SSLV1.1 builds & fairy tales
 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

 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
pedefede
diyAudio Member

Join Date: Aug 2008
Quote:
 Originally Posted by Salas Yes, I had run noise sims with 220uF and 200R. It can be a bigger cap for lower impedance depending how effective you wanna be for below 1/f noise knee.
So double C and half R (like 440uF and 100 ohm) would give the same frequency knee ??
And higher C, and same R - for better 1/f noise knee

Quote:
 Originally Posted by Salas Keep in mind that an non damped big cap can stretch semis during on/off there will be a practical threshold for each Vo level they could take.
2)
Do you mean that the big cap will unload charge through the Vref-chain, and give a high peak-current, Io? I tried to analyze it, and i cant see how - since basically the Current at on/off is the same as the normal working current, and is limited by R103:

in my understanding the size of the peak-current isnt determined by C. It is I = Io*exp(-t / RC). So C only determines the length of the peak.

Io is limited by the resistor, so Io = Vr / R103
Now asuming the chain is R + Zener:
- then Vr (V over R103) = Vtotal - V(zener)
- which basically gives the same Io as normal working current, determined by Idss of K117.

So if you make R103 less and C bigger, - Io stays the same, because V(zener) has to be bigger.

 11th July 2012, 04:15 PM #1642 Salas   diyAudio Chief Moderator     Join Date: Oct 2002 Location: Athens-Greece 1. Yes for filtering effect. Noise knee 1/F point is defined by the semis physics. 2. I had kills of 25V JXXX JFETs at the base of Vref in high Vo & high cap experiments.
schubert
diyAudio Member

Join Date: Sep 2008
Location: Pennsylvania, USA
Quote:
 Originally Posted by Salas First you got to get rid of the cables to the Mosfets. Only local PCB fit. You got wrong shape sinks for easy side or bottom fit I see.
OK I changed them - mosfets are soldered right to the board, but no change - now I get 3.6V instead of 3.7V. Any other ideas?

 11th July 2012, 08:31 PM #1644 Salas   diyAudio Chief Moderator     Join Date: Oct 2002 Location: Athens-Greece That had to be done, OK. 3.6V spells VGS potential only. See if you got any voltage drop across the outermost trimmer pins.
schubert
diyAudio Member

Join Date: Sep 2008
Location: Pennsylvania, USA
Quote:
 Originally Posted by Salas That had to be done, OK. 3.6V spells VGS potential only. See if you got any voltage drop across the outermost trimmer pins.
Only 0.189V, which at the current trimmer position gives about the same 0.1mA through the trimmer as I had through R103 before.

 11th July 2012, 08:42 PM #1646 Salas   diyAudio Chief Moderator     Join Date: Oct 2002 Location: Athens-Greece What happens if you will short the trimmer with a wire for a test?
schubert
diyAudio Member

Join Date: Sep 2008
Location: Pennsylvania, USA
Quote:
 Originally Posted by Salas What happens if you will short the trimmer with a wire for a test?
Still 3.6V.

 11th July 2012, 09:03 PM #1648 Salas   diyAudio Chief Moderator     Join Date: Oct 2002 Location: Athens-Greece Is Q304 a BC550? Is it flanked by a couple of 2SK117s?
 11th July 2012, 09:11 PM #1649 Salas   diyAudio Chief Moderator     Join Date: Oct 2002 Location: Athens-Greece If yes, does Q304 measure ~0.6V Vbe? Is R304 1 Ohm and not 1 kOhm by mistake?
 11th July 2012, 09:12 PM #1650 schubert   diyAudio Member     Join Date: Sep 2008 Location: Pennsylvania, USA Yes on both counts for the parts. The "1 ohm" resistors from Teabag's kit measured 1.2 ohms, but I figured they were close enough. I'll check Q304. Last edited by schubert; 11th July 2012 at 09:14 PM.

 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         Aussie Amplifiers         CSS         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 Tea-Bag Group Buys 1642 14th September 2017 01:50 PM CaNNA3IS Swap Meet 1 24th November 2013 09:43 AM korben69 Swap Meet 6 2nd July 2013 09:32 AM CSS/XBL CSS 0 11th April 2013 05:34 PM amp builder jb Tubes / Valves 29 15th July 2005 08:23 PM

 New To Site? Need Help?

All times are GMT. The time now is 02:50 AM.