Headphone amp

iceman · 14th August 2003, 04:37 PM

I've just built me an headphone-amp, it's an OPA2134 from Burr-Brown(Free samples). The powersupply is 2 6volt in serie(+-12volt).
The sound is great, atleast in my AKG headphones.
I post some pictures and schematic later(tomorrow) if anyone are intressed.

Question: Is it hard to build some kind of bassBoost to the amp ?
Anyone have a schema?

GrahamnDodder · 15th August 2003, 11:07 PM

Go to www.head-fi.org .

That is ground central for DIY headphoning. They can help you easily.

GnD

GrahamnDodder · 16th August 2003, 12:38 AM

Also, if you have a CMoy design (most common 1st headphone amp) you can tweak the bass by playing with the signal coupling cap values.

Mine headphone amp is under the thread "my new baby" on this forum. The circuit is at:

http://www.tangentsoft.net/audio/cmoy-tutorial/

His (Tangent's) advice on signal-coupling cap tweaking for bass enhancement is at:

http://www.tangentsoft.net/audio/cmo...eaks.html#caps

GnD

iceman · 19th August 2003, 05:15 AM

Here's the headphone-amp i've built:

peranders · 19th August 2003, 06:36 AM

Not bad, iceman but I would have put two 100nF/50-63V polyester, ceramic decoupling caps in parallel whith those you got (C1, C2). It never hurts, mostly the opposite.

iceman · 19th August 2003, 07:03 AM

Thanks for
I'm sorry for the confusing picture/text.
The input-caps are not electrolyt, I do have 0,1µF ceramic there instead of 4,7µF
But i do ghange it soon

A friend give me the advice to change the ceramic to MKT-caps instead because he think the ceramic could act like a highpass-filter, is he right about that ??

peranders · 19th August 2003, 07:39 AM

If you admit that you use ceramic caps as input caps you will get the big wolves after you.

It's not very common to use ceramics because of the poor properties in audio performance. I don't say that the amp will sound like a disaster but almost anything else is better. Start with polyester or polypropulene.

The input filter IS a highpass filter!

f = 1/(2*pi*R*C)

It never hurts to combine this filter with a lowpass filter. I would suggest 50-150 kHz as cut frequeny.

1 k + 1 n to 3.3 nF this is good to reject RF disturbance.

iceman · 19th August 2003, 07:44 AM

Beware of the wolves

Thanks for the help.
I go and buy me polypropulene caps today.

peranders · 19th August 2003, 07:48 AM

I forgot, it's common pratice to have 100 ohms in series with output. This is only if you use both low impedance or high impedance headphones.

joensd · 19th August 2003, 11:02 AM

Hi iceman,
I remember there was a nice bass boost circuit on either
Headwize or HeadFi .
Go to DIY-forums and search for bass boost from ppl.

Cheers
Jens

14th August 2003, 04:37 PM	#1
iceman diyAudio Member Join Date: Jun 2003 Location: Gothenburg	Headphone amp I've just built me an headphone-amp, it's an OPA2134 from Burr-Brown(Free samples). The powersupply is 2 6volt in serie(+-12volt). The sound is great, atleast in my AKG headphones. I post some pictures and schematic later(tomorrow) if anyone are intressed. Question: Is it hard to build some kind of bassBoost to the amp ? Anyone have a schema? __________________ "Quis custodiet ipsos custodes?"

15th August 2003, 11:07 PM	#2
GrahamnDodder diyAudio Member Join Date: Jun 2003 Location: Near Baltimore, MD	Go to www.head-fi.org . That is ground central for DIY headphoning. They can help you easily. GnD __________________ I had the right to remain silent. I just didn't have the ability. (Comedian Ron White)

16th August 2003, 12:38 AM	#3
GrahamnDodder diyAudio Member Join Date: Jun 2003 Location: Near Baltimore, MD	Also, if you have a CMoy design (most common 1st headphone amp) you can tweak the bass by playing with the signal coupling cap values. Mine headphone amp is under the thread "my new baby" on this forum. The circuit is at: http://www.tangentsoft.net/audio/cmoy-tutorial/ His (Tangent's) advice on signal-coupling cap tweaking for bass enhancement is at: http://www.tangentsoft.net/audio/cmo...eaks.html#caps GnD __________________ I had the right to remain silent. I just didn't have the ability. (Comedian Ron White)

19th August 2003, 06:36 AM	#5
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Not bad, iceman but I would have put two 100nF/50-63V polyester, ceramic decoupling caps in parallel whith those you got (C1, C2). It never hurts, mostly the opposite. __________________ /Per-Anders (my first name) or P-A as my friends call me Tube Buffered Gainclone in work \|Thread

19th August 2003, 07:03 AM	#6
iceman diyAudio Member Join Date: Jun 2003 Location: Gothenburg	caps Thanks for I'm sorry for the confusing picture/text. The input-caps are not electrolyt, I do have 0,1µF ceramic there instead of 4,7µF But i do ghange it soon A friend give me the advice to change the ceramic to MKT-caps instead because he think the ceramic could act like a highpass-filter, is he right about that ?? __________________ "Quis custodiet ipsos custodes?"


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19th August 2003, 07:39 AM	#7
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	If you admit that you use ceramic caps as input caps you will get the big wolves after you. It's not very common to use ceramics because of the poor properties in audio performance. I don't say that the amp will sound like a disaster but almost anything else is better. Start with polyester or polypropulene. The input filter IS a highpass filter! f = 1/(2piR*C) It never hurts to combine this filter with a lowpass filter. I would suggest 50-150 kHz as cut frequeny. 1 k + 1 n to 3.3 nF this is good to reject RF disturbance. __________________ /Per-Anders (my first name) or P-A as my friends call me Tube Buffered Gainclone in work \|Thread

19th August 2003, 07:44 AM	#8
iceman diyAudio Member Join Date: Jun 2003 Location: Gothenburg	caps Beware of the wolves Thanks for the help. I go and buy me polypropulene caps today. __________________ "Quis custodiet ipsos custodes?"

19th August 2003, 07:48 AM	#9
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	I forgot, it's common pratice to have 100 ohms in series with output. This is only if you use both low impedance or high impedance headphones. __________________ /Per-Anders (my first name) or P-A as my friends call me Tube Buffered Gainclone in work \|Thread

19th August 2003, 11:02 AM	#10
joensd diyAudio Member Join Date: Dec 2001 Location: Germany	Hi iceman, I remember there was a nice bass boost circuit on either Headwize or HeadFi . Go to DIY-forums and search for bass boost from ppl. Cheers Jens

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