bypass whaaaat???

Esreuter

Hey forum,

so from research i am getting that the issue of bypass caps are a can of worms prob like speaker wire.

all i ask of you is some clarity on the issue.

i have learned these two conflicting ideas,
first comes from a post on tech talk, the general idea is that the bypass cap only adds its characteristics to the circuits main cap, for example if the bypass is 1% then 99% of the sound characteristic is coming from the main cap. the closing argument of that post was bypass are worthless because they are too small to change sound quality and only lighten the wallet.

the other thing i got from the skiing ninja, and there the point is the purpose of the bypass cap is to short the main cap and reduce the amount of time it takes to fully drain the cap of its energy and prevent the cap from making the sound smear together.

I have also learned this in my findings, the reason to change caps from eltrolyic to the film and such is they have a faster response. this idea supports what i have been told as to just add the value of the bypass into the main cap when replacing the original electrolyic cap. for better sound.

using the ninja idea, i have heard some guys leaving the elctrolyic and bypassing it with something nicer like a sonic cap. thus shorting the elec cap out quicker and increasing sound clarity.


so after all this i learned, i am more confused than when i began. i got the basic physics of each idea, but from your guys experience what is true? are bypass caps not worth it because of thier small characteristic? or do they really short out the main cap and increase sound clarity?

then i want to know what happens when you replace the main cap with a higher grade cap, then bypassing that nice cap with another nice cap? is it not worth it? or is it perhaps having my cake and eating it too, situation.

so any of your expert advice is welcomed.

oh i am also aware that all of this is up to my ears and my liking, i would just like to hear what the field has say.

thanks in advance

ESR:biggrin::biggrin::biggrin:

Joe08867

The second theory is similar to what I learned about caps, but like you said in the third paragraph newer film caps are already faster than the caps used in the past.

This is also why you skip the bypass caps when replacing them in SDA's. It is unneeded after the upgrade and actually hurts the performance of the crossover with new poly caps.

saemark30

I have just been thinking the same thing.
Bypass using VISHAY-RODERSTEIN MKP-1837 0.01uF as recommended online.
I wouldn't go as low as electrolytics as they dry with age, but on the low end maybe Solens or even mylar caps.

F1nut

This will give you something else to think about.

So why use a bypass at all? There are actually components of very high frequencies in some audio waveforms. Some are high order harmonics. If you think of a square wave, the right angles at the top of the wave are extremely high in frequency. Sometimes there are high frequency components in very fast audio sounds, for example, the instantaneous tap of a drum stick on a cymbal. These are the sounds that should be "helped" by including a small-value bypass capacitor in a high pass crossover.

Well, I don't think so. If the 8 ?F capacitor blocks frequencies below 5000 Hz and passes frequencies above 5000 Hz, why do we need what is actually another crossover for the same tweeter, but operating at frequencies already passed by the big cap? I am sure engineers have a very good reason, and a couple of them have tried to educate me on this subject. I respect the science and electrical theory on this subject, and my technical background helps me to understand it fairly well. But there is one small problem: the bypasses all sound bad! They add a quality that at first sounds like an increase in air and detail, but after a couple of hours becomes an intrusive harshness and discontinuity in the upper treble. Remove the bypass: all of the detail is present but without that grating and annoying sound. The high frequencies are cleaner, smoother, and much more enjoyable. It doesn't matter if the bypass cap is Teflon?, polystyrene, or common polypropylene, the results are very similar. And to be avoided.

Esreuter

interesting.

to add to the pot of stew.

i was looking at how a bypass is made. As you all know its one cap and then another cap attached to its leads.

this got me to thinking, in the realm when you need to make your own cap value, for example (random) 65uf, so one would piggy back a 30 and a 35uf to achieve this goal.

now my electrical engineering skill is nill, but isnt that the same thing as bypassing? and when two caps are piggy back like this is there artifacts and harshness in sound like when small bypass are used?

i wanted to post about this because i seen in the LSI mods there are sometimes 3 caps piggied on each other to achieve a certain value.

reason i ask, is on the future when i can have lsi speakers i noticed there is a 130uf cap, so far i have only found solen to make a 130uf, personally i would like some higher quality cap(reasonable), so i would have to piggy some together and am curious about the effects of that procedure.

thanks,

ESR:biggrin::biggrin::biggrin:

saemark30

The reason why a large cap is bypassed is because it is wound into a large coil, similar to an inductor. If I want to replace a single 12uF cap I can use four 3uF ones, or a 10uF and 1.8uF and .1uF and .01uF all in parallel.
I am curious F1nut if you find these alternate combinations to sound BAD.

F1nut

this got me to thinking, in the realm when you need to make your own cap value, for example (random) 65uf, so one would piggy back a 30 and a 35uf to achieve this goal.

now my electrical engineering skill is nill, but isnt that the same thing as bypassing? and when two caps are piggy back like this is there artifacts and harshness in sound like when small bypass are used?

No, the values are close enough.

If I want to replace a single 12uF cap I can use four 3uF ones

When running caps in parallel, such as above, and using values either exactly the same or pretty close, that is not bypassing and there will be no adverse effects.

a 10uF and 1.8uF and .1uF and .01uF all in parallel.

In that combination you are bypassing and should notice adverse effects.

saemark30

I'll have to try it. Some amplifier designs used bypassing(with smaller polys), would this have the same adverse effects?

Esreuter

F1

ahh, very special, so a bypass only includes, or i should say loosely includes a large differential in cap values, 8uf and a .01uf. Or a 32uf and a 1uf.

just want to know if i am right or wrong on that concept.

and capacitive value is added when caps of similar capacitance are piggied together.

again just want to know if that is right or wrong.


and now the grand finally, hopefully you have had children and are used to this,

WHY?:rolleyes:

no need for intense explanations, and if the reason itself is complicated just go ahead and tell me to go back to school for elec engineer.

i ask wholly out of willing to understand, no other real reason.

thank you

ESR:biggrin::biggrin:

heiney9

saemark30 wrote: »

I'll have to try it.

Yes, try it, instead of faintly arguing about in multiple threads. Some of us have tried it both ways and most prefer NOT to bypass.......

saemark30 wrote:

as recommended online.

........if you are reading this you just read that on the internet as well

Joe08867

PS asking advice on this forum is like having something recommended online.

It is all an opinion of what we perceived when using or not using a bypass cap.

The best thing I can say is. The less stuff in the way of the audio signal the better. Every time you send the signal through another cap, coil or whatever it changes the signal. So in this case I will say less is most definitely more.

CoolJazz

Different capacitors are made of different materials. The basic materials are usually referred to in the description. Due to material differences, mostly the thickness dimension and the wrap tension, different resonances arise. Some are significant enough you can even audibly hear them when you sweep them with a sinewave. Frequency resonances are also phase shifts as are they are the same thing looked at in different ways.

If you bypass, normally a 1/100th value approx., then you may well damp a nasty resonance. However you also create another pole, or phase shift. The question is which is more audible of these? The original problems or the new one introduced with the bypass cap.

Remember that these results are effected by the impedances involved in the circuits...ie, the equipment specifics and how there impedance changes by frequency. So the results you experience could be different than someone else's results, due to the situations equipment involved.

So what many have learned is simply use a good enough cap to not have bad anomolies to begin with and avoid the problem to begin with, rather than to try to band-aid it after the fact.

Hope I said this fairly correctly and in a understandable fashion.

CJ

PS...also this doesn't touch on another factor...that when a cap is used as a blocking cap, you have a significant bias voltage present. This also can mean different values present in different equipment and differing leakage values between different caps. A whole 'nother set of issues.

saemark30

I have bypassed electrolytic caps before in amplifiers, the combination is better than just the electrolytic but not as good as a big plastic cap.

So I will try it on speakers, I promise!

saemark30

H9, I actually got a lot of information in these 2 days of discussion.
I know what caps are good and bypassing may not be as good as someone claims.
it saves me time and money. And that is always good