AB-dynamic
 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
 2nd April 2007, 09:15 AM #1 anli   diyAudio Member   Join Date: Oct 2004 AB-dynamic Sorry, the thread is closed. Last edited by anli; 4th January 2018 at 03:58 PM.
 2nd April 2007, 11:07 AM #2 anli   diyAudio Member   Join Date: Oct 2004 And to add an intrigue - there are mosfets currents: http://gaydenko.com/ab-dynamic/currents39.png
 2nd April 2007, 11:18 AM #3 jan.didden   diyAudio Member     Join Date: May 2002 Location: The great city of Turnhout, BE Andrew, This is pretty intriguing! I guess the Iq is aroundf 50mA? Have you tried to run it with larger current, what would the transfer function look like then? Do you know the open loop freq and phase response? Jan Didden __________________ Cable: a potential source of trouble interconnecting two other potential sources of trouble - Erik Margan Linear Audio pubs and articles . The SilentSwitcher now at diyaudio store SilentSwitcher. Keeping in touch with SY.
anli
diyAudio Member

Join Date: Oct 2004
Quote:
 Originally posted by janneman Andrew, This is pretty intriguing! I guess the Iq is aroundf 50mA? Have you tried to run it with larger current, what would the transfer function look like then? Do you know the open loop freq and phase response? Jan Didden
As shown at the schematics, Iq is about 210mA. With too low Iq derivation isn't so smooth around 0V. I think, Iq about 100-150mA will be acceptable. Will see.
dVout/sVin doesn't change with more amplitude of linear input signal: "all can happen already happened" inside +/-11V range :-) Only a clipping at ~19V is outside the picture.

As for frequency prediction, I have found simulated results rather differ from reality for gnfb topologies. Moreover, you can see rather "strong" hf correction. At any case I'm not a fanatic of using instrumental amps for listening to a music

 3rd April 2007, 02:32 PM #5 anli   diyAudio Member   Join Date: Oct 2004 Aha... Silence... The idea is perfect, and the realization via the schematics is beyond any criticism... ... or it is impossible to read a schematics beyond standards... ... or all gurus are at their vacations... ... or ... WHAT?
 3rd April 2007, 03:19 PM #6 CBS240   diyAudio Member     Join Date: Aug 2005 Location: K-town Hi Andrew Interesting way to drive a quasi fet output stage. Very asymmetrical, even for quasi. There are members here who chastise asymmetrical topologies, but not me. I believe choice of components is more important, depending on goal of the circuit. The input j-fet is cascoded and keeps 5-6 Vds. This is good, and no need for matching because there is only one. I do have one question, do you think there would be need to have an active turn off device for M2 instead of R7 even though it appears to never turn completely off, but operates as class AB, or some type of totem pole buffer to drive the gate capacitance? How is capacitive loading for a sqare wave look at that 2KHz? And 10KHz? __________________ All the trouble I've ever been in started out as fun......
anli
diyAudio Member

Join Date: Oct 2004
Quote:
 Originally posted by CBS240 Hi Andrew Interesting way to drive a quasi fet output stage. Very asymmetrical, even for quasi. There are members here who chastise asymmetrical topologies, but not me. I believe choice of components is more important, depending on goal of the circuit. The input j-fet is cascoded and keeps 5-6 Vds. This is good, and no need for matching because there is only one. I do have one question, do you think there would be need to have an active turn off device for M2 instead of R7 even though it appears to never turn completely off, but operates as class AB, or some type of totem pole buffer to drive the gate capacitance? How is capacitive loading for a sqare wave look at that 2KHz? And 10KHz?
I have tried CC-follower between R7 and R18 - at least in simulation all the amp seems to be closer to oscillator :-) Moreover, I have two amps with 560 and 680 ohm resistors at similar places with the same mosfets - both works fine.

As for square waves, at first, there isn't any difference which frequency we use to test. A rise or fall time period does mean only. At any case, the amp is sufficiently fast to work with sound - just from experience.

As I have mentioned above, I don't think we must use instrumental amplifiers for music listening. Say, -120db, 100MHz, 100V/uS or such numbers mean nothing. At first message I have listed few demands I consider to be important for audio amplifier, if we say about a schematics only, omitting realization (PS, PCB and so on) details. I can add monotonically falling spectrum as another demand - while increasing harmonics number or lowering signal level. Plus small spectrum dependency from frequency.

diyAudio Member

Join Date: Mar 2004
Location: Krakow
Quote:
 Originally posted by anli Aha... Silence... The idea is perfect, and the realization via the schematics is beyond any criticism...

da,
we were waiting from 2005 on your update,
so do not be surprised of the silence, everybody hard thinks.

It is hard to me to make some interesting comments,
please explain what parts should be matched (if any),

congratulations!
__________________
regards, Pawel

anli
diyAudio Member

Join Date: Oct 2004
Quote:
 Originally posted by padamiecki da, we were waiting from 2005 on your update,
Sorry, my fault... But... what do you mean?

Quote:
 Originally posted by padamiecki please explain what parts should be matched (if any),
Regulations were mentioned above. For two channels, probably, input fets must not be too different. A fet - current source must be able to generate ~4mA. Currently I don't see something else. Just want to repeat, the project isn't soldered yet - just design. But parts are ordered.

diyAudio Member

Join Date: Mar 2004
Location: Krakow
Quote:
 Originally posted by anli Sorry, my fault... But... what do you mean?
what fault? I am far from indicate someone's fault, there was no fault at all.
first time you showed similar project long time ago, and promissed finalize it. From your description I read that the sound did not make fatigue during listening and was fully detailed. I just could not be patient to wait for so long! As I remember you had even PCB for this project! This was good training for me waiting for your ready project.
Maybe before you wrote about another amp?

Quote:
 Originally posted by anli A fet - current source must be able to generate ~4mA.
This is exacly what I asked!

Anyway, the design is clever, I like it!

Thanks!
__________________
regards, Pawel

 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 Vikash Multi-Way 84 28th March 2016 09:02 PM c0nfu33io Multi-Way 2 31st July 2009 03:05 PM Lyra Digital Source 40 2nd October 2007 11:44 PM Stefanoo Tubes / Valves 28 10th January 2007 11:10 AM keyser Solid State 3 17th February 2005 07:41 PM

 New To Site? Need Help?

All times are GMT. The time now is 01:13 AM.

 Home - Contact Us - Advertise - Rules - diyAudio Store - Sponsors - Privacy Statement - Terms of Service - Top - Opt-out policy

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.