NE5534 compensation ?
 User Name Stay logged in? Password
 Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read Search

 Solid State Talk all about solid state amplification.

 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
 11th February 2006, 10:11 AM #1 AndrewT   R.I.P.   Join Date: Jul 2004 Location: Scottish Borders NE5534 compensation ? Hi, for unity gain the 5534 needs about 22pF as Ccomp. for gains greater than 5, Ccomp=opencircuit. Is there a way to determine the value of Ccomp for gains between 1 and 5? Is there any advantage in reducing Ccomp to the lowest value that consistently achieves stability? __________________ regards Andrew T.
 11th February 2006, 10:38 AM #2 davidsrsb   diyAudio Member   Join Date: Dec 2005 Location: Kuala Lumpur Intermediate gains require an intermediate value, I would try 10 or 12pF for x2 and 4p7 or 6p8 for x3 If you overcompensate with 22pF for x2 or x3 you waste bandwidth
 11th February 2006, 12:48 PM #3 AndrewT   R.I.P.   Join Date: Jul 2004 Location: Scottish Borders Hi all, David seems to be indicaing that there is an advantage in keeping the Ccomp low. His suggested values also fit a model:- Ccomp~=22pF/gain. Any other comments? __________________ regards Andrew T.
lineup
diyAudio Member

Join Date: Dec 2005
Location: the north
I do not think there is some formula for best Ccomp value.
Because different circuits, different loads and each individual NE5534 can have slight variations.

To set the lowest possible capacitance can only be done by using oscilloscope.

As you can see NE5534 is already compensated internally.
With 12 pF capacitor, that will be in parallel with external.
Across pins 5 and 8.

NE5534 does not need any external comp for gain >= 5
NE5534 will be stable at unity gain = 1, with 22 pF

Gain, Int, Ext cap
x5 = 12pF
x3 = 12pF + ??
x1 = 12pF + 22pF
Attached Images
 ne5534.png (13.8 KB, 1250 views)
__________________
lineup

 11th February 2006, 01:36 PM #5 AndrewT   R.I.P.   Join Date: Jul 2004 Location: Scottish Borders Hi, I am begining to understand the workings of 5534 as well as opamps generally. My current power amp uses 5534 gain of x2 with Ccomp=22pF as a pre conditioning stage (cap coupled at in & out) before the main 3stage amp. I am pondering further modifications. __________________ regards Andrew T.
 11th February 2006, 02:07 PM #6 peranders   Electrons are yellow and more is better! diyAudio Member     Join Date: Apr 2002 Location: Göteborg, Sweden If you use 22 pF you won't have to think. It just works. If you want to tune the value put in square wave and observe when you'll get a good output signal. __________________ /Per-Anders (my first name) or P-A as my friends call me Group buy: DCT03 DC trap for big toroidal transformers. Sign up for interest HERE. 65 pcb's in order. 61 paid.
peranders
Electrons are yellow and more is better!
diyAudio Member

Join Date: Apr 2002
Location: Göteborg, Sweden
Re: NE5534 compensation ?

Quote:
 Originally posted by AndrewT Is there any advantage in reducing Ccomp to the lowest value that consistently achieves stability?
For this particulary opamp, no not really.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Group buy: DCT03 DC trap for big toroidal transformers. Sign up for interest HERE. 65 pcb's in order. 61 paid.

 11th February 2006, 02:14 PM #8 davidsrsb   diyAudio Member   Join Date: Dec 2005 Location: Kuala Lumpur Is this part of an overall feedback loop? If it is then disturbing the opamp bandwidth will have consequences.
Tube_Dude
diyAudio Member

Join Date: Mar 2002
Location: Aveiro-Portugal
Re: NE5534 compensation ?

Quote:
 Originally posted by AndrewT Is there any advantage in reducing Ccomp to the lowest value that consistently achieves stability?
Yes...you will have more bandwidth and more feedback in the high frequencies , with the consequent reduction in distortion...

The NE5534 is a great Op-Amp...
__________________
Jorge

 11th February 2006, 02:37 PM #10 AndrewT   R.I.P.   Join Date: Jul 2004 Location: Scottish Borders Hi all, thanks so far. the times 2 gain at the front end is inside it's own feed back loop and completely separate from the global loop around the 3stage amp that follows. There is DC block & RF filter between the two gain stages as well as DC block at the input. I am almost set up to post the schematic but the 1.7Mb pic does not fit my floppy from work to home where I can compress it for posting. Maybe it would be easier to draw in schematic software __________________ regards Andrew T.

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Site     Site Announcements     Forum Problems Amplifiers     Solid State     Pass Labs     Tubes / Valves     Chip Amps     Class D     Power Supplies     Headphone Systems Source & Line     Analogue Source     Analog Line Level     Digital Source     Digital Line Level     PC Based Loudspeakers     Multi-Way     Full Range     Subwoofers     Planars & Exotics Live Sound     PA Systems     Instruments and Amps Design & Build     Parts     Equipment & Tools     Construction Tips     Software Tools General Interest     Car Audio     diyAudio.com Articles     Music     Everything Else Member Areas     Introductions     The Lounge     Clubs & Events     In Memoriam The Moving Image Commercial Sector     Swap Meet     Group Buys     The diyAudio Store     Vendor Forums         Vendor's Bazaar         Sonic Craft         Apex Jr         Audio Sector         Acoustic Fun         Chipamp         DIY HiFi Supply         Elekit         Elektor         Mains Cables R Us         Parts Connexion         Planet 10 hifi         Quanghao Audio Design         Siliconray Online Electronics Store         Tubelab     Manufacturers         AKSA         Audio Poutine         Musicaltech         Holton Precision Audio         CSS         Dx Classic Amplifiers         exaDevices         Feastrex         GedLee         Head 'n' HiFi - Walter         Heatsink USA         miniDSP         SITO Audio         Twin Audio         Twisted Pear         Wild Burro Audio

 Similar Threads Thread Thread Starter Forum Replies Last Post TimA Solid State 102 8th December 2010 02:23 AM pjpoes Parts 3 23rd January 2007 05:13 PM EchoWars Solid State 17 3rd January 2006 11:46 PM Wolvatron Chip Amps 6 20th January 2004 01:32 PM

 New To Site? Need Help?

All times are GMT. The time now is 08:18 AM.