Matt,
Not yet. I have to order my Dam 1021's first.
Deimsch was using the input selector switch. I have the board and could use it, but took my build in a slightly different direction. I plan to put in an arduino and control 3 Dam1021 and 3 Tortuga preamp boards with a front LCD. I will either use a RPi 3 or an Odroid C2 into the input board. I will try them both out and pick out my favorite. I would like to connect the RPi via I2S for 2 channel, but also use a DIYinHK multichannel USB to I2S converter to run multichannel I2S to all 3 Dam 1021 so I can do 5.1. The outputs from the Dam 1021s will go to the Tortuga V25 boards for volume control. One of the Dam1021s will be connected to the input board and be for 2 channel/front multichannel use. This Dac's output goes through the Tortuga board and into a Hypex DLCP for DSP for 3 way speakers.
So basically I needed a controller that could interface with different boards. So I will start with DimDim's arduino code and go from there for the integrating the Totuga boards. The Hypex DSP shouldn't need any control. So I basically created a combination Preamp/DAC/DSP/Streamer for combined 2 channel and multichannel use.
Thanks for the resources. I will take a look at them to try to figure things out.
What's the rationale for using the Tortuga boards? The DAMs have digital volume control and you're planning on using a uC so, with some tweaking of Dimdims code, you could implement volume control and have a simpler output signal path.
The new Tortuga boards have Uart control, so the micro controller will be controlling the Tortuga and the Dam1021. The reason for the Tortuga is for the analog inputs. I have a turntable and a Home Theater input from my AV Receiver. So volume control will be done in the Tortuga. I will switch Analog inputs (DAC, Phono, HT) with the Tortuga and Digital (Coax, Toslink, RaspPi, USB) with the Dam1021.
Okay, I see. Just thought that if the 'table was handled by the AV receiver then there'd be no need for the preamp - making for a simpler signal path. All you'd need was a few relays to handle the the HT bypass on a board that the Soekris plugged into. Essentially you'd use the uC to toggle between the Soekris digital inputs plus the AV bypass - all things analog would be handled by the AV receiver, thus allowing what you're aiming at (like me) - the 2-channel fronts and sub to be also used by the AV receiver when AV was selected on the board.
I highly recommend using that Soekris digital volume control straight to your amps if you can. I have run the DAMs into 'preamps' (including Townshend Audio and Bent Audio autoformers) and came down on the side of the direct connection. Guess it's a matter of which source you listen to most....
Two channel music through the AV receiver could stand some improvement, which is one of the reasons for undertaking this project. I have went back and forth over different scenarios for audio routing and volume control. I settled on Digital in>Soekris Dam1021>Tortuga V2.5(volume control)>Hypex DLCP>amps(TDA7297's). I have demoed the Tortuga preamp and liked it. Since this is a DIY project things are subject to change. I will test out the Dam1021 direct and into the DLCP to see what the difference is.
I had originally given thought to running the phono and HT inputs through an ADC and into the DAM1021, but if I have the DLCP in the chain that would be 2 ADC/DAC conversions. Probably is better to limit it to 1 ADC/DAC conversion in the DLCP or none if I use a speaker with a passive crossover.
I had originally given thought to running the phono and HT inputs through an ADC and into the DAM1021, but if I have the DLCP in the chain that would be 2 ADC/DAC conversions. Probably is better to limit it to 1 ADC/DAC conversion in the DLCP or none if I use a speaker with a passive crossover.
Yes, the AV rcvrs are rarely good for 2-channel. Decisions, decisions... never easy to get an ideal, always a compromise somewhere, if only in your mind! Which always leads to 'v.2' of the project. But that's DIY!!
That's what my comments are based on - a compromise to my mind, using additional steps for convenience sake. But don't mind me, yours is an interesting project, press on..... and keep us informed as it progresses.
Derek
That's what my comments are based on - a compromise to my mind, using additional steps for convenience sake. But don't mind me, yours is an interesting project, press on..... and keep us informed as it progresses.
Derek
Well I have some of the boards in hand and the others are on order. Still need transformers and a few parts for my Salas PS boards until I can fire them up. Next step is to try different configurations and see which sounds best. Still will be a while until I get a case for it. Back panel may be a bit crowded so I may have to split into two cases to fit all the connections. We will see.
Today I tried to eliminate some possible “stupid” mistakes.
I connected the Raspi via I2S directly to the Soekris (without Input/Switch-Boards). Works great!
So way back - installed Input/Switch/Connector board and connected C1/C5 – but with no effect. I noticed, that when playing a song in moode the PWR-smd-led starts to light. This happens with the switch rotated to I2s-1 and I2S-2 … Seems to be my first “contact”
But still the POWERLED on Soekris and switch-board are flashing.
So I tried to set the dam input via serial port with the switch board disconnected. Works fine for spdif, but still no lock or music on I2S.
After that I did some measuring (having C1 and C5 connected):
GPIO22:
I2S-1 = 0,44V
I2S-2 = 0,00V
Auto = 0,00V
Pin 8 / 16 on SN74HC157PW (U2):
Auto= 0,38V
I2S-1 = 0,53V
I2S-2 = 0,38V
Seems likes there is a mistake on the input-board, but where?
I bought this preassembled boards second hand – some parts were soldered, some not. Leaves me a bit frustrated …
(by the way: thank you very much everyone for your help!)
I connected the Raspi via I2S directly to the Soekris (without Input/Switch-Boards). Works great!
So way back - installed Input/Switch/Connector board and connected C1/C5 – but with no effect. I noticed, that when playing a song in moode the PWR-smd-led starts to light. This happens with the switch rotated to I2s-1 and I2S-2 … Seems to be my first “contact”
But still the POWERLED on Soekris and switch-board are flashing.
So I tried to set the dam input via serial port with the switch board disconnected. Works fine for spdif, but still no lock or music on I2S.
After that I did some measuring (having C1 and C5 connected):
GPIO22:
I2S-1 = 0,44V
I2S-2 = 0,00V
Auto = 0,00V
Pin 8 / 16 on SN74HC157PW (U2):
Auto= 0,38V
I2S-1 = 0,53V
I2S-2 = 0,38V
Seems likes there is a mistake on the input-board, but where?
I bought this preassembled boards second hand – some parts were soldered, some not. Leaves me a bit frustrated …
(by the way: thank you very much everyone for your help!)
The way you have it wired you should have 3.3V after the regulator. Do you?
The IC used for I2S requires 3.3V to operate. If yes, then run a jumper from I2S pins on the RaspPi header into one of the USB to I2S headers for Amanero or DIYinHK adaptors. If you get a signal then your MUX IC is bad an needs replacement.
The IC used for I2S requires 3.3V to operate. If yes, then run a jumper from I2S pins on the RaspPi header into one of the USB to I2S headers for Amanero or DIYinHK adaptors. If you get a signal then your MUX IC is bad an needs replacement.
Did some measuring again:
Switch to I2S-2 / Auto / I2S-1
U4:
out-gnd 0,39V / 0,39V / 0,53V
in-gnd 0,09V / 0,09V / 0,25V
U3:
in-gnd 8,44V / 8,44V / 8,44V
out-gnd 3,30V / 3,30V / 3,30V
U2:
pin 8/16 0,38V / 0,38V / 0,54V
U5:
in 0,00V / 0,00V / 0,00V
out 0,09V / 0,09V / 0,23V
(how is this possible??? Am I wrong - the short, not connected pin in the middle is ground?)
Pin 16 of the mux-chip U2 is Vcc – that means it is the “input”, isn´t it?
As far as I understand that, there is no power (or to less) on the mux-chip.
But 0,00V should nevertheless be interpreted as "low", so why is I2S-2 not selected?
Switch to I2S-2 / Auto / I2S-1
U4:
out-gnd 0,39V / 0,39V / 0,53V
in-gnd 0,09V / 0,09V / 0,25V
U3:
in-gnd 8,44V / 8,44V / 8,44V
out-gnd 3,30V / 3,30V / 3,30V
U2:
pin 8/16 0,38V / 0,38V / 0,54V
U5:
in 0,00V / 0,00V / 0,00V
out 0,09V / 0,09V / 0,23V
(how is this possible??? Am I wrong - the short, not connected pin in the middle is ground?)
Pin 16 of the mux-chip U2 is Vcc – that means it is the “input”, isn´t it?
As far as I understand that, there is no power (or to less) on the mux-chip.
But 0,00V should nevertheless be interpreted as "low", so why is I2S-2 not selected?
One thing I don’t understand: according to the data sheet for the L7805 D2T, it has a minimum input voltage of 10V?
Is this the correct L7805 version?
Spannungsregler 5 V D2PAK, ST, L7805ABD2T-TR kaufen | Distrelec Deutschland
Is this the correct L7805 version?
Spannungsregler 5 V D2PAK, ST, L7805ABD2T-TR kaufen | Distrelec Deutschland
So it took me quite a while to try some things again.
First i replaced the IRF9333 and the L7805 ( the correct one with 7V minimum power input
)… but still got the same problems. 0,00V on the input of U5 and 0,09V / 0,23V on the output …. damn … why??
Not knowing what to do next, I read the input-board documentation again and again – and finally got it:
What about trying to use an external 3,3V power supply? My power supply is switchable, in case of using 3,3V external, I’m no longer in need of the 7-9V. So I changed this to 3,3V, connected it as documented and – bang
– the leds stopped flashing and music is playing!
I don´t know why via the 7-9V power supply my input board doesn´t behavior as it should, but I’m very happy that I found a way to get this thing running!
A big thank you to everyone helping me!
Greetings,
Jens
First i replaced the IRF9333 and the L7805 ( the correct one with 7V minimum power input
)… but still got the same problems. 0,00V on the input of U5 and 0,09V / 0,23V on the output …. damn … why?? Not knowing what to do next, I read the input-board documentation again and again – and finally got it:
What about trying to use an external 3,3V power supply? My power supply is switchable, in case of using 3,3V external, I’m no longer in need of the 7-9V. So I changed this to 3,3V, connected it as documented and – bang
– the leds stopped flashing and music is playing! I don´t know why via the 7-9V power supply my input board doesn´t behavior as it should, but I’m very happy that I found a way to get this thing running!
A big thank you to everyone helping me!
Greetings,
Jens
Gerber files for all the boards
Here are the Gerber files for the latest versions of all the boards. They are free to use for non-commercial purposes. I do not plan to produce any more myself. The schematics, BOM and general documentation are linked in the first post of this thread.
DAM11MU - muting board
DAM23IN - Input board
DAM22RPI - Raspberry Pi connector (contained in DAM23IN.zip)
DAM23SW - Switch board
Here are the Gerber files for the latest versions of all the boards. They are free to use for non-commercial purposes. I do not plan to produce any more myself. The schematics, BOM and general documentation are linked in the first post of this thread.
DAM11MU - muting board
DAM23IN - Input board
DAM22RPI - Raspberry Pi connector (contained in DAM23IN.zip)
DAM23SW - Switch board