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Gear / Technical Help => Playback Forum => Topic started by: DF81 on October 19, 2014, 06:00:57 AM

Title: Rotel RX-402
Post by: DF81 on October 19, 2014, 06:00:57 AM
I just bought a Rotel RX-402 (mid 70's receiver/tuner)...  sounds good.  The tuner doesn't dial in as well as Yamaha CR-400 (mid-70's), but it has a nice tone.  Does anyone know why the tape/aux input levels are low? (drastically compared to phono input) It's not very loud with volume at 10.  The phono input has much more volume/power, but the bass is blown out unless you turn it down to zero. (edit:  I'm running rca f/ laptop, not a turntable)


(http://www.oocities.org/siliconvalley/program/3092/ClassicAudio/images/RotelRX402AluFront.jpg)
Title: Re: Rotel RX-402
Post by: voltronic on October 19, 2014, 11:16:39 AM
Danger, Will Robinson!  You shouldn't be using the Phono input for anything except a turntable.  You run the risk of damage if you are running a line-level source like a CD player into Phono.  This is because the phono input connects to a preamp circuit which amplifies the very low-level signals coming from a phono cartridge.  And the reason for the blown-out bass is the RIAA circuit - again something you only use coming from a turntable.  https://en.wikipedia.org/wiki/RIAA_equalization (https://en.wikipedia.org/wiki/RIAA_equalization) 

Title: Re: Rotel RX-402
Post by: DF81 on October 19, 2014, 09:32:47 PM
Danger, Will Robinson!  You shouldn't be using the Phono input for anything except a turntable.  You run the risk of damage if you are running a line-level source like a CD player into Phono.  This is because the phono input connects to a preamp circuit which amplifies the very low-level signals coming from a phono cartridge.  And the reason for the blown-out bass is the RIAA circuit - again something you only use coming from a turntable.  https://en.wikipedia.org/wiki/RIAA_equalization (https://en.wikipedia.org/wiki/RIAA_equalization)

Ha, yeah I had to look up Will Robinson.  I bought this for a secondary two channel receiver.

Thanks for the message.


Anyone know if the aux input levels can increase?
Title: Re: Rotel RX-402
Post by: voltronic on October 19, 2014, 09:51:56 PM
I'm not sure your aux inputs are actually "low" - they just don't have the additional gain stage of the Phono input (nor should they).  The Phono input will always be WAY louder than the others if you run a line source into it, but like I said that's a very, very bad idea to do so.
Title: Re: Rotel RX-402
Post by: DF81 on October 19, 2014, 11:41:03 PM
I'm not sure your aux inputs are actually "low" - they just don't have the additional gain stage of the Phono input (nor should they).  The Phono input will always be WAY louder than the others if you run a line source into it, but like I said that's a very, very bad idea to do so.


The AUX input max volume is like a 4 or 5 on most other stereos I've used (if that).  I'd say it's an average volume at max, and you can't really push it at all.  Just wondering if there may be a setting on these older receivers, or if it needs repair.  Also note, the tuner is much louder (2-3 x's).

30 watts/channel
8 ohm
Title: Re: Rotel RX-402
Post by: H₂O on October 20, 2014, 12:04:15 PM
I would doubt the tuner should be 2-3x louder

Do you have any repair history on the unit?  The display looks bright which would seem to point to repairs at some point in the past or low usage.

If the unit has not been repaired at some point in the past I would think any electrolytic capacitors in the unit are probably out of spec and could cause the issue you are experiencing.

There may also be pots that need adjusting as well.
Title: Re: Rotel RX-402
Post by: DF81 on October 29, 2014, 11:49:34 PM
It may have been a bad cable.  I used an iPhone 4s with a new RCA cable and it was much better.