zen without feedback

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#43
Oh. . the master put a little more salt than I expected. . Maybe . . you have more water in your aluminum cookpot.

I am seriously planning for an X-zenlite or an X-current source power . . Over the several years I still love all sound of my X-Zen V2 . . . .

Regards
jH
 
#47
Hi,

I think that Nelson uses output cap on F2.

Or, depending on what he used on the input, maybe he isn't using output cap at all. And a dual rail, of course. I tend to imagine a "Transconductance Aleph 3". Have I gone too far?😀

Vix
 
#50
The Master must be building F2's during a coffee break...

Since we started "assuming" how F2 is made, then let's move further...

For example, I assume that F2 uses lower supply voltage (between 25-30 v) and a higher bias (3 A perhaps?). It is yet unclear whether it uses a buffer or nor, but I have some indications that is built without a buffer, one mosfet only. Now, it makes me think which device Nelson employed :IRFP044. Or maybe something else, like 2SK1529??🙄

Am I wrong?😀

Regards,

Vix
 
#51
Wa~ow. . . 15,000. . . ? !? !
Sounds DonQihote. . .

Aaah. . . it is for an real ac short, your considering the amp a current source. It lets me think that I need to buy number of that size for both PSU and the output coupling. Thanks, I like to simplify also the shopping list.

Regards
jH
 
#52
Vix said:
For example, I assume that F2 uses lower supply voltage (between 25-30 v) and a higher bias (3 A perhaps?). It is yet unclear whether it uses a buffer or nor, but I have some indications that is built without a buffer, one mosfet only. Now, it makes me think which device Nelson employed :IRFP044. Or maybe something else, like 2SK1529??🙄
Click to expand...

24V
2.7A
no buffer
IRFP240 (gain) / IRFP9240 (ccs)
5 watts into 8 ohm
15.5 dB gain
-1 dB @ 100 KHz
20 uV noise

😎
 
#56
Nelson Pass said:


Seems that way, doesn't it?
Click to expand...


Anxious to try this amp with the FE164’s hopefully will be quite near of F2 😀

I'll be running at 30V 2+A. Asume this will have 30W disipation per device. Or maybe will unwind the secondary of the trafo to get those 24V to run full bias.

Aleph CCS type? Will this work?
 
#57
Hi Nelson

I am currently driving with a modified balanced v7 with ccs, 30V, 2.8amp per side, input caps of 10uf. I am using 3 pair of CCS per side. All the mosfet used were 044N. Got myself the 9140 few months back, intend to change the two CCS each side. But never got the time.

Even as it is, comparied to zenlite (unbalanced), this amp sound as good. But different in presentation

Can you please kindly comment on using p-channel for the CCS?

Would love to try these P-channel CCS and the no-feed back thingy.

🙂

Hock Hua
 
#58
Hi!

Nelson is being really generous🙂

With all these numbers provided, we can safely start assembling...

It's a bit weird that IRFP9240 was used, but hey, that's just CCS, so it shouldn't matter whether we use it or IRFP240 (or a lightbulb, if you wish). And no, I assume there's no Aleph CCS...

It seems that Nelson's goal was to show us how marevelous the original Zen was, and how little is needed to make another marvelous amp. Keep it simple....

I can't stop making questions. Since there's no buffer,what is puzzling me now is the input impedance of that circuit. So, Nelson, what value of the input resistor do you use?
(referring to R5 4,75 Kohm in the original Zen)

Thanks,

Vix
 
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