[BradJudy]

I have changed my mind and decided to add a bass boost to the PPA I am building (it's done except for the casing). Unfortunately, I didn't order any of the BC 416 0.1uF caps and it isn't worth ordering just those. I do have two options lying around (nearly identical options):

1) 0.1uF metalized polyester box cap for PPA C3 postion (works fine without them populated and will eventually use Glassman's buffer) Mouser part 75-MKT1826410064

2) 0.1uF metalized polyester box cap for STEPS C6 position (extras to meet the minimum quantity) Digikey part BC1621

3) Find a head-fier with a couple of extra 0.1uF BC 416s to sell me.

Are options 1 and 2 worth trying or should I just try for 3?

Thanks in advance.

Brad

 

[Glassman]

I'm not sure if it was you I was sending two 0.1uF caps for bass boost together with a buffers, anyway, I have lots of them, just tell me and I'll send you some..

 

[MisterX]

IMHO .1uF is way way way way way to big for a bass boost cap.
.03uF is as big as I would ever use there.

Shoot me a pm with your address and I can drop a few of them in the mail to you on Monday.

 

[tangent]

Quote:

.1uF is way way way way way to big for a bass boost cap.

Some of us don't like bass boost touching the midbass. The bigger C1 is, the lower the point where boosting begins.

 

[doobooloo]

Quote:

Originally Posted by MisterX IMHO .1uF is way way way way way to big for a bass boost cap. .03uF is as big as I would ever use there. Shoot me a pm with your address and I can drop a few of them in the mail to you on Monday.

I have used 0.33uF until now, I am building a PPA with 0.47uF as C7...

I feel the point of bass boost is not to create a Sony MegaBass type boost but to merely compensate for the natural bass response decay of headphones. 0.33uF~0.47uF does that quite well, IMO. 0.1uF boosts way too much for my liking.

 

[BradJudy]

Glassman - we haven't discussed bass boost caps before, but I am on the waiting list for the next round of buffers, so this looks like the best option for me. Thanks.

MisterX: I have to agree with Tangent that I don't want a bass boost that goes that far up. 0.03uF puts you at an fs of 531Hz, not what I'm shooting for. Thank you for the offer of sending some, though.

doobooloo: I'll have to try and see what I like. Since there have been opinions on both higher and lower already, I'll start with the standard 0.1uF and see if that seems like too much or too little. I will probably socket R7 initially to play with the boost level as well.

In the end, I will have Glassman add some 0.1uF BCs into my buffer order when they are ready.

Thanks to everyone for your help.

Brad

 

[doobooloo]

Brad,

You should experiment with MicroCap and see what the results will be. You'll see what kind of frequency response you'll get with different C7/R7 values. This helped me a lot in choosing the right C7/R7 combo.

The data is on Tangent's website: http://www.tangentsoft.net/audio/ppa/amp/tweaks.html

 

[MisterX]

Wow... ever posted something and said:
What was I thinking when I posted that?
I just did.

 

[ITZBITZ]

I typically use the Panasonic Film and Foil type at Digikey. The line includes P/N P3223-ND or something like that. The 0.27 are perfect. They are cheap too.

 

[doobooloo]

Quote:

3) Find a head-fier with a couple of extra 0.1uF BC 416s to sell me.

I actually have a few 0.12uF BC 416s lying around, if you're interested.