Yamaha RX-385 started hissing - 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 13th April 2011, 04:28 PM   #1
diyAudio Member
 
Join Date: Apr 2011
Default Yamaha RX-385 started hissing

My Yamaha RX-385 started hissing, even with the volume at minimum. I turned off the speakers and listened with headphones - still hisses. I unplugged all the input cables and the antenna - still hisses. I plugged the AC into a different receptacle, and into a power strip - still hisses. Perhaps it needs a good cleaning? How is that done?

- theSpinnerBoy
  Reply With Quote
Old 13th April 2011, 04:45 PM   #2
Boofers is offline Boofers  Canada
diyAudio Member
 
Join Date: Oct 2008
Location: Ontario
Blog Entries: 1
Have you tried selecting different inputs as well? How old is the unit?
  Reply With Quote
Old 13th April 2011, 07:11 PM   #3
diyAudio Member
 
Join Date: Apr 2011
The Rx-385 is from the mid-late 90's. Our local recycling center had an electronics recycling day a few years back, and I found this receiver there with a dent on the left rear top. Brought it home, found it didn't work, but I opened the unit and found the problem was a loose power cable that I was able to fix. Not sure if the dent was why it was discarded or if it received the dent at the recycling center before I picked it up. It was missing the remote but I found a universal remote that works with it. I've had it for years now and had no problems.
The unit started hissing badly last week. It hisses no matter which input is selected, and the hissing does not increase when the volume is turned up. I've unplugged all the inputs, tried it w headphones, tried a different AC receptacle. I think it needs cleaning inside. I have Radio Shack Tuner Cleaner and I thought I'd start with that.
  Reply With Quote
Old 13th April 2011, 08:13 PM   #4
diyAudio Member
 
Join Date: Apr 2011
The hissing seems to lessen as the unit warms up - is this a clue?
  Reply With Quote
Old 14th April 2011, 09:00 PM   #5
diyAudio Member
 
Join Date: Apr 2011
Default Reducing hiss

Hiss can be reduced, and sometimes eliminated, by going through the amp and replacing all the aging capacitors AND resistors (surprisingly, aging resistors contribute most to that low-level background hiss, in my experience). Using isolation transformers will further help eliminate some of it, or at least seem to eliminate background noise when playing music. I would guess that adequately shielded cables would also play a role. Even vibration damping, and shielding off sections within the amplifier (or perhaps putting the whole amp inside a Faraday cage?) might help.

But I don't think you completely eliminate it; you just reduce it below the audible threshold, at normal listening volumes. Turn the volume up high enough, and you'll usually still hear a little
hiss.

It's a lot of work to try to get rid of it, but I think it is worth some effort, at least up to a point. Recapping and upgrading resistors will usually bring the most significant improvement in this area, it seems.
  Reply With Quote
Old 15th April 2011, 12:08 AM   #6
diyAudio Member
 
mrfeedback's Avatar
 
Join Date: Feb 2002
Location: Perth, Australia.
Default Well Worth Repairing...

A mid nineties Yamaha will be full of suspect/bad solder joints by now.
Dismantle and inspect all boards and resolder as required - especially output stages and regulator stages.
Better is to blanket resolder output stages and clean boards.
My guess is that a low value solid cap is dry jointed, or a low value electro.
Resistors do not usually deteriorate.

Eric.
__________________
I believe not to believe in any fixed belief system.
  Reply With Quote
Old 15th April 2011, 12:33 AM   #7
diyAudio Member
 
Join Date: Apr 2011
It seems two-channel stereos are the electronic backwater in a world of 6 and 8 speaker home theatres. A two-channel stereo receiver can be bought new for about one third of what they cost in the nineties. That being said, what do you mean by "electro"? Thanks.
  Reply With Quote
Old 15th April 2011, 03:03 AM   #8
diyAudio Member
 
mrfeedback's Avatar
 
Join Date: Feb 2002
Location: Perth, Australia.
electrolytic capacitor....elcap.....electro.
__________________
I believe not to believe in any fixed belief system.
  Reply With Quote
Old 15th April 2011, 09:10 PM   #9
diyAudio Member
 
Join Date: Apr 2011
The hissing is definately worse when unit is cold. As it warms up the hissing lessens. Could this be bc the solder is expanding and making a better connection? or could it the caps and electros do a better job when they're warm? I didn't think "solid state" had much of a warm-up issue.
  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
Yamaha RX-770 Jimmy154 Swap Meet 1 12th June 2010 03:38 PM
Yamaha RX-797 opinions ? dimka100 Solid State 2 12th June 2009 08:35 AM
yamaha rx-v870 steven344 Solid State 3 22nd October 2008 11:53 PM
Please Help Diagnose Yamaha RX-V1000 reidcc Solid State 0 2nd September 2008 12:39 PM
Yamaha RX-777 quasi Solid State 4 15th November 2007 01:58 PM


New To Site? Need Help?

All times are GMT. The time now is 04:56 PM.


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