KA30se "KRYPTON" SE class A amplifier

bogdan_borko · 26th September 2007, 05:23 PM

This is the finall version of the amplifier I`ve been working on lately. It is a class A amplifier single ended with impemented "aleph ccs".

30W on 4Ohm load
Open loop distortion @ 1W/4Ohm = 0.03
Open loop bandwidth 48KHz (-3dB)
CL distortion @ 95% power = 0.08%
CL bandwidth 480KHz

bogdan_borko · 26th September 2007, 05:25 PM

ps regulator

bogdan_borko · 26th September 2007, 05:31 PM

pcb

bogdan_borko · 26th September 2007, 05:34 PM

What I`d like to ask is it comensated right and is there any specific type of compensation i should try?

BTW the sound is VERY good and precise nothing like the classic SE amplifiers..

Thanks in advance, Borko.

Nelson Pass · 26th September 2007, 08:32 PM

Very nice looking circuit. I would expect that simply
trimming C9 and the Gate/Base stopper values
plus potentially capacitance around Q3 (CE or CB)
would cover the whole subject of compensation.

Easiest to adjust against a square wave into the loads
of interest.

bogdan_borko · 27th September 2007, 08:54 PM

Thanks mr.Pass I`ll try it.

BTW you , mr.John Curl any many others are proposing low feedback design...

I tried to remove (C10/C11) in order to decrese OLG and descovered that amplifier sounded worse. Hi OLG mode sounded more opened with more details!

What`s the catch??

bogdan_borko · 28th September 2007, 04:33 PM

I admit that "What`s the catch??" is a bit silly formulated question, but the listening tests confirmed that the Hi-OLG mode sounded better. I`m bit confused now..

Nelson Pass · 28th September 2007, 06:11 PM

Quote:

Originally posted by bogdan_borko
I tried to remove (C10/C11) in order to decrese OLG and descovered that amplifier sounded worse. Hi OLG mode sounded more opened with more details!

Without knowing values of components, it's difficult to judge.

bogdan_borko · 28th September 2007, 07:27 PM

No problem...

bogdan_borko · 28th September 2007, 08:14 PM

Some data:
Q1 current 11.6mA
Q2 current 13mA
Total bias of output stage = 2A (1A per device)

1. I also tried 2SJ103BL low gm jfet for Q1 ( the only I could find here) and the sound was lot worse, kind a "muddy".

2. I descovered that lowering R6/R7 for higher Q1 gm sound better.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
What makes an amplifier "bright", "warm", or "neutral"?	JohnS	Solid State	51	13th December 2009 06:42 PM
KA30se "KRYPTON" SE class A amplifier	bogdan_borko	Solid State	10	30th September 2007 07:57 PM
Schematic for Zetex "ZXCD500MOEVAL" - Class D Eval Board ?	CAindoAUDIO	Class D	1	16th November 2006 03:44 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

26th September 2007, 05:34 PM	#4
bogdan_borko diyAudio Member Join Date: Nov 2005 Location: serbia, zajecar	What I`d like to ask is it comensated right and is there any specific type of compensation i should try? BTW the sound is VERY good and precise nothing like the classic SE amplifiers.. Thanks in advance, Borko.

26th September 2007, 08:32 PM	#5
Nelson Pass The one and only Join Date: Mar 2001	Very nice looking circuit. I would expect that simply trimming C9 and the Gate/Base stopper values plus potentially capacitance around Q3 (CE or CB) would cover the whole subject of compensation. Easiest to adjust against a square wave into the loads of interest.

27th September 2007, 08:54 PM	#6
bogdan_borko diyAudio Member Join Date: Nov 2005 Location: serbia, zajecar	Thanks mr.Pass I`ll try it. BTW you , mr.John Curl any many others are proposing low feedback design... I tried to remove (C10/C11) in order to decrese OLG and descovered that amplifier sounded worse. Hi OLG mode sounded more opened with more details! What`s the catch??

28th September 2007, 04:33 PM	#7
bogdan_borko diyAudio Member Join Date: Nov 2005 Location: serbia, zajecar	I admit that "What`s the catch??" is a bit silly formulated question, but the listening tests confirmed that the Hi-OLG mode sounded better. I`m bit confused now..

28th September 2007, 08:14 PM	#10
bogdan_borko diyAudio Member Join Date: Nov 2005 Location: serbia, zajecar	Some data: Q1 current 11.6mA Q2 current 13mA Total bias of output stage = 2A (1A per device) 1. I also tried 2SJ103BL low gm jfet for Q1 ( the only I could find here) and the sound was lot worse, kind a "muddy". 2. I descovered that lowering R6/R7 for higher Q1 gm sound better.