Douglas Self Sixth Edition
 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
 22nd February 2019, 09:07 AM #1 FengLiu diyAudio Member   Join Date: Apr 2018 Douglas Self Sixth Edition About Chapter 17, Class A Power Amplifier, Figure 17.19. Why is it wrong to connect C5 to the circuit in the simulation? Who can tell the effect of C5? In fact, I only want to be a Class A, Figure 17.7, it can't be used. It seems that his Class A quiescent current control, I don't understand, who can help me explain. Last edited by FengLiu; 22nd February 2019 at 09:10 AM.
 22nd February 2019, 07:22 PM #2 ostripper   diyAudio Member     Join Date: May 2008 Location: Smoky Mountains , Tennessee Post it. (Chapter 17, Class A Power Amplifier, Figure 17.19) __________________ Wanderer - GREENAMP , less is MORE. https://www.diyaudio.com/forums/soli...ss-output.html
FengLiu
diyAudio Member

Join Date: Apr 2018
Analyze Class A quiescent current control. Thank you! !
Attached Images
 1.jpg (116.5 KB, 589 views) 2.jpg (144.1 KB, 590 views)

Last edited by FengLiu; 23rd February 2019 at 01:34 AM.

 23rd February 2019, 01:41 AM #4 FengLiu diyAudio Member   Join Date: Apr 2018 If you make a class A according to Figure 17.7, can you? Figure 17.19 is a class A and class AB class B. I only want class A. Last edited by FengLiu; 23rd February 2019 at 01:45 AM.
 23rd February 2019, 01:42 PM #5 Bonsai   diyAudio Member     Join Date: Jul 2003 Location: Europe You can make class A with fig 17.7. To set the class A current, you must set Vref = Iq * (2*Re). So, for example, if you want say 1 Amp standing current, set Vref to 0.44V C5 is a boot strap capacitor and gives you more voltage swing. __________________ bonsai https://www.ovationhifidelity.com/ and DIY here http://hifisonix.com/ Ground Loops http://hifisonix.com/ground-loops/ Last edited by Bonsai; 23rd February 2019 at 01:45 PM.
 24th February 2019, 07:13 AM #6 bimo   diyAudio Member     Join Date: Sep 2010 Location: Depok, West of Java VREF can use diode 1N4148, it is around 0,6V. __________________ #Perkutut#Emprit#GagakHitam#Elang#Pelatuk#Colibri# Blameless100#Blameless150#Blameless1200#AX14Mod#FX 8Mod#AX11Mod#LM1875InvertingWithBuffer#LM3886Inter tingWithBufferAndDCServo#more...
 12th March 2019, 04:38 AM #7 FengLiu diyAudio Member   Join Date: Apr 2018 What is the role of D1-D4 in Figure 17.19? No need?
 12th March 2019, 05:05 AM #8 nauta   diyAudio Member   Join Date: Sep 2017 hi The bias circuit in Self's class-A amp is in strong contradiction to the words he wrote regarding bias spreaders in general. He showed that the CFP bias spreader was superior even to his resistor-enhanced single-BJT circuit, but stated he did not want to risk failure of the circuit by adding more parts. Doctors take a hypacratic oath; maybe engineers take a hypocritical oath? The diodes across the feedback shunt cap are to protect the cap in case the output fails shorted to either rail. Feedback at DC is unity-gain (1), so the cap would theoretically be subject to the full rail voltage. Last edited by nauta; 12th March 2019 at 05:08 AM.
 12th March 2019, 08:04 AM #9 jan.didden   diyAudio Member     Join Date: May 2002 Location: Westende Resort, BE coast Why the aggression? What's wrong with showing something is technically better but deciding against it for other reasons? It's something a real designer does all the time. You may not agree but that doesn't mean you should insult and imply hypocrisy. Jan __________________ 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.
FengLiu
diyAudio Member

Join Date: Apr 2018
I don't know the actual effect of this circuit? I have drawn the PCB, please correct me. This circuit has many very old triodes. Which new transistors should be used for replacement?
Attached Images
 wuquexian.jpg (70.4 KB, 338 views)

Last edited by FengLiu; 12th March 2019 at 10:46 AM.

 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     Room Acoustics & Mods     Music     diyAudio.com Articles     Car Audio     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         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 vitalstates Swap Meet 2 14th February 2018 01:17 PM ClaveFremen Group Buys 83 29th November 2015 01:13 PM DouglasSelf Solid State 676 24th September 2014 06:57 PM

 New To Site? Need Help?

All times are GMT. The time now is 01:00 AM.