Active Current Source for TDA1543
 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

 Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

 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
stefanobilliani
diyAudio Member

Join Date: Jun 2002
Location: Italy
Quote:
 Originally posted by Andypairo I'd say it depends on which voltage you are operating it from. If you use 5V it is probably too high, if you use 7V you can go even higher. The output current is equal to Ibias (=2*Iref)- IDac , which is sunk by a controlled current sink. Therefore the "zero" signal current for IDac should be 2.65 mA /2 (if we take the maximum value). In your case with 2.2 mA Ibias = 4.4 mA and AOR should source about 4.4 - 1.325 = 3.075 mA * 1k = 3.075V With 2.7 mA you probably saturated the bias current source at 5 mA (its rated maximum), so in this case we should have a theoretical 5- 1.325 = 3.675 V... not corrisponding to the actual value. Can anyone explain why? Cheers Andrea

Ok Andrea ,
I apologie for non-precise numbers regardin my "effective working values".
I must say first that the current source runs in real life at 2.3mA couse the tipical negative voltage of the jfet is not so tipical and it is 0.254volt and not 0.3v.The vref as above mentioned is 2.120 stable with or without music. I measure 3.212 v at one channel output resistor that is something like 985 ohm.
That's all.

 12th November 2003, 01:24 PM #12 Andypairo   diyAudio Member     Join Date: Sep 2002 Location: near Milano , Italy Stefano, which Vcc do you use? 5V or higher? Cheers Andrea
stefanobilliani
diyAudio Member

Join Date: Jun 2002
Location: Italy
Updating

After correct measure of the crucial parameters I update the first post schematic:

If -Your- jfet looks like this for a 2.3mA current the resistor is 130ohm. Otherwise is better measure the jfet vgs for precise current setting.

2.7mA as shown in the first post is just too much

Attached Images
 acs.jpg (7.9 KB, 696 views)

stefanobilliani
diyAudio Member

Join Date: Jun 2002
Location: Italy
Quote:
 Originally posted by Andypairo Stefano, which Vcc do you use? 5V or higher? Cheers Andrea

Aaah! Here we go ! I use now 6.15Volts

 12th November 2003, 01:44 PM #15 Andypairo   diyAudio Member     Join Date: Sep 2002 Location: near Milano , Italy Well, with 6.15Vcc the "ideal" output voltage (halfway between the minimum and maximum value given by the datasheet) is (6.15-1.2-1.8)/2 +1.8 = 3,375 V, so I think you have a quite perfect idle voltage. Cheers Andrea PS Do you still use your balanced version?
stefanobilliani
diyAudio Member

Join Date: Jun 2002
Location: Italy
Quote:
 Do you still use your balanced version?
I like very much balanced operation but I paused it for a while couse I was searching for a different PS to power it and a more detailed and precise sound .Now the ASR is battery powered and I use fets for the TDA 6.15volts. Finally , the current source .

Spectacular result...now I'm ready and back for the balanced version.

 12th November 2003, 02:06 PM #17 Andypairo   diyAudio Member     Join Date: Sep 2002 Location: near Milano , Italy I'd be very happy if you could post a complete schematic of your setup... mine is halfway between Doede's and the convertus, but I think I'll include the ASR soon, so it will be ready for balanced operation! BTW should the ASR (and its clock) have its own PS? (I guess so..) Cheers Andrea
 12th November 2003, 02:18 PM #18 stefanobilliani   diyAudio Member   Join Date: Jun 2002 Location: Italy OK Andrea . I'll see what can I do to post a decent schematic of my setup. Regarding the ASR the answer is yes.Currently I power it with batteries.One for the clock and one for the sinchronizer. The difference between PS and battery here is noticeable.

 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 EUVL Pass Labs 17 8th February 2012 03:31 AM Nixie Solid State 7 4th December 2006 09:31 PM tschrama Pass Labs 4 29th July 2005 12:55 PM jeff mai Digital Source 4 21st February 2004 07:46 AM woody Everything Else 2 19th September 2002 03:33 AM

 New To Site? Need Help?

All times are GMT. The time now is 05:25 AM.