custom" for someone's guitar amp. I was checking out something on my old Cary SLP 74 pre-amp - there are exactly 2 caps in the lines stage - per channel : a 2 uf 600 volt output coupling cap and a .1 uf feedback cap. I had already replaced the 2 uf output cap a few years ago with a high quality polyprop aluminum foil cap. The .1 uf cap was used as a feedback from the cathode follower output stage back to the "not quite grounded grid" of the common cathode input stage. That cap was a Kimber metalized polyprop. I have this habit of not leaving anything alone, so removed the Kimbers and installed the Thetas. The first 5 minutes were almost unlistenable, but 2 hours later it was quit nice and now with 48 hours break-in time they are very very nice. The initial "harshness" is completely gone and has been replaced with a smooth tonal balance with great detail and imaging. I listened to Ahmad Jamal's new CD "Its Magic" last night - I just intended 1 track but I ended up listening to the whole thing as I was quite "riveted" by the experience. Makes me wonder what Audio Note Copper Foil caps would do in that position....

Bob

[Bob from Florida]

Not being able to leave "well enough" alone I ordered 4 more Theta caps for the phono section of my pre-amp - .33 uf. They barely fit in the space available but they did fit. These caps behaved exactly the same as before - too much detail at first then smoothing out nicely while retaining more detail than the original Kimber Kaps.

A very good tweak.

Bob