Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: Colonl_Charisma on January 08, 2021, 12:27:02 PM

Title: Quick Question about Bypass Caps
Post by: Colonl_Charisma on January 08, 2021, 12:27:02 PM

I bought some Dayton Audio 1uf 250v film caps to bypass my Dayton Audio 100uf 250v output caps. Is this the recommended ratio?

I bypassed the last PSU cap with a WIMA 2.2uf 250v film cap and liked the subtle sound change that resulted from it. Thought I would just bypass the other capacitors for fun.

Title: Re: Quick Question about Bypass Caps
Post by: Paul Joppa on January 08, 2021, 02:29:49 PM

Since there is no plausible theory for bypassing caps (except for old-technology electrolytics), there is no way to establish a "right" ratio. I've heard everything from a ratio of 10:1 to a ratio of 10,000:1. Experimentation is the only way to determine whether it  is an improvement. When theory fails, trust your ears!

Title: Re: Quick Question about Bypass Caps
Post by: Colonl_Charisma on January 08, 2021, 03:42:25 PM

Thanks PJ! I appreciate the help.

Title: Re: Quick Question about Bypass Caps
Post by: Colonl_Charisma on January 25, 2021, 02:25:06 PM

Instead of starting a new thread I thought I would come back to this one.

From an older forum post (https://forum.bottlehead.com/index.php?topic=1263.0) ironbut stated that he experienced "mids have sucked in" after replacing his PS caps. I have noticed something a bit similar after I replaced the stock electrolytic cap with a 220uF/250V film cap in the last PSU position. If I turn up the volume things start sounding better, but I'm reaching volume territory that is a bit loud.

It was recommended by Grainger49 in the same forum post to bypass with 0.1uF 600V KK Teflons.

What does the bypass cap actually do to affect the sound? Or if you have tried it, did you like the change in sound? I am going to bypass my last PSU cap with a K75-10 PIO 2.2uF/250V, but I am waiting on the cap to arrive.

Title: Re: Quick Question about Bypass Caps
Post by: 2wo on January 25, 2021, 05:20:14 PM

Well, as  the thinking goes, large caps especially  those subject to the rigors of the power supply  are slower to charge and discharge have larger ESR or what have you.  Bypassing with a smaller, faster and maybe cheaper hi-performance cap can make up for it.

The other camp says  using two or more caps with different time constant leads to smearing.  Opinion seems to be about 50/50 on this...John

Title: Re: Quick Question about Bypass Caps
Post by: Colonl_Charisma on January 25, 2021, 07:05:50 PM

Thanks John! I appreciate the answer.

Title: Re: Quick Question about Bypass Caps
Post by: cddc on February 02, 2021, 01:24:19 PM

The most common ratio that people use is 100:1.

So you bypass it with a 100:1 first, if you want go further you can add more bypassing caps with 10:1, 1000:1, 10000:1, etc.  ;D


Check the values here:
https://www.head-fi.org/threads/crack-bottlehead-otl.476650/post-15890390