I always wanted a system on my bedside. Some light music to help me sleep. But the dresser is rather small and can’t take a pair of speakers even bookshelf. And no, I’m determined not getting those crappy bluetooth speakers. 

So I thought to myself why not a mono system? It’s near field listening anyway. With a smaller budget in mind I also dived into the DIY route with Nelson Pass Amp Camp Amp and a self made volume control. See details in the components.

Along with the Spendor speaker and the Topping DAC, the result is a fantastic sounding system and it’s very satisfying.

I sleep better every night now.


Components Toggle details

    • Spendor S3/5R (2) [CR3]
    So one speaker. Mono mono.

    I started with using a single Celestion 3 putting sideway and then I upgraded to the Spendor. I had Spendor before in my other room and really like the sound sig. so when I got a chance to buy this I didn't hesitate.

    This is the CR3 version of the same Spendor S3/5R2. It's meant to be for the centre channel in HT but it's essentially the same speaker side way with a horizontal grill.

    My main focus is jazz, light classical and female voice. So these BBC derived speakers with sweetest mid-range is indeed a great choice. I'm looking for someone who's willing to sell me a single Harbeth P3ESR. If you have one (yes, one !) let me know :-) 
    • Nelson Pass Designed Amp Camp Amp (ACA)
    As I venture into DIY I'm thankful for what Nelson did. Well designed Class A power amp, very easy to assemble with the kit. I think everyone who's into audio should try it once. It's a lot of fun and very satisfying. 

    And of course I run it in Mono mode. It runs rather hot as it would be for Pure Class A.
    • DIY Signal summing box with Passive Volume Control
    This is the critical part of the system as I need to "merge" the Stereo signal into Mono. As the Amp Camp Amp is a power amp, I need a Passive Volume Control also. 

    Important : Simply using a Y-splitter in reverse will not work. It'll cause leakage and distortion. Searching the web, the right way to do in summing is to add a 1K ohms resistor into each path before merge them. 

    So I put together a box for that. All parts from PCX ( The ALPS potentiometer is a great option without breaking the bank. Smooth, zero-noise. 

    Outcome : a simple and high quality Volume Control within arm reach. 
    • Topping D10
    Topping has gained rave review in Audio Science Review based the excellent measurement. I think the outcome is great. I picked the D10 not only because of the price but also the fact that it doesn't req separate power. It's a good DAC for the money and support DSD very well.
    • Moode Audio Moode Audio Player
    My streamer is simply a Raspberry Pi 4 with Moode Audio. I tried several of them such as piCoreplayer, Volumio, and settled with Moode which I feel it gives me the best sound quality. Very easy to use !
    • Audio Sensibility Statement RCA
    It might be overkill here but since I have a few pairs not used I put them in anyway. As I explained in the Volume Control piece, it's stereo in and mono out, so there're three cables. All from Steve of Audio Sensibility.

    To me it's the best cable for the money, bar none. I use AS in my main system also.

    • HDPLEX 200W LPSU
    As my system is mainly digital. A good Linear Power Supply is crucial. the HDPlex not only powers the Pi, but it has a 19V input which I plug that with the Amp Camp Amp also. The result is quiet background and only music.

Comments 2

Smart setup you have there.  Mono makes a lot of sense in a bedroom.  I built a pair of ACAs and went on to build a pair of F4s.  NP is a treasure.


This such a refreshing take on the bedroom system.  Thanks for sharing.


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