Rotel RB-970BX problem - 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 17th September 2010, 02:35 AM   #1
00dc2 is offline 00dc2  Australia
diyAudio Member
 
Join Date: Sep 2010
Default Rotel RB-970BX problem

I bought one of these power amps off ebay hoping that i could drive it from the output of my total bithead (DAC and headphone amp)

Headroom Total Bithead - Headphone Amplifier | HeadRoom Audio

I connected it up and slowly ramped the gain on the bithead and i heard a slight noise from the speakers and the rotel powered off and now doesnt power on at all.

I know i am supposed to use a preamp, but I didnt think the input to a power amp would be so sensitive. The manual for the rotel says the overload level is 5V and i assumed the USB powered headphone amp can only got that high at the most.

I've just downloaded the service manual and will take a look at that but i have no experience doing this sort of thing so any help would be really appreciated.
  Reply With Quote
Old 17th September 2010, 03:04 AM   #2
diyAudio Member
 
Join Date: Mar 2010
Start with the power line and main switch and fuse if any. If you get power to the transformer, see if you get power out of the rectifiers.

If you don't get power to the transformer, maybe you blew a fuse. Yeah, a volt or so at the input of a power amplifier will drive it pretty hard.
  Reply With Quote
Old 17th September 2010, 08:12 AM   #3
00dc2 is offline 00dc2  Australia
diyAudio Member
 
Join Date: Sep 2010
The rail fuses blew, i replaced them and she plays fine through the total bithead.. i just had the volume turned up too high in windows.. i turned that right down and started from there...

now i set the volume to 50% in winamp or mpc and then use the vol control on the little headphone amp starting at 0.. gives good volume control

What is the chance that i damaged the rotel by overdriving the input on it?
  Reply With Quote
Old 17th September 2010, 03:34 PM   #4
diyAudio Member
 
Join Date: Jan 2010
Depends on your head phone amp output voltage level.
In reality, Not so high of chance.........is it??
  Reply With Quote
Old 17th September 2010, 04:55 PM   #5
00dc2 is offline 00dc2  Australia
diyAudio Member
 
Join Date: Sep 2010
not entirely happy with the rotel, it is hissing when there is no music playing.. i'd like to figure out if its the headphone amp that is feeding it or the rotel itself

with the headphone amp plugged into the rotel but with the input level/gain turned down to zero there is a hiss.. when there is nothing connected to the input of the rotel it produces complete silence..

i wonder if the headphone amp has some dc or i dunno some noise or there is a mismatch between its output and the rotel's input.. cos the headphone amp plays very cleanly with my Sennheiser HD600s

i am guessing that the headphone amp isnt really that clean and the headphones are far less sensitive to noise on their inputs than the rotel.. but if only i could find a nice and clean source to drive them with to really test them.
  Reply With Quote
Old 17th September 2010, 09:14 PM   #6
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
A quick fix might be a 1:1 transformer.

EDCOR - S2S10K/10K
__________________
Candidates for the Darwin Award should not read this author.
  Reply With Quote
Old 19th September 2010, 10:53 AM   #7
Banned
 
Join Date: Nov 2006
Location: Torpoint
Try running with no input or, even better a shorting plug on the input of the Rotel. The Power Amplifier should be virtually silent in this situation.

I would suspect that your "hiss" is coming from the output of the computer.
  Reply With Quote
Old 19th September 2010, 11:10 AM   #8
00dc2 is offline 00dc2  Australia
diyAudio Member
 
Join Date: Sep 2010
when i run it with the input open circuit it is silent.. your suggesting i short the inputs? is that a good idea (gulp)? (i have no idea)

silence with open circuit inputs suggests the amp is in good nick?
  Reply With Quote
Old 19th September 2010, 02:40 PM   #9
Banned
 
Join Date: Nov 2006
Location: Torpoint
If it's silent with NO INPUT there is no need to try it with shorting plugs.

The amplifier sounds good to me.
  Reply With Quote
Old 19th September 2010, 09:56 PM   #10
00dc2 is offline 00dc2  Australia
diyAudio Member
 
Join Date: Sep 2010
great, thanks for your help!
  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
Rotel RQ-970BX schematic wanted Sjef Analogue Source 7 3rd July 2011 10:47 PM
Rotel RA-970BX schematic needed agoraphobic Solid State 2 26th June 2010 09:15 AM
Rotel RB 1080 Glue Problem birdyman Solid State 3 5th June 2010 07:16 PM
Problem with Rotel RB-985 MKII 5 channel home cinema amplifier... hoppaz Solid State 2 9th April 2009 08:04 AM
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 10:44 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