Douk Audio G7 is Coming! TPA3255 Amplifier with a Built-in Power Supply!

[Jimster480]

it's 489$ on Aliexpress as well, from "official trader" including shipping. that's very expensive, specially for buying AE , in which one know that returning the product (on any issue) is extremely unaffordable .

I think they will get all this sorted out very soon. The amp itself is great, and at their actual target price... its basically a steal considering all the features that you get.

 

[Audionaut]

I think they will get all this sorted out very soon. The amp itself is great, and at their actual target price... its basically a steal considering all the features that you get.

Yes, all in all, everything you could wish for is on board.

BUT: This is not particularly clever

"In fact, G7 is 2 x 2.0 channel output with 2 TPA3255 chips, which means 1 3255 chip is responsible for 2.0 channel.
If used like that, both TPA3255 chips are operational, but only half of each chip is active, dedicated to either the left or right channel."

You have two TPA3255s in the amplifier, a large power supply—and you're not taking advantage of the opportunity for 2 ohm stability.
I have no idea why they didn't do that.

 

[antcollinet]

Yes, all in all, everything you could wish for is on board.

BUT: This is not particularly clever

"In fact, G7 is 2 x 2.0 channel output with 2 TPA3255 chips, which means 1 3255 chip is responsible for 2.0 channel.
If used like that, both TPA3255 chips are operational, but only half of each chip is active, dedicated to either the left or right channel."

You have two TPA3255s in the amplifier, a large power supply—and you're not taking advantage of the opportunity for 2 ohm stability.
I have no idea why they didn't do that.

Where is that quote from? I struggle to believe they are not using PBTL if they are putting two chips in there.

 

[Jimster480]

Yes, all in all, everything you could wish for is on board.

BUT: This is not particularly clever

"In fact, G7 is 2 x 2.0 channel output with 2 TPA3255 chips, which means 1 3255 chip is responsible for 2.0 channel.
If used like that, both TPA3255 chips are operational, but only half of each chip is active, dedicated to either the left or right channel."

You have two TPA3255s in the amplifier, a large power supply—and you're not taking advantage of the opportunity for 2 ohm stability.
I have no idea why they didn't do that.

Maybe they couldn't wire it in both ways?
There is also no auto on/off without 12V trigger. I provided feedback about this and they will see if can be in future batches.

 

[Audionaut]

Where is that quote from? I struggle to believe they are not using PBTL if they are putting two chips in there.

Douk Audio G7 is Coming! TPA3255 Amplifier with a Built-in Power Supply!

This thing is awesome (unlike my cable management) Not able to take any measurements of the amp itself, but it sounds pretty indistinguishable from my other amps: 3e A7, Fosi V3 Mono, Douk A5, and Buckeye NC502mp. Which is to say that it does the intended job! Currently powering some Elac...

www.audiosciencereview.com

 

[antcollinet]

Douk Audio G7 is Coming! TPA3255 Amplifier with a Built-in Power Supply!

This thing is awesome (unlike my cable management) Not able to take any measurements of the amp itself, but it sounds pretty indistinguishable from my other amps: 3e A7, Fosi V3 Mono, Douk A5, and Buckeye NC502mp. Which is to say that it does the intended job! Currently powering some Elac...

www.audiosciencereview.com

Thanks @Audionaut



@Douk Audio - is this correct - you are not using PBTL to get the higher current capability for low impedance loads?

Or is this just a misunderstanding?

 

[scorlee]

It features a USB input that functions both as a DAC and for configuring the DSP chip. Ideally, it would also include a USB-HID interface to facilitate easy pushing and pulling of DSP filters, and adding a subwoofer output could serve as a useful enhancement. It is assumed that the VU meters are electronic rather than physical moving-coil meters; if this is the case, there should be an option for VU or True-Peak ballistics. For a power amplifier, peak levels are critical—unlike average power, which is roughly what a VU meter displays. If the meters are indeed moving-coil types, a quasi-peak mode with a 1 or 2ms integration time should be offered, as VU meters again provide little useful information for power amplifiers.

 

[Jimster480]

It features a USB input that functions both as a DAC and for configuring the DSP chip. Ideally, it would also include a USB-HID interface to facilitate easy pushing and pulling of DSP filters, and adding a subwoofer output could serve as a useful enhancement. It is assumed that the VU meters are electronic rather than physical moving-coil meters; if this is the case, there should be an option for VU or True-Peak ballistics. For a power amplifier, peak levels are critical—unlike average power, which is roughly what a VU meter displays. If the meters are indeed moving-coil types, a quasi-peak mode with a 1 or 2ms integration time should be offered, as VU meters again provide little useful information for power amplifiers.

What are you referring to? There is no DAC or USB port?

 

[scorlee]

What are you referring to? There is no DAC or USB port?

sorry, missed a word 'should'

 

[john61ct]

The Douk rep has contradicted themselves several times, I think not just a language problem but from simply not understanding how dual-mono, PBTL and 2ohm stability are all equivalent terms with the TI 3255 design architecture.

This statement I believe is true and accurate:

"In fact, G7 is 2 x 2.0 channel output with 2 TPA3255 chips, which means 1 3255 chip is responsible for 2.0 channel.
If used like that, both TPA3255 chips are operational, but only half of each chip is active, dedicated to either the left or right channel."

This was in response to a member testing one pair of speakers, using one Left channel from the G7 Speaker A output, and the Right channel from the Speaker B pair, hoping they would get dual-mono PBTL, i.e. greater power output at lower impedances and stability down to 2ohms.

Douk's answer shows clearly this is NOT the case, and for speakers that are hard to drive, requiring high CURRENT in order to support Voltage from collapsing as impedance is lowered, this G7 amp will NOT give the same power-amp performance as 3e A7, Fosi V3 mono nor Wiim Amp Ultra.

I suspect that PFFB even if present is not so relevant for such speakers where impedance varies widely dropping at high SPL and low frequencies.

The 48V PS could probably just as well be 5A without hurting any aspect of performance.

And yes the VU meters are pretty lights bouncing to the beat but not displaying anything objective.

Ability to A/B test speakers would be nice if the outputs to each pair could be level matched and thus switching made relatively safe without turning SPL down between cycles.

I would LOVE for my above WAG conclusions to be proven wrong, but for myself I will not rely on vendor statements but Amir measurement / testing.

At a $200 price point I will be happy to fund that testing with a drop-ship to Amir, so long as they can get the unit to me within a couple months after receipt. If I am correct the amp is plenty for my L/R Rear surrounds, and I do enjoy pretty bouncing blue lights...

 

[john61ct]

Since the G7 is in production shipping already, there is not much point using this thread to suggest improvements.

Clearly mark such as "general feedback for future models" to prevent confusion.

 

[Bob101]

300 Wpc in stereo = 600 W. From a 480 W PSU. Magic

 

[antcollinet]

300 Wpc in stereo = 600 W. From a 480 W PSU. Magic

Not particularly - that 480W PSU can probably sustain higher output for short periods. We see it all the time in measurements of this type of amp. Amir has even commented on it with one of them.

 

[ICIETDIYEUR]

People hi

This is by far the most well-designed and affordable class D amplifier with integrated power supply to date (369 euros in France including shipping with Prime advantage).

Too bad that the circuit is not 'full balanced' (use of NJW1194 which only has 2 channels) and that the PBTL mode is not available to obtain all the power of the 2xTPA3255 although for that it would have been necessary to integrate a 1200W PSU !!!

Personally, this is what I would have proposed with the optional possibility of inserting a DAC card (*) including TOSLINK, coaxial and USB inputs inside the device via an access 'hatch' so as not to force the user to lose their warranty by opening the device...

...so dear designers: it's up to you

(*) this would make the device upgradable with the next DAC chips and would be much cheaper than replacing a complete device (which is 'green' at the same time)

 

[Bob101]

Not particularly - that 480W PSU can probably sustain higher output for short periods. We see it all the time in measurements of this type of amp. Amir has even commented on it with one of them.

Ok, I admit I knew that. But when we're going to advertising power output numbers, didn't 'we' here on ASR somewhat agree on publishing continuous power output (as measured by Amir...) rather than going back to the eighties and PMPO values? I do think this is a great value amp BTW

 

[antcollinet]

Ok, I admit I knew that. But when we're going to advertising power output numbers, didn't 'we' here on ASR somewhat agree on publishing continuous power output (as measured by Amir...) rather than going back to the eighties and PMPO values? I do think this is a great value amp BTW

Amir doesn't measure continous power. His test set up only measures max power for a few seconds at most. Similar to how the majority of amps are rated these days. There is a long (88 page) discussion of it here;

Power amplifier tests with respect to FTC: 16 CFR Part 432 (July 5, 2024) requirements on output power claims

Some of us feel the need of honest specifications of amplifier output power according to acknowledged documents like FTC regulations and IEC standards. The reason is to get comparable data, protect potential customers and draw attention to false claims of some manufacturers. I have decided to...

www.audiosciencereview.com

(this is nothing like PMPO though, which was rated based in the instantaneous peak of a sine-wave, typically only milliseconds duration)

 

[ICIETDIYEUR]

Antcollinet, you who have the answer to everything and always reason in hi-fi:
can you tell us how many milliseconds the infrasound lasts at 16Hz in Richard Strauss' classic work "Also sprach Zarathustra"?

A (very good Hi-Fi installation (i.e. an amplifier) shouldn't be able to reproduce this and at the level that its user (but not his neighbors!) wanted?

 

[Jimster480]

I use this amp almost every single day for several hours, I've been happy with it so far. Although I haven't done any side by side sound quality comparison directly with the Fosi Mono V3. As that is what I came from before having this amp.

 

[ICIETDIYEUR]

What matters most Jimster480 is that you are satisfied with your new acquisition and that it reproduces your favorite music as you like and appreciate it:
the 'rest' are just objective 'numbers' that cannot be compared with your necessarily subjective emotions since they are your own, which in this case is often called by some 'musicality'

 

[Jimster480]

What matters most Jimster480 is that you are satisfied with your new acquisition and that it reproduces your favorite music as you like and appreciate it:
the 'rest' are just objective 'numbers' that cannot be compared with your necessarily subjective emotions since they are your own, which in this case is often called by some 'musicality'

That is an interesting viewpoint. Soon Amir will publish a test result on this very amp. I was going to send him mine, but Douk has sent one to him directly; which means they are obviously confident with its performance.