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brianco

brianco

Member
Joined 2005
Thanks for that - I had totally forgotten about Goethe's "theory", but its more than 50 years since I last heard of that construct.:rolleyes:

I suspect that this is the passage from your link which may apply?

Goethe expresses this more succinctly:
Yellow (Golden?) is a light which has been dampened by darkness; Blue is a darkness weakened by light. :D

No more OT nonsense - for now!;)​
 
RCruz

RCruz

Member
Joined 2006
Paid Member
FdW said:
Hi All,

Best wishes for the new year, and if you was wondering what I did during the holidays :) then here is a picture.

2 x (both sides) Mains 'ground-rail' guard (no solder mask)
1 x Mains DC-blocker
3 x Fuses for Transformers
1 x 12VA 9V Transformer + Rectifier + Capacitors
4 x 20Amp Bridges + Snubbers
6 x DDRC ( InR/InL, OutR/OutL, 12V and Case )
2 x N0X

All connection support for Mains(3x) Primaries(4x) Secondary(8x) Elco's(8x) and DDRC's/N0X's using headers(3x).

The boards will be 2.5mm thick with 4oz copper.

It is designed to set on top of 2 toroids (in my case 2x 600VA) The 4 blue circles (on the large circle) used for rubber standoffs and the big central hole used for mounting on the same screw that is used for mounting the toroids. The 3 holes (in the HV section) should be used to mount a Plexiglas 'roof' over the HV section for safety.

Tomorrow I will order 10 of these for myself, but if you would like to have (unlikely) a few then quickly drop me a PM.
Click to expand...

complex psu... what are you using it for ?
 
FdW

FdW

Member
Joined 2009
FdW said:
Hi All,

Best wishes for the new year, and if you was wondering what I did during the holidays :) then here is a picture.

2 x (both sides) Mains 'ground-rail' guard (no solder mask)
1 x Mains DC-blocker
3 x Fuses for Transformers
1 x 12VA 9V Transformer + Rectifier + Capacitors
4 x 20Amp Bridges + Snubbers
6 x DDRC ( InR/InL, OutR/OutL, 12V and Case )
2 x N0X

All connection support for Mains(3x) Primaries(4x) Secondary(8x) Elco's(8x) and DDRC's/N0X's using headers(3x).

The boards will be 2.5mm thick with 4oz copper.

It is designed to set on top of 2 toroids (in my case 2x 600VA) The 4 blue circles (on the large circle) used for rubber standoffs and the big central hole used for mounting on the same screw that is used for mounting the toroids. The 3 holes (in the HV section) should be used to mount a Plexiglas 'roof' over the HV section for safety.

Tomorrow I will order 10 of these for myself, but if you would like to have (unlikely) a few then quickly drop me a PM.
Click to expand...

If you want to know, the next step :)
Hobby Electronics | Flickr - Photo Sharing!
 
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3

31697B

Disabled Account
Joined 2012
Distortion cancellation --

keantoken said:
It doesn't seem you guys realize this, but the Vbe nonlinearities in this EC topology cancel.
Instead of using two PNP's for the mirror, it is better to use an NPN and PNP, that way the complimentary parts' differences in matching are also cancelled.
Click to expand...

Cancelled? Did I hear someone say CANCEL!

:cool::)


Thx-RNMarsh

:D
 
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3

31697B

Disabled Account
Joined 2012
Cancallation of thd --

keantoken said:
It doesn't seem you guys realize this, but the Vbe nonlinearities in this EC topology cancel. It is essentially the Tringlotron, except input and output are able to share a common ground. I came up with this independently many months ago and have done several experiments with this topology since it is extremely fast and should allow improvement in linearity of various circuits by canceling Vbe distortion directly rather than hoping to attenuate it to a satisfying number of zeros. As it turns out, BC5xx/BC3x7-40 have close enough Vbe that they should be matched enough to do very well in this topology.

Instead of using two PNP's for the mirror, it is better to use an NPN and PNP, that way the complimentary parts' differences in matching are also cancelled. I have built this circuit several times and it works as expected. By trimming the match you can get a positive or negative 2nd harmonic. This gives very subtle acoustic effects. You can get very visceral bass this way.

I have tried NXP BC8xxC duals for this but surprisingly, they don't actually seem to achieve better thermal coupling then two TO92's. This frustrated me, besides the attempt to p-p solder the SMD package.

The speed of this configuration makes it useful as a very fast buffer, and so naturally it could find application in linear regulators, amplifier stages and so on. One problem is that input resistance is negative at at high frequencies, and output resistance may be negative, which is what the 4.7R is for.

So I regard this as an improvement on the Tringlotron.

The biasing scheme keeps the temp of the transistors roughly equal; coupling TO92 transistors really doesn't help much with the thermal differential.

Also attached are FFT plots with and without the buffer. I don't trust these results, because the 2nd harmonics did not respond to trimming at all. I think something else was causing the 2nd harmonic and the buffer's actual H2 was obscured by it. I seem to remember getting -90db with some other configuration. Still, we know that THD is at least that good.
Click to expand...


:cool::)

This is where its at. Cancellation techniques. Lets see more of these techniques instead of nfb etc to reduce distortion.

Thx-RNMarsh
 
3

31697B

Disabled Account
Joined 2012
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