Simple Symetrical Amplifier - Page 164 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

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
Reply
 
Thread Tools Search this Thread
Old 5th December 2011, 01:42 AM   #1631
diyAudio Member
 
Join Date: Dec 2010
Location: Malaysia, Selangor
Quote:
Originally Posted by Lazy Cat View Post
Hi guitar

Quick answers:
- I am apologizing for that, no complexity, just well dressed TT version
- input DC offset nulling
- look very carefully +/- 15 V already present on both zeners
- fine adjustment for both halves - info on wikipedia
- it is
- 5 Ampere/Time lag fuse - info on wikipedia
- green LED colour means regular - normal operation, RED the opposite (alarm, faulty conditions, warning etc.)
- not mandatory
- calculate the Joules (energy), than calculate the Farrads (capacitance) - formula on wikipedia
- power ratings in Watt - formula on wikipedia
- different standards some 63 V, 0,66 W etc.
- yes you could
- BC-s are here because of their low noise, high hFE, high fT, etc. performance, not Watt-age, but you can try and smoke some plastic

Regards Andrej
Thanks, Andrej. I kinda love short and quick answer.
- What is "TT" stands for ?
- So should the +-15V of "DC input offset nulling" connect to point between zener & 1k 1W ohm resistor ? (each respective half )
- What is the maximum RMS of this design without much distortion ? So that I could give adequate reservoir.
- fried plastic sounds special.

Regards, Yang
  Reply With Quote
Old 5th December 2011, 03:13 AM   #1632
Bigun is offline Bigun  Canada
diyAudio Member
 
Bigun's Avatar
 
Join Date: Jan 2009
Blog Entries: 2
Quote:
Originally Posted by guitar89 View Post
DO you mean something like my draft attached ? (more output stages) Will this relieve the VAS somehow ? (the emitter resistor value is estimation only....)
Or is there any better implication ?
no, what you have there are two output devices in parallel with each other, the VAS collectors still have to drive the output devices directly.

My thought was to insert an extra emitter follower pair between the VAS and the output devices. Look at the output stage of some of the amps published on the forum, my TGM1,2 and 4, the DX amp series, the 'class AB amp for DIYaudio', etc.

I don't remember ever seeing a Class AB power amp with the output devices taken straight off the VAS collectors so I assume it's not recommended - I can't say I've tried it and that it doesn't work.
__________________
"The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.
  Reply With Quote
Old 5th December 2011, 03:51 AM   #1633
gannaji is offline gannaji  India
diyAudio Member
 
Join Date: Jan 2011
Location: Hyderabad
Quote:
Originally Posted by Lazy Cat View Post
Hi guitar

You can find all requested info in attached schematic. This one has all capacitors and other features needed for real world realization.
I take this schematic as a reply to my question also in post #1596.
I have 5 pairs of 2SA1302/2SC3281 and 10 pairs of 2SA1837/2SC4793, purchased from MCM in 1997. I was planning to make Self's WW project. Those transistors are still with me unused.
To use the above, a thermally compensated bias generator is also required. As I intend use only +-35 Volts only, replacing the TTD diodes circuit with a suitable transister circuit as in post No 183 or 418 or 723 or 1005 may be required. Or may be like the one in 1449 with the transistor mounted on the heatsink. On the input side, a lp filter may be required. Can you kindly post a full diagram as SSA-BJT basic.
Can I use 1837/4793 in the place of BD 140/139 ? It is over kill, but I have those with me.
Thanking you for this wonderful thread,
--gannaji
  Reply With Quote
Old 5th December 2011, 03:54 AM   #1634
Jay is offline Jay  Indonesia
diyAudio Member
 
Join Date: Feb 2003
Location: Jakarta
Quote:
Originally Posted by SOUND_Rays View Post
for better and more natural sound
For so long I have not been able to describe the sound of such common drain output. "NATURAL SOUND". Hmmm... may be that would fit. I found that many people are attached very strongly to this kind of amp. I think Joachim also will like it

But why mosfet there, I don't like it. You can use TO-92 device to replace the mosfet. Something like this:

EDIT: Doesn't need double output stage for such a small amp.
Attached Images
File Type: jpg SSA_DrainFollower.jpg (410.8 KB, 632 views)

Last edited by Jay; 5th December 2011 at 04:07 AM.
  Reply With Quote
Old 5th December 2011, 05:19 AM   #1635
Jay is offline Jay  Indonesia
diyAudio Member
 
Join Date: Feb 2003
Location: Jakarta
Default Lateral Versions

Quote:
Originally Posted by cats squirrel View Post
I suggest a fresh thread be started, for just this design, then all subsequent questions/answers can be on that thread only, and only that design will be discussed.
Problem is, there are so many possibilities with SSA, and this is amp is not "mature" enough yet. But LC already posted some basic circuits for some different types of SSA (ThermalTrack, BJT, Lateral, IGBT, BIGBT). Of course there could be others such as V-FET, JFET (Semisouth), Quassies...

For BJT, imo Bigun's triplet is the best. He has started a different thread for the SSA-TGM5 (and LC are also helping there).

For BIGBT, this main thread is the one, as LC is focusing more on this output stage.

For other types of SSA, of course somebody else may start another new thread. But without strong skill, who wants to do it? Better post here so many can help.

For Thermaltrack, Idefixes is in this main thread.

For lateral, besides a few "small" projects herein this main thread, there is SSA-Crescendo by Esperado.

From speaker building I have learnt that whenever "possible" start with the simplest circuit to achieve the "objective". Because complex circuit always has "unpredictable" effect that makes the design become difficult (to achieve acceptable performance by subjective ears). So here are what I consider from SSA-Lateral version (which is my favorite):

#1) Input Stage --> Lateral Output (Simplest SSA)
#2) Input Stage --> Input Cascode --> Lateral Output (Ruwe version)
#3) Input Stage --> (Input Cascode) --> TO-92 VAS/driver --> Lateral Output (Basic SSA)
#4) Input Stage --> (Input Cascode) --> TO-92 VAS --> TO-92 driver --> Lateral Output (Common Drain)
#5) Input Stage --> Input Cascode --> TO-92 VAS --> TO-92 driver --> Lateral Output (Common Source)

Option #1 is too simple to be useful. I prefer a class-A version if possible.

Option #2 is one of my favorite for low wattage amp

Option #3 is too general/common. I prefer to remove the input cascode, but front end regulator is a must, and it must be sophisticated (a.k.a Mosfet shunt regulator)

Option #4 is always a different animal. A somebody's pet.

Option #5 is my favorite for high wattage amp. Rail voltage must be high (note that the driver is emitter follower). Regulated front end supply may be needed to help stability (of course a mosfet shunt regulator). Tripple or double laterals. But double is enough because I insist the use of TO-92 drivers so power will not reach more than 100W I believe.

Last edited by Jay; 5th December 2011 at 05:45 AM.
  Reply With Quote
Old 6th December 2011, 12:41 AM   #1636
diyAudio Member
 
Join Date: Dec 2010
Location: Malaysia, Selangor
Andrej, mind giving me simple instruction of adjustment for SSA Thermal Track Basic ? (Bias, offset, etc setting) Not very good understanding to those things
  Reply With Quote
Old 6th December 2011, 02:18 AM   #1637
diyAudio Member
 
SOUND_Rays's Avatar
 
Join Date: Mar 2009
Quote:
Originally Posted by Jay View Post
For so long I have not been able to describe the sound of such common drain output. "NATURAL SOUND". Hmmm... may be that would fit. I found that many people are attached very strongly to this kind of amp. I think Joachim also will like it

But why mosfet there, I don't like it. You can use TO-92 device to replace the mosfet. Something like this:

EDIT: Doesn't need double output stage for such a small amp.
Jay,

Thank You for Yours comment,
Mosfet vas for best uncompromissed driving the i/p capacitance of 2. fet OP pairs, which are there on purpose to drive with ease 2. OHm loads.

Kind regards
  Reply With Quote
Old 6th December 2011, 09:26 AM   #1638
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
Quote:
Originally Posted by SOUND_Rays View Post
LC

I opt. finally for this Basic - MosFet version of the SSA-Bal. If You think there would be anything to add to this chosen final, for better and more natural sound of Yours basic SSA-Mosfet version, than I would be more than happy for any suggestion, otherwise the "masters" confirmation is on the wish list.

Thank You,

Hi SOUND_Rays

I finally found the time to look over your sch and here are the comments:
- T1 should be BC560C
- input offset trimmer's +/- 15 V is provided by the existing two zeners, if the tracks on PCB will be longer than 2cm than you should also decouple +/- 15 V DC rails with 1 uF caps close at trimmers side
- I suggest you to supply front-end with +/-45 V regulated PSU to make max efficiency from the output stage swing according to supply rails
- in this case change R10, R11 to 1,5 kohm/2 W
- driver's gate DC voltage is app. 8V, so I suggest to change R19 to 2,2 kohm and P4 to 1 kohm
- VAS loading impedance is very high, there is practically no fT limitation by the load and most probable point of local oscillation, amp is also without any freq compensation, so I suggest you to put in small local feedback compensating capacitor (10-22 pF, will be practically tested) between collector and base of T9, T10

I think now you're good to go.

Last edited by Lazy Cat; 6th December 2011 at 09:33 AM.
  Reply With Quote
Old 6th December 2011, 09:33 AM   #1639
diyAudio Member
 
Idefixes's Avatar
 
Join Date: Dec 2003
Location: Mulhouse - Alsace
Send a message via ICQ to Idefixes
Another modification according LC comments.

For input res i will go 10k and use the input combination from LowZ with 10u cap

Marc
Attached Images
File Type: jpg SSA_TT35_sch6.JPG (97.5 KB, 493 views)
File Type: jpg SSA_TT35_brd9.JPG (114.3 KB, 461 views)
__________________
website : http://audiyofield.wifeo.com/index.php

Last edited by Idefixes; 6th December 2011 at 09:36 AM.
  Reply With Quote
Old 6th December 2011, 09:41 AM   #1640
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
Quote:
Originally Posted by SOUND_Rays View Post
Jay,

Thank You for Yours comment,
Mosfet vas for best uncompromissed driving the i/p capacitance of 2. fet OP pairs, which are there on purpose to drive with ease 2. OHm loads.

Kind regards
I think it is good to try this kind of output stage with drivers and outputs as mosfets. Pin layout of IRF's is adequate to standard TO-220 BJT so if there will be need to change the mosfet drivers to BJTs it will be like "piece of cake" (only some minor adjustments to Vbe multiplier).

Regards, Andrej
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Symetrical schematics are alike plague in Brazil, do you like them? destroyer X Solid State 151 1st July 2010 02:09 PM
Symetrical out low Zout karsten21 Tubes / Valves 5 1st February 2010 10:19 PM
going balanced/symetrical - what benefits? weissi Solid State 15 20th October 2007 08:06 AM
Symetrical field, is this? Raka Multi-Way 6 14th September 2003 01:21 PM
Non-symetrical SMPS output cm961 Parts 4 21st August 2003 10:27 PM


New To Site? Need Help?

All times are GMT. The time now is 08:17 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2