Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

5.1 channel preamp
5.1 channel preamp
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 3rd November 2019, 06:16 PM   #11
os77 is offline os77
diyAudio Member
 
Join Date: Dec 2010
Location: France - Gujan-Mestras
Default Help about 5.1 project

Thank you very much, I did not understand that you set the 48 bits of PGA2311 directly with lines of code, more simply doesn't exist
I thought you were using the SPI possibility of the Arduino chain.
I think I understoud (approximately) everything about your project.
Code seems easy to modify, because it has all the bases that I search.
I would like to help you so, certainly not in software ... may be in hardware for ground wiring, if you have any noises or oddities between the digital part and the analog. I know what to do for this.
I think this project, with or without LOW MID and HIGHT corrections should be on the market.
And it is not so, I don't understand why.
Still thank

PS : warnings are not importants, they are also with last version of Arduino. there are in the middle of the long text write by compiler, sometimes I don't see them...
  Reply With Quote
Old 4th November 2019, 12:39 AM   #12
stratus46 is offline stratus46  United States
diyAudio Member
 
Join Date: Nov 2009
Location: Los Angeles
"Bit banging" the data loading in this case is trivial as there is no need for a steady clock rate, just the
right number of them. The actual block is "load8vol" and is only 5 lines of active code. The rest of it
would be needed to correct the level values based on the offsets whether using SPI or not.

As far as should be on the market, it already is. If you search eBay "5.1 remote volume" you'll find
several items, right now it's 5, based on the Mitsubishi M62446 6 channel volume control chip, all less
than $50 and all with proprietary controllers. I had one of those interfaced to an Arduino and it worked
well enough. But, I wanted to do the derived center and subwoofer from the simple stereo L and R,
I wanted to go back to the PGA2311 (same as the Cirrus Logic CS33010) because it claims better
channel to channel balance, more accurate steps and more control range (127dB for PGA chips and
79 dB for the Mitsubishi) lower distortion and noise. Could I actually hear these "shortcomings"?
No but I feel better about it. Under VERY noisy conditions the Mitsubishi chip did not mute completely
though I have not tried that same noise into the new unit. Mission creep being what it is, I added
tone controls to all 6 channels which then gave me an excuse to try a KiCad project and do another
DIY thing. At the end I finally added the mute as fade up/sown and the "dim" mode to partially mute.
I can't think of much more to do to it but you never know...

I've been doing broadcast TV for almost 43 years and have been through some stubborn ground loop
issues and have beat all of them but thanks for the offer. I may take you up on something down the road.

G
  Reply With Quote
Old 6th November 2019, 04:32 PM   #13
os77 is offline os77
diyAudio Member
 
Join Date: Dec 2010
Location: France - Gujan-Mestras
Default Help about 5.1 project

Thank you, I dissect your software and I learn at the same time some subtleties of c ++: you treated the details with great care, I caught "headache" by following the data format (volume, trimvol, table "adjust", and your "elaborate" mechanism of the mute fade (tables of constants and slowrate and slowinc and so on).

I will try to use some of your code, I will focus on the volume and maybe a slight offset setting on each channel.
With the I2c there will be enough "pins" to control one or two triggers, an ON / OFF button and why not +/- buttons.

Chinese kits : I knew them, I bought 3 since 2014, I join some pictures of the realization around this kit, but what I did in reality is to build a cathedral ( ok: just a big church on a "pile of manure".
- the remote control is a crap, contacts does not last long, no volume backup when power off, no choice of the increment, CPU does not follow when we turn the encoder too fast, etc, etc ...
I join a picture of my "cathedral" and the Chinese kit, the guilty I am going to replace.

Well, it's not all that. I have to work a lot if I want to throw this Chinese kit in the trash, as soon as possible.

PS: I can not translate your last sentence, USA expression (I may take you up on something down the road) ?
OS
Attached Images
File Type: jpg 1.jpg (260.2 KB, 112 views)
File Type: jpg 2.jpg (389.5 KB, 109 views)
File Type: jpg 3.jpg (294.2 KB, 105 views)
File Type: jpg 4.jpg (294.2 KB, 101 views)
  Reply With Quote
Old 7th November 2019, 06:49 AM   #14
stratus46 is offline stratus46  United States
diyAudio Member
 
Join Date: Nov 2009
Location: Los Angeles
"down the road" means "In the future".

G
  Reply With Quote
Old 7th November 2019, 05:57 PM   #15
stratus46 is offline stratus46  United States
diyAudio Member
 
Join Date: Nov 2009
Location: Los Angeles
Quote:
Originally Posted by stratus46 View Post
"down the road" means "In the future".

G
Better description is "I might ask you for help sometime in the future"
  Reply With Quote
Old 10th November 2019, 07:44 AM   #16
jimk04 is offline jimk04  United Kingdom
diyAudio Member
 
Join Date: Jul 2018
Location: North Notts
What DAC chips are in these 5.1 optical units from Ebay etc. ? Are they any good. I would like to get rid of my Denon AVR but I do like the 5.1 for occasional film watching and then main system front end does TV aswell.

So these units dont properly put out the 5 channels and Dolby intended? Is the SW channel low passed?

Thanks
  Reply With Quote
Old 10th November 2019, 07:00 PM   #17
stratus46 is offline stratus46  United States
diyAudio Member
 
Join Date: Nov 2009
Location: Los Angeles
Quote:
Originally Posted by jimk04 View Post
What DAC chips are in these 5.1 optical units from Ebay etc. ? Are they any good. I would like to get rid of my Denon AVR but I do like the 5.1 for occasional film watching and then main system front end does TV aswell.

So these units dont properly put out the 5 channels and Dolby intended? Is the SW channel low passed?

Thanks
I have no idea what DACs are used in the unit. I DO know that the last time I heard a DAC that bothered me was in a Citizen portable CD in 1989. I think you'd have a hard time finding a DAC in the last 10 years that sounds bad .

All the channels are always where they are supposed to be. The fake center _I_ generate is for plain 2 channel stereo, L and R only to use the center and sub. I include a 100Hz LPF for the sub that is only used in stereo mode. When center channel audio is detected it switches back to 5.1 mode. I don't know if UK TV shows are 5.1 but in the US it is very common for the scripted shows.

Seeing an elevated train go from left rear to right front on screen is a little better when the audio does the same.

G
  Reply With Quote
Old 10th November 2019, 08:39 PM   #18
jimk04 is offline jimk04  United Kingdom
diyAudio Member
 
Join Date: Jul 2018
Location: North Notts
Thankyou. Yes I would not want to be without my proper Dolby Digital 5.1 but my big Denon AVR is taking up lots of rack room. I wandered if one of these 5.1 units and some class d amp modules could replace it .
  Reply With Quote
Old 11th November 2019, 04:15 AM   #19
stratus46 is offline stratus46  United States
diyAudio Member
 
Join Date: Nov 2009
Location: Los Angeles
Quote:
Originally Posted by jimk04 View Post
Thankyou. Yes I would not want to be without my proper Dolby Digital 5.1 but my big Denon AVR is taking up lots of rack room. I wandered if one of these 5.1 units and some class d amp modules could replace it .
That is precisely what I did. Search on eBay for "TPA3116 5.1" and you'll find several types.
I used a power amp only module with no remote or controls.

5.1 TPA3116 digital amplifier board 6 channel amp board 50W*4 + 100W*2 L163-8 822933248485 | eBay

The boards like this all have a silk screen error. Notice all the '+' outputs are to the right
except for the 'MS' output which is really 'SW' upside down. The '+' output is to the right
just like the rest. As far as I can tell, the less expensive units use 1 main power input
cap rather than 2 and have 5 screws rather than 3 to hold the heatsink. Keep in mind that
100 Watt thing for the center and sub assumes you use a 2 ohm load. With a 24V supply
all 6 channels will do 25 Watts at 8 ohms and 50 Watts into 4. I used 19 Volt laptop supply
because it is completely enclosed and no worries about exposed wires. One other thing
that might surprise you is the output DC is 1/2 the power supply value. In my case that is
9.5 but it's a bridge amp so the value across the speaker is 0 but you need to be careful how
you connect test gear. You could add output caps but they would only waste space and money
with no sonic benefit.

The space occupied by this box is 203x144x68 mm. I used blue plexiglas for the front rather
than the metal plates supplied and black plastic for the back as it's easier to cut the holes.
The recess for the knob is a PVC end cap for PVC pipe cut to size and glued to the plexiglas.

I later added a USB extension from the Arduino to the back panel to GREATLY simplify firmware
updates. The HTPC in the system simply has the Arduino IDE on it for this purpose. There is
one change since the rev 7 I posted in August. Any remote keypress while the display says
HI and the audio is muted (always muted for the first 5 seconds) will remain in MUTE until a
volume up or Mute button is pressed.

G
  Reply With Quote
Old 11th November 2019, 05:16 AM   #20
jimk04 is offline jimk04  United Kingdom
diyAudio Member
 
Join Date: Jul 2018
Location: North Notts
Thanka for that. I have some class d modules. I already have a tpa 3255 powering front channels that use the AVR pre outs. I have a tpa3251 3 channel that could do the centre and surrounds. My sub is active so just feed it a signal but it needs to be an 'LF' signal.
Is the SW output from these 5.1 ebay units 'fullrange' or is it low passed?

I've read all this thread but all the arduino stuff is beyond me I'm afraid.!
  Reply With Quote

Reply


5.1 channel preampHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Removing gain channel preamp tube(s) Palomino V50 for better clean channel tone? tubeFrank Instruments and Amps 2 22nd March 2012 11:54 AM
Cause of weak Preamp channel orbanator7577 Analog Line Level 13 11th February 2012 06:45 AM
7 channel Preamp jupiterjune Pass Labs 4 26th February 2011 05:29 AM
6-channel DSP preamp HorseWisperer Class D 3 29th December 2010 07:46 AM
6 Channel Preamp Project DC Dave Chip Amps 7 6th December 2005 02:00 AM


New To Site? Need Help?

All times are GMT. The time now is 05:44 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki