[HT cOz]

I've started a new amp project from Mirand Audio http://mirand-audio.dk/ This company has been posting to DIYAudio for a few years and has a no cost compromise mentality.  Their newest amplifier is not on the website but can be found in this long DIY Thread https://www.diyaudio.com/forums/vendor-s-bazaar/274456-ak4490-usb-dac-dsd-support-158.html#post5488359  The amplifier module has a manual which is located at this link https://www.dropbox.com/s/we59snroi051bjc/Mirand%20A1%20V12%20Manual.pdf?dl=0

The vendor is very professional and the shipping and packaging of the boards/power supply is first rate.  The vendor has a real electronics company that pays the bills so some patience is needed in communications and expectations.  I'm not a pro at this so it takes me a long time to figure out basic things but am confident that the project will go well. 

I ordered an Avel Lindberg Y236803 500VA 35V+35V Toroidal Transformer from parts express and two amp boards, soft start and power supply from Mirand.  The Mirand parts are not inexpensive but I decided to build it to their exact specs and pay for the quality parts. 

My first problem is that my existing chassis was too small.  I began looking for an alternative and decided to order a unit from Takachi
  I found it in stock at their US supplier https://us.misumi-ec.com/vona2/detail/222000227816/?curSearch=%7b%22field%22%3a%22%40search%22%2c%22seriesCode%22%3a%22222000227816%22%2c%22innerCode%22%3a%22%22%2c%22sort%22%3a1%2c%22specSortFlag%22%3a0%2c%22allSpecFlag%22%3a0%2c%22page%22%3a1%2c%22pageSize%22%3a%2260%22%7d&Tab=codeList  Again this is not the least expensive solution, but is of high quality.

I'm starting to mock up the layout which should be easy as it is a fairly large chassis if you mount the amp modules to the side heat sinks. 

 
I'm pretty excited about this project but know it will take a few months to complete. 

Thanks for looking,
Robert

[HT cOz]

Update to my project...

I picked up the amp chassis at Christmas and am working to get it assembled.  Here are a few pictures of my progress. 










I've also created a file on Google Drive with relevant documents etc. 
https://drive.google.com/open?id=1mJ_K9M-_A1LbRCiwQik_Nc_5dYXdNpXZ

[mresseguie]

Hi. Thanks for posting this project.

Can you explain the reason why you're mounting a card on the left-hand heatsink? I'm not an engineer, and I have precious little DIY experience.

Regards,

Michael

[poseidonsvoice]

Hi Robert,

As a fellow diy hobbyist, I'm just here to cheer you on. I've got a few dozen projects under my belt and in the last 2-3 years it's almost universally been amplifier builds (courtesy of diyaudio, etc...).

The Takachi enclosures are very nice from a fit and finish standpoint, and I would reserve them for low bias Class AB designs mostly. I have a few Class A projects going and all of them need beefy heatsinks which although the Takachi HY series (even the 6U sized ones) have heatsinks, they are not very deep at all and hence their heat dissipation is quite low. I think for your project, you'll be fine. In fact, I am looking into Takachi for my next amp build, although the Modushop enclosures really make my life easy because of the baseplates you can order with them. If you need some inspiration, send me a pm.

Hopefully you are surviving in hectic sunny Chennai. Eat some dosas, idlis, sambar and chutney for me!

Michael, I think Robert has a pair of amplifier boards and he has shown you just one of them mounted thus far.

I ordered an Avel Lindberg Y236803 500VA 35V+35V Toroidal Transformer from parts express and two amp boards, soft start and power supply from Mirand.

My very best,

Anand.

[HT cOz]

Hi. Thanks for posting this project.

Can you explain the reason why you're mounting a card on the left-hand heatsink? I'm not an engineer, and I have precious little DIY experience.

Regards,

Michael

Michael,

I will also be mounting an amp module on the right side.  These photos were just to illustrate what I'm planning.  The design is to keep power in the middle and push the left and right channel to each side, using the heat sinks for heat dissipation.  A few advantages are that the power, signal and speaker wires can be run without crossing which should help prevent noise.  I'm honestly not very experienced either but an willing to try and sometimes make mistakes.  Before turning it on, I will have it checked by a qualified engineer but I'm trying to do as much on my own to help learn. 

[HT cOz]

Hi Robert,

As a fellow diy hobbyist, I'm just here to cheer you on. I've got a few dozen projects under my belt and in the last 2-3 years it's almost universally been amplifier builds (courtesy of diyaudio, etc...).

The Takachi enclosures are very nice from a fit and finish standpoint, and I would reserve them for low bias Class AB designs mostly. I have a few Class A projects going and all of them need beefy heatsinks which although the Takachi HY series (even the 6U sized ones) have heatsinks, they are not very deep at all and hence their heat dissipation is quite low. I think for your project, you'll be fine. In fact, I am looking into Takachi for my next amp build, although the Modushop enclosures really make my life easy because of the baseplates you can order with them. If you need some inspiration, send me a pm.

Hopefully you are surviving in hectic sunny Chennai. Eat some dosas, idlis, sambar and chutney for me!

Michael, I think Robert has a pair of amplifier boards and he has shown you just one of them mounted thus far.

My very best,

Anand.

Hello Anand,

I've taken inspiration from some of your projects and these are fun and rewarding.  I won't know until it is finished but I think this Mirand Amp is of high quality.  I imagine a retail version would be well out of my league!  Sonny (Mirand Audio Owner) is mounting them to the chassis base plate, so low bias class AB without the need for a lot of heat dissipation.  I didn't do the math but assume that the Takachi heatsinks are better than base plate mounting.  I'm fairly confused on the wiring but have some help here to get me through it.  Mirand could make this a little easier but I think Sonny is pretty busy.  Once I figure it out, I'll post information to make it easier for the common guy with less experience!     The Takachi case is pretty awesome and not too expensive in the USA.  In India it was 3X the cost of USA!!! Crazy and why I think there is a lot of opportunity in India.  Naturally, I've already messed it up a little, next time I'll bring back some painters tape and tape it all up before starting to work on it!!!    I don't stress too much on it though, nothing stays perfect forever.   

What is your next build?  If this Mirand goes well, I was thinking about building a second pair running from SMPS to bi-amp my new speakers. 

Chennai is pretty awesome for the audio hobby.  I was excited to get back to my big speaker project and help is readily available.  India is chaotic but at the same time if you work with the flow you can accomplish anything! 

One question I have is if you think I've mounted the RCA and Speaker output to far from center?  I'm trying to keep them away from the power section but it would probably look better if they were a bit more centered. 


Cheers
Robert

[poseidonsvoice]

Robert,

I’ve sent you a pm.

Best,
Anand.

[HT cOz]

Progress has been a bit slow as many of the processes in this build are my first time to attempt them. 

I had an unsuccessful hole tap which broke due to not having the right tap wrench.  This one worked but the small size of the M3 holes was still a bit tricky.  I taped 18 holes in total so by the end I was getting the hang of it. 




Opening up the rectangle for the IEC was a challenge.  I first used a stepped drill bit and decided that I don't really care for them.  They are fine for smaller holes but bigger holes like the ones needed for the Nuetrik cutouts (24mm) are not going to go well.  I ended up buying a cheap rectangular file and though it took some time, got the IEC installed.





Here is my plan for the 24mm Nuetrik primary hole.  These are made to cut steal so aluminum should be like butter.  Part of this process is learning what works for me. 




Now I'm on to mounting the transistors using a silicone pad and thermal paste.  I naturally used too much past and had to do everything twice.  I don't like the screws so I ordered some new ones and its on to more waiting. 



Next up is understanding the wiring... This is a bit of a challenge for me but it is coming along. 

[HT cOz]

A few more...

I've wired the transformer to the soft-start





The outside of the IEC



Next step is to wire the transformer to the power supply