Amp Camp Amp - ACA

[ItsAllInMyHead]

[amirmaj]

Originally Posted by Loudthud

Please look at the measurements I posted in reply 576 of this thread and see if you can duplicate the measurements.

That's good work there! As for me duplicating them, I already returned the unit to its owner so can't perform any more measurements.

[spiggs]

Originally Posted by Skylar88

I'm sorry that I have to say this, but I find it hard to believe anything coming from you after reading your slanted and biased "review" of the ACA.

My experience with the ACA, and I'm pretty sure everybody else's, is the complete opposite of your "findings".

You know I don't think any of the measurements are invalid, the unit tested over at ASR matched what is published here on diyAudio. It's more about how the measurements are interpreted and presented. When I chose to build an ACA it was after much research and learning (that's the fun right!) on my part to understand if it would work for me. My speakers are fairly easy to drive 8 ohm full rangers and after some measurements I found my listening levels don't exceed 2 watts and really 1 watt and under is most typical. The ACA has worked out well and taught me about some of the basics of this hobby. In fact I had a good chuckle to myself today thinking of the ASR review while listening to Rammstein loud enough that I could hear it clearly while I was out in the yard.

So I think this is where the ASR review falls short. The reviewer presents the standard battery of tests and knowing that these tests are outside the optimal range for the ACA misses the opportunity to educate about why anyone would want to build this amp and what might be it's best use cases. A pity because speaking for myself this little amp has brought me a lot of enjoyment and has been a vehicle to introduced me to a much broader range of the audio hobby than I ever imagined existed.

[amirmaj]

Originally Posted by spiggs

So I think this is where the ASR review falls short. The reviewer presents the standard battery of tests and knowing that these tests are outside the optimal range for the ACA misses the opportunity to educate about why anyone would want to build this amp and what might be it's best use cases.

This reviewer missed nothing. This is the second sentence in the review:

" It is a DIY design by the famous designer, Nelson Pass, meant to be starter amplifier for people new to audio electronics to build."

Same is stated in the conclusion section of the review:

"Conclusions
As a starter hobby amplifier to get some sound coming out of a speaker, with relatively few components, the Pass ACA Class A Amp does the job. Build it, have fun with it and then put it aside and get a proper amplifier. Amplifiers need to have a lot more power. And much less distortion. We are not even close here folks."

So its role as a hobby build is fully recognized. If you want to tell me it is the best amplifier for the job, it simply is not. Certainly not at the price for the one I reviewed. There are cheaper, much lower distortion, more powerful and nicer sounding amplifiers than it. These are facts that are backed by measurements and my listening tests.

A pity because speaking for myself this little amp has brought me a lot of enjoyment and has been a vehicle to introduced me to a much broader range of the audio hobby than I ever imagined existed.

I get enjoyment out of a clock radio playing one of my favorite track. What you experienced there is not being challenged whatsoever.

My job is to bring objective, reliable information about performance of audio products. Once you have the data, you can choose to use it in however you wish.

I don't know why you guys are so surprised by my final judgement on this amp. This is how it finished the race:



If you were me, you would whistle dixie while ignoring all the information in the review and misinform the reader that this is a great option for amplification?

[amirmaj]

And to be clear, the above performance chart is for all amplifiers producing just 5 watts.

[Zen Mod]

your problem is exactly that - you're calling majority of these - amplifiers ..... while I'm recognizing just few of them , worthy of that title

this site is not dealing with mediocre commercial products , except in cases when some is willing to repair his own, and we are helping in that

also , this site is not dealing with advertising

[amirmaj]

Originally Posted by tjw59

If you look at analytics of that site: You see that people spend an average of 3 minutes on it and leave.

Only site administrators have true site analytics. What source did you use for that information then? Similareweb? If so, this is what they say about ASR: https://pro.similarweb.com/#/website...ebSource=Total



As you see, it says average time on site is 8 minutes+. Not 3 minutes.

Alexa estimates it at 3:54, rounded to four minutes, not three. Asking Alexa to show the stats for DIYAudio.com reports even lower number of 3:10!

Once the bump of the traffic counter has come and gone, you are right back where you started. Horrible rankings.

Yeh right. From Similarweb above:



I suggest you stick to the topic of the thread and facts you can defend, not manufacture.

[spiggs]

Originally Posted by amirmaj

...

"Conclusions
As a starter hobby amplifier to get some sound coming out of a speaker, with relatively few components, the Pass ACA Class A Amp does the job. Build it, have fun with it and then put it aside and get a proper amplifier. Amplifiers need to have a lot more power. And much less distortion. We are not even close here folks."

...

For example enough power is based on use case, your 5 watt measure is not universally applicable.

[amirmaj]

Originally Posted by Zen Mod

your problem is exactly that - you're calling majority of these - amplifiers ..... while I'm recognizing just few of them , worthy of that title

They are all the ones I have reviewed. The ACR performs worse than all of them by far. The design simply is not performant. Read Rod's article if you think a MOSFET power stage is the right solution: Death of Zen - A new Class-A power amp

"Having looked at the original and many of the 'improvements' currently on the web, I did a few tests of my own and frankly, found the amp lacking in the fidelity department. Hi-Fi this most certainly is not."

this site is not dealing with mediocre commercial products , except in cases when some is willing to repair his own, and we are helping in that

also , this site is not dealing with advertising

There is zero advertising or sponsorship on ASR Forum. Kind donations from members and my own funds keep it going.

I consider DIYAudio and ASR to be complimentary sites. I routinely review products with the same silicon or module used in commercial amplifiers. I also test DIY builds like the ACA we are discussing.

This notion of "us versus them" is very much unlike the very positive impression I have of DIYAudio.

I hope you guys keep your emotions in check and start to value objective information. Engineers thrive on that. You will never be good at this field if you continue to act the way you have been. Learn to separate your emotions from facts. The owner of the ACA amp has done that. Not sure why the few of you are having so much angst over learning more about performance of these designs.

[amirmaj]

Originally Posted by spiggs

For example enough power is based on use case, your 5 watt measure is not universally applicable.

5 watt dashboard view has nothing to do with use case. Use case comes later as full power is measured versus distortion and noise into different loads.

All amplifiers tested can reach 5 watts so it is a good common data point to have across wide range of amplifiers. Don't know why you think that represents a use case.