Hi Magura,
Here's a decent explaination around the taiwan ladder attenuator that might be helpful.
http://www.penguinlovers.net/audio/Attenuator.html
-David
Here's a decent explaination around the taiwan ladder attenuator that might be helpful.
http://www.penguinlovers.net/audio/Attenuator.html
-David
You can find it here in passdiy.com
http://www.passdiy.com/legacy.htm
There is also many DIY reports in the Gallery section. A wonderful preamp I have!
Thomas
BOSOZ
Tomchaoda,
Sorry for stupid question, but is it the "Balanced Zen Line Stage" article?
One more question: I'm planning to build Zen Penultimate (v4) and I heard that bosoz is very good couple for it. But can I simply use variable stereo resistor to control the volume or it is necessary to use preamp?
Tomchaoda,
Sorry for stupid question, but is it the "Balanced Zen Line Stage" article?
One more question: I'm planning to build Zen Penultimate (v4) and I heard that bosoz is very good couple for it. But can I simply use variable stereo resistor to control the volume or it is necessary to use preamp?
I was wondering which resistors and capacitors are the most crucial for the sonic signature of this circuit. So if someone whants to use better parts in the construction of this project then what components need to be upgraded? As a first build I wish to use the best parts only where necessary.
Thanks
George
Thanks
George
Recommended BOSOZ initial upgrades
Hi George,
The circuit as designed sounds fabulous! I'd recommend building as designed to set a baseline, and from there tweak it further from there. Some biuld tips...
Transformer:
Lots of guys have used a 55-0-55 at 120va the Avel-Lindberg #Y236457 http://avellindberg.com/transformers/y23_range.htm
I used one transformer to drive two power supplies for the BOSOZ.
Wire:
Upgrade the chasis wire from standard hook-up wire to pure copper with silver coating, with Teflon insulation. 20ga Wonder Wire from Micheal Percy audio works great. Get enough of it since it seems to magically disappear inside the case. :7)
Solder:
Try a high quality solder that's not too exotic with a standard melting point like Wonder "Ultraclear" available from http://www.percyaudio.com a 1/4 pound is enough.
Connectors:
Consider Cardas connectors like Vampire or XLO.
Next steps:
Listen to the circuit for while and experiment with the attuenation device you are using; perhaps upgrade it first, and then try the exotic resistors and caps that are in the signal path.
Also money spent on a balanced signal source like your CD player makes a bigger improvement than the exotic components. I was surprised at the improvement when I added an ADCOM GDA 700 balanced DAC to my Marantz CD-63SE.
Just FYI.... Good luck,
-David
Hi George,
The circuit as designed sounds fabulous! I'd recommend building as designed to set a baseline, and from there tweak it further from there. Some biuld tips...
Transformer:
Lots of guys have used a 55-0-55 at 120va the Avel-Lindberg #Y236457 http://avellindberg.com/transformers/y23_range.htm
I used one transformer to drive two power supplies for the BOSOZ.
Wire:
Upgrade the chasis wire from standard hook-up wire to pure copper with silver coating, with Teflon insulation. 20ga Wonder Wire from Micheal Percy audio works great. Get enough of it since it seems to magically disappear inside the case. :7)
Solder:
Try a high quality solder that's not too exotic with a standard melting point like Wonder "Ultraclear" available from http://www.percyaudio.com a 1/4 pound is enough.
Connectors:
Consider Cardas connectors like Vampire or XLO.
Next steps:
Listen to the circuit for while and experiment with the attuenation device you are using; perhaps upgrade it first, and then try the exotic resistors and caps that are in the signal path.
Also money spent on a balanced signal source like your CD player makes a bigger improvement than the exotic components. I was surprised at the improvement when I added an ADCOM GDA 700 balanced DAC to my Marantz CD-63SE.
Just FYI.... Good luck,
-David
I have been considering building a P2P wired BOSOZ for way too long. So far all I have done is design/layout the perfboards for the seperate PS & pre.
I am rather confused about something on the passdiy site: In the pdf. text it says we use transformers with 40+40 secondaries, which we pad down to 60V for the fets, right? But in the parts list for the PS a 30+30 transformer is listed. What have you guys done? Are the R values critical between 60V and 60V rails?
Please help a weary potential DIYer! Thanks, Andy Bacon
I am rather confused about something on the passdiy site: In the pdf. text it says we use transformers with 40+40 secondaries, which we pad down to 60V for the fets, right? But in the parts list for the PS a 30+30 transformer is listed. What have you guys done? Are the R values critical between 60V and 60V rails?
Please help a weary potential DIYer! Thanks, Andy Bacon
A 30 VAC tranny will provide around +/- 40 volts dc.
A multiplier of 1.2 or 1.4 is usually used to spec the transformer out for the needed dc voltage. Check out http://synergy.sager.com/ProductPDFs/PowerTransformer_FilterRatings.pdf
Tom
A multiplier of 1.2 or 1.4 is usually used to spec the transformer out for the needed dc voltage. Check out http://synergy.sager.com/ProductPDFs/PowerTransformer_FilterRatings.pdf
Tom
ampsarus said:
Hello ampsarus,
Nelson originally spec'd two transformers, since a cost effective 60VAC was not readily available for DIYer's. Under the original parts specified, a person needs four transformers for true dual power supplies. I just used the one 55+55 AvelLindberg listed above to drive two powersupplies with excellent results. The rail voltages for me are +60.1 and -60.2 using this transformer. I would hazzard to guess that a single powersupply would sound the about same, and simplifies the P2P wiring to use one supply. I'm going to experiment with a single supply myself to see if I can hear any difference.
BTW, There is HUGE sonic difference when I went to a balanced DAC as a source with the BOSOZ.
Good luck,
-David
Gentelemen,
Thanks you for your responses. And thanks to raincheck for the power supply spec article- A great resource which I have saved.
dw8083: My CDP has balanced outs (meridian 588) which now feeds a classe cp60 through balanced lines. My hope is that the bosoz will outperform the classe to a point where I can dismiss it's convienence and sell it.
(this is where it might get wierd)
Further, what I'd really like to do, if possible is build 4 or 6 independent L/R preamps so I can quad-amp my 4-way JBL's and have an extra L/R channel for external subs. Then I will have level control over each driver, desireable IMO when using 116dB sensitivity compression drivers with 99dB sensitive woofers! (I despise using resistors in my crossovers, even the good ones stink)
Could I feed my source signals to 1 bosoz, (or to my classe pre) and then use that signal to drive 4 or 6 more bosoz inputs in parallel? I imagine I would build 2 large power supplies, 1 for right and 1 for left. Seems like a better idea than sourcing a couple dozen transformers. I'm wondering if the regulator fets would be up to supplying that much, of if I'm stuck building 4 or 6 independent power supplies to realize this idea.
Thanks again for your help guys, please let me know if this half-baked idea would even work.
-Andy Bacon
Thanks you for your responses. And thanks to raincheck for the power supply spec article- A great resource which I have saved.
dw8083: My CDP has balanced outs (meridian 588) which now feeds a classe cp60 through balanced lines. My hope is that the bosoz will outperform the classe to a point where I can dismiss it's convienence and sell it.
(this is where it might get wierd)
Further, what I'd really like to do, if possible is build 4 or 6 independent L/R preamps so I can quad-amp my 4-way JBL's and have an extra L/R channel for external subs. Then I will have level control over each driver, desireable IMO when using 116dB sensitivity compression drivers with 99dB sensitive woofers! (I despise using resistors in my crossovers, even the good ones stink)
Could I feed my source signals to 1 bosoz, (or to my classe pre) and then use that signal to drive 4 or 6 more bosoz inputs in parallel? I imagine I would build 2 large power supplies, 1 for right and 1 for left. Seems like a better idea than sourcing a couple dozen transformers. I'm wondering if the regulator fets would be up to supplying that much, of if I'm stuck building 4 or 6 independent power supplies to realize this idea.
Thanks again for your help guys, please let me know if this half-baked idea would even work.
-Andy Bacon
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