Technics su v4x and SVI2004 operating temperature - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 25th January 2015, 02:39 PM   #1
PerecNS is offline PerecNS  Serbia
diyAudio Member
 
Join Date: Jan 2015
Default Technics su v4x and SVI2004 operating temperature

hi

I have bought Technics SU V4X amplifier - vintage.

Sounds OK, but I noticed that it runs quite hot even when I am listening it at low volume...

seems that it should be cooler... any experience with a/m

thanks in advance
  Reply With Quote
Old 26th January 2015, 09:34 AM   #2
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
No experience of the amp but if you have suspicions then the three definitive tests are to check the rails are correct and if that is OK then to confirm that the output stage bias is correct as per the service manual together with a confirmation of the DC offset (should be less than say 60 millivolts DC)
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 26th January 2015, 10:28 AM   #3
diyAudio Member
 
Max Headroom's Avatar
 
Join Date: Jan 2013
Location: West Australia, near to the beach, natural ambient sounds only.
Computer Drive New Class A Integrated Amplifier
Expect these series Technics amplifiers to run pretty warm.
Ensure unrestricted ventilation...ie better to not put other items on top.

Dan.
  Reply With Quote
Old 26th January 2015, 12:42 PM   #4
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Curiosity got the better of me so I looked at the circuit... hmmm... it uses an IC based output stage. No adjustments possible.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 26th January 2015, 01:13 PM   #5
diyAudio Member
 
Join Date: Sep 2009
Location: Timisoara
I am using A900s Technics amps and i can confirm that they always heat up even when not driven. The idle bias is set quite high by the design and increased as the signal amplitude increases. Do not worry, just make sure the power supply is filtered correctly. Measure the ripple because being an old design, it might be time to re-cap the amp.
  Reply With Quote
Old 26th January 2015, 03:33 PM   #6
johnr66 is offline johnr66  United States
diyAudio Member
 
Join Date: Mar 2009
These are Technics "New Class A". Not sure of the circuit design, but as stated, they must run the bias higher than typical AB amps.
  Reply With Quote
Old 26th January 2015, 03:42 PM   #7
diyAudio Member
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
Send a message via Skype™ to JonSnell Electronic
They run, with no signal, hot. About 60degrees Celsius. They are true class A and dissipate heat like a 100W incandescent light bulb!
__________________
Support for Flying Mole, Allen & Heath, Valve amps and older designs. www.jonsnell.co.uk
  Reply With Quote
Old 26th January 2015, 03:47 PM   #8
diyAudio Member
 
Max Headroom's Avatar
 
Join Date: Jan 2013
Location: West Australia, near to the beach, natural ambient sounds only.
Quote:
Originally Posted by JonSnell Electronic View Post
They run, with no signal, hot. About 60degrees Celsius. They are true class A and dissipate heat like a 100W incandescent light bulb!
And electricity running cost is similar also.

Dan.
  Reply With Quote
Old 26th January 2015, 08:54 PM   #9
PerecNS is offline PerecNS  Serbia
diyAudio Member
 
Join Date: Jan 2015
thanks,

they eat power but sound is quite surprising!!! and it is vintage....

I am looking also for original rack, for now I have all components acc. to catalog from Technics 84/85
RSM 253X
SH 8044
SU V 4X
ST G5... not on pic...

very nice - fun staff to use them... it brings me back when I was a kid...

excluding the all CAP especially 10000 um should I change something else... everything is original in amp... never repaid...

Click the image to open in full size.
  Reply With Quote
Old 28th January 2015, 11:11 AM   #10
diyAudio Member
 
Join Date: Sep 2009
Location: Timisoara
Quote:
Originally Posted by PerecNS View Post
thanks,

excluding the all CAP especially 10000 um should I change something else... everything is original in amp... never repaid...

Click the image to open in full size.
I have modified a lot of Technics units and i recommend that you start by changing the op-amps to OPA1612 or similar. Also, there are a lot of 4,7uF Pansonic aluminium caps in the signal path. These are easily and directly replaced with Wima 4,7uF 50V film caps since they use 5mm pin spacing.
  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
Help Fixing Technics SU-V4X Flibble Solid State 9 3rd May 2013 11:02 PM
Panasonic SU-2700 Repair (Otherwise known as the Technics SU Z1) MChandler Solid State 22 11th April 2013 08:25 AM
Technics SU-V4X Dead? bitbandit Chip Amps 5 12th June 2011 12:45 AM
Technics SU-V4X zoluic Parts 1 7th December 2006 06:29 AM


New To Site? Need Help?

All times are GMT. The time now is 12:08 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2