Crossover bypass caps......where to from here?

Little green meanies added!
0.005 Russian military polystyrene caps....not sure if these will make any difference, but at least I have bragging rights!
Have only added them to one crossover to see if I can perceive any difference, had to buy a whole bunch of these so if anyone is interested in any please pm me :thmbsp:
 

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Little green meanies added!
0.005 Russian military polystyrene caps....not sure if these will make any difference, but at least I have bragging rights!
Have only added them to one crossover to see if I can perceive any difference, had to buy a whole bunch of these so if anyone is interested in any please pm me :thmbsp:

This is one of those things you have to experiment with. You will never know if it works for you unless you try.

I find it works for me. :D
 
I personally find it USUALLY takes about five different value film caps, or more, to act as a linear bypass bundle, and to get bypassing done properly in any one capacitor position in a circuit. So, it becomes a question first, of what values to use, and second, finding caps that bypass with each other without serious " fighting" between the caps of different values.

Done properly, I find it highly advantageous. You will have to teach yourselves, what values effects what part of the spectrum, and use good judgement.

A single ended tube amp, unlike a push pull tube amp, also REQUIRES such multiple film cap bypassing, in every capacitor position in the circuit, if you expect it to provide more than the typical midrange-only ( narrow band ) SET playback. I find 99% of the SETs flunk, get a F-, in playing the highs well.

Jeff Medwin
 
I personally find it USUALLY takes about five different value film caps, or more, to act as a linear bypass bundle, and to get bypassing done properly in any one capacitor position in a circuit. So, it becomes a question first, of what values to use, and second, finding caps that bypass with each other without serious " fighting" between the caps of different values.

Done properly, I find it highly advantageous. You will have to teach yourselves, what values effects what part of the spectrum, and use good judgement.

A single ended tube amp, unlike a push pull tube amp, also REQUIRES such multiple film cap bypassing, in every capacitor position in the circuit, if you expect it to provide more than the typical midrange-only ( narrow band ) SET playback. I find 99% of the SETs flunk, get a F-, in playing the highs well.

Jeff Medwin

I've read that cascaded bypass capacitors are supposed to sound better than a single bypass capacitor. But, like a single bypass, I don't know why they improve the sound. I just think it does. Another thing, with cascaded bypass caps, aren't each capacitor required to be different values from each other, plus as additional bypass caps are added, each needs to be a higher voltage too?

Also, I've been discussing the topic of bypass capacitors with friends. Mainly, if they do benefit the circuit, and improve sound quality? We're all AR fans, and have been doing recaps, and were confused if bypass capacitors should be utilized? So, I'm trying them (Auricaps on tweeters, Mundorf Supremes on mids, and Dayton F&F on bass and shunt caps). My friends did too, though one was somewhat reluctant. But, the interesting thing was, when the reluctant friend finally added bypass caps, he did one speaker at a time, and compared to the standard recapped speaker. He liked what he heard, but felt the speakers weren't as 'bright' afterwards. Further listening revealed that the bypassed speaker was actually smoother sounding and offered better detail. Less spitty too. Another interesting thing, my fried measured ESR before and after adding the bypass caps, and the ESR values didn't change. The differences in sound couldn't be attributed to ESR shifts. So, maybe there is something to it after all?
 
I've read that cascaded bypass capacitors are supposed to sound better than a single bypass capacitor. But, like a single bypass, I don't know why they improve the sound. I just think it does. Another thing, with cascaded bypass caps, aren't each capacitor required to be different values from each other, plus as additional bypass caps are added, each needs to be a higher voltage too?

Also, I've been discussing the topic of bypass capacitors with friends. Mainly, if they do benefit the circuit, and improve sound quality? We're all AR fans, and have been doing recaps, and were confused if bypass capacitors should be utilized? So, I'm trying them (Auricaps on tweeters, Mundorf Supremes on mids, and Dayton F&F on bass and shunt caps). My friends did too, though one was somewhat reluctant. But, the interesting thing was, when the reluctant friend finally added bypass caps, he did one speaker at a time, and compared to the standard recapped speaker. He liked what he heard, but felt the speakers weren't as 'bright' afterwards. Further listening revealed that the bypassed speaker was actually smoother sounding and offered better detail. Less spitty too. Another interesting thing, my fried measured ESR before and after adding the bypass caps, and the ESR values didn't change. The differences in sound couldn't be attributed to ESR shifts. So, maybe there is something to it after all?
North Creek Music (now shut down) was the big proponent of cascading bypass caps. The reason being they sold those caps they were promoting. Their arguments sounded so convincing. If you visit the Lansing Heritage tech pages you find JBL engineers were some of the first to use a single bypass caps in a number of loudspeaker designs. JBL didn't cascade.
What bypass caps value did your friend use? Also, what value cap was he bypassing?
 
Small world! My first experience with bypass caps was also with a pair of JBL L36 Decades I restored 13 months ago. I used the little 0.01uF Vishay-Roderstein MKP-1837 caps to bypass 3.0uF Sonicap Gen1 caps I used in the tweeter circuit. Unfortunately, I did not take a photo after adding the bypass caps, but here's what my recapped crossovers looked like before adding them:

JBL_Decade_Crossover_4_zpsq0b8ojpv.jpg


The little Vishays are placed between the two caps and held in place with hot glue and a tie wrap. I wish I'd taken a photo with them in place before I reinstalled the crossovers and buttoned everything up. I really like the way these L36 Decades sound. I have several other decent sounding speakers, and have sold off a number of speakers in the last year, but still enjoy my rebuilt L36 Decades daily.

I have since also used the Vishay-Roderstein MKP-1837s in combination with Sonicaps in other crossovvers I have rebuilt. I really like this combination, and the little Vishays are so cheap, it really doesn't make sense not to use them. I bought a whole bunch of them from AK sponsor Parts Connexion when they were having one of their 20% off sales, so my cost was $0.80 each. Just for reference, here's a photo of one installed in a Rectilinear Highboy III crossover I recently recapped:

Rectilinear_III_Crossover_Complete.jpg
 
It would take a better ear than mine to detect the differences to the tweeter from the bypass caps - I could hear none. The midrange probably benefited more from replacing electrolytics with poly-caps than they did from bypass caps. If it costed a fortune or was mechanically difficult to implement, I probably wouldn't do it.

After and before

Photo_7_BeforeAndAfter.gif
 
He tried 0.01uF's, both Dayton F&F and Vishay, on a Dayton 1% poly. He seemed to liked both equally well, after listening tests.
You mentioned he bypassed a Dayton 1% poly but didn't state the uF value for that cap. That is what I was asking for. Thanks in advance.
 
You mentioned he bypassed a Dayton 1% poly but didn't state the uF value for that cap. That is what I was asking for. Thanks in advance.

Sorry. I thought that I had included the value in the reply. Regardless, it was a 4.0uF Dayton 1%.
 
A 0.01 uF bypass on a 4 uF cap makes sense. There's another bypass thread on pg one of this forum. IIRC, the OP wants to bypass a 10 uF EPI speaker cap with a 0.01 uF also but was asking about comparison of Dayton FF and Theta FF. For a 10 uF cap, I'd recommend a 0.1 uF bypass cap.
 
A 0.01 uF bypass on a 4 uF cap makes sense. There's another bypass thread on pg one of this forum. IIRC, the OP wants to bypass a 10 uF EPI speaker cap with a 0.01 uF also but was asking about comparison of Dayton FF and Theta FF. For a 10 uF cap, I'd recommend a 0.1 uF bypass cap.

That's something that has only been briefly touched upon before, but I'm still curious about; what's the correct ratio, between the primary capacitor and the bypass capacitor? What tells you how big or how small to make the bypass, in relation to the main capacitor? And if you don't quite pick the right size bypass, is there a sonic penalty?
 
IIRC, North Creek Audio did quote ratios in their cascading bypass paper. However, I don't recall what they were.
I have personally tested the ESR of Vishay 0.01 uF and Dayton 0.1 FF caps. The tests consisted of a 10 to 20,000 hz sweep. What I found was the 0.1 uF cap had a high ESR until about 1 kHz and it dropped down to < 0.5 ohms which would provide current pass thru past the primary cap at an audible level. With the Vishay, ESR didn't drop < 0.5 ohms until the 2-3 kHz range, more amenable to use with the lower value primary cap. Hence the 'science' and reasoning behind my earlier recommendations.
 
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