Go Back   Home > Forums > >

Solid State Talk all about solid state amplification.

cancelling memory distortion ?
cancelling memory distortion ?
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
Old 10th April 2021, 09:32 AM   #91
N101N is offline N101N
diyAudio Member
 
Join Date: May 2018
Since the common emitter/collector/base amplifier by definition consists of one amplifying device, its input and output necessarily have to be referred to ground by a passive component.

An amplifier stage comprising two amplifying devices in series connection, the input and output necessarily have to be balanced to ground. The result is markedly altered transfer characteristics:

Markedly raised amplification factor / efficiency
Markedly raised instability
Markedly raised distortion
Markedly distinct spectral content

I have not made up anything.
  Reply With Quote
Old 10th April 2021, 09:32 AM   #92
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Westende Resort, BE coast
Quote:
Originally Posted by N101N View Post
The common emitter/collector/base amplifier stage consists of one amplifying device where the common input/output terminals are referred to ground rather than balanced to ground.
I'd like to understand what you mean by this. "referred to ground rather than balanced to ground"?

Jan
  Reply With Quote
Old 10th April 2021, 09:50 AM   #93
N101N is offline N101N
diyAudio Member
 
Join Date: May 2018
Referred to ground means connected to ground by a wire or resistor. It does not work well in the case of push-pull configuration.
  Reply With Quote
Old 10th April 2021, 10:29 AM   #94
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Westende Resort, BE coast
Again, no direct answer, just some tapdancing around. Aren't you getting tired to be viewed like this?

Jan
  Reply With Quote
Old 10th April 2021, 09:23 PM   #95
maxlorenz is offline maxlorenz  Chile
diyAudio Member
 
maxlorenz's Avatar
 
Join Date: Oct 2003
Location: osorno , Chile
Anyway...

As I understand it, Thermal Memory in solid state devices is produced by current passing through the junctions, generating increase in temperature of said junctions, which last for a certain time (a "temperature tail"), which causes a transitory change in the amplifying properties of the device and which is not in sync with the complex musical signal. Hence distortion occurs...

The proposed remedy from the Wise is: keep power as constant as possible in the significant device...and I would add, as low as possible...

(Maybe not entirelly correct explanation but you know what I mean).

I propose another circuit to play with the hypothesis, or simply replace your input pair with a bootstrapped CFP in a daughter-board.
The LSK170 being easier to find than the P channel.

Edit: though VFETs are best at the output, this one with Mosfets is also cool, easier to find and way cheaper.

Cheers,
M.
__________________
Trascend Duality and Dance in the Field of Unlimited Possibilities.

Last edited by maxlorenz; 10th April 2021 at 09:41 PM.
  Reply With Quote
Old 13th April 2021, 12:05 PM   #96
Alexandre is offline Alexandre
diyAudio Member
 
Join Date: Jan 2004
Location: Brazil
Default Another unusual circuit

Good explanation dear Mauricio. Unlike tubes, solid state semiconductors suffer a big change of parameters with change of temperature. Feedback might fail to correct this, as Pierre has shown: Memory Distortion Philosophies

Back to "unusual circuits"... Altough I really dislike the brand name, I have to show this one. It is a preamp, single ended out (common source again), cascoded. Uses lateral mosfets, TO220 driver type: 2SJ77 2SK214. Using medium power TO220 and using cascodes helps with the memory type distortion.

The unusual thing is T11 and T15, at the output stage, with gates connected to the drains. The only explanation provided is "it reduces crossover distortion" (T11 and T15). But how? I think it's due to the capacitances of the complementary devices: when current has to change through cascode T10, the charge on the device capacitances must change, and these capacitances create an error at high frequencies as we know. The higher the frequency the higher the distortion due to the capacitances. But the complementary device T11 partially cancels this error, because the charge at its capacitances must change by a similar amount in opposite polarity. Same for cascode T20 and "correction" T15. The cancellation will be partial because they are not perfect complements. It's a similar situation to a fully complementary diff pair with jfets (John Curl): there is partial cancellation of the gate capacitances.
Attached Files
File Type: pdf Pages from Elettronica Flash 1998_10.pdf (716.9 KB, 33 views)

Last edited by Alexandre; 13th April 2021 at 12:18 PM.
  Reply to this post

Reply


cancelling memory distortion ?Hide this!Advertise here!
Thread Tools

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 Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Lavaradin Amp and "Memory distortion"... Lisandro_P Solid State 104 19th February 2019 09:25 AM
Memory distortion, crap or serious? Pjotr Everything Else 22 10th August 2018 01:43 PM
Aleph (Single Ended) + Larvadin (no Memory Distortion) = Ultimate Aleph? tiefbassuebertr Pass Labs 21 9th August 2018 04:04 PM
Memory Distortion? and some new beginnings. vynuhl.addict Solid State 175 22nd January 2018 09:33 AM
Hum cancelling scheme? slor Tubes / Valves 15 24th January 2008 12:07 AM


New To Site? Need Help?

All times are GMT. The time now is 10:12 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki