SuSy OpAmp => mixing amp

rkn · 27th September 2008, 05:10 PM

Well I'm still thinking about the design of an discrete OpAmp.
I should explain that I want to use it for mixing audio signals and the mixing bus itself is already balanced. I want to keep the balance also for the output of the mixing amp.
Now anothoer idea came into my mind: Why not to build a OpAmp that uses SuSy? The idea is to build something like the SuSy-GC arrangment: Using a JFET-diff-pair in front and then two hig-quality OpAmps instead of the gainclones. Set everything to gain 1 and voila. Ok it is not overall discrete but we have a low-noise front-end and the two OpAmps of the 2nd stage provide some current if needed. Additionally two dc-servos are applied in orer to deal with dc offsets.
What do you think? Good idea?

Raphael

Nelson Pass · 28th September 2008, 06:52 PM

SuSy makes a good mixer because it has a virtual ground input,
like opamps used in inverting mode.

rkn · 29th September 2008, 09:21 PM

Thank you Nelson for your reply. I'm already busy with doing some SPICE simulations now. I'll publish results as soon as I think they 're good enough to publish them.

Raphael

27th September 2008, 05:10 PM	#1
rkn diyAudio Member Join Date: Aug 2008	SuSy OpAmp => mixing amp Well I'm still thinking about the design of an discrete OpAmp. I should explain that I want to use it for mixing audio signals and the mixing bus itself is already balanced. I want to keep the balance also for the output of the mixing amp. Now anothoer idea came into my mind: Why not to build a OpAmp that uses SuSy? The idea is to build something like the SuSy-GC arrangment: Using a JFET-diff-pair in front and then two hig-quality OpAmps instead of the gainclones. Set everything to gain 1 and voila. Ok it is not overall discrete but we have a low-noise front-end and the two OpAmps of the 2nd stage provide some current if needed. Additionally two dc-servos are applied in orer to deal with dc offsets. What do you think? Good idea? Raphael

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
Four for SuSy?	Onvinyl	Pass Labs	24	24th July 2005 04:56 PM
A Question about SuSy and the X2	metalman	Pass Labs	5	1st April 2005 03:55 AM
Complimentary-symmetry SUSY?	vossie	Pass Labs	19	16th February 2004 06:01 AM
How Super-Symmetric can SuSy be?	Netlist	Pass Labs	24	11th December 2003 10:27 PM
Susy and test equipment.	Netlist	Pass Labs	18	21st October 2003 01:27 AM

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

28th September 2008, 06:52 PM	#2
Nelson Pass The one and only Join Date: Mar 2001	SuSy makes a good mixer because it has a virtual ground input, like opamps used in inverting mode.

29th September 2008, 09:21 PM	#3
rkn diyAudio Member Join Date: Aug 2008	Thank you Nelson for your reply. I'm already busy with doing some SPICE simulations now. I'll publish results as soon as I think they 're good enough to publish them. Raphael

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)