Bass Boost

[Anthrax]

before u guys go nuts, and tell me to search. i have, and i have read all about the PPA, and pimeta bass boosts. i have a question though about a differnt idea.

is there a bass boost curcuit that goes at the input ? i want to make a small device with an input and output socket that can be added to any amp. with a pot so that you can control the bass boost.

is this idea feasible ?

 

[james902]

here's the thread i opened... hope this helps. In fact I think it address an input fix that's not recommended

http://www4.head-fi.org/forums/showthread.php?t=93926

cheers,
~jay

 

[dr_digits]

You can make a device with about the same parts as a cmoy that will do bass boost only. I just made one for my brother. I used these sources for the math:
http://www.linkwitzlab.com/images/graphics/shlv-lpf.gif
http://www6.head-fi.org/forums/showthread.php?t=104392

Tangent's bass boost calculator was helpful and amb's bass boost calculator from the m3 site gives nice graphs. Sorry I can't give more details but I am at work right now. I used a 50k panasonic evj pot, a .22uF radioshack cap, vishay-dale resistors and an opa2227 and it worked nicely.

 

[mono]

TO put it simply. a "boost" is a voltage gain at the target frequency range. Along with that voltage increase, you "may" find a current limit too.

What it means is that you're essentially building an amp, like a CMOY in it's simplest form (you could leave off the volume knob if you liked) and in the opamp's feedback loop, you would add a bass boost circuit similar to that seen on a PPA or (take your pick). THEN, having added that boost, if you find there isn't enough current for this boosted bass (which is likely, depends on the opamp and cans too) you'd add at least a L, R channel buffers to provide it.

So it's a headphone amp like any other, but presumably you want a gain of 1 on all frequencies except that boosted bass. It'd be roughly the same size, and simlar power requirements as a CMOY... slightly larger to do it right with good polypropylene caps for best sound.

So essentially, what you'd build is an entire amp in itself. If you built it well enough (to your tastes) it elminates the amp you'd have after it.

 

[Anthrax]

thanks for the help. uv given me some good ideas

infact, i'm thinking, is it possible to have a treble control as well ?

 

[mono]

It's possible, there is probably a thread or two (search for them). I have to wonder though if you might need a better source or cans if you find you need to adjust these things.

 

[PeterR]

Quote:

Originally Posted by Anthrax thanks for the help. uv given me some good ideas infact, i'm thinking, is it possible to have a treble control as well ?

http://www6.head-fi.org/forums/showthread.php?t=107568