IanCanada's Latest RPi GB Goodies Impressions... and your tweaks, mods and hints...

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G

Grarea

Member
Joined 2019
Could I ask another basic question please?
I am so new to this.
I got a LifePo4, Pi 3B+ , Fifopi, transportpi, Khadas tone board.
Loving the difference from what i had before.

Can I please check I am wired up as optimally as I can for a basic set up.
II have read stuff, but don't understand all the words, let alone the inferences.

I am poweriing pi via fifopi from non-isolated 5v output on LifePo4.
Powering fifopi from isolated 3.3v
Powering KTB from USB from Pi.
Using Coaxal from transporterpi to KTB.
Then RCA to amp.

Thanks.
 
M

misterdog

Member
Joined 2011
Grarea said:
I am poweriing pi via fifopi from non-isolated 5v output on LifePo4.

Powering KTB from USB from Pi.
Click to expand...

The Pi is a very noisy device, I would use the other non-isolated 5V from LiFeP04 as a minimum. The Pi has a shared USB/ethernet bus and DC switchers which will add noise to the supply of your KTB.

Better still use a separate super regulated supply for the KTB.
 
Last edited:
G

Grarea

Member
Joined 2019
misterdog said:
The Pi is a very noisy device, I would use the other non-isolated 5V from LiFeP04 as a minimum. The Pi has a shared USB/ethernet bus and DC switchers which will add noise to the supply of your KTB.

Better still use a separate super regulated supply for the KTB.
Click to expand...

OK, thank you for that.
LiFePO4 only has the one non-isolated 5v, but can use one of the other isolated outputs.

I was vaguely wondering that.
 
G

Grarea

Member
Joined 2019
OK, I give in.
I have forgotten what i did or didn't do.
I feel like I have tried everything but am completely confused now.

Is there a set up guide for noobs somewhere rather than filling this thread up with it?
I think i might need to change something again in Raspbian.

I wasn't as far ahead as I thought.
I think that sound was still going through the USB.
I have looked through all the settings on Raspbian and VLC, but can't seem to get it out of Coax.
I can only find HDMI output options. (which works btw. I am getting sound)

FifoPi status is empty.
Is that a light on the other side that would indicate I2S?
That is not on.

I have read the manuals, but I think i am stuck.
New at all of this. Until last year, my tool of choice was a club hammer :)
 
M

misterdog

Member
Joined 2011
I think your issues are more to do with the KTB connectivity, of which I know nothing. It appears that there are several versions, some with the 40 pin GPIO connector (for Pi/FIFO)
and some with only USB input.

I knew sod all about DAC's until I assembled Ians stack, it required much reading and slowly understanding the basics.
The end result was worth the effort though, during the process I did question this though...
Luckily we have time on our hands, I have just been told to lockdown for 12 weeks !!!!
I am allowed to open my window though..

Some lite reading.
khadas tone board power supply - Google Search

i2s into khadas tone board - Google Search
 
G

Grarea

Member
Joined 2019
:)
Not sure if I am pleased for you or not or envious of being locked down.

Thanks for those. The first few on those searches are already highlighted as read lol.

I am trying to get Coaxial to KTB from the transportpi.
I know what you mean about reading.
Boy I have read a lot this last few months.
Not really understanding most of it.
Then understanding something and rereading with the new bit of knowledge.

I was alright running the KTB until i bring in the fifopi and transportpi. (Although I Iguess I wasn't using I2s there)
The I2S question is whether there should be an on status light on the fifopi.
I don't think I have I2S enabled or something somewhere. I think in raspbian.


What have you got in your stack?
 
J

jimk04

Member
Joined 2018
Paid Member
DC on the output

Morning all. Hope we are keeping healthy.

Having a little measure of DC on 2 of Ian's IV Std I have here. One was problematic on delivery...it was one of the free giveaways so no issue with that. With help from Simon that got sorted and ended up in the streamer I built for my brother.

It began to show signs of DC on the signal and it triggered his amp protection once or twice when it was cranked up. He also commented on some HF distortion on one channel so I have taken it apart for testing

The numbers I got

XLR L
Pin2 75mV
Pin2 1.15v.....yes V not mV
XLR R
Pin2 75mv
Pin2 75mv

SE L 0.5V
R 0.5mV
My brother uses the balanced outputs
So clearly something amiss in the L channel. What should I be testing?

Out of interest I measured my working IV Std. I do get the smallest of clicks when altering the volume

XLR L
Pin2 51mv
Pin2 40mv

XLR R
Pin2 54mv
Pin2 40mv

SE L
0.5mV
R 4mv

So my SE R is maybe higher than it should be? I use the SE outputs

Any advice on what I should look for?

Thanks
 
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