to back up what gus is saying in my own special brand of abrasiveness, if you havent spent the time listening to different caps in different circuits, you might as well just pick something you can get in the value you need which you can afford and not pay attention to any of this. No, I dont mean this in some snotty Ive done the leg work and you havent so fuck off kind of way but Im beginning to see more and more that context and application always need to be considered before simply labeling a cap good or bad or hifi or bright or whatever. Many or probably all of us have the best intentions in mind when reccomending stuff, but I think a lot of the labeling can be misleading if you havent actually heard the cap in question and how it can benefit the *specific* situation you have at hand. When you listen to the same type of cap in different circuits, you get a real good idea of how the advantages or disadvantages of that cap can work for you. I think the absolute first consideration you have to make when selecting a cap is the type of input and output transformer you are using or if you are using one at all. I find myself compensating for the effects of a transformer most with the choice of electrolytics in the circuit. Here's one such example:
I typically do not at all like panasonic FC caps. I dont know or care what they measure on test equipment or how long they last or any of that stuff, I just dont normally like the sound that comes out of the speakers after installing them. I recently built (or am still building, argh) an 8x2 mixer from api 312 and 325 amplifiers. The busses are fed from a transformer and the output line amplifiers have a transformer on the output. I used BC caps for the channel amps but selected FC caps for the buss output to "speed up" the output amps. So far, sounds nice. I dont care for the FC's on the channels as I dont typically reach for an api type amp when I want "open" sounding, so while those caps work against the idea Im trying to get with a direct channel output, they most definitely help the buss from getting overly muddy. Sure, I may label them "bright" caps, but they dont sound bright in the application Im using them in as a result of the "darkened" content that is passing through them.
Im also working on another 8x2 mixer with 1272's. The 283's mostly got bc's on the boards, but all the power decoupling is FC and I'll probably go to some real super hifi type cap for the make up amps. People talk about 1272's in other places like they are the holy grail or something, but summing 8 channels is going to be a muddy wreck of a mess but careful attention to tthe type of caps in strategic places or where or where not to use transformers can all help to "even" things out a bit.
Its important to not label a cap as something and then throw it away, you never know how it may be able to balance your circuit. If you have a "hifi" type cap in a circuit with a lundahl, its going to do a much different thing coming out of the speakers than installing that same exact type of cap in a circuit with cloudy carnhills. You really should judge the cap on an application specific basis working back from the transformer you intend to use. Thats the flow chart that has led me to most success, but you really do need to listen to a few different things to get the perspective on how the strong and weak points of a cap compare to each other. you can set up a neve or api circuit to sound night and day different from the next guy and we all have such incredibly different taste, so much of this should really be judged for yourself. A guy, with my background and taste and typical working application calling something "hi-fi" probably doesnt even chart on the classical music guy's chart of fidelity...
caps, well electro caps at least, are typically cheap enough to buy a bunch of different stuff. It is so so so so worth your time to make the small investment in a handful of different things and spend a day or two comparing as many different types of caps as you can, making recordings as you go so you can compare all your tests, at once, a day or week later with a fresh head. If you bother to put the time in, all your DIY projects after will benefit as you can make a choice about these things with some personal authority instead of trusting that I said so and so was crappy on the internet. Before I realized I didnt like panasonic FC caps in most applications I tried them in, I read everywhere online by people who's opinion I trust that they were the best cap available. go figure.
dave