Zen Phase Shift, Feedback in BOZ - diyAudio
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Old 13th February 2003, 04:32 AM   #1
Jay is offline Jay  Indonesia
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Default Zen Phase Shift, Feedback in BOZ

I don't understand what Mr. Pass mentioned about the importance of maintaining a proper phase in the Zen amp. How could this be so bad?

In the Zen, positive speaker is connected to ground. What if we use Bride Of Zen for the Zen. Will this still apply?

I'm not happy with my BOZ. To drive the Aleph, I prefer to add feedback, or simply a bypass resistor in the BOZ (18KOhms). With my system, the expected advantage is for the vocal to be more neutral and not striking the ears. What do you think of this approach? I want to know possible disadvantages...
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Old 13th February 2003, 05:00 AM   #2
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Default Re: Zen Phase Shift, Feedback in BOZ

Quote:
Originally posted by Jay
I'm not happy with my BOZ. To drive the Aleph, ...
BOZ has 15dB gain, which is welcomed by Zen of the low gain.
I would add 5-10K input attenuator to BOZ to give the Aleph happiness.

JH
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Old 17th February 2003, 03:36 AM   #3
Jay is offline Jay  Indonesia
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Hi jh6you,

Assuming that regular metal films are superior than are regular potentiometers, when I was a kid I used to replace potentiometers with resistors to save the signal loss on cables and connections. Hard to believe, in every occasion I preferred the sound produced by the potentiometer in place (at least that is what I can remember).

Mr. Pass advised to use input volume control (in addition to the output volume control) to increase BOZ performance. I think this is what you mean with input attenuator. So I add various arrangements of resistors in the input representing a pot of 5K to 10K. After several hours of listening, I donít think I like the sound (compared to using output pot alone)

About the 18K bypass resistor, itís gone (and so is the BOZ). I donít like the BOZ for an Aleph (I heard about Aleph pre-amp, and may soon find the info). Ironically, I have managed to match the BOZ with many bipolar amplifiers, and it worked great with efficient and un-efficient speakers.

Yesterday I slightly modified my CD player and connected it directly to Aleph3. I listened to the worse CD I have (I donít like the synthesizer or the programmed keyboard of Lighthouse Family) till 3 o-clock in the morning. I think I can accept the sound quality, so what I want to do next is to optimize the performance of this arrangement: Burr Brown OPA 2134 ŗ level shifting stage ŗ IRF9610 differential stage ŗ IRFP250 output ŗ 88dB speaker.

But then I have questions regarding Aleph series, and I want to post it in a new thread.
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Old 17th February 2003, 04:36 AM   #4
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Quote:
Originally posted by Jay

input volume control (in addition to the output volume control) to increase BOZ performance. ...

Hi Jay

I talked about the input attenuator with respect to the gain control only.
And, I am much intersted in reading your post about the sound. Thanks.

JH
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