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Old 6th June 2011, 02:56 PM   #191
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Quote:
Originally Posted by teamacc View Post
Is it possible to have a board that is just 2.0 fully digital, 2x100w output @ 4ohm?
customized product.
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Old 6th June 2011, 03:02 PM   #192
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Originally Posted by Havoc08 View Post
Totally agree with you soldierant. I just wonder if the .1 channel can be left unused, but powered? I know some types of oscillating amps need a load to stay stable, but do not know enough about it to comment in a useful manner .

I am also in for a 2.1 system or more channels.
yes, just leave it unused if you don't need the 3rd channel, just some power wasting, and don't worry about that.
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Old 6th June 2011, 03:22 PM   #193
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Default news about DDX320.

Quote:
Originally Posted by Mitch311 View Post
Any possible work in progress updates Hifimediy? I think we are happy with where the idea is now heading, and are very very interested in some information about the amp section?

Thanks!
yes and thank u.
Quote:
Originally Posted by gychang View Post
Agreed... waiting.

gychang
thank u too.
Quote:
Originally Posted by SoldierAnt76 View Post
I think we've gotten spoiled by Hifimediy's fast development times. For the past year now he's come out with a new amp every 2-3 months. But those boards were really all just modest variations on the same chips (i.e., analog Tripath), while this project is based on a substantially different amplifier technology.

Like you, I keep checking back for updates. But I'm glad he's taking the time to get it right. Hopefully we won't be waiting much longer.
Some times I have to pause the project and make things more leisurely.
Here is the news about DDX320.
Actually I was troubling by some noise problem on this project, and finally I solved that. The background noise is a little louder than my AMT2050 boards, and I found it's caused by some incorrect software configuration, now everything is ok and I will prepare the sample soon.
And after carefully consideration, I will not add the volume for DDX320 boards, we can control volume from the source(PC etc.) instead. That will make this board as pure digital amplifier. That will make things easier and we will have AMu320 later to have more advanced functions.
We will use the DIP switches for the 3rd channel crossover frequency setup. so we have 15x frequency points, from 80Hz to 360Hz with 20Hz per step. And 1 setup option for pass-through by every switch off.
We will also add a function which can detect the input automatically.
And there will be a switch interface for stand by(power down).
Any ideas?
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Old 6th June 2011, 03:27 PM   #194
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Demo under debugging.
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File Type: jpg DDX320.jpg (65.9 KB, 356 views)
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Old 6th June 2011, 07:16 PM   #195
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Hifimediy - good to see that you're still on track. Will the final version have a heat sink like your Tripath amps? Also - I notice this board has three power terminals for use with a transformer. What are the power/voltage requirements?

I may need to hold out for a version with a volume knob. The internal volume controls on laptops and PCs are generally designed with small, underpowered desktop speakers or headphones in mind. So they often don't have enough range to work well with an external amplifier - i.e., the signal is either too loud or too soft, even when the volume is turned all the way down or up. A second volume control on the amplifier itself fixes this problem.

That said, most of my experience has been with analog sound cards. Maybe a digital/SPDIF output has more range, or can be controlled through software?

Last edited by SoldierAnt76; 6th June 2011 at 07:22 PM.
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Old 6th June 2011, 09:07 PM   #196
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I use spdif - no problem at all. Jumpers for gain setting is enough
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Old 7th June 2011, 06:55 AM   #197
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Hi Hifimediy,

I just sent out an order for 2 DACs less than an hour ago, hoping to get it soon. Back to the topic online.

I think dropping the volume control is a really bad idea. I thin of all things this is the one thing you should not drop!!!

1) First of all, I want to use it with my CD player not my computer. I don't really like the idea of starting up the computer everytime I listen to music. Need a volume control for that.

2) The way the volume control is implemented in a PC can cause sever loss of quality. It would be OK IMHO if the signal has been resampled from 16 bit to 24 bit and then attenuated digitally. The additional bits from the upsampling would still retain the resolution. However in a computer the attenuation could be done at a 16 bit level and could result in a serious loss of resolution. I mostly listed from my media player now (ACRyan) although it has a built in volume control, I believe the signal is still in its 16 bit format at the spdif side. So using the volume control would also reduce the bit resolution by quite a bit...

Other than that hope to have a go at it when it finally comes out...

Oon
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Old 7th June 2011, 07:05 AM   #198
bkdog is offline bkdog  Australia
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Quote:
Originally Posted by oon_the_kid View Post
Hi Hifimediy,

2) The way the volume control is implemented in a PC can cause sever loss of quality. It would be OK IMHO if the signal has been resampled from 16 bit to 24 bit and then attenuated digitally. The additional bits from the upsampling would still retain the resolution. However in a computer the attenuation could be done at a 16 bit level and could result in a serious loss of resolution. I mostly listed from my media player now (ACRyan) although it has a built in volume control, I believe the signal is still in its 16 bit format at the spdif side. So using the volume control would also reduce the bit resolution by quite a bit...

Other than that hope to have a go at it when it finally comes out...

Oon
Just to clarify - the above is not necessarily true... I've used Amara, Fidelia and Decibel with my MacMini music server, and all turn the audio stream into 32-bit or 64-bit floats, and implement the volume control there, and it's properly dithered... So there is no loss of resolution. So, I don't care about a volume control at all, I'm very happy with controlling that from the music server.

However, with a CD or DVD player, yes, I can easily understand why you would want one.

bk
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Old 7th June 2011, 08:39 AM   #199
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Quote:
Originally Posted by bkdog View Post
Just to clarify - the above is not necessarily true... I've used Amara, Fidelia and Decibel with my MacMini music server, and all turn the audio stream into 32-bit or 64-bit floats, and implement the volume control there, and it's properly dithered... So there is no loss of resolution. So, I don't care about a volume control at all, I'm very happy with controlling that from the music server.

However, with a CD or DVD player, yes, I can easily understand why you would want one.

bk
Hi,

Agree with you on that. However there are those of us who are not PC audio competent, and other than playing things from windows media player, I wouldn't know much about the software you mentioned, although I am sure they do a pretty good job. So having a volume control on our set even if it just the two button variety (push up or down button) would have been pretty nice. If you could build something somewhat similar to this on a much cheaper scale it would be really nice.

151

Oon
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Old 7th June 2011, 11:39 AM   #200
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thank you guys.
About volume display, do you think some LED dots is ok? like 0dB, 5dB...,20dB. if we add a rotary for volume.
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