Can I add a headphone jack to BZLS

tomchaoda · 10th September 2003, 04:49 PM

I plan to do my first DIY project for BZLS (Balanced Zen Line Stage). Is it hard to add a headphone on this pre-amp? (I do need this, since my mom is sick and sleep early at night!)

If yes, can anyone give me a hint how to? I am new in DIY.

Thanks

paulb · 10th September 2003, 06:29 PM

The BZLS has a balanced output (+ and - for each channel), but you could drive the headphones from one side of each balanced output (say, the + side).
If I were doing this, I'd have a separate circuit to drive the headphones that you can run the BZLS into. See Figure 1 at http://sound.westhost.com/project87.htm or Figure A8 at http://headwize2.powerpill.org/proje...cmoy2_prj.htm.

Anorgan · 11th September 2003, 01:47 PM

Can you do it with BOZ? Haven't tried it yet.

Anorgan · 25th September 2003, 12:56 PM

So I put headphone jack in my BOZ. Nice sound, but very quiet!! I'm driving it with 0.23mA gain. Is it too low, or it doesn't matter?

protos · 25th September 2003, 01:21 PM

I have played around with my BZLS as a head amp. What you have to realize is that if you only have the output pots then this set up will not work well since the pot impedance is too high for proper volume management into headphones.If you also have the input pots then that is no problem since you can turn the out pots all the way up and use the input pots for volume control.
If you also want to experiment with balanced operation fully into headphones then you might need a repacement head cord that you can modify with a four pin connector so that you have +- left and +-right.
The BZLS has a great sound driving headphones and I am currently using it as a headphone amp although modified to run on batteries at+- 12V.
The stock unit would be difficult to modify with a headphone jack connected in parallel to the outputs because you would have to short the two negative outputs pemanently.The solution is to use a small four pole switch that would be wired appropriately to switch between normal balanced line out and headphone out.This is workable but ultimately you would have to take the output before the output 10mf caps so you don't lose any low frequencies.
All this sounds complicated but in the end may simplify your set up by having your pre and head amp in component.

JOE DIRT® · 25th September 2003, 02:09 PM

I would build a small amplifer on the output of the preamp as I do beleive that the BZL can be single ended also

DIRT®

Anorgan · 25th September 2003, 06:22 PM

When I cranck the volume up, it is still quiet! BTW, I have Bride of Zen, not bzls - so do I still need to take the output before the output 10mf caps? Also, I hooked it up onto a discman, not some line player - maybe that's why. Also, it was connected to a headphone jack to my Marantz cd63 - then it played good, but that's allready an headphone amp!! Can you help me a bit? Thanks!!

protos · 26th September 2003, 10:22 AM

Unfortunately the BOZ has an output pot which , because of its high impedance , will not allow it to output enough voltage if connected to a low impedance load like a few hundred ohm headphones. Do not attempt to take any output from before the caps since there is a lot of DC which will blow your headphones.
On the BZLS you can get away with not using caps if you use just the balanced outputs and not output to ground since the balanced +- outputs only have relatively little DC offset between them.
As mentioned in previous postings perhaps the best solution is to build a separate head amp which is very easy to do such as the c-moy or even meta-42.These will not work with the power supply of the BOZ since they can only handle about +- 15V maximum. However they work well with batteries or even a simple (linear please) wall wart.

Anorgan · 30th September 2003, 11:58 AM

I connected it to my PC - loud!!! I was wrong about my discman - it just can't deliver enough power.

10th September 2003, 04:49 PM	#1
tomchaoda diyAudio Member Join Date: Sep 2003 Location: New Jersey	Can I add a headphone jack to BZLS I plan to do my first DIY project for BZLS (Balanced Zen Line Stage). Is it hard to add a headphone on this pre-amp? (I do need this, since my mom is sick and sleep early at night!) If yes, can anyone give me a hint how to? I am new in DIY. Thanks

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10th September 2003, 06:29 PM	#2
paulb diyAudio Member Join Date: Jun 2001 Location: Calgary	The BZLS has a balanced output (+ and - for each channel), but you could drive the headphones from one side of each balanced output (say, the + side). If I were doing this, I'd have a separate circuit to drive the headphones that you can run the BZLS into. See Figure 1 at http://sound.westhost.com/project87.htm or Figure A8 at http://headwize2.powerpill.org/proje...cmoy2_prj.htm.

11th September 2003, 01:47 PM	#3
Anorgan diyAudio Member Join Date: Jul 2003 Location: Croatia	Can you do it with BOZ? Haven't tried it yet.

25th September 2003, 12:56 PM	#4
Anorgan diyAudio Member Join Date: Jul 2003 Location: Croatia	So I put headphone jack in my BOZ. Nice sound, but very quiet!! I'm driving it with 0.23mA gain. Is it too low, or it doesn't matter?

25th September 2003, 01:21 PM	#5
protos diyAudio Member Join Date: Mar 2002 Location: Athens+Addis Ababa	I have played around with my BZLS as a head amp. What you have to realize is that if you only have the output pots then this set up will not work well since the pot impedance is too high for proper volume management into headphones.If you also have the input pots then that is no problem since you can turn the out pots all the way up and use the input pots for volume control. If you also want to experiment with balanced operation fully into headphones then you might need a repacement head cord that you can modify with a four pin connector so that you have +- left and +-right. The BZLS has a great sound driving headphones and I am currently using it as a headphone amp although modified to run on batteries at+- 12V. The stock unit would be difficult to modify with a headphone jack connected in parallel to the outputs because you would have to short the two negative outputs pemanently.The solution is to use a small four pole switch that would be wired appropriately to switch between normal balanced line out and headphone out.This is workable but ultimately you would have to take the output before the output 10mf caps so you don't lose any low frequencies. All this sounds complicated but in the end may simplify your set up by having your pre and head amp in component.

25th September 2003, 02:09 PM	#6
JOE DIRT® diyAudio Member Join Date: Apr 2003 Location: Brantford, ON	I would build a small amplifer on the output of the preamp as I do beleive that the BZL can be single ended also DIRT®

25th September 2003, 06:22 PM	#7
Anorgan diyAudio Member Join Date: Jul 2003 Location: Croatia	When I cranck the volume up, it is still quiet! BTW, I have Bride of Zen, not bzls - so do I still need to take the output before the output 10mf caps? Also, I hooked it up onto a discman, not some line player - maybe that's why. Also, it was connected to a headphone jack to my Marantz cd63 - then it played good, but that's allready an headphone amp!! Can you help me a bit? Thanks!!

26th September 2003, 10:22 AM	#8
protos diyAudio Member Join Date: Mar 2002 Location: Athens+Addis Ababa	Unfortunately the BOZ has an output pot which , because of its high impedance , will not allow it to output enough voltage if connected to a low impedance load like a few hundred ohm headphones. Do not attempt to take any output from before the caps since there is a lot of DC which will blow your headphones. On the BZLS you can get away with not using caps if you use just the balanced outputs and not output to ground since the balanced +- outputs only have relatively little DC offset between them. As mentioned in previous postings perhaps the best solution is to build a separate head amp which is very easy to do such as the c-moy or even meta-42.These will not work with the power supply of the BOZ since they can only handle about +- 15V maximum. However they work well with batteries or even a simple (linear please) wall wart.

30th September 2003, 11:58 AM	#9
Anorgan diyAudio Member Join Date: Jul 2003 Location: Croatia	I connected it to my PC - loud!!! I was wrong about my discman - it just can't deliver enough power.

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