Rotel RQ-970BX schematic wanted - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

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 8th April 2003, 04:23 PM   #1
Sjef is offline Sjef  Netherlands
diyAudio Member
 
Join Date: Jan 2003
Location: Amsterdam
Default Rotel RQ-970BX schematic wanted

Does anyone have the schematics of the Rotel RQ-970BX phono preamp.

I'm using one, but the problem is that the output is quite low compared with my CD player. My linestage does not have enough gain so normal listening levels are now with the potmeter almost full open. That's why I want to try to get some more gain out of the Rotel.

Anyone ?
  Reply With Quote
Old 8th April 2003, 05:25 PM   #2
diyAudio Member
 
Join Date: Jun 2002
Location: Italy
Sjef

I am reading and seeing the schematic . I find it in an Italian review.

This phono stage has a differential pair at the input , and a part of the eq (hi freq) is in this stage .

Every feedback loop in the op amps is also a eq stage.

So I think the only way for increasing the gain without affecting the RIAA curve is R123 , between IC101 (AD744JN) and ICI103 (NE5534AN) . R123 is now 75K and connects the output of IC101 and the input of IC103 . Try decreasing value of this resistor.
  Reply With Quote
Old 8th April 2003, 05:39 PM   #3
diyAudio Member
 
Join Date: Jun 2002
Location: Italy
HERE is a nice forum were you can register and download phono amps manuals , don't know if schematics are included.
  Reply With Quote
Old 8th April 2003, 10:26 PM   #4
Sjef is offline Sjef  Netherlands
diyAudio Member
 
Join Date: Jan 2003
Location: Amsterdam
Decreasing this resistor would not help much in winning gain because it sees a very high impednace at the input of the second opamp.

I was afraid that the riaa correction was done in the feedback lines of both the opamps. I was hoping that the second opamp was only a linear amplifying stage, so then it would not be a problem to set it's gain for another extra 10dB or so.

Still want the schematic. Maybe I can recalculate the riaa eq and set it for higer gain.
  Reply With Quote
Old 19th August 2003, 09:24 AM   #5
Werner is offline Werner  Europe
diyAudio Member
 
Join Date: Jan 2002
Location: Belgium
I have an RQ970 which I will demolish in the coming weeks. I'll try to reverse engineer it then.

Seems like a triumph of fashion over function: Black Gates all over, but a so-so circuit.
  Reply With Quote
Old 1st September 2003, 05:46 AM   #6
Werner is offline Werner  Europe
diyAudio Member
 
Join Date: Jan 2002
Location: Belgium
Here is a partial schematic. Never mind the input transistor types, they are just placeholders.

I'd suggest to modify the two gain setting resistors by soldering additional values on top of them.

R117=560 and sets MM gain. Another 560 on top gives you an extra 6dB without much pain.


R119=47 sets MC gain. Same story, put a 47 on top.

Same for the other channel.

You could tweak R125=4k7 too, but eventually this will lead to aberrations in the RIAA response.
Attached Images
File Type: gif rotel_rq970_1.gif (73.8 KB, 543 views)
  Reply With Quote
Old 3rd July 2011, 10:41 PM   #7
KBK is offline KBK  Canada
diyAudio Member
 
Join Date: Dec 2003
Location: The Wilds Of Canada
Photo 1 of 17, Rotel RQ970BX HFW -Andy Grove upgrade

and the Rotel RHQ-10 (RHQ10) phono preamp tech manual is on the same page. Older Rotel schematics can be obtained via direct contact with Rotel, via email, or even calling them first.

Many times the email with the tech schematic will be sent to you in the same day as first contact. Cudos to Rotel for being a great company.

Last edited by KBK; 3rd July 2011 at 10:48 PM.
  Reply With Quote
Old 3rd July 2011, 10:47 PM   #8
diyAudio Member
 
Join Date: Jun 2004
Location: England
All rotel (and B&W and Classe) service manuals can be found at:

B&W Group North America Service & Support Homepage

You have to click on the Service Manuals link and then click on a button to agree to some terms and conditions before they let you view the service manuals...
  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
Schematics of NAD 208 & Rotel 1080/1090 wanted! Ultima Thule Solid State 33 18th June 2012 01:38 AM
Service Manual/ schematic for Rotel ROTEL RHCD-10 Michi CD player Staykov Digital Source 5 16th May 2012 12:24 AM
Rotel/NAD amp Wanted MellowTone Swap Meet 0 8th July 2006 10:39 AM
WANTED: ROTEL RCD-955AX analog schemaic cartman Digital Source 3 18th September 2005 09:02 AM
Rotel RMCD910 circuit diagram Wanted ben_w Solid State 0 7th May 2003 11:13 PM


New To Site? Need Help?

All times are GMT. The time now is 03:30 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