Spooky measurments.
Power supply
+/-50V /2x22.000uf
Out tran. MJW21195,96 one pair.
Idle current 60mA.
Bandwidth (tested at 10v RMS OUT) 3,2Hz-160KHz (-3db)
Vout just before clipping=24V RMS/8R/10KHz 850mV inp.
Visible(scope)clipping at 1v rms inp.
Vout hard clipping=34V RMS/8R
Scopes.UP out signal,down inp signal
1)10KHz
2)20KHz
3)50KHz
Square wave scopes.
4)50KHz
5)100KHz
6)200KHz
7)clip 1KHz
8)clip 20KHz
Power supply
+/-50V /2x22.000uf
Out tran. MJW21195,96 one pair.
Idle current 60mA.
Bandwidth (tested at 10v RMS OUT) 3,2Hz-160KHz (-3db)
Vout just before clipping=24V RMS/8R/10KHz 850mV inp.
Visible(scope)clipping at 1v rms inp.
Vout hard clipping=34V RMS/8R
Scopes.UP out signal,down inp signal
1)10KHz
2)20KHz
3)50KHz
Square wave scopes.
4)50KHz
5)100KHz
6)200KHz
7)clip 1KHz
8)clip 20KHz
Attachments
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Well I more or less thought from the start of this thread (actually I think it was the 'other' thread - you know the one) that we'd not find a real world difference between CFA and VFA and based on this thread it doesn't seem that I'll need to eat my hat anytime soon ... but I'm still watching 😀
Thimios, can you turn down the square wave as much as you can, so we can see small-signal behavior? The asymmetric square wave is a result of overloading the frontend - this doesn't happen with normal listening. Small-signal square wave shape however shows how the amp behaves at listening levels.
Don't use a volume pot, connect the generator directly to the amp input and lower the square voltage. If there is a resistor between the input and the LTP input base, then short the resistor for this test.
Don't use a volume pot, connect the generator directly to the amp input and lower the square voltage. If there is a resistor between the input and the LTP input base, then short the resistor for this test.
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The "side benefit" of all this CFA/VFA banter is better amps on both sides
of the fence. Also , the EF3 bridge has been crossed , no turning back.
CF is a elegant technique , no V/I conversion needed for NFB. but it
has both strengths and weaknesses.
The spooky and the NAD both do the same thing , just the nad omits
the NFB V/I devices.
OS
From a little time listening i have the feeling that cymbals and drums comes ahead with NAD(CFA)
It's my feeling?
It's my feeling?
From a little time listening i have the feeling that cymbals and drums comes ahead with NAD(CFA)
It's my feeling?
Put better (Cdom) in the spook ... those ceramics are quite inferior.
Actually , put silver mica in both , then compare.
OS
OS ,silver mica capacitors aren't available in Greece.
The only way to have these is from outside, so we must wait a long time.
Regards.
Thimios.
Thimios,
Put up some values and perhaps someone can mail you a few caps? That may be faster than anything else.
Put up some values and perhaps someone can mail you a few caps? That may be faster than anything else.
Nad uses 1x33pF
Spooky 1x150pF,2X22pF
looks generous if someone can send these .🙂
Best Regards.
Thimios.
Nad= 1 X150pf multi-ceramic/poly 50v for input filter.
1 X 33-39pf silver mica for comp.
Spooky = 1 X 150pF multi-ceramic/poly 50v for input filter ...
2 X 22pf silver-mica (cdom1/2), Also 2.2-2.7pf silver for "LC" (try this - it
will kill any "overshoot" - increase slew).
OS
From a little time listening i have the feeling that cymbals and drums comes ahead with NAD(CFA)
It's my feeling?
Interesting....
Please do some more listening. I want to know your opinion about spooky and NAD comparison.
OS ,is this type of capacitor (styroflex) recommended for inp.filter?
Attachments
Good , as long as they aren't ceramic. Ones like that would even be better
for Cdom1/2 (instead of ceramic).
BTW - a newer NAD is on the drawing board.
I'll squeeze this on the smallest IPS board (76.2 X 76.2mm) ,
and make it very "pretty" 😀 .
OS
Attachments
OS or Thimios, can you short the amp input with a 5uH inductor to see if it oscillates? Also try higher and low inductor values if possible.
New progress on the road
I have a burned 21195/96 pair already😱
Possible if OS can simulate this first
Thimios.