Sorry, I modded several things at the same time so I can't really pin point the changes other than its easier to listen to.
I guess too low esr might cause resonance but I have nothing to measure it. It might be better just stick it in and listen.
I just received my I.AM.D V200 from AliExpress. I got the basic model without wifi or bluetooth.
Does anyone know what the situation is with EQ/DSP ?
The remote control has a button marked "EQ" but this same button is illustrated in the single-page instructions as being "CH-" and indeed, when I press it, the input selection changes in reverse order than if I press the "CH" button.
I'm guessing the "EQ" function is only available on the wifi or bluetooth models, or is perhaps completely absent, perhaps awaiting upgraded firmware?
In any case, I'm hoping that no DSP/tone control is active, and my amp is at optimum quality status?
Thanks
Does anyone know what the situation is with EQ/DSP ?
The remote control has a button marked "EQ" but this same button is illustrated in the single-page instructions as being "CH-" and indeed, when I press it, the input selection changes in reverse order than if I press the "CH" button.
I'm guessing the "EQ" function is only available on the wifi or bluetooth models, or is perhaps completely absent, perhaps awaiting upgraded firmware?
In any case, I'm hoping that no DSP/tone control is active, and my amp is at optimum quality status?
Thanks
Nope the plain no-wifi/Bluetooth model has an Eq built in to destroy your music as well.
From memory just press the Tone button until it says 'Flat' which should do it. The 'Eq' button on the remote should I think toggle it off and on as well as a shortcut but I'll look again if you are still stuck. Its not subtle when the EQ is doing its evil little job so it should be easy to distinguish when its on or not
Thanks, but there is no "Tone" button. Neither can I find any tone/EQ settings. There are 6 buttons on the remote:
POWER
CH
EQ (which is actually CH-)
MUTE
VOL+
VOL-
On the front of the amplifier is a single power button, and a rotary dial.
Turning the rotary dial increases/decreases the volume.
Turning the rotary dial while pressing it inwards changes input selection.
The single-page instructions make no reference to EQ or tone, but they they do refer to a "hidden" gain setting -
My front panel always displays "+ 0db"
POWER
CH
EQ (which is actually CH-)
MUTE
VOL+
VOL-
On the front of the amplifier is a single power button, and a rotary dial.
Turning the rotary dial increases/decreases the volume.
Turning the rotary dial while pressing it inwards changes input selection.
The single-page instructions make no reference to EQ or tone, but they they do refer to a "hidden" gain setting -
I cannot decode this Chinese English, and there is no combination of button presses which give any such result.
My front panel always displays "+ 0db"
Sorry my bad. I misread your post as referring to the d802 not the v200.
I had a similar experience to yourself and eventually ran out of buttons to poke. As far as I could see, unless it is a really obscure control sequence, this amp didn't offer any control of the EQ section. I haven't investigated much further as I much prefer the sound from the d802.
I had a similar experience to yourself and eventually ran out of buttons to poke. As far as I could see, unless it is a really obscure control sequence, this amp didn't offer any control of the EQ section. I haven't investigated much further as I much prefer the sound from the d802.
OK, that's interesting. globulegl rates the V200 best of the cheap models, assuming no upgrades/modifications.
I intend to run this amp with 3 inch fullrange speakers in compact boxes just for TV/DVD listening, but I have temporarily connected the V200 amp to my old Tannoy Jupiters for some critical listening. I consider the amp good, but not great. It's certainly not as refined as I remember my old Harman/Kardon PM660 sounding when connected to these speakers. It sounds to me that there is some bass "bloom" with the V200.
For the D802, there is a difference in sound quality between USB and SPDIF input. The SPDIF input sound better to my ears. Maybe the usb receiver chip is not that good.
Darn, when I asked globulegl about which amp sounds best, I should have mentioned that I use s/pdif input.
I see that the D802 has a very ordinary USB input (VT1630) but good s/pdif (AK4113)
and my V200 has good UAC2.0 USB input (CM6631A) but ordinary s/pdif (CS8416).
Aaargh, thanks for bring this up guys - I think.
When I have critically compared the d802 and v200 it has been via spdif/coax. I haven't currently got a convenient HQ USB source but as my intended final application would need USB input I think I'll have to redo my listening tests.
FWIW i've also done a lot of casual iradio listening through the d802's optical inputs. Plainly this can't be compared and sounds nothing like sending HQ 24/192 direct to the amp via coax but it sounds as good as could possibly be expected given the source quality.
It's feasible, of course, to modify the D802/V200 to add a better interface, be it USB or S/PDIF
as, indeed, globulegl did with a V200 here (French forum) -
Amplificateurs FDA - Page 38 - 30063064 - sur le forum Amplificateurs Intégrés - 1030 - du site Homecinema-fr.com
Such a modification is relatively easy in the case of the V200 because its "Auxiliary" I2S input connection points are accessible on the PCB.
Since this is just my "TV" amplifier, I was aiming to just use it out-of-the-box, no tweaks. Mmm.
as, indeed, globulegl did with a V200 here (French forum) -
Amplificateurs FDA - Page 38 - 30063064 - sur le forum Amplificateurs Intégrés - 1030 - du site Homecinema-fr.com
Such a modification is relatively easy in the case of the V200 because its "Auxiliary" I2S input connection points are accessible on the PCB.
Since this is just my "TV" amplifier, I was aiming to just use it out-of-the-box, no tweaks. Mmm.
The 'flat' setting has substantially lower gain than 'tone', you could try that.
I think the d802 sounds better with tone but the gain there is sensible on my system. If its too much flat may well work better.
I'm trying to understand some of the design drivers for digital interface to achieve sound performance. I'm not so clear about the difference of performance between USB and SPDIF, and between good/bad USB, good/bad SPDIF. I would be happy to learn about your understanding about this.
For example, in both cases, I believe the the clock of the source is the master.
Many people control SPDIF clients with USB to SPDIF interfaces. Can this be better than direct USB?
One reason about my question: I currently drive 2 D802 from an OrangePi PC with USB. People say tha D802 SPDIF is better than D802 USB. Could I improve my set-up ?
Best regards,
JMF
my tweak of the D802 .... in french.
Amplificateurs FDA - Page 293 - 30063064 - sur le forum Amplificateurs Intégrés - 1030 - du site Homecinema-fr.com
Amplificateurs FDA - Page 293 - 30063064 - sur le forum Amplificateurs Intégrés - 1030 - du site Homecinema-fr.com
Hi Globulegl,
Thank you for the link, I bookmark it. Just in case, did you had a look at how to connect directly to the I2S on the D802 (like you did on the V200)? In the digital chain taht I consider, I2S would be the perfect match. But on the other side, I would be happy to keep the USB and SPDIF (le beurre et l'agent du beurre). Any idea welcomed.
Best regards,
JM
Thank you for the link, I bookmark it. Just in case, did you had a look at how to connect directly to the I2S on the D802 (like you did on the V200)? In the digital chain taht I consider, I2S would be the perfect match. But on the other side, I would be happy to keep the USB and SPDIF (le beurre et l'agent du beurre). Any idea welcomed.
Best regards,
JM
That's a broad question, which may explain why no one else has attempted an answer for you.
With some trepidation I offer you my layman's take:
"Good" and "bad", roughly speaking in the above context, comes down to new technology chips versus old technology chips.
In the case of S/PDIF the newer WM8805 and AK411x chips are considered better than the other S/PDIF chips which came before. This depends, of course, upon implementation, and you can generally get a better outcome, still, with improved reference clocks and improved power supplies.
In the case of USB, the newer generation of USB Audio Class 2.0 products are the current heroes - XMOS xCORE, Atmel 8051, Savitech SA9227, C-Media CM6631A, VIA VT1731. Again, good clocks and/or good power supplies are a step up.
On this forum you can find DIY kits with such high end USB interfaces - for example from Amanero, Lorien, JLSounds.
Sure, but there are practical restraints with a direct I2S connection:
- you need to locate your digital transport (Orange Pi) very close to the amplifier, because I2S cables need to be short ...
unless you go one step further and install an LVDS transmitter/receiver for your I2S connection.
- you should also check that the Orange Pi will tolerate external voltage on its GPIO pins when powered down, otherwise you may risk damage to the Pi if it is off while the amp remains on. This problem applies to other single board computers such as the Beaglebone Black.
With even more trepidation I'll reply as well, largely because I think we are both aiming to do the same thing i.e. drive multiple d802 amps in an active setup. Personally I'm aiming to do a three way from an Odroid C2 as source and see the difficulties as:
a) The d802 has something special to my ears over the other amps here. But this is if, and only if, the input is spdif and the amp is in 'tone' mode bypassing all the eq and base/treble sections. I would like to try direct i2s input but so far there isn't a method.
b) The C2, and neither any other platform I know about, doesn't directly provide three i2s outputs so USB from the source is going to be necessary.
c) The C2 does provide 3xUSB outputs and I believe they all come from the same controller so I could have 3 USB connections to three d802s or indirectly 3xUSB -> 3xUSB/spdif external interface -> 3xd802 which I suspect might sound better. But it is inelegant and in this mode it would be essential to use the more normal synchronous USB methods not the newer/later/greater asynchronous USB interfaces.
I think I see a way forward using something like the DIYINHK async Xmos multichannel board to provide a single high quality asynchronous USB output to multiple i2s channels. Ideally these would go straight into the d802s but until this becomes possible I have at least found on ebay a WM8805 i2s->spdif interface that seems decent quality, is cheap, and is uncluttered by extra unwanted functionality. This would give a solution where I can have a single HQ masterclock in Xmos controlling all channels plus galvanic isolation to the d802s and so seems elegant, at least to me. I've got some of these spdif interfaces on the way to try them out.
Hello,
My last experiments bring me in a sort of dead end. If you have a look at http://www.diyaudio.com/forums/pc-based/288848-rpi-2x-usb-fda-amps-time-synch-ok-issue.html, you will see that my set-up Orange Pi + 2x D802 does not fly from time synch perspective. At the moment I'm listening really nice music with it, but teh stereo image is pulled on one side. I ddi not succeded to get the 2 D802 on the same controller with alsa.
I think that as sbc with multiple I2S, there is the BBB. But it may be a bit short in term of CPU power. It seems to me however as the most mature sbc able to run Linux and has multiple I2S.
At the moment, I seriously consider trying something with a STM32 F4 discovery board. I should need more low level coding, bus has good potential with 2 x I2S (maybe more), and dsp instruction set. The bigger brother STM32 has even more.
Last, I just discovered today this https://www.element14.com/community.../technical/document/data_brief/DM00247185.pdf.
Same family as the STA326 (I think), simple design. Direct access to all controls of the amp chip, and application libraries for the STM32+STA350. Interesting to dig...
I would be interested by the link to the I2S to SPDIF mobule you found on ebay ?
Best regards,
JMF
Sure. I popped the link in another thread for you, but here it is WM8805 I2S to SPDIF Coaxial Output Module support CD Player 44.1K 48K 96K ~ 192K | eBay
Have you tried tracing out the input pins on the AK4113? It looks like it supports 6 inputs. On the base model d802, at most three would be used, if that (from board photos it looks like the optical and coax in might be connected to the vt1630a USB chip). They probably break out one channel for the bluetooth module, and another channel should go to pads for the ADC chip, both used on the C variant.
The firmware might not make it easy to use the unused channels, but it seems like you could repurpose one of the enabled ones.
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