I'm pulling old-but-good audio stuff out of storage to set up a TV/music area in the family/living room. I'd like some advice about how to connect the audio stuff. Weirdly enough, the main issue is how to control the overall gain (volume). I want a system which is simple enough that family members, including my 80+ mother in law, can use it without help from me.
The output side is ACI Sub1 + Sapphire Two loudspeakers and a Parasound HCA1200 amp. The input to the amp is RCA analog L/R line level. The amp has a front panel gain control, but I'd prefer not to use that if possible.
The audio sources are:
CD: Sony CDP C79ES, ouputs are RCA L/R analog + Toslink Has front panel and remote volume control (motorized potentiometer).
Bluetooth: 1Mii interface for streaing devicesL has RCA L/R analog line level outputs
Audio/Video sources:
Sony PS4: used for games, streaming movies, DVDs, outputs are HDMI + Toslink
Sky satellite box: outputs are HDMI + Toslink + RCA L/R analog
The last two devices are connected to a LG 60PV250 TV via HDMI. The TV also has a cable input which we use, but tne ONLY audio output is
Toslink (fixed volume!).
My current plan: an inexpensive relay switch that has three pairs of L/R RCA analog inputs and one L/R RCA analog output. The relay switch output goes to the amplifier. Input 1 comes from the CD player, Input 2 comes from the Bluetooth interface, and input 3 is going to come from the TV set.
When listening to the CD player, we'll use its remote and volume control. When streaming bluetooth we'll use the app's volume control. When watching TV/Video the TV remote will do the volume control.
I had hoped to connect the TV to the audio system via a Toslink->Analog converter. Problem is, if I do this then there is no way to control the volume, the TV remote won't do that.
Easiest solution is (I think) to open up the TV set, and wire a DPDT switch to turn off the internal loudspeakers and redirect their output to a voltage divider followed by a pair of analog RCA L/R output jacks. My only concern here, I don't know if the frequency response of the built in audio amp has been shaped to match/compensate for the inbuilt speakers. (And no, there is sadly no headphone jack I can use to get line outputs!).
Is there another simple approach? I don't want to introduce yet another remote control into the pile, and it seems to me that since my family is used to contolling the volume of the Sky satellite box, the PS4 and the cable TV via the TV remote, keeping it working like that is the best solution.
Thanks for any advice or other solutions!
Bruce
The output side is ACI Sub1 + Sapphire Two loudspeakers and a Parasound HCA1200 amp. The input to the amp is RCA analog L/R line level. The amp has a front panel gain control, but I'd prefer not to use that if possible.
The audio sources are:
CD: Sony CDP C79ES, ouputs are RCA L/R analog + Toslink Has front panel and remote volume control (motorized potentiometer).
Bluetooth: 1Mii interface for streaing devicesL has RCA L/R analog line level outputs
Audio/Video sources:
Sony PS4: used for games, streaming movies, DVDs, outputs are HDMI + Toslink
Sky satellite box: outputs are HDMI + Toslink + RCA L/R analog
The last two devices are connected to a LG 60PV250 TV via HDMI. The TV also has a cable input which we use, but tne ONLY audio output is
Toslink (fixed volume!).
My current plan: an inexpensive relay switch that has three pairs of L/R RCA analog inputs and one L/R RCA analog output. The relay switch output goes to the amplifier. Input 1 comes from the CD player, Input 2 comes from the Bluetooth interface, and input 3 is going to come from the TV set.
When listening to the CD player, we'll use its remote and volume control. When streaming bluetooth we'll use the app's volume control. When watching TV/Video the TV remote will do the volume control.
I had hoped to connect the TV to the audio system via a Toslink->Analog converter. Problem is, if I do this then there is no way to control the volume, the TV remote won't do that.
Easiest solution is (I think) to open up the TV set, and wire a DPDT switch to turn off the internal loudspeakers and redirect their output to a voltage divider followed by a pair of analog RCA L/R output jacks. My only concern here, I don't know if the frequency response of the built in audio amp has been shaped to match/compensate for the inbuilt speakers. (And no, there is sadly no headphone jack I can use to get line outputs!).
Is there another simple approach? I don't want to introduce yet another remote control into the pile, and it seems to me that since my family is used to contolling the volume of the Sky satellite box, the PS4 and the cable TV via the TV remote, keeping it working like that is the best solution.
Thanks for any advice or other solutions!
Bruce
Problem: No remote control for the relay switches ... ?
1) With some effort it maybe possible to trace the line level input of the TV's inbuilt amplifier and use that output to feed the amp ....
2) If the correct button codes can be picked up, the external TOSLINK amplifier could be operated using the TV remote as usual. However, you need to scan the +/-/volume/mute keys using an oscilloscope etc and then detect the respective codes using a microcontroller. I think LG TVs use the RC5 remote code format.
https://en.wikipedia.org/wiki/RC-5#System_number_recommendations
Last edited:
Hi newvirus, these are good points. I've found a block diagram of the LV 60PV250 TV and after looking at the audio circuit have decided that going with the Toslink-encoded stream is the right approach. For the moment I am going to try the inexpensive and simple solution: add another remote and a passive volume control/switching box. I've ordered this one with 10k resistance:
https://www.aliexpress.com/item/1005004396895083.html
I could have bought the bare boards for 25 Euros, but cost of a box and power supply and the time to mount everything and make it look nice is more than the extra 90 Euro for the pretty box and other stuff.
If my family can not deal with yet another remote, then I'll try to hack the hardware to respond to the (presumably) RC-5 volume commands from the TV remote, and the input switching can be done by getting up from the couch and turning the front panel knob 🙂.
https://www.aliexpress.com/item/1005004396895083.html
I could have bought the bare boards for 25 Euros, but cost of a box and power supply and the time to mount everything and make it look nice is more than the extra 90 Euro for the pretty box and other stuff.
If my family can not deal with yet another remote, then I'll try to hack the hardware to respond to the (presumably) RC-5 volume commands from the TV remote, and the input switching can be done by getting up from the couch and turning the front panel knob 🙂.
