kiatel97
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Turn Pi Into Analog Receiver For Speakers

Tue Sep 15, 2015 3:03 am

I know absolutely nothing about raspberry pi or programming. What I do know is that the Pi is a powerful little computer that can be used for several projects.

I have an idea for a project, but I don't know how to find the information to bring this idea to life. I want to take the analog connection from a turntable tonearm and connect those analog cables with a Pi. The Pi will be connected to speakers. I want it to be able to take the sound from the analog connection to the speakers. I want the pi to also be able to take bluetooth connection from a cell phone and play with the speakers too.

This is just an idea. I really have no clue how to bring this into fruition. Guidance would be much appreciated.

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Burngate
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Re: Turn Pi Into Analog Receiver For Speakers

Tue Sep 15, 2015 10:15 am

the analog connection from a turntable tonearm
Since that is rather low-level, you'll need a preamp of some sort, and since the Pi has no analogue inputs, you'll need a converter - an ADC.
The Pi will be connected to speakers
but the Pi's output will need to be amplified since it's too low-level to drive them directly.
Why not connect the preamp directly to the speaker amplifier? Precisely what a HiFi amp does.
take bluetooth connection from a cell phone
okay, the Pi can connect to a bluetooth receiver and produce audio, so mix that with the turntable output inside the HiFi amp.

What I'm saying is have your Pi as a side-chain input on your ordinary HiFi amp

ghans
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Re: Turn Pi Into Analog Receiver For Speakers

Tue Sep 15, 2015 10:24 am

Solve the analog amplification problem first (speaker and turntable) before adding the digital part (Raspberry Pi).

ghans
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ChAoS
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Re: Turn Pi Into Analog Receiver For Speakers

Tue Sep 15, 2015 10:33 am

kiatel97 wrote:I want to take the analog connection from a turntable tonearm and connect those analog cables with a Pi.
Will RIAA equalisation not have to be done somewhere? Perhaps things have changed, but when I was interested in this sort of stuff in the 1980s, the equalisation was done in the amplifier. I remember bypassing such equalisation in an amplifier so that I could have an extra "aux" input since I had no turntable.

Regards,

Mark.

Hopkins
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Re: Turn Pi Into Analog Receiver For Speakers

Wed Aug 15, 2018 4:19 am

I want to do the same as OP. Sounds like we’re better off with a regular amp, instead of...having our pi and eating it too.

(Am I the first to use that joke?)

drgeoff
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Re: Turn Pi Into Analog Receiver For Speakers

Wed Aug 15, 2018 12:45 pm

ChAoS wrote:
Tue Sep 15, 2015 10:33 am
kiatel97 wrote:I want to take the analog connection from a turntable tonearm and connect those analog cables with a Pi.
Will RIAA equalisation not have to be done somewhere? Perhaps things have changed, but when I was interested in this sort of stuff in the 1980s, the equalisation was done in the amplifier. I remember bypassing such equalisation in an amplifier so that I could have an extra "aux" input since I had no turntable.

Regards,

Mark.
RIAA equalisation is performed in the preamplifier section, not in the preamp.

TBH, I don't see the point in using a RPi in this at all. You need a phono preamp and power amp, neither of which an RPi can do. Once you have those two, possibly together in a single off-the-shelf Hi-Fi component, get a Bluetooth to analogue audio adaptor (they start at less than £10 on ebay) and connect it to the AUX input on the amplifier..

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Paul Webster
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Re: Turn Pi Into Analog Receiver For Speakers

Wed Aug 15, 2018 5:01 pm

I do it with a Behringer UFO202 (around 25GBP) connected to RPi which in turn makes it available to other players.
Means can put a record on and then go somewhere else to listen to it ... and come back 20 minutes later to turn the record over ... yes, was more of an academic exercise than practical use.

drgeoff
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Re: Turn Pi Into Analog Receiver For Speakers

Wed Aug 15, 2018 5:22 pm

Paul Webster wrote:
Wed Aug 15, 2018 5:01 pm
I do it with a Behringer UFO202 (around 25GBP) connected to RPi which in turn makes it available to other players.
Means can put a record on and then go somewhere else to listen to it ... and come back 20 minutes later to turn the record over ... yes, was more of an academic exercise than practical use.
I read the 'What HI-FI' review of that unit. What a load of clap. For example:

"There isn’t a great amount of detail rvealed - the UFO202 settles for an up-front presentation heavy on midrange, rather than digging deep into textures or auxiliary lines. But these are always recognisably the broad strokes of songs, and the performance is not entirely bereft of dynamic range.

Organisation and timing are the UFO202’s main difficulties. Having such little a confined audio space in which to play leaves it with nowhere secure to place the strands it is digging out of the mix."

Probably didn't sound good because the reviewer had inadvertently plugged in his unidirectional single crystal 99.999% pure copper leads the wrong way round. :)

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