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Wireless Amplifier Input

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(@mark-bolton)
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Joined: 3 years ago
Posts: 108
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I just built the Currawong Valve Amplifier Kit from Altronics and built a foam block speaker system using those electrodynamic excirer thingamies. (My hearing is not so great anymore but I would like for it to be pleasant for those that can hear well - but I digress).

20220727 135321

I use Linux Mint.

To act as a Audio Signal source I was look in at proprietory  "HiFi" Raspberry Pi hats and other absolute silliness and overkill.

I order to get some audio into the thing - just to see if it workes, I bought a cheap and cheerful Bluetooth to Audio unit. Two problems arose:

No matter how I got power into it the thing made a huge racket. Not 50hz but just a racket of hash. It has 6 hours of on board battery. In the end I built a battery pack with about a week of charge. Annoying but tolerable.

I am constantly having Bluetooth dropouts - an having to manually reconnect after a reboot. Likely I could write some script to reconnect automatically ..

It seems to reconnect at a whim if it feels like it.  It has tiny demons in it just to torment me.

I realize that the ESP23 only has 16bit sound DAC but is that really so bad?  Would it be worth looking at the more exotic Audio DAC chips ? I already have a house full if ESP32 devices running smarthome devices (12 volt off grid DIY setup). All these are so robust I dont even notice them. All use WiFi.

How hard would it be to build an ESP32 device powered off the 12volt DC (yes you read that right filament voltage) outputting audio into the front end of the amp from a WiFi signal off the computer?

I am just at the head scratching stage here as I have a few other projects to complete.

Ref : http://marksfieldnotes.blogspot.com/2022/06/k5528-currawong-valve-amplifier-made-me.html

Kindest Regards

Mark Bolton

 

 

 

20220727 135321

   
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Ron
 Ron
(@zander)
Father of a miniature Wookie
Joined: 4 years ago
Posts: 7283
 

@mark-bolton Hi Mark, search Bill's videos, I think he did an esp32 audio project recently. I might be misremembering but sometimes I guess right.

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
My personal scorecard is now 1 PC hardware fix (circa 1982), 1 open source fix (at age 82), and 2 zero day bugs in a major OS.


   
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(@davee)
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Joined: 3 years ago
Posts: 1742
 

Hi @mark-bolton,

   Interesting project, but sorry to hear you are having issues.

  My nearest experience is far from Hi-Fi in its aspirations, but produces a 'pleasing sound' with my old Whafedale speakers, albeit my hearing is far from great. The Bluetooth+amplifier is simply one of the tiny class-D modules from Ali-Express costing under £10 delivered, powered by an 'recycled' Laptop 19V 65W power supply. I can't hear any hums or hisses, nor is dropout a problem.

The Bluetooth connects directly to either of my cheapish Android phones, without any apps. (The module apparently supports two bluetooth routes, one using an App, the other just vanilla Android.) I haven't noticed dropouts to be a problem, though if the phone gets a message, it semi-mutes it for a few seconds. The range of Bluetooth is limited, and it is easily stopped by walls, etc. so I normally keep the phone and amplifier within 'sight' of each other.

I am wondering if at least some of your problems are resulting from your power supply arrangement. It is suspicious you suggest the interference isn't present when it runs from a battery.

Also, Bluetooth's specification seems to get revised almost weekly, and some hardware modules are almost certainly relics of an early specification, some of which may have issues with music and/or incompatibility with later versions. This might explain dropouts.

I haven't looked at using an ESP32 in this way, but beware that ESP32 is not just a single device anymore, but rather a whole family. You may find some are better than others for that application. However, if your power source is contributing, the ESP32 might not be an improvement.

Best wishes and good luck. Dave


   
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(@mark-bolton)
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Joined: 3 years ago
Posts: 108
Topic starter  

I suspect you are right about the drop outs. I have two speakers. One is a digitech remote speaker that usually stays connected / reconnects reliably (but no always. The other is a bluetooth front end to RCA which hooks up to the valve amplifier. It is really buggy about reconnecting. My experience with bluetooth in 'phones / cars / headphones etc. Is that it is bulletproof. I should look more deeply into the bluetooth side of things. It is likely that a script could be written to reconnect these devices , in order of preference after a reboot. My NUC has no inbuilt speakers.

My wish to go Audio over WfFi IP is more so as I can use it as an alternative to Bluetooth and probably address it directly from Node Red that runs the rest of my automated household lighting / temp / heating humidity reading / CAMs  etc. 

Maybe best to see if I cant tame Bluetooth first?

Kindest M

 


   
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Ron
 Ron
(@zander)
Father of a miniature Wookie
Joined: 4 years ago
Posts: 7283
 

@mark-bolton Use the reply link at the bottom right so the person you are talking to will get an email telling them there is a reply. Maybe read the help on the right above under your profile and above recent posts.

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
My personal scorecard is now 1 PC hardware fix (circa 1982), 1 open source fix (at age 82), and 2 zero day bugs in a major OS.


   
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