L12-2 CFP OUTPUT AMP 120W*2 8R - Page 2 - 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 16th February 2013, 09:06 PM   #11
diyAudio Member
 
Join Date: Apr 2010
Location: Coffs Harbour, on the east coast
Quote:
Mine came with Toshiba TTC5200 and TTA1943 even though the picture on ebay shows Sanken.
Hmm ...I thought the advertised LAPT Sankens were too good to be true. Well, that's HK Ebay stores.
I've had a look at old threads and tried to find data sheets for those TT prefix equivalents to 2SC5200/A1943.
'Can't see anything credible yet, other than that they are indeed Toshiba products - perhaps not made
to the same process as in the Thai plant.

They should be up to the task though, given the rating and larger case for better dissipation.
__________________
regards
  Reply With Quote
Old 17th February 2013, 05:31 AM   #12
diyAudio Member
 
Join Date: Apr 2010
Location: Coffs Harbour, on the east coast
Doing a small amount of digging, it seems from Toshiba's own website references, that TT prefix parts identify Chinese production.
Officially, there is no need for concern there.
There are a few suppliers of kits and built-up L12-2 modules. One of them, Zoe_Tsang, shows pics of original On-semi ss transistor
packaging and Sanken output transistors. I think they are trying to tell us something there.
This is the schematic they post on the web. You can see it is not screwed up like that above in #6 :

Click the image to open in full size..
__________________
regards
  Reply With Quote
Old 17th February 2013, 11:22 AM   #13
diyAudio Member
 
Join Date: Apr 2009
Dear Ian Finch

I tottaly agred with you.
This schematic is very similar with Yamaha small amplifier and it have extra compenents like the transistor like diode in position Q17 and Q19(i suppose). When you see the PCB there is one TO92 TR missing.
Worth by the price offer.

regards
  Reply With Quote
Old 17th February 2013, 03:56 PM   #14
diyAudio Member
 
Join Date: Apr 2007
Quote:
Originally Posted by Ian Finch View Post
Click the image to open in full size..
Which resistor controls bias?
  Reply With Quote
Old 17th February 2013, 04:01 PM   #15
ATAUDIO is offline ATAUDIO  Austria
diyAudio Member
 
Join Date: May 2011
Location: Wien
Quote:
Originally Posted by Ian Finch View Post
Doing a small amount of digging, it seems from Toshiba's own website references,
Very interesting amp!

One of the few that I have seen around with double output CFP. Once I had published here a simple design (JAS - Just Another Sziklai) in such way (it is still under very slow development, ( I have recently modified the VAS but it come up one day...)
Some people here and elsewhere argue that such kind of output is almost impossible to stabilize, so the fact that it is around with a mixed choice of outputs is somehow reassuring.
From my few tests , it is not so.
Thermal stabilty is rock solid (never really had a problem in such sense with a CFP in general), high frequency stability can be an issue, but if the PCB routing is done well and you do not get too extreme compensation values, it is easily working. My impression on prototype listening is that those amps sound really "fast" , i.e. with cristal crear highs and well controlled bass. Ideal for soprano voices, letīs say.
__________________
@Audio

Last edited by ATAUDIO; 17th February 2013 at 04:20 PM.
  Reply With Quote
Old 17th February 2013, 04:16 PM   #16
ATAUDIO is offline ATAUDIO  Austria
diyAudio Member
 
Join Date: May 2011
Location: Wien
Quote:
Originally Posted by Evenharmonics View Post
Which resistor controls bias?
Guess the ratio R10/R19 or do you mean you would like a pot?
__________________
@Audio
  Reply With Quote
Old 17th February 2013, 04:20 PM   #17
diyAudio Member
 
Join Date: Apr 2007
Quote:
Originally Posted by ATAUDIO View Post
Guess the ratio R10/R19 or do you mean you would like a pot?
May be in the future if I have more free time to play around with it.

On mine, the voltage across R13 and R20 measure 12mV and 10mv. What do you think?
  Reply With Quote
Old 17th February 2013, 04:28 PM   #18
ATAUDIO is offline ATAUDIO  Austria
diyAudio Member
 
Join Date: May 2011
Location: Wien
Quote:
Originally Posted by Evenharmonics View Post
May be in the future if I have more free time to play around with it.

On mine, the voltage across R13 and R20 measure 12mV and 10mv. What do you think?
That should be around 40-50 mA. Thatīs perfect for my taste, but you migh hear different opinions. I follow the current of thinking that CFP should be biased low, at the limit of the crossover distortion. People more skilled than me have given some physics about that, but I cannot reacall who, at the momement.
__________________
@Audio
  Reply With Quote
Old 17th February 2013, 04:51 PM   #19
Boscoe is offline Boscoe  United Kingdom
diyAudio Member
 
Join Date: Feb 2010
Location: England
Quote:
Originally Posted by Evenharmonics View Post
May be in the future if I have more free time to play around with it.

On mine, the voltage across R13 and R20 measure 12mV and 10mv. What do you think?
Do you measure any DC offset?
__________________
I thought about it once, but then thought again.
  Reply With Quote
Old 17th February 2013, 06:04 PM   #20
diyAudio Member
 
Join Date: Apr 2007
Quote:
Originally Posted by Boscoe View Post
Do you measure any DC offset?
It's -24mV DC 5 minutes after powering up with no input and no load.
  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
"Blameless" style ~100W amp with CFP output. mnturner Solid State 40 17th May 2011 01:14 AM
CFP output variation di$tortion Solid State 6 9th May 2010 06:58 PM
A trashed currentfeedback amp from 2003 with CFP output.... sonnya Solid State 0 23rd October 2009 06:31 AM
non-switching CFP output ? Bigun Solid State 17 31st August 2009 12:36 PM
Output from Shiva with 120w? nrgy Subwoofers 2 12th November 2004 12:18 PM


New To Site? Need Help?

All times are GMT. The time now is 01:02 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2