Stunning Amplifier Development!! Feedforwardback & Feedbackforward

Status
Not open for further replies.
Jump to Latest
#46
I don't know what the fuss is about. It is simply a circuit where the feedbackforward path is half the length of the signal path, and the feedforwardback path is twice as long as the signal path. Big deal, anyone could have figured that out.
 
#48
I was hoping for a breakthrough in the use of positive feedback loops.

It would be an adman's dream since the heavy use of positive feedback would be so much easier to sell to the masses who have problems accepting that something negative can be good and vice versa. Unfortunately as far as I am aware positive feedback in electrical equipment usually leads to the release of the magic smoke that makes everything work.
 
#49
Positive feedback in the preamp to get infinitive gain gives zero input needed.
Now apply negative feedback from the output stage to astablish the input sensitivity.
The output is now defined for 100% by the feedback, no distortion anymore.
It's as simple as that 🙂
Mona
 
#50
Charles Darwin said:
I was hoping for a breakthrough in the use of positive feedback loops.

It would be an adman's dream since the heavy use of positive feedback would be so much easier to sell to the masses who have problems accepting that something negative can be good and vice versa. Unfortunately as far as I am aware positive feedback in electrical equipment usually leads to the release of the magic smoke that makes everything work.
Click to expand...

Positive feedback has been used since the 50-ies in audio (tube) power amps. Pos feedback increases the loop gain, and if unchecked therefor leads to oscillation. But in combination with neg feedback it works great, because neg feedback works better with large loop gain (assuming you keep it stable of course).

Jan
 
#51
bear said:
Look, this is serious stuff.

The basic principal is based on the sub nanosecond propagation time in the "error correction" portion acting upon the lethargic turtle-like already low distortion topology of the main amplification path.

The only reason that we at BEAR Labs have been able to implement the design in hardware is that we have access or entre to the nearby nano-tech center that has a specialized foundry. Working with their staff, and some select post-grads we solved the timing problems by stacking and interspersing the ultra-highspeed GaAs circuitry with the standard silicon path. Solving the problems of creating circuits that have unusual height was quite a challenge. Path lengths were critical and sometimes in the nanometer scale. These being in height. Remember now that the fast path has to be so fast that it is in effect "waiting for the train to arrive", and then the Correlated Relational Angular Phase control circuit has to be very precisely laser trimmed.

So the result of this is what has been called "Super Height Integrated Technology".
THAT is what makes it possible!

Read it and weep.

_-_-
Click to expand...

Hello bear. The acronym attendant to "Super Height Integrated Technology"!.
 
#53
davada said:
You've have to hand it to Bear. It was very clever.
Click to expand...

Hello davada. bear appears to uncover a ravenous hunger of DIYers for newer and improved amplifier tech.This important subject of reducing amplifier distortion; in this case to a value lesser than the reciprocal of Avogadro's # is still flirted in mind; at least theoretically. Talk about his successful survey naming a need or want.
 
#54
jan.didden said:
Positive feedback has been used since the 50-ies in audio (tube) power amps. Pos feedback increases the loop gain, and if unchecked therefor leads to oscillation. But in combination with neg feedback it works great, because neg feedback works better with large loop gain (assuming you keep it stable of course).

Jan
Click to expand...

A good example is HEC (Hawksford Error Correction).

Cheers, E.
 
#57
Tom Danley said:
I have a pair of weird old ultra low distortion tube amp's which have both positive and negative feed back.

http://www.burwenaudio.com/Krohn-Hite_UF-101.pdf
Click to expand...
That's no real positive feedback, only bootstrapping the driver anode voltage from the output tubes anodes.
You find PFB in the Philips AG9014,AG9015 and HF309 of the late '50 eary '60.Also the same principle in the Harman Kardon HK20.
Mona
 
Status
Not open for further replies.
Top Bottom