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PostPosted: 13 Jul 2010, 08:07 
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dtsup1 wrote:
KrammeAcoustics wrote:
It will be a dual PS then and i have a lot of 10 Ohm's 10W resistors, so the load can be 10 Ohm, by coupling 2 x 2 in serial/parallel or 15 Ohm load will also be possible with 2 x 3 of them in serial/parallel.

Use as many resistors as you can to reduce internal heat of the enclosure =)
Also keep the heat away from the electro caps/FET. I dropped some red ants on the 4 series-parallel resistors and they didn't survive for more than 1 second...

Gio wrote:
Congrats Dinesh, enjoy the amp! With the right speakers a SE FET can sound great!

Thx Gio. Am enjoying the amp now but will try building a more efficient speaker system to better match the amp.

Does anyone know the distortion levels of the ZCA, into 4 watts and total bandwidth?
It sounds so clean that im guessing it is below 0.1%.

No I think it is quite high but even high distortion has little to do with the musical sound of an amp. I wouldn't worry.

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Projects: "Sanctum" - 12AU7 and 6AS7 direct coupled headphone amp | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


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PostPosted: 13 Jul 2010, 13:51 
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My K272 Oatley pre-amp batteries ran out so I temporarily hooked up a chinese made DAC, the Yulong UA-188. Cost around US90 with premium caps/shielded toriod/metal film resistors. All those fancy components did not make it sound any better. Sound was flat, uninspiring and thin but with good punchy bass. K272 still delivers big time. Indeed a valve pre-amp is a great match for the ZCA.


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PostPosted: 13 Jul 2010, 17:39 
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Does look good. But I think some times excessive NFB and some cost cutting can kill dynamics. It probably measures very well but often there is little relation between measurements and musical flow.

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Projects: "Sanctum" - 12AU7 and 6AS7 direct coupled headphone amp | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


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PostPosted: 15 Jul 2010, 01:33 
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C'MON you gutless sissies!............try the high power ZCA................................I dare you! :lildevil:

Think you won't hear a difference?.................................think again! :eek:


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PostPosted: 15 Jul 2010, 01:38 
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Ziggy,

I will as soon as I build enough confidence to tackle high voltages !! :bawling:
So how many watts does your high voltage ZCA output ?

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PostPosted: 16 Jul 2010, 16:23 
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Hi

To complete the bom list of this build, i was looking all my capacitors through, looking especially for Low ESR types, but it was frustrating, because it was hard to find some ...but with help, from a Farnell and RS catalog, i were getting closer. For now, i haven't found the right components ( still searching ). The nearest i've got in stock, is Nichicon PL(M), but after what i learned today, they should be named PS(M) for being Low ESR types. I've found a link where some few Low ESR brands and types are listed. Maybe it can help others, to find Low ESR capacitors.

http://www.badcaps.net/forum/showthread.php?t=921

PS: I've only got 9 pcs. of 10 Ohm's resistors ( needed 12 of them ), thoughts i got more of them :bawling: , so i've ordered 10 pcs. of 50 W 15 Ohm Dale resistors, with heatsinks and 4 pcs. of 2SK1058 Mos-Fet's on Ebay yesterday, hope to see the parts soon ....so the game can begin. :wizard:


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PostPosted: 16 Jul 2010, 16:59 
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dtsup1 wrote:
I will as soon as I build enough confidence to tackle high voltages !! :bawling:
So how many watts does your high voltage ZCA output ?

It doesn't have to be DANGEROUS :nuke: HIGH VOLTAGE, what about a new build with ex. 40 VDC ? I guess higher voltage would push "this build" over the limit. Mark mentioned to reduce the loadresistors to a lower value, when increasing to a higher voltage ( good info ). Later i'm thinking to experimenting with ex. 7,5 Ohm with a 50 - 60 VDC PS ( but for now i'll try 15 Ohm with a 24 - 30 VDC PS ).

Just to get things into perspective, there are other kinds of Zen's in the world feeding with up to 70 - 80 VDC.


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PostPosted: 17 Jul 2010, 01:32 
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Hi Kramme,

I have sourced for parts to make an ultra premium ZCA. Attached is the BOM.
Low DCR, very high ripple current caps. Wirewound non inductive resistors 0.1% where possible.
I tried searching for a 1M wirewound resistor on farnell but couldn't find one =(

The thing is, I don't know how much more power the higher voltage version will supply. Ziggy says it's still 4 watts.

QUote by Ziggy:
I have just been informed that I have only 4 watts of power output and am confused as to how this can be so considering the use of 3 times more voltage and paralleling the output device?


Going to a higher voltage will require changing all my caps to a higher voltage type. Same for the power tranny. So it's still the standard ZCA for me :mrgreen:


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PostPosted: 17 Jul 2010, 08:43 
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dtsup1 wrote:
Hi Kramme,

I have sourced for parts to make an ultra premium ZCA. Attached is the BOM.


Wauuw, really fine components you've found there Dinesh ...all deserves, to be presented in pictures :P

Image Image Image Image Image Image Image Image Image Image


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PostPosted: 17 Jul 2010, 09:01 
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dtsup1 wrote:
The thing is, I don't know how much more power the higher voltage version will supply. Ziggy says it's still 4 watts.

QUote by Ziggy:
I have just been informed that I have only 4 watts of power output and am confused as to how this can be so considering the use of 3 times more voltage and paralleling the output device?


Going to a higher voltage will require changing all my caps to a higher voltage type. Same for the power tranny. So it's still the standard ZCA for me :mrgreen:

Maybe to little consumption = bias current (?). It's a must to get higher current and voltage, when wanting higher power ...what i have understood, the distortion also will be improved, when doing so.

I think it's best to leave the ZCA build, as Mark has mentioned it to be. Another well proofed build with acceptance of higher voltage, is the Pass Zen. Good and understandable reading, can be found here: http://passdiy.com/pdf/zenlite.pdf


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