No - feedback amplifier - Page 2

SemperFi · 25th September 2011, 07:56 PM

Quote:

Originally Posted by jaycee

Why on earth would you choose to use crap like the TIP41/42 as drivers to 2SC3281/2SA1302's...

I guess LC knew something you don't. LOL!

Lazy Cat · 08:51 PM

Quote:

Originally Posted by SemperFi

I guess LC knew something you don't. LOL!

If LC refers to me I can assure you that I never used TIP type of BJT's anywhere. BF471/472 in my schematics are completely different kind of animals, for pre-drivers only.

For drivers I would certainly recommend something like 2SA1930/2SC5171.

And for outputs not a crap as 2SC3281/2SA1302 but something like 2SA2121/2SC5949.

SemperFi · 25th September 2011, 08:58 PM

LC is the constructor of the OP's amp. Think its Lars Clausen or something Danish like that.

Lazy Cat · 25th September 2011, 09:00 PM

Quote:

Originally Posted by SemperFi

LC is the constructor of the OP's amp. Think its Lars Clausen or something Danish like that.

Appologize from me. Now I see LC refers to L.H. Clausen.

forr · 25th September 2011, 10:06 PM

Janneman
Things like the grounding layout, (remember, not all grounds are created equal!) or power supply decoupling, and supply routing probably have at least the same impact as the topology.

Not often said, not enough known !

Gudmund · 26th September 2011, 06:13 AM

Quote:

Originally Posted by jaycee

Plenty of feedback, just not the usual type. Looks like current rather than voltage feedback. Why on earth would you choose to use crap like the TIP41/42 as drivers to 2SC3281/2SA1302's...

A little research showed that faster drivers in the mkII version could make the circuit unstable.
It seems that L.H.Clausen changed drivers as well as o/p transistors in the mk3 version, which I found at the same site.

As to your statement concerning 3281/1302, the mentioned powertransistors has been used more than once, and messured linearity of the Toshiba's equals the types that you suggest.

Gudmund · 26th September 2011, 07:01 AM

Quote:

Originally Posted by Gudmund

A little research showed that faster drivers in the mkII version could make the circuit unstable.
It seems that L.H.Clausen changed drivers as well as o/p transistors in the mk3 version, which I found at the same site.

As to your statement concerning 3281/1302, the mentioned powertransistors has been used more than once, and messured linearity of the Toshiba's equals the types that you suggest.

Sorry ....was suggested by Lacy Cat !

jez · 26th September 2011, 09:20 AM

Quote:

Originally Posted by forr

Janneman
Things like the grounding layout, (remember, not all grounds are created equal!) or power supply decoupling, and supply routing probably have at least the same impact as the topology.

Not often said, not enough known !

Totally agree! In fact I would say that they are FAR more important than the topology

tiefbassuebertr · 10:26 AM

knutn · 26th September 2011, 11:25 AM

So now Gudmund, you have something to do to next summer!

26th September 2011, 09:57 AM	#19
tiefbassuebertr diyAudio Member Join Date: Jul 2005 Location: D-55629 Schwarzerden	check out this thread: Better Audio with or without NFB (Negative Feedback) - for me the wrong Question also this threads and URLs perhaps are of interest: URL collection of Totem Pole and CSPP (Single Ended related) Solid State Output Stage TIP3055/2N3055 based power amps Output Buffer Stages Help with this amp (Harman's T-Circuit: Post #151) Replacement transistors in Leach Superamp. Help needed! Baxandall Super Pair (CFP, Sziklai-Darlington) Edwin 20 watt (Elektor 1970 - May) Quad 303 triple cascade four transistor emitter follower (diamond buffer) as power output stage? Best topology for no-feedback ClassAB buffer ? Hot Follower 99 Power follower 99c Vs Zen Jfet audio buffer Anyone built this mosfet follower (or similar)? Buffer Amp Buffer Power amp. Quasi complementary concepts How to identify a quasi-complementary amplifier? 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25th September 2011, 08:58 PM	#13
SemperFi diyAudio Member Join Date: Jan 2002 Location: nowhere	LC is the constructor of the OP's amp. Think its Lars Clausen or something Danish like that.

25th September 2011, 10:06 PM	#15
forr diyAudio Member Join Date: Dec 2004 Location: Next door	Janneman Things like the grounding layout, (remember, not all grounds are created equal!) or power supply decoupling, and supply routing probably have at least the same impact as the topology. Not often said, not enough known !

26th September 2011, 11:25 AM	#20
knutn diyAudio Member Join Date: Mar 2006 Location: Oslo	So now Gudmund, you have something to do to next summer!