Vinyl Heresy

Music_Lover

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I currently use an iFi Neo iDSD, which is Bluetooth capable, as a DAC/preamp however, it has no provision for analogue inputs. I've been trying to figure out how to add my turntable to the DAC and considered an ADC or phono pre with a digital output. I really did not want to add another preamp into the mix for multiple reasons. I have no experience with ADCs and all the ones I saw looked pretty much the same. The phono preamps with digital out mostly required a computer to be hooked up to the units as they were mainly designed for ripping vinyl.

In an effort to declutter my audio equipment collection I came across an Avantree Oasis BT receiver/transmitter which is APTx capable and a Firestone Audio Korora-MM/MC phono pre which can run off 2 9V batteries as well as AC. The Avantree BT unit accepts optical and aux inputs when acting as a transmitter. I decided to try connecting the Korora outputs, using the necessary cable adapter, to the aux in on the Avantree and transmit to the Neo IDSD. I really didn't expect good results at all but much to my surprise, the sound exceeded all expectations. It sounds pretty darn good actually and really brought a smile to my face. It may be that I am so chuffed with the results because my expectations were so low at the outset.

Everything is not all roses though. There is significant hum and hiss which may be because the Korora minimum gain is 51 dB which is high for the MM cartridge I am using although with music playing, this ceases to be an issue. I would still like to get rid of both problems if possible. The high gain also means that there seems to be overload when the volume is turned up.

It might appal many vinyl purists but it was a fun little experiment and gives me the opportunity to listen to vinyl in a digital system. It also allows me to repurpose equipment that were not being used and get rid of equipment that were replaced by other pieces in the chain. Another probably useful feature is that I can move the turntable away from other equipment which may cause interference.
 

fredeb

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Interesting experiment , sounds like fun .

If you're experiencing hum whilst using batteries to power the Korora there may be ground issues somewhere . Does it happen when you're using the phono straight to amp too ?

Try putting a 47k resistor in parallel with the input to the korora , effectively halving input impedance , this should lower gain somewhat .  https://www.hifisystemcomponents.com/forum/cartridge-loading-plugs_topic1246.html

index.php


http://www.sengpielaudio.com/calculator-paralresist.htm


 

Music_Lover

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fredeb said:
Interesting experiment , sounds like fun .

If you're experiencing hum whilst using batteries to power the Korora there may be ground issues somewhere . Does it happen when you're using the phono straight to amp too ?

Try putting a 47k resistor in parallel with the input to the korora , effectively halving input impedance , this should lower gain somewhat .  https://www.hifisystemcomponents.com/forum/cartridge-loading-plugs_topic1246.html

index.php


http://www.sengpielaudio.com/calculator-paralresist.htm

It was fun and pretty cool that one can do something like that.

It does hum even when connected directly to the preamp as well. I've had this hum issue with other amps with built in phono stages as well so the Korora just exacerbates the problem due to its high gain.
I'll try a different plug point as well.

I'm reading through those links, thank you very much.
 

Music_Lover

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The cables are a complete rats nest so there is some work to be done there.

I'm using a SOTA Moonbeam (probably version 2, with a Jelco arm), Grado Prestige Red cartridge.
 
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