Budget Douk Audio A5 Class D Amp Mod- Nice amp addition for all audio enthusiast

nlitworld · « **Reply #80 on:** 21 Oct 2025, 09:40 pm »

Hoping to have a busy weekend tinkering. Antek LPS with 44v, 6.8A of power. I don't think it'll fit inside the case

, so I'll be building a bigger custom case. I'll be doing some other mods while I'm in there of removing volume control, IEC connector and GR B24 power cord.

Will definitely report back when I get it up and running.

YEEEEGZ · « **Reply #81 on:** 22 Oct 2025, 12:50 am »

You guys aren't messing around with these mods, the amps are looking wild!

NXSTUDIO-DRUMMER · « **Reply #82 on:** 23 Oct 2025, 06:31 pm »

Quote from: nlitworld on 21 Oct 2025, 09:40 pm

Hoping to have a busy weekend tinkering. Antek LPS with 44v, 6.8A of power. I don't think it'll fit inside the case , so I'll be building a bigger custom case. I'll be doing some other mods while I'm in there of removing volume control, IEC connector and GR B24 power cord.

Lloyd,
Here is one resource selling chassis's.
https://www.hammfg.com/electronics/small-case/chassis

https://www.aliexpress.us/item/3256807440743180.html?spm=a2g0o.detail.pcDetailTopMoreOtherSeller.11.3c03zcQGzcQGfR&gps-id=pcDetailTopMoreOtherSeller&scm=1007.40196.439370.0&scm_id=1007.40196.439370.0&scm-url=1007.40196.439370.0&pvid=265e331b-dc3e-4177-9e7d-3f0204d6d608&_t=gps-id:pcDetailTopMoreOtherSeller,scm-url:1007.40196.439370.0,pvid:265e331b-dc3e-4177-9e7d-3f0204d6d608,tpp_buckets:668%232846%238115%232000&pdp_ext_f=%7B%22order%22%3A%2225%22%2C%22eval%22%3A%221%22%2C%22sceneId%22%3A%2230050%22%2C%22fromPage%22%3A%22recommend%22%7D&pdp_npi=6%40dis%21USD%21257.79%2176.77%21%21%211828.33%21544.49%21%40210328d417612447300811038ebd06%2112000041558059998%21rec%21US%21%21ABX%211%210%21n_tag%3A-29910%3Bd%3A950cf7ce%3Bm03_new_user%3A-29895%3BpisId%3A5000000189703955&utparam-url=scene%3ApcDetailTopMoreOtherSeller%7Cquery_from%3A%7Cx_object_id%3A1005007627057932%7C_p_origin_prod%3A

Even Douk / Nobosound offers some chassis as well, on eBay.
https://www.ebay.com/str/doukmall?_trksid=p4429486.m3561.l161211

BrandonB · « **Reply #83 on:** 23 Oct 2025, 07:33 pm »

Hey fellows I wanted to ask where is a good place to start I am interested in some DIY builds but don't have a background in electronics?

NXSTUDIO-DRUMMER · « **Reply #84 on:** 23 Oct 2025, 08:16 pm »

Quote from: BrandonB on 23 Oct 2025, 07:33 pm

Hey fellows I wanted to ask where is a good place to start I am interested in some DIY builds but don't have a background in electronics?

So many options available for you Brandon,
It just depends on where you wish to start? Interested in building a amp, pre-amp, DAC or speakers?
Jaytor, mkrawcz are both very knowledgable, displaying some beautiful workmanship. I personally don't build as much electronics anymore as I used too.

Although, I have my eye on this DIY project. https://diyaudiostore.com/products/f5m-core-psu?variant=49173688418583
The good news, your on the right forum to receive advice for your DIY build, whatever you decide on.

nlitworld · « **Reply #85 on:** 23 Oct 2025, 09:00 pm »

Yeah I looked at those chassis but that power supply is 3in tall and wanted something vented on top. Will build a12x10 box with oak 1x4 sides, metal inlay panel for connections on back, and open mesh vented top for good heat dissipation. Bottom will be heavy steel for structural stability and good heat sink. Luckily I have some thermal paste around from building pcs so it should work out nicely.

Also Brandon, depending on what type of stuff you're wanting to build, there are many good resources and kits to start out with. Tubes4hifi, Elekit, Bottlehead and Akitika all make some pretty easy builds with tolerable but thorough instructions. Built and tinkered with a few Tubes4HiFi kits and have another EL84 amp going to complete this winter. All of these brands have good resources from the company with lots of help here and on the diyaudio forum. Welcome to the dark side!

NXSTUDIO-DRUMMER · « **Reply #86 on:** 23 Oct 2025, 09:31 pm »

Lloyd,
Look forward to hearing your assessment of the new LPS build.

KTS · « **Reply #87 on:** 23 Oct 2025, 11:07 pm »

Quote from: BrandonB on 23 Oct 2025, 07:33 pm

Hey fellows I wanted to ask where is a good place to start I am interested in some DIY builds but don't have a background in electronics?

+1 for DIY audio, I had no experience in building electronics, so far I have built 6 amps and 2 preamps. The build guides and helpful members on the forum are exceptional. Be careful any always keep your safety in the forefront of any electronics build, it’s addictive well. The DIY audio store has great service and response times.

Kelly

NXSTUDIO-DRUMMER · « **Reply #88 on:** 24 Oct 2025, 05:38 pm »

Lloyd,
Curious about a follow up on your new caps you installed on your A5, and how it compares to the stock caps. Care to share some feedback?
https://partsconnexion.com/nichicon-capacitor-10uf-100vdc-kz/

nlitworld · « **Reply #89 on:** 25 Oct 2025, 05:00 am »

So from what I remember of the old 10uf caps to Nichicon, everything seemed to smooth out and open up. I also know the Sparkos op-amps really did a big help with this amp, much more than the caps. Probably about 80/20 split on % positive change, but not a surprise given $ of opamps vs caps. I know in the weeks since all the mods, everything has really settled in nicely. I haven't heard much in the $$ category to compare against, but it sounds pretty darn good in my humble setup with my Tubes4HiFi SP9 preamp. More immediate attack with airy decay in the soundstage, but not so gainy as before, so I'm pretty happy with it. Really looking forward to busting out the soldering iron tomorrow. If there's space in there, I may look to upgrade those caps again away from electrolytic caps, but we'll see how silly I get with mods in the big case.

I will be installing high pass caps on the input RCA as well, so that they're set and in with each amp when I swap amps back and forth. Previously it was always on the output of my preamp, but now I'm setting inside each amp case. No extra connections or junction boxes.

NXSTUDIO-DRUMMER · « **Reply #90 on:** 26 Oct 2025, 03:37 am »

Quote from: nlitworld on 25 Oct 2025, 05:00 am

So from what I remember of the old 10uf caps to Nichicon, everything seemed to smooth out and open up. I also know the Sparkos op-amps really did a big help with this amp, much more than the caps. Probably about 80/20 split on % positive change, but not a surprise given $ of opamps vs caps. I know in the weeks since all the mods, everything has really settled in nicely. I haven't heard much in the $$ category to compare against, but it sounds pretty darn good in my humble setup with my Tubes4HiFi SP9 preamp. More immediate attack with airy decay in the soundstage, but not so gainy as before, so I'm pretty happy with it. Really looking forward to busting out the soldering iron tomorrow. If there's space in there, I may look to upgrade those caps again away from electrolytic caps, but we'll see how silly I get with mods in the big case.

I will be installing high pass caps on the input RCA as well, so that they're set and in with each amp when I swap amps back and forth. Previously it was always on the output of my preamp, but now I'm setting inside each amp case. No extra connections or junction boxes.

Sounds like might be a worthy capacitor upgrade. Your SP-9 is a nice preamp.

nlitworld · « **Reply #91 on:** 26 Oct 2025, 04:06 am »

Was a little slower progress than I wanted, but case is built. Still need to stain it nicely, but it'll be good. I did find an aluminum sheet in the garage from an old Hammond chassis that I used for the bottom base. The open lattice should be nice for ventilation. Tomorrow and Monday will be a little tied up so likely won't bust out soldering iron til mid-week. You know I'll report back as soon as it's up and running.

Also my SP9 has had some good upgrades as well, cause tinkering is fun. Audyn MKP caps in power supply, Miflex input caps, Jantzen Superior coupling caps with Miflex bypass, upgraded all RCA connectors, RCA 5751 tubes and a few other thingsI know I'm forgetting.

That A.I. preamp always sounds appealing but I always hear they are torture on tubes. It does make me laugh when you see the warnings on places like Upscale. Gives kind of the notorious bad-boy mystique. A friend has an older gen and always says nice things about it.

Tyson · « **Reply #92 on:** 26 Oct 2025, 04:38 am »

I have never had a device eat through tubes the way the Audible Illusions did. It was my first piece of tubed gear and I thought I just wouldn’t be able to afford to run tube gear, lol.

NXSTUDIO-DRUMMER · « **Reply #93 on:** 26 Oct 2025, 05:15 am »

Yes,
The Audible Illusion Modulus 3A does eat tubes. I bought it when I purchased my Aragon 4004 mk ll years ago. The two really mated up well.
But Tyson is right, it does eat tubes! LOL I do like the sound though. I haven't used it for few years now, so I set it up with the A5. They sound really nice together. I may seek out a tube preamp that would match up well with a class D amp, that's easier on tubes! No hybrid preamp's though!
_______________________________________ _______________________________________ _______________________________________ _________________
Addressing Tyson’s point with Audible Illusions Modulus 3A for shortening the life of tubes.

The solution discovered for tube longevity on the AI modulus 3A. Use 6922 grey plates, or 6H23NEB Russian tubes, RU-6H23P-EB Reflector 6H23P-EB / 6922
Ensure the internal regulated B+ voltage is within the specified range (typically 110-135VDC depending on the tube). If it is out of spec, a faulty regulator (such as the 723-14 pin chip) may be cooking the tubes prematurely. Checking plate voltage is important.

I have also discovered using a Dac that is no higher than a 2 volt output, is better suited, otherwise it pushes the tubes too hard. While the unit features a "standby" mode that keeps filaments warm to prevent "cold start" thermal shock, this continuous idling still contributes to gradual wear. For long periods of non-use, fully disconnecting the power or using a power strip to shut it down completely can save hundreds of hours on the tubes as well.

I Don’t recommend this preamp for usage with a Douk Audio A5, without using something like a Rothwell Attenuator. Without a product like the Rothwell Attenuators, the AI 3A has too much gain. 30 db actually. Adjusting the volume is touchy, going from 0 to 100 too quickly. Even though I did use it carefully. It just runs way to hot, gain wise, to use or suggest with a Douk A5.
Although if somone has a high gain preamplifier that may overdrive the Douk A5, hereis a high quality solution. It is available in a 10db or 20db reduction of gain output. http://www.rothwellaudioproducts.co.uk/html/attenuators.html

https://www.hlabs.com/products/attenuators/

In summary:
The A5 being a class D amp mates up better with a tube preamp IMO. I've heard it set up on two different tube preamps now, and I'm sold on the signature the tubes used with the A5 class D amplification.

KTS · « **Reply #94 on:** 26 Oct 2025, 10:37 am »

Quote from: nlitworld on 26 Oct 2025, 04:06 am

Was a little slower progress than I wanted, but case is built. Still need to stain it nicely, but it'll be good. I did find an aluminum sheet in the garage from an old Hammond chassis that I used for the bottom base. The open lattice should be nice for ventilation. Tomorrow and Monday will be a little tied up so likely won't bust out soldering iron til mid-week. You know I'll report back as soon as it's up and running.

Also my SP9 has had some good upgrades as well, cause tinkering is fun. Audyn MKP caps in power supply, Miflex input caps, Jantzen Superior coupling caps with Miflex bypass, upgraded all RCA connectors, RCA 5751 tubes and a few other thingsI know I'm forgetting.

That A.I. preamp always sounds appealing but I always hear they are torture on tubes. It does make me laugh when you see the warnings on places like Upscale. Gives kind of the notorious bad-boy mystique. A friend has an older gen and always says nice things about it.

The case you made is very cool! Did you mill the plate to hold the inputs, outputs and AC? I have not listened to any class D before, very interesting thread.

I am assuming the setup your building could be made balanced by adding a universal buffer?

nlitworld · « **Reply #95 on:** 26 Oct 2025, 12:41 pm »

Quote from: KTS on 26 Oct 2025, 10:37 am

The case you made is very cool! Did you mill the plate to hold the inputs, outputs and AC? I have not listened to any class D before, very interesting thread.

I am assuming the setup your building could be made balanced by adding a universal buffer?

Yes, I bought a 1½ aluminum piece from home depot, and used my good ol Milwaukee drill and dremel to make the piece. Tube connectors will be glued into place just for extra secure hold, but everything else just snugs right in.

As for the buffer, I'm not sure as I've never ran balanced components but I'm sure it could be engineered to work.

tremrej65 · « **Reply #96 on:** 26 Oct 2025, 02:59 pm »

nlitworld,
Nice looking chassis!

goggle1824 · « **Reply #97 on:** 26 Oct 2025, 03:03 pm »

Step bit or twist bit to drill your aluminum?

I’m pretty interested in learning more about working with Aluminum specifically for enclosures, etc, but realistically, I’ll just be using more basic, powered woodworking tools and hand tools. I’ve been doing some searching online as well, does anybody have a really good link or source for good basics or entry level type tutorials? 😇🤔

nc42acc · « **Reply #98 on:** 26 Oct 2025, 03:09 pm »

“I'm really looking forward to purchasing the Staccato op-amps, and evaluating them. I hear nothing but good about Jakub's w/ Staccato op amps. I've heard, they sound even better than the Sparko's op amps. Anyone interested in his op-amps, he also sells the extenders for the A5 too. Not sure how his pricing compares to Parts Connexion?”

In my comparison I preferred the Staccato over the Sparkos. I look forward to reading your thoughts.

nlitworld · « **Reply #99 on:** 26 Oct 2025, 04:06 pm »

I used a regular twist bit and dial calipers to double check sizing needed. I think I used a 3/8 or 13/32 bit for everything which is an easy fit for those rca but I have to wiggle around and open up a smidge for the tube connectors. One day I'll get a real 7/16 bit for tube connectors, but no big deal.

You'd be surprised how easy everything is with a few basic tools. Jigsaw, cutoff wheel, dremel, drill and saw and you're good to go.