Cambridge CXN into Sansui AU-919

Multimode

Active Member
Having worked hard and saved hard over the years, I decided to treat myself to a Cambridge Audio CXN network player, received yesterday.

I like the CXN very much, other than its sound level via my Sansui AU-919 amplifier being too high. At normal (not soft, not loud) listening level the amp's volume control sits at around the -50db level on a scale which runs from -70db to 0db over a rotation of about 320 degrees. Ideally it would be at about -20db as it is for other inputs.

Cambridge Audio gave a same-day response to my email about this, suggesting I try the digital pre-amp that's built into the CXN. This reduced the signal through the RCA outputs, but by too much. The sound level was now too low even with the volume control screwed round to its maximum. From one extreme to the other. :(

Ideally, I'd fit an adjustable attenuating device to the relevant input on the amplifier, but that's probably one of my sillier ideas!

Any suggestions, please?
 
I may be able to answer my own question. Some research this evening has brought Rothwell Audio in-line attenuators to my attention, these reducing the signal strength by 10, 15 or 20 db, depending on the version bought. http://www.rothwellaudioproducts.co.uk/html/attenuators.html

I also discovered, and many of you will already know, that amplifiers from pre-CD days had a much lower input sensitivity than later ones. The input sensitivity of the AU-919 is given as 150 mV whereas a CD player or network player is likely to push out 2 Volts or more, this overloading the amplifier's input and causing the problems I'm experiencing with my new toy.

Do I get a prize for providing the answer? Is that how it works? ;) :)
 
I don't know about getting a prize for answering my own question, but I'm a prize idiot for not doing a search on AK before asking for help! Lots of info therein on in-line attenuators, if only I'd looked. :oops:

All sorted now. I bought a pair of Rothwell -10dB attenuators which reduced but didn't overcome the problem. The Russ Andrews website suggests that, for 2V output into 150mV input, -16dB is required (http://www.russandrews.com/what-is-attenuation/). I emulated that by switching in the Jump control (with attenuators removed) which coincidentally gives -16dB. Much better but still not enough attenuation for some sources. I then tried using Muting (-20dB) and that gave a better result.

Andrew Rothwell agreed without hesitation to replace the -10dB attenuators with -20dB, so I sent back the former. A pair of -20dB were dispatched to me next business day, by 1st Class post at their expense, and are exactly what was needed. The usable volume range is now between the 10 o'clock and 2 o'clock positions of the control, normally close to 12 o'clock (-20 to -16dB), and the sound quality is very noticeably improved now that the control is out of the original 8-9 o'clock range.

The Rothwell attenuators are very well made and extremely good looking little gems; it's a shame they are hidden behind the amplifier! The Russ Andrews ones look similarly impressive but they cost 2.1/2 times more than the Rothwells.
 
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I have a question though. I read this http://www.russandrews.com/what-is-attenuation/). But how different is a mini volume pot from the attenuators ? What I have done to reduce the input sensitivity from my DVD player to the amp is, added a mini volume pot (those small volume controls you get in wired PC headphones/speakers) in line with the RCA cables, so i could decrease the input sensitivity to how much I want which feeds into the amp.

So are the attenuators better/recommended than my mini volume control ? I am asking this question because I dont see any noticeable difference in quality of music. Also one thing I have noticed on my Pioneer a-7 is that the volume pot works well before passing the 11 o clock position or even further. If it does need to pass those positions for a louder enjoyable music listening, then I notice the bass reduces and the mid frequencies become louder and harsh.
When I purchased the system new back in 1990 it was always a pretty sensitive volume control ever since. Meaning, for the achieving proper full balance of all sounds/ bass punch/ mids and highs without over powering each other, you need not pass the 10 o clock position. ( once your ears and speakers tell you its 99% the maximum volume/output)

I have a 20db muting switch on the amp. If I switch this on, its good because the volume goes to zero ( faintly little sound which I am ok with) But the fun is lost when I want to turn up the volume to enjoy certain songs ( at the full out put) that's when this happens - the bass reduces after passing 11 o clock position( since the 20db switch is on) .
If the mute switch is off the max position I can go to is 10 o clock which gives an over all well balanced sound of bass mids and highs.

So yea, my question which is in the first line of this post, Is connecting a mini volume pot ( in my case) same as the attenuators solution when it comes to db reduction ? :)
 
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