Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Help diagonizing Rotel RX 304
Help diagonizing Rotel RX 304
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
Thread Tools Search this Thread
Old 17th October 2020, 09:40 PM   #1
Labienus is offline Labienus
diyAudio Member
Join Date: Oct 2020
Default Help diagonizing Rotel RX 304

Hi everybody,

that's my first post here, but let me already thank everybody - the last few days I was working on my old Rotel RX 304 and this forum was a great resource.

What I've done so far is replacing all old electrolytic capacitors with new ones. After the recap, the amp sounds way better than before, so I'm quite happy. There is still one problem with a background noise which wasn't fixed by the recap.

Here is a bit of initial diagnosis obtained by playing around with Online Tone Generator - generate pure tones of any frequency:

- There is already auditable noise coming at very low Hz, in fact there is a tone at approximately the input frequency (so if I put in 1Hz sinus, I get a tone every second).
- This tone disappears if the volume is lowered, but the exact volume depends on the frequency: if the input signal has a higher frequency, then the noise appears already at a lower volume. It doesn't matter if the volume is controlled from the PC or by the volume button of the Rotel.
- The noise is there over the whole frequency range, even if the input signal is 20kHz (where it sounds like a tone of about 10kHz).
- The noise (at least for lower input frequencies) is not affected by the treble control, but its volume goes down linearly with the bass control (but is still there even with bass -10).

- The problem is in both channels, but slightly different. The noise in the left channel has lower amplitude of the noise (as displayed in the Watt display from the Rotel) and twice the frequency of the right channel (for 1Hz input).
- There is also a white noise at higher volume (probably not related, but if somebody has an idea how to fix that...).

I sadly don't have good equipment to measure things (not even a voltmeter), but I'm planning to go to a repair cafe and check a few things. So would like to have advice what to check. Thanks!
  Reply to this post


Help diagonizing Rotel RX 304Hide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Service Manual/ schematic for Rotel ROTEL RHCD-10 Michi CD player Staykov Digital Source 9 1st March 2016 10:40 AM
WANTED : Rotel Preamp (with Remote) & Rotel Power Amps - Working or NOT dtm1962 Swap Meet 7 18th December 2012 06:45 PM
ROTEL 981 or something else..? MUSIC Solid State 1 3rd September 2010 03:56 PM
rotel ra 820 diymax62 Solid State 1 11th May 2009 12:05 PM
Rotel RC-850 Pre Amp + Rotel RB-870BX bleachershane Analog Line Level 4 9th February 2009 11:20 AM

New To Site? Need Help?

All times are GMT. The time now is 12:06 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio