ADC + Bluetooth (LDAC/Aptx-HD) Transmitter
Apr 29, 2020 at 2:25 AM Thread Starter Post #1 of 8

sono delirii

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Hi All, long time reader, first time poster :)

I am looking for something but a cursory search did not turn up what I was hoping; maybe you guys may have some suggestions!

I would like to have the ability to give any audio playback device with an analog output ability to work with BT headphones.

In a nutshell: take analog input (from 1/4" or XRL jack), encode for BT transmission with LDAC or Aptx-HD, transmit.

Hopefully for under $500?

Thanks!
:beerchug:
 
May 5, 2020 at 8:54 PM Post #3 of 8

dazzerfong

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The iFi Zen Blue uses BT for input, not output. As in, it streams from your phone to the DAC via BT.

You'll need something like the TaoTronics TT-BA014 or an Avantree Oasis Plus. That one can both send and/or receive BT audio streams: however, it only supports up to AptX LL. The Avantree Oasis Plus does AptX HD though.
 
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May 5, 2020 at 9:50 PM Post #4 of 8

Maelob

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The iFi Zen Blue uses BT for input, not output. As in, it streams from your phone to the DAC via BT.

You'll need something like the TaoTronics TT-BA014 or an Avantree Oasis Plus. That one can both send and/or receive BT audio streams: however, it only supports up to AptX LL. The Avantree Oasis Plus does AptX HD though.
Good catch my bad
 
May 7, 2020 at 3:57 AM Post #5 of 8

sono delirii

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The iFi Zen Blue uses BT for input, not output. As in, it streams from your phone to the DAC via BT.

You'll need something like the TaoTronics TT-BA014 or an Avantree Oasis Plus. That one can both send and/or receive BT audio streams: however, it only supports up to AptX LL. The Avantree Oasis Plus does AptX HD though.

That's basically the only option I found so far, but I have some reservations.

With a digital input all it needs to do is compress well, and it has AptX-HD for that.

But with an analog input it needs to run it though a ADC first, and that's a gray area.

I don't know much about the ADC market, but the ES9038PRO DAC chip in my DX7 PRO costs ~$75 itself, and that's not counting the actual implementation, so its hard to imagine that a ~$75 product had enough in its margins to do a decent job here.

If anyone knows what they use for ADC and how its implemented do tell!
 
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May 7, 2020 at 5:20 AM Post #6 of 8

sono delirii

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PS: list of problems with Oasis Plus from a review for reference, edited and enumerated for brevity.

1) The Oasis seems to be built around keeping a Bluetooth device always connected when in Bluetooth + Passive mode as when there isn't a Bluetooth device connected you run into numerous issues.

The first of which is when using the bypass + Bluetooth mode there is an electrical hum that lasts 7 seconds then silences for 13 seconds before it starts the hum for 7 seconds again. It goes on forever. This happens if there is no Bluetooth device connected it seems so it must be a hum from the wireless chipset doing a scan for devices.

Another issue is that the built-in speaker which is only meant for the voice prompts starts acting as a normal speaker if no Bluetooth device is connected. I noticed what seemed like whispers coming from somewhere in my apartment and found out it was the Oasis Plus. It was playing the audio from my cable TV through it's internal speaker, but at a very low and uncontrollable volume which is obviously a design issue. Once I connected a Bluetooth device to the transmitter the issues stopped.

2) Needs Better shielding - There's an electrical buzz when running straight 3.5mm from my PC's headphone (just headphone, not a dual line in/microphone port) port to the Oasis transmitter. I don't have this problem when connecting headphones directly to the PC or even when outputting to other mixer devices.

3) Needs Better sound quality through 3.5mm ports - there is a major difference in quality when using 3.5mm directly on source device and when going through the 3.5mm port on the transmitter. When going through the transmitter the sound quality drops significantly and is also noticeably muffled.

4) Better audio detection - As it is now, there doesn't seem to be a signal sent to let connected devices know there's no audio coming through, as a result when I'm using a Bluetooth headphone DAC receiver there's major trouble switching audio between the Oasis transmitter and something like my phone on it because the Oasis is "always transmitting" even when there's no sound. This frequently results in my Bluetooth headphone receiver not switching over if I start playing audio on my phone. Even if I mute things or turn off the TV its no go for switching audio most of the time.

5) Needs microphone aux support or add a microphone to the device itself - I would love to be able to route my PC's sound card through here, but it's useless without mic support It would also be nice to be able to connect a phone and take calls.

6) Needs Bluetooth 5.0 & LDAC (32 bit audio quality if possible)
 
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May 7, 2020 at 7:37 AM Post #7 of 8

dazzerfong

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Fair points except point number 6. That being said, you might want to highlight your actual intentions rather than being vague if you want people to suggest better products to you.

If you understood BT standards, you'd have immediately discounted point 6. Bluetooth 5 does absolutely nothing for audio quality except range. And when you have a Class I transmitter that's around 10x more powerful than your phone, it's a moot point. LDAC also does not support 32-bit quality, only up to 24-bit.

Other alternative I came across is the Sennheiser BT-T100: maybe that's more your speed. However, that one only outputs BT: no analog out.
 
May 7, 2020 at 6:32 PM Post #8 of 8

sono delirii

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Fair points except point number 6. That being said, you might want to highlight your actual intentions rather than being vague if you want people to suggest better products to you.

If you understood BT standards, you'd have immediately discounted point 6. Bluetooth 5 does absolutely nothing for audio quality except range. And when you have a Class I transmitter that's around 10x more powerful than your phone, it's a moot point. LDAC also does not support 32-bit quality, only up to 24-bit.

Other alternative I came across is the Sennheiser BT-T100: maybe that's more your speed. However, that one only outputs BT: no analog out.

haha, thanks Dazz!

1) Didn't say BT5 effects quality. I agree, absence of BT5.0 is not really a problem for me. Just left the guys points as-is in case someone does care.

2) Correct, LDAC is 24bit, did not catch the guys typo. I don't "need" LDAC, but would strongly prefer it. Everything I have runs it, including the WH-1000XM3 so it would be nice.

3) My main issues is are 1-4, plus I don't know what ADC they use or how well they implement it, the fact that people complain about analog output makes me doubt their analog handling. Also based on their marketing and how majority of people use this product, it seems to be geared more for a mid level home theater setup rather than a HiFi experience.

4) Regarding Sennheiser BT-T100, according to their website it doesn't seem to support Aptx-HD or LDAC.
 

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