[NXSTUDIO-DRUMMER]

Had some fun buying the little Douk Audio A5 amp for my bedroom set up. I just noticed like Lloyd mentioned, Amazon has a crazy deal on it sold with the 48 Volt power adapter.

https://www.amazon.com/Douk-Audio-Channel-TPA3255-Amplifier/dp/B0F22FN8Z8?adgrpid=180038505042&hvpone=&hvptwo=&hvadid=748008509502&hvpos=&hvnetw=g&hvrand=15225987599662680634&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9007762&hvtargid=dsa-1574853651722&hydadcr=&mcid=&hvocijid=15225987599662680634--&hvexpln=67&tag=googhydr-20&hvsb=Business_d&hvcampaign=dsadesk&th=1




Danny's GR-Research review: https://www.youtube.com/watch?v=-E8wEJF5jAs&t=1206s

https://doukaudio.com/products/douk-audio-a5-tpa3255-stereo-amp-hifi-audio-class-d-amplifier-high-pass-filter?variant=47038634950888

Ron's NRD Review:
https://www.youtube.com/watch?v=7tqudUsJgEY

I'm impressed, for what it cost in stock form. Based on the shoot out Danny, Ron and Hobbs did on the A5. https://www.youtube.com/watch?v=-E8wEJF5jAs
Link for Staccato's op-amps,  https://staccatoaudio.com/

Link for Sparko's op-amps, https://sparkoslabs.com/discrete-op-amps/





However, I really wanted to go with the Staccato op amps, versus the Sparkos op amps in the A5 though. Inspecting the circuit board and corresponding with Jakub Honkisz with Staccato, he advised me, in order to use their op amps, I'll need to use these DIP8pin extenders.

Link for DIP8 Extenders, Jakub said he can obtain them too.
https://analogclassics.com/product/dip8-op-amp-socket-extender/?srsltid=AfmBOoqxIERT6Q6RiXtYO1zQzakqDPsi2HAFxw_5y7Q8pwR3Sgr7EeM4










I decided to see how it would sound, in stock form, running it through my primary audio set up in my listening room. Connected it up to the pre-out on my Galion TS 120 SE Integrated amp. I would never imagine a $100 dollar amp could sound pretty good, running through my NX-Studio's. Even though, in stock form. I'm looking forward to hearing the amp with the Staccato's installed, taking it to another level. A tube pre-amp makes it feel more analog for sure. I also support using this little amp with a tube pre-amplifier.

Unfortunately, Danny, Ron and Hobbs didn't get a chance to test the A5 in their shoot out, with the Staccato's installed, because they didn't have the DIP8pin extenders to retrofit into the Douk Audio A5 Class D amp. In their testing, they had a smaller power supply too. They were using a 32V/5amp power supply. I bought the 48V/ 10Amp power supply. The 48V/ 10 Amp makes a big difference, having drive versus a 32V/ 5amp power supply. I've been considering a linear power supply, to see how much it may lower the noise floor. Although, I'll have to say even cranked up, I didn't notice any noise, it was dead silent. Interesting article on GaN technology.
 https://futureaudiophile.com/what-the-hell-is-a-gan-gallium-nitride-amp-and-why-is-it-changing-the-way-audiophiles-now-see-power-amps/

Laughing, I feel like I just bought a grown man's Tonka toy!  This little rascal is going to be a nice addition to my other bedroom stereo system. Needless to say, I'm very pleased!

Thanks for the review of the Douk A5 Class D Digital Amp, Danny, Ron & Hobb's! 
Even Amir with ASR was impressed with the A5 Amp, and we all know Amir, never see's eye to eye with Danny and Ron's audio equipment reviews.
https://www.youtube.com/watch?v=7jyvdgMCOaM&t=2s

Someone who is building some of Danny's kits on a budget, this little amp is a worthy addition too!

[NIGHTFALL1970]

I also purchased a 10 amp power brick and it makes a night and day difference! Symbol crashes sound a lot more life like. I haven’t played around with different opamps yet but,  I bet the power brick has the same difference in quality.

[Jon L]

Who did this and aside from how it looks, did the opamps work kinked like this?  I'd rather use the standard extender and bend the pins than use the super-long wire extenders.

[NXSTUDIO-DRUMMER]

Who did this and aside from how it looks, did the opamps work kinked like this?  I'd rather use the standard extender and bend the pins than use the super-long wire extenders.

So your thinking of using a set up like this?
https://www.peconnectors.com/sockets-wire-wrap/hws3469/?utm_source=googleads&vt_keyword=&gad_source=1&gad_campaignid=1362472447&gbraid=0AAAAAD-J6wTc0UknapjjpllYVZ6jw5z5A&gclid=CjwKCAjwg7PDBhBxEiwAf1CVu7r_g7xl-Ad8dmrGEh2v2DIWFcuPytCBIdudmu01usoOz2plIjnoWxoCPkQQAvD_BwE


Jakub from Staccato sent me that photo, of a another customer attempting to install. Yes, it is a mess for sure! Very obvious, who ever attempted this, has never worked on a amp, let alone build one from the ground up.

I'm building my own standoff- platform configuration. once I receive the op-amps. I'll modify the wire length on the extenders to accommodate my final layout. The wire lengths will be shorter when I finish the task.   

[Jon L]

IF I were to get Staccato, I would just use two extenders on one side. 

But I'm trying to refrain from buying any more discrete opamps, including the interesting-looking Virtual Hifi opamps:
https://www.youtube.com/watch?v=Mub-xo619PY&lc=UgxdVC0dgL6KaUa1-qN4AaABAg.AKBzsVzeGuyAKIDM8Gt2Ms

[nlitworld]

Has anyone measured the input impedance of this little guy? Curiosity got the best of me and I just ordered on prime day deal. $95 with the 48v power supply is too tempting. Asking on impedance since I usually run a high pass filter on my preamp output.

[tremrej65]

Has anyone measured the input impedance of this little guy? Curiosity got the best of me and I just ordered on prime day deal. $95 with the 48v power supply is too tempting. Asking on impedance since I usually run a high pass filter on my preamp output.

There's an integrated adjustable high pass filter in that box (the left knob). You most likely don't need an external one.

[nlitworld]

Yeah but typical audiophile neurosis says the capacitors in there to facilitate an adjustable high pass are not very quality compared to the Miflex and Duelund I'm used to hearing. We're guilty of falling down our own rabbit holes in this hobby.  I'll figure out tomorrow when I get it and can report back.

[NXSTUDIO-DRUMMER]

Yeah but typical audiophile neurosis says the capacitors in there to facilitate an adjustable high pass are not very quality compared to the Miflex and Duelund I'm used to hearing. We're guilty of falling down our own rabbit holes in this hobby.  I'll figure out tomorrow when I get it and can report back.

Hey Lloyd, I wondered about it too, however, it has impressed me enough, I don't feel a need to go that route.
Some others have commented on it too. Being we both have the NX-Studio's, that are very revealing monitors.

"The Douk Audio A5 amplifier uses C0G/NP0 ceramic capacitors for high-pass filtering, specifically for their superior performance in audio applications, according to TI.com and In Compliance Magazine. These capacitors are favored for their low distortion, stability over temperature and time, and suitability for high-frequency filtering, according to In Compliance Magazine. Additionally, the amplifier utilizes aluminum electrolytic capacitors for enhanced reliability and longevity."


Here is a nice detailed large photo of the internal components on the circuit board.





I'm sure a larger 63V 4700uf electrolytic capacitor, giving the amp more gas on the bottom end reserves. Just a matter of space on such a small chassis. I could always fabricate my own top deck. I've already thought about this with installing the Staccato op-amps.

[NIGHTFALL1970]

We are all crazy here (so I feel at home) and I thought about adding Danny’s Tube Connectors, but I don’t think there’s room.

[nlitworld]

Yep, I figured at such a cheap entry point, getting wild with a soldering iron on there sounded like fun. RCA jack, speaker post, opamps, etc. Worth it given the cost of the unit, surely not. Fun project for a weekend of tinkering, heck yes. Thanks for the internals photo. Wheels turning for possibilities.

[NXSTUDIO-DRUMMER]

IF I were to get Staccato, I would just use two extenders on one side. 

But I'm trying to refrain from buying any more discrete opamps, including the interesting-looking Virtual Hifi opamps:
https://www.youtube.com/watch?v=Mub-xo619PY&lc=UgxdVC0dgL6KaUa1-qN4AaABAg.AKBzsVzeGuyAKIDM8Gt2Ms

 John, thanks for posting another op-amp option for the viewers. I never thought of these things, like one guy reviewing them said. Just think of rolling them like people do with tube's. You get a different sound signature. Danny, Ron and Hobb's totally validated there are differences, in their audio performance.

Here is another manufacture John L offered to the A5 owners. Thanks John! 
https://virtualhifi.com/products/supersonic-v1-op-amp

Offering 4 different models

[Jon L]

I really love what Virtual Hifi is doing with Qualio line of speakers, and these opamps do look very interesting.  However!  Make sure your equipment can handle the extra heat and current requirement of Virtual Hifi opamps 

[nlitworld]

First listen in straight stock form, pleasantly surprised, even without subs. Will let it break in then start to mod in a couple weeks. I really don't need another project, but this will be fun.

Also, input impedance is 7,900 if anyone is wondering. That'd make a 0.22uf cap roughly about 90hz xo. Probably have one of those laying around. 

[NXSTUDIO-DRUMMER]

Good information to know Llyod, thanks for advising us all.

In regards to John L discussion on the temperatures of the Virtual Hifi op amps, I could always fabricate a top deck and leave the hood off the A5 to ventilate properly, versus setting inside the unit itself. That's if I decide to go with the Virtual Hifi op amps. My tube amps have their tubes sitting outside the chassis too, so what's the difference.  Looks like the Brute Force One is a beast! Perhaps, it's cousin is Danny's "Bully." LOL

If someone installs the Brute Force One on the A5, and it performs like this, your in for one hell of a ride! 


All kidding aside,
Seriously, if any owners of the Douk Audio A5 have experience with different Op-Amp manufacturers, please take the time out, and share your thoughts with the community. Like tube rolling, these op-amps do have a different sound signature, regardless what the flat earth guys say.
As I'm discovering, there is quite a vast number of variations out in the market, to select from. I'm sure everyone would appreciate feedback on the topic. 

[NXSTUDIO-DRUMMER]

I've heard and read favorable reviews on a SX52B OP-Amp. This YouTube reviewer, is sharing his subjective listening experiences with multiple Op-amp's.
https://www.youtube.com/watch?v=LyV6mZk5GGw&t=1262s

He seems to display integrity with his opinions. I decided to purchase the SX52B on Ali-Express, with free shipping for peanuts. Evidently, based on some peoples assessments. The SX52B performance level, falls somewhere in between, the stock A5's 5552 op-amp, and the Sparkos SS3602 op-amp sound signature on material playback. Exactly what that entails, soundstage, decay wise, etc.?

Another guy comments on this op-amp is below,








I've seen it for sale as low as $10-$12.00 dollars, with free shipping.
 

Here are a few photo's of the SX52B Op-Amp. Yes, it does retrofit into the Douk Audio A5, without modifications or additional parts being required.








I'm sure, some may be shaking their heads, why bother?

Bottom line,
After hearing the evaluations from Danny, Ron and Hobb's and a few other reviewers.
Hearing their comments about this little amp, competing with 5-6k amps, performance wise, with the right electronics of course. Now that caught my attention big time! And I truly trust the ears of Danny's evaluation on the A5. Or, I wouldn't have a beautiful pair of NX-Studio's in my household. So to potentially drop a few dollars upgrading, connectors, op-amp rolling, even GaN technology power supplies, or linear power supplies on a 100 dollar amp? I believe it's worthy, no matter what level one wishes to take it!