Date   
Re: Distorted RX audio at higher volumes #ubitx-help

Mike Woods
 

Pez 

Mouser has them and Surplus Electronics here in NZ (
https://surplustronics.co.nz/products/4797-tda2822-2-x-1w-audio-amplifier-ic
)

Should be sources in Aus

Mike


On Fri, 23 Feb 2018 at 9:07 PM, Pez T <vk3xpt@...> wrote:

Thanks for the suggestions everyone.

When I first connected the pot, the wiring was as per the schematic (and therefore incorrect). I has this corrected in the first 10 minutes of operation, so it is now wired the correct way. Unfortunately this didn't fix "this" audio problem .

The fact it is getting hot sounds like its not very happy. I will double check the values of the surrounding caps and resistors are correct, and then order a new TDA2822 I think. (Unfortunately I don't know of a local supplier here in VK land.. I might have to wait for some to arrive from china.... :/ )

Unless anyone has anything else to suggest?

@Raj vu2zap - regarding the R51 change - will this have any impact on TX audio? or will it change RX only? 


Thanks again you all. 

Re: Distorted RX audio at higher volumes #ubitx-help

 

R51 change is only in the RX path. It changes the biasing to Q70 and allows
it to handle bigger signals without distortion.

Alternatively you can change R50 to 180 or 220K and get the same results.
With this Q70 will run cooler.

If you have a scope check the output of the TDA at the speaker for any
oscillation when you turn up the volume.

I hope the speaker ground and volume ground are separate and not common
with others or connected to chassis.

In my usage of TDA2822 running so hot that it melted a breadboard but
worked happily. Never blew a single one so far!

Raj

At 23/02/2018, you wrote:

Thanks for the suggestions everyone.

When I first connected the pot, the wiring was as per the schematic (and therefore incorrect). I has this corrected in the first 10 minutes of operation, so it is now wired the correct way. Unfortunately this didn't fix "this" audio problem .

The fact it is getting hot sounds like its not very happy. I will double check the values of the surrounding caps and resistors are correct, and then order a new TDA2822 I think. (Unfortunately I don't know of a local supplier here in VK land.. I might have to wait for some to arrive from china.... :/ )

Unless anyone has anything else to suggest?

@Raj vu2zap - regarding the R51 change - will this have any impact on TX audio? or will it change RX only?

Re: Distorted RX audio at higher volumes #ubitx-help

Pez T
 

Thanks for the suggestions everyone.

When I first connected the pot, the wiring was as per the schematic (and therefore incorrect). I has this corrected in the first 10 minutes of operation, so it is now wired the correct way. Unfortunately this didn't fix "this" audio problem .

The fact it is getting hot sounds like its not very happy. I will double check the values of the surrounding caps and resistors are correct, and then order a new TDA2822 I think. (Unfortunately I don't know of a local supplier here in VK land.. I might have to wait for some to arrive from china.... :/ )

Unless anyone has anything else to suggest?

@Raj vu2zap - regarding the R51 change - will this have any impact on TX audio? or will it change RX only? 


Thanks again you all. 

Re: #ubitx replaced Arduino Nano gives a lot of I2C interference during reception #ubitx

Alex - PA1FOX
 

Thanks John,

As far as I can determine now, I do think there is a differenced in Nano version. At least one difference is.... the old one has a green led while uploading firmware and the new one has a red led... hi

I might just leave it and order some extra Nano's from the original supplier hoping I get the same type as the old one. If I can manage to desolder it from my homebrew board I will place both versions next to eachother to see if I can find different type indications.

A thing which could trigger the I2C interference would be that the IO ports handle the output mosfets differently. Maybe there is a moment during the bit switch that two mosfets are counterpulling the output voltage causing a current spike. Normally only one mosfet at a time should be conducting.

Thanks for all the comments, it is good to have confirmed by others that there is indeed a difference in Nano behaviour. In cases where you do not build a sensitive receiver it does not matter and the new Nano's work perfectly. 

73, Alex

Buying new raduino board #ubitx

César EA3IAV
 

Hi guys
Where can I buy a new Raduino board for the ubitx? I need a spare. Do you think I may contact the seller somehow?

Regards

Re: Second batch of uBITX shipping? #ubitx

at91r40008
 

Mine ordered on 12/25 was shipped on 12/20 and came in today. No duties or extra fees form DHL.
--
73, Yvon NU6I

Re: Distorted RX audio at higher volumes #ubitx-help

 

I think so too.. swapping the volume control wires may solve it.

I have never had a TDA2822 misbehave and they have been solidly stable.

Raj


At 23/02/2018, you wrote:

Sounds like the TDA2822 is oscillating.


Cheers,

Will,

ZL1TAO

Re: Another Ubitx Case Possibility

Andy Robins
 

I'm just completing a uBitx and vhf/uhf build in an ammo can. I'll post details when it's finished.

Sent from my iPad

Re: Distorted RX audio at higher volumes #ubitx-help

William Kimber <zl1tao@...>
 

Sounds like the TDA2822 is oscillating.


Cheers,

Will,

ZL1TAO


On 23/02/18 19:23, Jerry Gaffke via Groups.Io wrote:
No, it should not get hot.


On Thu, Feb 22, 2018 at 09:37 pm, Pez T wrote:
Does the TDA2822 normally get hot? 

Re: rv2- messed up setting and txing like mad!!!

Alan -MMØWXT
 

Hi Folks. Just a little update, all well so far. Had it on receive and it seems fine. txtd on CW into a load and got 1.53 amps. 

My problem started by twiddling were I shouldnt have. the Rig had run fine even post twiddle, but once the 4.7k broke of the connector then the 510 blew.

What a great education you guys provided me with on this thread, Raj, Jerry and Marco, thank you for patiently and methodically guiding me through taking a blown 510 to getting my rig back up and running.

Thank You

Alan 
MM0WXT

Re: Distorted RX audio at higher volumes #ubitx-help

 

As you may have read that the volume control wires are incorrectly shown in the wireup diagram.

Please interchange the yellow and red on the volume control. This may solve the problem.
If it becomes worse then there is some other problem..

On all my boards I changed R51 or equivalent (in Bitx40) to 2.2K and even 1K and got much better
audio on strong signals.

Raj

At 23/02/2018, you wrote:
Hi All,

My uBITX has arrived and went together with no issues. I have a question about the audio stage and a potential issue with my uBITX.

At LOW volume levels, the RX audio is smooth and sounds great, however any volume setting above roughly 20% starts to distort badly, and sound horrible. Therefore I have the leave the radio volume set very quietly to use it.

Re: Distorted RX audio at higher volumes #ubitx-help

Jerry Gaffke
 

No, it should not get hot.


On Thu, Feb 22, 2018 at 09:37 pm, Pez T wrote:
Does the TDA2822 normally get hot? 

Re: wiring harness bitx40

Jerry Gaffke
 

For some reason, Tayda calls them "Serie 2500", not "KF2510". 
  https://www.taydaelectronics.com/connectors-sockets/wafer-housing-crimp-terminal/serie-2500-2-54mm.html

Unfortunate as there is a 2500 family of connectors from 3M which is considerably different.

Jerry


On Thu, Feb 22, 2018 at 07:29 pm, Jim Sheldon wrote:
I've always had long delivery times from them and their on site search shows no KF2510 connectors even now.  If they have them, I can't find them.
Jim

Re: uBITX AGC - Adafruit TPA2016, A Success! #ubitx

Mike Doty
 

Hi Nik,
I have two questions for you in regards to using the TPA2016 module.  First question is are you taking the audio input to the module directly from the volume pot wiper? That was my take on an earlier post you made.  I have two modules and both behave the same.  One module I connected as just a stock amplifier, with no connections to the I2C bus, and the audio output is extremely low.  In order to hear a 50uV 1KHz signal I have to turn the volume control to maximum.  The second module I have configured with the I2C connections to the Arduino Nano and have the Vcc line for the I2C connected to the 3.3V port.  The Vdd line is connected to 5V.  I have the same results - extremely low audio.  I'm using the left channel for input and output.  My speaker is not grounded in either case. 

The second question is more of a request.  Would you post your modified Adafruit library files in the File section here on Groups IO?  I thought I had your library modifications figured out but now I'm not completely certain.  Before I start chasing my tail in the wrong direction I'd like to know that at least the files I've modified and am using are not part of the problem.

Thanks for your work, I certainly appreciate it.
--73-- Mike  --  W0MNE

Re: Distorted RX audio at higher volumes #ubitx-help

Pez T
 

"Multiple speakers and headphones have been tried with no improvement."

Re: Distorted RX audio at higher volumes #ubitx-help

Clark Martin
 

Have you tried a different speaker.


Clark Martin
KK6ISP

On Feb 22, 2018, at 9:24 PM, Pez T <vk3xpt@...> wrote:

At LOW volume levels, the RX audio is smooth and sounds great, however any volume setting above roughly 20% starts to distort badly, and sound horrible. Therefore I have the leave the radio volume set very quietly to use it. 

Re: Distorted RX audio at higher volumes #ubitx-help

Pez T
 

Thanks Mvs Sarma.

There is no change at 12V.

Does the TDA2822 normally get hot? 

I have some spare LM386s here, but I have not looked to see if they are directly swappable. (I have never used a TDA2822 before) .

Thanks

Re: Distorted RX audio at higher volumes #ubitx-help

MVS Sarma
 

Also limit the power supply to 12V while testing the audio in RX.
 

Regards
MVS Sarma
 

On Fri, Feb 23, 2018 at 11:00 AM, Mvs Sarma <mvssarma@...> wrote:
why not try  replacing the TDA2822. !!

Regards
MVS Sarma
 

On Fri, Feb 23, 2018 at 10:54 AM, Pez T <vk3xpt@...> wrote:
Hi All,

My uBITX has arrived and went together with no issues. I have a question about the audio stage and a potential issue with my uBITX. 

At LOW volume levels, the RX audio is smooth and sounds great, however any volume setting above roughly 20% starts to distort badly, and sound horrible. Therefore I have the leave the radio volume set very quietly to use it. 

NOTES:
My BFO settings are all good (now running KD8CEC firmware, but it was the same with standard firmware).
TX audio is very good.
Multiple speakers and headphones have been tried with no improvement.
I understand how AGC works and I know that the uBITX has no AGC :)
Also, the audio IC runs very HOT. 

Can anyone here provide some suggestions please? I have watched a number of YouTube videos and others do not seem to be having this RX audio problem. 

Thanks in advance! 



Re: Distorted RX audio at higher volumes #ubitx-help

MVS Sarma
 

why not try  replacing the TDA2822. !!

Regards
MVS Sarma
 

On Fri, Feb 23, 2018 at 10:54 AM, Pez T <vk3xpt@...> wrote:
Hi All,

My uBITX has arrived and went together with no issues. I have a question about the audio stage and a potential issue with my uBITX. 

At LOW volume levels, the RX audio is smooth and sounds great, however any volume setting above roughly 20% starts to distort badly, and sound horrible. Therefore I have the leave the radio volume set very quietly to use it. 

NOTES:
My BFO settings are all good (now running KD8CEC firmware, but it was the same with standard firmware).
TX audio is very good.
Multiple speakers and headphones have been tried with no improvement.
I understand how AGC works and I know that the uBITX has no AGC :)
Also, the audio IC runs very HOT. 

Can anyone here provide some suggestions please? I have watched a number of YouTube videos and others do not seem to be having this RX audio problem. 

Thanks in advance! 


Distorted RX audio at higher volumes #ubitx-help

Pez T
 

Hi All,

My uBITX has arrived and went together with no issues. I have a question about the audio stage and a potential issue with my uBITX. 

At LOW volume levels, the RX audio is smooth and sounds great, however any volume setting above roughly 20% starts to distort badly, and sound horrible. Therefore I have the leave the radio volume set very quietly to use it. 

NOTES:
My BFO settings are all good (now running KD8CEC firmware, but it was the same with standard firmware).
TX audio is very good.
Multiple speakers and headphones have been tried with no improvement.
I understand how AGC works and I know that the uBITX has no AGC :)
Also, the audio IC runs very HOT. 

Can anyone here provide some suggestions please? I have watched a number of YouTube videos and others do not seem to be having this RX audio problem. 

Thanks in advance!