Ampapa D1 Stereo Amplifier Review

[john61ct]

MEANWELL LOP

Yes that series has a good rep for clean power, but I'd want it boxed and cabled. The fan cooling might be an issue if higher amps get pulled, but likely not.

I've seen lots of the finished "power brick" type 48V/10A targeted toward TPA3255 amps usage but under $80 mostly no-brand, the ones with Fosi-etc logo well over $100 in the states

bigger but - not adjustable.

more suggestions welcome but no need to get all intensive about it ;-}

 

[ICIETDIYEUR]

People hi

After watching many videos, visiting many forums and above all carrying out a lot of different calculations, it seems to me that the best maximum PSU to exploit and in the best conditions (consumption in IDLE is part of it because in certain cases it is not negligible) taking into account the heat of the amplifier in operation ((with its 'load' of 4 or 8 Ohms which will further decrease when reproducing low frequencies and/or 'complex load' linked to the filter as well as the number of speakers that can be mounted in parallel for example) that it could actually withstand in continuous operation for this type of amplifier would be:

- for 4 Ohm speakers -> 150W per channel (with around 30W in 'full load' of heat to dissipate, anyway ).
This is possible with a power supply of approximately 36V/13A.
There is one that seems very well designed here ->

- for 8 Ohm speakers -> 100W per channel (with less than 15W in 'full load' of heat to dissipate, i.e. half as much as with 4 Ohm speakers ).
This is possible with a power supply of approximately 42V/7,5A.
There is one that seems very well designed here ->

The ideal is to use speakers with at least 90dB/W/m (more would be even better) in order to reduce the power requirement to reach the desired listening level ('sound pressure level' in dB SPL), which seems to me to be a much more logical approach 'scientifically' speaking.

In order to give additional details concerning my remarks, I let you discover 2 videos from Youtube ->

You will notice that this person has made many very interesting videos and that there is even one where you can find links to download for free ebooks (I did) concerning power supplies

Furthermore, as these power supplies are easily removable, we can easily reduce their ripple by proceeding as demonstrated in this video ->

TI mentions this in its user guide for its 'TPA3255EVM' test card but without providing an explanation (this is so 'obvious' to them) ->

Here is in fact what we were supposed to have 'naturally' understood ->

Enjoy

 

[john61ct]

I think best to just buy one PSU for each voltage you want to use, or adjustable even better.

An infrared temp gun and restraint on the volume knob being the path to reliability / longevity

switching to a lower voltage PSU if that seem wise

Each at a current capacity higher than any of your current or future TPA3255 amps needs, don't derate that factor.

These can then be shared (one at a time) across all the amps you want to feed the same voltage, buying more than one instance of the same model if needed after testing / selection stage is complete.

That being the point where you can be saving some money by purposefully derating both voltage and current. I would still stick to better brands and sources though for safety issues, genuine CE / UL / ETL / CSA-US marks

 

[ICIETDIYEUR]

Hello john61ct

I realize that you obviously haven't understood at all what I'm trying in vain to explain...

Under 'optimal' conditions of use and with a 'closed' cabinet without active ventilation, an amplifier like the AMPAPA D1 (and other 'equivalent' brands) must be able to operate at the maximum power that can be achieved in continuous operation provided that the temperature dissipated can be reasonably accepted by the device, with distortion levels acceptable for a so-called 'Hi-Fi' device and therefore therefore a suitable power supply.

This is why after my calculations, taking into account all these parameters, I mentioned power supplies in my previous message which meet these conditions according to the load which will be applied to them.

I therefore draw your attention (and that of the readers, of course) to the powers that I mentioned according to the loads and the quantity of heat that it will be necessary to dissipate knowing that in the context of using a 4 Ohm load this will double (15W under 8 Ohms and 30W under 4 Ohms) and I let you imagine if in this case the internal protection for the temperature of the TPA3255 chip will not come into play. in function (with the original case, without adding a cooling device).

It will be false and completely utopian to claim otherwise, knowing that mathematics and science tell us the opposite

This is valid for all brands and models which use boxes in such formats and with this type of heat sink implemented: this is in no way a sort of 'trial of intent' at DOUK Audio which has carried out an absolutely fantastic job with this model

I take advantage of having mentioned DOUK Audio to suggest that in an AMPAPA pro, vII or other model they do the same thing with work on the box and its dissipation, to include 'real' balanced input connectors (XLR), to use a TYPE B USB input connector (much more reliable than the 'ridiculously small and fragile' USB C connector) and above all to include a Bluetooth chip which supports the LDAC or better LHDC and LLAC (LHDC LL) or even LC3 !

It should also be possible to integrate (if the size of the case allows) a PCB inspired for example by the TRN Black Pearl portable DAC which allows the use of the EQ WALK PLAY and its numerous functions (such as modifying the equalization and the type of digital filter for example) which allow the various parameters to be saved in the dedicated chip of this DAC

Also don't forget the possibility of being able to completely turn off the display whether in standby mode or in use.

Furthermore, would it be possible for you to make this last modification proposal on the AMPAPA D1 by proposing a new firmware version ?

I wish you all a great day

 

[jck2001]

As an owner of both a 3e A5 and Ampapa D1 I do not agree. "Better choice" is subjective until you lay down the criteria that determine what better choice means. Lets ignore the look.

If Better Choice means the Amp ASR members rate best in the poll, then the A5 wins by a lot. The majority rate it Great Golfing Panther and the D1 Fine Happy Panther. Amir Golfs both.

If Better Choice means performing better on Amir's tests then the A5 wins as it beats the D1 on most all but the power output test. Note that this would only make it the best choice for those who have read Amir's tests and believe performance measurement is most important. ASR members who complete the poll have read the tests.

If Better Choice means objectively evaluating Amir's results to determine which amp is most transparent the answer is not clear. Two performance differences could be audible in normal use: PFFB (load dependence) and Output Power.

The PFFB performance difference results in a worse case 1.6 dB variation that starts above 10kHz and peaks above 20kHz. Even with excellent hearing this will be nearly imperceptible. The difference is small, in a region with no music fundamentals, where our ears are least sensitive. The difference is dwarfed by speaker anomalies, toe in, and listening location. OTOH, once you read the tests, if you make a sighted listening comparison you will most certainly hear a predictive perception difference because the D1's PFFB graph looks nasty.

The power output difference favors the D1. At 4 ohms the D1 outputs 136w and the A5 92w. But, this results in just a 1.7dB difference in maximum output which is quite small, and does not matter if you never utilize maximum power. I think neither Output Power or PFFB Performance differences will impact objective listening for the vast majority of owners. However, many of us at ASR will see the PFFB issue as more problematical because it probably results from an engineering flaw rather than a design choice.

If Better Choice means useability and features the D1 has many more of them but whether they have positive or negative value to you is subjective. The LPF and Tone Controls may significantly improve objective performance depending on your circumstance.

If Better Choice includes price, the Ampapa D1 sells for 28% less ($200 vs $280 on Amazon)

When I put on my audio consultant shoes I would recommend the D1 as the better choice for most people. I would recommend the A5 to those who read ASR. I like them both, use them equally, and gave both great golf scores.

how many amps here hv been downrated for far less 20khz bump than this Amp? Yet we'll give it a pass because we like a couple of relatively worthless meters? You have denigrated the objectivity this forum is supposed to support! Incredible

 

[ICIETDIYEUR]

Good morning.

For my part, I think you are right but also wrong:

- you are right in indicating that this forum is based on objectivity which is incontestable and scientific.

- you are wrong because we cannot say that we are 'violating' anything when we refer to measurements which are imperceptible or even inaudible since this is also scientifically incontestable.

I think that Amirm created this site to confirm that the products offered respect the technical specifications announced in the commercial proposals mainly.

Secondly, this makes it possible to verify the technical mastery as well as in terms of design of the products offered which come closest to what we can 'define' as 'State Of the Art'.

This does not mean that we should exclude slightly 'less good' devices (in terms of SINAD) as long as they allow them to function correctly within the limits 'imposed' by the threshold of human hearing.

To all this is added the inevitable which is characterized by the (purely subjective) sensation felt by the listener but that is still 'another story'...

However, we cannot say, impose or contest this subjectivity, since it depends on each person (the one who is going to listen), who will be able to appreciate or not the sound rendering finally obtained and this regardless of their 'position' in the 'SINAD' classification: it is one of the characteristics of the human being whether we like it or not.

I would like to point out that these comments are my own but they seem 'reasonable' and 'logical' to me, I am not questioning anything or anyone:

I am neither 'creator of an institution', nor 'dictator/influencer of will': I am just passionate about sound reproduction equipment (and creator or participant in creations when I feel the desire).

Have a nice day everyone.

 

[john61ct]

To the extent I do not understand your posts, it's because of your language issues, I admit I have little clue what you are on about the way you phrase most things

combined perhaps with my "laziness" (not worth the effort of trying to decipher)

I am certainly not trying to make any "utopian" claims outside my own usage and preferences.

I disagree about changing the USB connector.

I don't think BT - nor a DAC - should be anywhere near a power amp.

I agree about a balanced input option and ability to disable the display.

> Furthermore, would it be possible for you to make this last modification proposal ?

Me? no.

Under 'optimal' conditions of use and with a 'closed' cabinet without active ventilation

I have no reason to impose those conditions for my own use case, I never use the former, and have no problem using the latter.

Also, I always measure, so IF I measured high temps under my most-intensive anticipated usage then I would take necessary measures, from a long list of possibilities.

Buying a PSU that did not allow the amplifier to put out its maximum clean and safe SPL, would never be included in that list.

> I wish you all a great day

same from me

 

[ICIETDIYEUR]

Hello john61ct.

With all due respect, I do indeed note your 'laziness'... just to simply read my messages otherwise you would have noticed that my last intervention was addressed to DOUK Audio and not to you although that does not actually prevent you from giving your opinions, of course.

I wish you a good day.

 

[ICIETDIYEUR]

john61ct,

Since you seem friendly to me, I will try to explain to you my thoughts regarding the choice of my PSU taking into account the characteristics of my installation and the real possibilities of this amplifier in these conditions.

I will try to be as simple and precise as possible...

My objective in terms of power to be achieved is to exceed the limits authorized in France (because I am French) for performance halls, i.e. 118dB in low frequencies.

NB: I respect the institutions, their laws and rules also I would NEVER use such power knowing that for this it is necessary to have a room which allows the speakers to reproduce the frequencies in good conditions, if the latter are otherwise capable of doing so...
This is 'my real world' ->
8 Ohm speakers with an admissible power of 100W RMS, 90dB for 1W at 1 meter.

If I apply an RMS power of 100W, I obtain an increase of + 20dB: the maximum level will then be 120dB, or more than 118dB which is my primary objective.

However, this level will be reached at low frequencies as I specified above and at these frequencies my bass driver sees its impedance lower to around 4 Ohms.

It is therefore with these 4 Ohms that I must calculate the necessary power that the PSU must be able to provide under these conditions.

I then observe the TI datasheets which tell me that 42V allows the TPA3255 chip to reach 100W RMS at 8 Ohms for around 5A measured in real life.

For 4 Ohms, this will then reach 10A or 200W RMS which will be necessary for the bass speaker to reproduce this power (clipping protection of the TPA3255 is 17A max).

The PSU must therefore be able to provide 42V and 10A at least and this will allow me to:

- achieve my goal (+ 118db in low frequencies).
- lower the temperature of the amplifier in IDLE since it depends directly on the voltage applied to the amplifier (48V with the original power supply).

Now apply my reasoning with 4 Ohm speakers and a 48V/10A Gan power supply:

1> the temperature in IDLE will be higher than with 42V, that's obvious.

2> Do you need to exceed the objective that I initially set for myself (120dB) but above all are your room and your speakers capable of doing so?

3> are you more 'muscular' than your neighbors and don't you fear a visit from the authorities?

4> you do not pay or do not pay much for your electricity and thanks to your amplifier you will heat your room.

NB: the last two points are humorous

 

[john61ct]

Yes I want to be friendly, but I doubt this discussion is of interest to others, and it no longer is relevant to this particular amp, which as stated basically interests me for the VU meter.

Once I select a given power amp for a particular (pair of) speaker(s), I will buy the PSU that allows it to output its maximum clear SQ / safe output.

I think it is just silly to buy only a derated PSU, in fact having a variety of them makes more sense, or adjustable ones as I discussed above.

Is that clear to you? My approach to this topic is based on that principle, and not motivated by any specific use case, certainly not as detailed as you outline yours.

If that PSU ALLOWS FOR generating too much heat, high distortion, destroying the speaker(s), shattering the walls, neighbors calling in a SWAT team,

that is fine with me, I will take measures **at the line level stage** to prevent those problems, not solve them through purchasing a lower voltage or current PSU.

My system is mobile, to mostly be used off grid, usually no neighbors, not in any particular "room" in fact sometimes outdoors, in the desert, at sea...

90% of the cost of my energy is in fixed-cost investment, depreciating capital, not variable per AH consumption. Also managing waste heat is rarely an issue affected by such a trivial device, and I have not used any aircon for many decades.

Sorry, feel free to post what you like but FYI I am simply not interested in your counter thoughts on this specific topic, nor any further narrative of your personal details.

the last two points are humorous

 

[ICIETDIYEUR]

If you are bored talking about technology and science then you are in the wrong place... sorry for wasting your time.

 

[VintageFlanker]

If I apply an RMS power of 100W, I obtain an increase of + 20dB: the maximum level will then be 120dB, or more than 118dB which is my primary objective

I'm struggling to perceive if it is some kind of joke (sorry if it is), but :
1) Your speakers most likely aren't "90dB" sensitive as rated by manufacturer.
2 ) Even if these indeed are, it would require at least 6 to 7 times 100W to reach 118dBSPL at 1M.
3 ) ...Which your speaker cannot hold (both power and SPL) without getting fried.
4 ) ...Which 99.99% of domestic rooms in France can't handle anyway.

 

[john61ct]

If you are bored talking about technology and science then you are in the wrong place... sorry for wasting your time.

No I am not at all bored by that in general.

Setting a boundary for OUR interactions specifically, to avoid you wasting YOUR time

and more importantly that of the other members

and helping to preserve the value of the thread

 

[ICIETDIYEUR]

At least VintageFlanker has a sense of humor

Indeed, with a speaker of 90 dB / 1 W / 1 m (real), we will obtain by calculation ->

With 200W RMS:

SPL=90+10.log^10/(200)

10.log^10/(200)= ~23

SPL=90+23=113dB at 1 meter, 107dB at 2 meters (-6dB) and 101dB at 4 meters (again - 6dB).

(113dB is equivalent to listening to a rock concert right in front of the stage).

With 100W RMS:

We will obtain 'only' 110dB at 1 meter (example of office configuration), 104dB (-6dB) at 2 meters (example of a bedroom) and 98dB (again - 6dB) at 4 meters (example of a living room).

'Curiously', these 98dB are close to the 96dB that we frequently encounter on the speakers tested by Amirm before they reproduce too much distortion.

So I wanted to bring this out with my objective remarks

So I logically wonder if it is really necessary to go beyond these powers if the installation does not allow it or if we do not need it ?

Are we really 'obliged' to follow 'the fashion' by purchasing a Gan 48V/10A power supply to 'do like everyone else' when we do not actually master the technique or do not interpret it correctly ?

This is my question which may lead to the reflection or questioning of certain users/readers, quite simply

@ john61ct, you remarked: "...preserve the quality of the discussion...".

This is just your opinion and is therefore purely subjective, sorry (again).

NB: don't make the readers speak or think for them, if they express the need, they will know how to do it, thank you for them.

 

[john61ct]

No one said anything about Gan.

Nothing to do with "fashion" why are you disparaging those with different preferences?

Since my choice is 3e A7, I want to buy one PSU to go up to 52V for testing and verification, for comparison with GFA-555 for my hard-to-drive speakers.

Nothing to do with "need" - max SQ-safe SPL in itself **is my goal**.

For your personal use case, do what you like!

Once all my testing has settled down, I may well choose "in production" to run my various amplifiers at a lower voltage, but again a lower available current spec is 100% pointless.

 

[ICIETDIYEUR]

I mentioned Gan.

I'm not denigrating anyone and if you mention a 'preference' then you haven't understood anything about me and if I talked about 'fashion' it's only because most people who buy it don't really know why, or if they really need it: it's easy to understand though...

That said, also do what you want because it's not my problem either

I hope you will do us the honor of presenting your tests (and your calculations ?).

Good luck.

 

[john61ct]

I will be getting help wherever I can and yes posting once valid "settled" results if anyone's interested

 

[StivVid]

I mentioned Gan.

I'm not denigrating anyone and if you mention a 'preference' then you haven't understood anything about me and if I talked about 'fashion' it's only because most people who buy it don't really know why, or if they really need it: it's easy to understand though...

That said, also do what you want because it's not my problem either

I hope you will do us the honor of presenting your tests (and your calculations ?).

Good luck.

I, for one, would really like this pointless back and forth to end. Can I get a second?

 

[john61ct]

Seconded, with apologies

 

[lunaria]

@amirm
I find your (lack of) judgement baffling. I thought, this site was supposed to be based on science (in my mind focused on audible differences, which can be confirmed in blind tests). This amp will have audible differences/issues with real world speakers with its load-depended frequency response. Yet, you criticize DACs that are orders of magnitude better than causing audible differences.

I can tell a difference between various amplifiers, they have measurable differences (in particular audible noise and load-dependent frequency response).

I can't tell a difference between high-quality DAC implementations. Pretty much nobody will be able to differentiate between good quality DAC implementations, like the Apple USB dongle, good quality PC Realtek audio or high-end transparent DACs (which don't have audible distortions which some people like).