john, i don´t understand what should be the advantage of using only 2 diodes. Wouldn´t a normal bridge rectifier on every secundary and parallel them make sense? With a 1kVA transformer you should have plenty amperes, and for the lightbulb Zen a higer voltage (50V*1,42 = 70V) should be no problem, since most voltage is burned in the bulb, and you will have more current.
more voltage......
I have eight computer grade 20k uF caps that are rated at 50 volts each. I'd like to experiment with what I have on hand. I will purchase higher value caps if someone can tell me that the higher voltages sound significantly superior.
Futhermore, I can use 6 300 watt bulbs per monoblock with these transformers configured at 45 volts. At 70 volts, I'm limited to 3 bulbs per monoblock.
I have eight computer grade 20k uF caps that are rated at 50 volts each. I'd like to experiment with what I have on hand. I will purchase higher value caps if someone can tell me that the higher voltages sound significantly superior.
Futhermore, I can use 6 300 watt bulbs per monoblock with these transformers configured at 45 volts. At 70 volts, I'm limited to 3 bulbs per monoblock.
Ok, this is a reason i do understand.
Question: anybody from mexico who could say if it is possible there (and at which place) to buy tose 300W 110V bulbs and the sockets Nelson uses? http://www.passdiy.com/images/projects/zenlite.jpg
Question: anybody from mexico who could say if it is possible there (and at which place) to buy tose 300W 110V bulbs and the sockets Nelson uses? http://www.passdiy.com/images/projects/zenlite.jpg
The schematic below show some modification that reflects listning tests preference.
The first is the rail: from 45 volts to 57 , with 2 light bulbs the current trough the circuit is 1.9A.
The second is the implementation of a cascode operation for the buffer. The Ztx550 infact cascodes the Irf9610 .
IMHO the amplifier sounds VERY good and I like the changes that cascoding the buffer produce.They are mainly a sense of lack of compressions especially in the sound of the bass guitars.
I listen to some records for the tests:
AbsoluteBenson - George Benson
Live in Paris - Diana Krall
Ten Summoner's Tales - Sting
Illumination - Paul Weller
... and many others
🙂
The first is the rail: from 45 volts to 57 , with 2 light bulbs the current trough the circuit is 1.9A.
The second is the implementation of a cascode operation for the buffer. The Ztx550 infact cascodes the Irf9610 .
IMHO the amplifier sounds VERY good and I like the changes that cascoding the buffer produce.They are mainly a sense of lack of compressions especially in the sound of the bass guitars.
I listen to some records for the tests:
AbsoluteBenson - George Benson
Live in Paris - Diana Krall
Ten Summoner's Tales - Sting
Illumination - Paul Weller
... and many others
🙂
Attachments
OK thanks.
The difference is that irf9610 eat 4volt gate to source ,
the bjt ZTX only 0.7volt base to emitter.
So with the bjt the dc point were the input cap is connected is near the same of the 044's gate pootential and favours the distorsion cancellation.
The difference is that irf9610 eat 4volt gate to source ,
the bjt ZTX only 0.7volt base to emitter.
So with the bjt the dc point were the input cap is connected is near the same of the 044's gate pootential and favours the distorsion cancellation.
Cool!!
Stefano,
I'll be using IRFP240 FETs. Is this going to work with the cascode arrangement you created? Also, do I create a balanced amplifier by mirroring the single ended amp you've drawn?
Many thanks,
John Inlow
Stefano,
I'll be using IRFP240 FETs. Is this going to work with the cascode arrangement you created? Also, do I create a balanced amplifier by mirroring the single ended amp you've drawn?
Many thanks,
John Inlow
In Nelsons balanced circuit without output C´s the bias - setting resistors are lower value, i don´t understand why.
What i would like to know: with the input buffer, why C2 is still 100uF? I don´t have 100uF film cap, isn´t a much lower value enough?
What i would like to know: with the input buffer, why C2 is still 100uF? I don´t have 100uF film cap, isn´t a much lower value enough?
I still don't understant your exitement about a balanced zen, since there is something called the soz 
just another way of doing things......
Hi Bricolo,
The SOZ is a bit too simple for my taste. I like things like a buffer circuit, cascodes and lightbulbs and besides, it's one of Nelson's latest ideas and looks like it might be fun to explore. I have all the amplifiers a man could ever want. Heck, I've even got 1100 watts per channel for the bottom end. Still, there's always one more hill to climb and one more bend in the road. It's such an adventure to learn something new with a great group of individuals like we find in this forum.
John Inlow
Hi Bricolo,
The SOZ is a bit too simple for my taste. I like things like a buffer circuit, cascodes and lightbulbs and besides, it's one of Nelson's latest ideas and looks like it might be fun to explore. I have all the amplifiers a man could ever want. Heck, I've even got 1100 watts per channel for the bottom end. Still, there's always one more hill to climb and one more bend in the road. It's such an adventure to learn something new with a great group of individuals like we find in this forum.
John Inlow
Yes you can . Use a 220uF to connect the feedbak loop (R7) at the output. , like the previous attached balanced schematic.
Please keep us informed on the heated resistance of these and other bulbs as you experiment. They sure are puurty
I don't want to rain on any parade, but the bipolar transistor is not cascoding the input device. Its connection makes just a diode in series with the Drain.
More to the point, the input P channel Mosfet doesn't benefit from cascoding as its Drain is already seeing a low impedance (ground) and the Drain-Source voltage is held constant because the input to the main gain stage (which the Source of the input device looks at) is a virtual ground.
More to the point, the input P channel Mosfet doesn't benefit from cascoding as its Drain is already seeing a low impedance (ground) and the Drain-Source voltage is held constant because the input to the main gain stage (which the Source of the input device looks at) is a virtual ground.
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