ajscomp372

If I correctly understand what you're saying, that setup should work. Now, the Performance Teknique ICBM-5.1 amplifier has the optical input and the 5.1 rca input, which is what you're looking for. If you can still find it, it could be your best bet.

BTW: For anyone who doesn't have a remote for this amp, I have a solution. Just message me for more info.

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jschrauwen

Still running the PT 5.1?
I STILL haven't installed it yet because of the nagging delays for that double din all singing all dancing unit fromt Brent. So frustrating that my CarPC has been ready to install for over a year and a half.
Love to see/hear what your solution was for the MIA remote.

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ajscomp372

Well, I actually did originally receive a remote with my amp, and because of incredible foresight, I decided to record the IR signals using winlirc on my computer, thinking that I would use them to have the computer control the amp in the future. Several months later when I lost the remote, I simply hooked up the IR transmitter to my serial port and set winlirc to simulate pushing the power button on the remote when it booted up. Now I basically have a virtual remote on the computer, that I can program or script to manipulate the amp any way I want.

If anyone needs the config file for winlirc that would allow you to simulate the remote, I could give the file and (if they wanted) build them the box that connects between the computer and the amp (PT ICBM-5.1).

MeeM

ajscomp372: good job with the IR capturing.

So excuse my ignorance ppl, but what's wrong with setting the volume to a decent level on the amp, and then controlling the PC volume thru ur touchscreen as normal? Atm, with my desktop PC here in my room, I've got an optical cable from my PC to my amp ... and the amp is turned up to a decent level and I hardly adjust it (except for movies etc.). I usually just control my volume in Winamp or Windows Media Player or the taskbar volume control.

Am I missing somethin in this thread?

jschrauwen

^^^ Are you using the ICBM5.1 as well?

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MeeM

Nope, I haven't got a 5.1ch amp with optical input yet.

enigma9o7

Unless I'm also ignorant, when the signal goes from your deck/pc to an amp optically, there's no volume control from the sending device... you adjust the volume with the amp. All that's going thru the fiber is the digitally encoded audio.... there are no levels involved, either the led/laser is on or off to indicate 1 or 0. I can set the volume to 0 on my deck and optical signal is not affected. The same thing happens with my home theatre components - i.e. I can set my HDTV volume to zero, but signal coming optical out into my amp doesn't change.

However, if the signal is coming from your deck/pc to an amp analog, then when you change the volume on your deck/pc it is changing the voltage levels going into the amp, so it does control volume, in essence your amp is applying the same amplification to whatever comes into it if you dont change it. i.e. if the amp does 3db gain, it'll apply that gain/increase to whatever voltage is coming in.

What I did in my car was run optical from my deck to the the phoenix gold 5.1 amp and use pacswix to have my steering wheel volume control adjust the amp volume. This worked for cds, mp3s & dvds. For the radio & tv, I didn't get sound from my deck on the optical (I wasn't lucky enough to get a deck with analog to pcm encoding) so I also ran rca's from my deck to the amp. I made one of my steering wheel buttons the input select on the amp, and then adjusted the volume on the deck so it was approx the same level as a CD via optical, then from there never touched the deck volume again.

MeeM

Thanks for your input. You worked around the problem quite well in your car


I'm still not sure about this. I understand your reasoning and in theory that's how it probably should (or would?) work. But most optical setups I've used (including my current desktop PC with optical cable running to my 5.1 ch amp) allow volume to be adjusted at the source. So maybe the optical output on PCs might be setup differently to other devices

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pcpete

I think , at least in winamp, if I select 'wavout' as path I can't control volume, if set for directsound then windows mixer messes with the bits (ie adjusts volume) and then sends to spdif out, if so configured.

The holy grail is to have the bits untouched and sent through spdif out, hence no volume control without losing quality...

MeeM

ye my winamp is set to directsound. If I use directsound, the audio output is softer compared to the output if I used waveout. Not sure why that is so ...

And now I've just noticed that because I have my PC connected to my amp with an optical cable, the master volume slider in the windows mixer has no effect on the volume. So I guess this is what ppl are talking about in this thread.

Still though, if I had the same setup in my car, I'd use winamp and I'd use the volume in winamp cos that still works with an optical cable. It's just the windows master volume that seems useless with optical.

dacho

So I can't seem to find to buy any of these amps anywhere. Could some one point me in the right direction please. I just need a optical in amp with at least 4 channels.

Thank you

MeeM

Yeah I've also found it difficult to source any of these units. I've decided not to have an amp with optical input, and I bought an ordinary 4 channel amp. For my next car PC upgrade, I intend to buy an amp with optical input ... hopefully the range of these units will be better by then.

Bxsteez

I'm not sure if anyone still cares but i was able to find Alpine MRA-D550 on ebay. If you have a coaxial output on ur motherboard like the new gigabyte minitx mb you can get a coaxial to optical adapter for like 18 dollars and use this alpine amp.

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black_mamba

I just took a look at that amp. From the owner's manual, it looks like it has to be used with an Alpine head unit.

From page 11, under "Operation Method"

For the operation method, refer to “External Audio
Processor” in the Owner's Manual of the DVD Audio/
Visual Head Unit.
This unit does not work independently of the head
unit.

I'm assuming you'll be using it with a compatible head unit. I thought this amp might work for me and it's not too expensive (on eBay), but I'd like to be able to get rid of the HU.

tameanaka

So the MRA-D550 needs an Alpine HU to work??

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