Go Back   Home > Forums > >

Digital Line Level DACs, Digital Crossovers, Equalizers, etc.

Lite audio DAC 83 problem
Lite audio DAC 83 problem
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 18th July 2021, 07:30 AM   #1
DECKY999 is online now DECKY999  Australia
diyAudio Member
 
DECKY999's Avatar
 
Join Date: Jul 2007
Default Lite audio DAC 83 problem

Does anyone have experience with moding or repairing Lite audio DAC 83? I have one with a dead channel and it seems to be a common problem. I appreciate any guidance.
__________________
The only true way is no way.
  Reply With Quote
Old 19th July 2021, 02:11 PM   #2
Markw4 is offline Markw4  United States
diyAudio Member
 
Join Date: Jul 2016
Location: California
Do you have a scope?
  Reply With Quote
Old 19th July 2021, 10:41 PM   #3
clay-speakers is offline clay-speakers  Australia
diyAudio Member
 
Join Date: Aug 2006
Location: Gold Coast, Australia
There is a strong possibility it is one of the PCM1704's that has gone defective but as Mark said you really need a scope to check it out properly.
  Reply With Quote
Old 20th July 2021, 03:09 AM   #4
kinsei is offline kinsei
diyAudio Member
 
Join Date: Nov 2013
should it be quad 1704s?
anyway i think at least a DMM with frequency counter is needed
  Reply With Quote
Old 20th July 2021, 11:08 AM   #5
DECKY999 is online now DECKY999  Australia
diyAudio Member
 
DECKY999's Avatar
 
Join Date: Jul 2007
Yep - I got a scope and a DMM with a freq counter. Yes, it is a quad 1704 design. I just pulled the boards out of the chassis and will check the output of each of them tomorrow. Any specific tests I should do in addition to that?
__________________
The only true way is no way.
  Reply With Quote
Old 20th July 2021, 12:16 PM   #6
DECKY999 is online now DECKY999  Australia
diyAudio Member
 
DECKY999's Avatar
 
Join Date: Jul 2007
Is it even worth considering getting some of those ebay specials - "original" 1704 replacements?
__________________
The only true way is no way.
  Reply With Quote
Old 20th July 2021, 12:27 PM   #7
androa76 is offline androa76  Slovenia
diyAudio Member
 
Join Date: Mar 2007
Location: Maribor
My friends dac was repaired 3 times. I think this dac has problems with overheating regulators and all sorounding material. When i glued 4 haeatsinks ont the top it was better. But not 100% solved the issue. One designer wrote that 1704 has problem when supply voltages for dac chip are not present at similar time.Can be that this shunt regulators are turning on differently.My friend bought Denon receiver where 6 dac were in. I replaced 2dacs and 2 times 1. Measure DC voltage on red I/V resistor. It should be 0v. I think on damaged channel was always some dc present. If you need schematic i can send it to you. Try to find denon receiver or dvd or yamaha receiver, if you want to have this dac. You will for sure repair it at some time. Sound....for me nothing special. Best sound was from i2s input. But built like tank .
  Reply With Quote
Old 21st July 2021, 07:45 AM   #8
DECKY999 is online now DECKY999  Australia
diyAudio Member
 
DECKY999's Avatar
 
Join Date: Jul 2007
Hvala androa

I will check it out. It is not my DAC, just repairing it for a friend. I was never a big supporter of NOS DACs myself TBH. As you said - sound is nothing special with almost any I/V stage I tried - tube, SS, opamps.

I would not mind checking the schematics if you have it handy.
__________________
The only true way is no way.

Last edited by DECKY999; 21st July 2021 at 07:59 AM.
  Reply With Quote
Old 22nd July 2021, 08:39 AM   #9
DECKY999 is online now DECKY999  Australia
diyAudio Member
 
DECKY999's Avatar
 
Join Date: Jul 2007
... and just by probing around couple of checkpoints I managed to lose the other channel as well. Not good.
__________________
The only true way is no way.
  Reply With Quote
Old 23rd July 2021, 06:19 AM   #10
jean-paul is offline jean-paul  Netherlands
diyAudio Moderator Emeritus
 
jean-paul's Avatar
 
Join Date: Sep 2002
Location: Germany
Quote:
Originally Posted by androa76 View Post
One designer wrote that 1704 has problem when supply voltages for dac chip are not present at similar time.
PCM1704 is notoriously unreliable. I never had any device that had these DAC chips but I often read of the problems. Nevertheless I do have experience with other chips that had latch up with supply voltages not ramping up simultaneously. There is a simple solution for that.

I suggest to use 2 antiparallel Schottky diodes (like BAT46) between +Vdd and +Vcc. Of course the same with -Vdd en -Vcc. I do hope the issue is not that the positive lines are ramping up faster than the negative lines.
__________________
It's only audio. Member of the non modular PCB design committee.

Last edited by jean-paul; 23rd July 2021 at 06:34 AM.
  Reply to this post

Reply


Lite audio DAC 83 problemHide 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
FS: *Broken* Lite Audio DAC-83 + LT-One Transport JoshK Swap Meet 2 3rd August 2016 09:46 PM
FS (UK): Lite-Audio DAC-AM AD1853 DAC i-s Swap Meet 0 14th August 2012 01:47 PM
De-Lite strange problem Puffin Pass Labs 38 3rd August 2012 05:38 PM
I broke my Lite Audio DAC-60 aespen Digital Source 0 12th October 2008 11:38 PM
FS/T: Lite Audio Chinese audio preamp PCBs CaliforniaBob Swap Meet 0 26th July 2007 09:36 PM


New To Site? Need Help?

All times are GMT. The time now is 12:32 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki