Apex SR 200 Power AMP - Build

bijinmb

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This is APEX Studio Reference 200 Power AMP using Toshiba 2sc5200/2sa1943 OT.

This can be changed to MJL4281/ MJL4032 complimentary pair if needed.

Output power is: 200W/8R RMS.


More details can be found over here: Studio Reference Amplifier - diyAudio

I am posting few images of its work in progress below.

Schematics:



WIP
















Cabinet revised to Version 3.0

Changes:

1. Front panel 5mm SS Hex allen botls are now flush to the face plate.




2. Face plate now has rounded the edges when compared to previous beveled style.













Sharing few WIP images related with the fixing of the Caps in the PSU section.

6 x 20,000uF, 100V Alcon Caps.



Fixing the caps with screws from top:





 
Last edited by a moderator:
Hi Friends,

Instead of starting new thread i decided to wake up this post from 2013 which is already dedicated for Apex Studio Reference Amplifier “SR 200”. I came across this amplifier during lockdown period it had good reviews on www.diyaudio.com (the link for thread has already shared by Mr Bijin) so decided to built one for myself, Later I may sell it. Of-course for funding of next project. I must say this amplifier is one of the best sounding amp. It has the ability to play all kind of music with full power & authority. One of the Best amplifier in its class. This amplifier is capable to deliver 200 watts @ 8 Ohms with 75 VDC rail & I am feeding my amp the same voltage.

Initially my friend Mr. Muthukrishnan helped with DIY boards which were suitable for Sanken transistors. He did a good job, In a good will as a friend he gave me the pcbs without a single penny, not only PCBs he also provided with the OPamp IC and 12 Nos capacitors 470uf/100V. I am really very much thankful to him to provide so much stuff without his personal interest or penny. I was able to get this boards singing but was unable to set the bais. So experimenting with different resistor values and trim pot, it was unfortunate that i did managed to damage the tracks.

So now I decided to make the Boards from JLC. I looked for gerbers on internet and found gerbers from Mr Juan Vargas which he had shared for DIYers like us. Immediately without thinking left or right I placed the Order for PCBs to JLC. I received the PCBs after 20 or 25 days and then started to built my amplifier. This Boards used the transistors 2SC5200 & 2SA1943 from toshiba.

BOM:
Transformer is 50-0-50 AC / 600 VA “R-Core” Shielded from Shilchar. Soft-start & all connectors from diyaudiocrafts, Capacitor Bank & speaker protect pcb was given my our FM @Aniket , Heatsinks are from Akash Enterprise HS 300 model machined at a local engineering shop as per my dimensions. The complete enclosure is from aluminum sheet 3 mm laser cut and anodized as per my requirement. Face plate is 12.7 mm (1/2") thick machined at a local engineering shop as per my dimensions.

As I have mentioned above... This is indeed one of the best sounding amplifier and dead silent (zero hiss or hum). Enough of write up and sharing some photos of built. I will not be sharing the complete built just the highlights.

Below are the Boards and components provided by my friend Mr Muthukrishnan. Many FM from our forum may know him
IMG_20200713_230605.jpg

Assembly of his Boards
IMG_20200812_224249.jpg

Below are the PCBs from JLC. I liked the white color
IMG_20200912_234254.jpg

IMG_20200927_214828.jpg

R-Core from Shilchar.
IMG_20201005_190752.jpg

Testing & Bais setting. I managed to blow one cap due to my own mistake. the polarity was reversed, you can also see the green LED besides the capacitor is not glowing. I had to replace all the small transistors to get this PCB running again. (Always there is a lesson to learn) so lesson learned No over-confidence.
IMG_20201007_203117.jpg

Now coming to the enclosure. The aluminum plates were plain, I was trying for brush finish but ended with this beautiful pattern. I am loving it. The Owner of the anodizing plant said its the problem of material that is why it got its texture.
IMG_20201014_232713.jpg

IMG_20201017_202401.jpg

IMG_20201017_202420.jpg

Layout
IMG_20201018_144118.jpg

Wiring. One of my cleanest wiring i can say.
IMG_20201020_085427.jpg

Today i have given the face plate for machining. Tomorrow i will get it done. Will update more once i am finished with face plate.
 
Now coming to the enclosure. The aluminum plates were plain, I was trying for brush finish but ended with this beautiful pattern. I am loving it. The Owner of the anodizing plant said its the problem of material that is why it got its texture.
View attachment 51078
That "finish" actually looks great!Any idea how to repeat this process?
 
Hi Friends,

Instead of starting new thread i decided to wake up this post from 2013 which is already dedicated for Apex Studio Reference Amplifier “SR 200”. I came across this amplifier during lockdown period it had good reviews on www.diyaudio.com (the link for thread has already shared by Mr Bijin) so decided to built one for myself, Later I may sell it. Of-course for funding of next project. I must say this amplifier is one of the best sounding amp. It has the ability to play all kind of music with full power & authority. One of the Best amplifier in its class. This amplifier is capable to deliver 200 watts @ 8 Ohms with 75 VDC rail & I am feeding my amp the same voltage.

Initially my friend Mr. Muthukrishnan helped with DIY boards which were suitable for Sanken transistors. He did a good job, In a good will as a friend he gave me the pcbs without a single penny, not only PCBs he also provided with the OPamp IC and 12 Nos capacitors 470uf/100V. I am really very much thankful to him to provide so much stuff without his personal interest or penny. I was able to get this boards singing but was unable to set the bais. So experimenting with different resistor values and trim pot, it was unfortunate that i did managed to damage the tracks.

So now I decided to make the Boards from JLC. I looked for gerbers on internet and found gerbers from Mr Juan Vargas which he had shared for DIYers like us. Immediately without thinking left or right I placed the Order for PCBs to JLC. I received the PCBs after 20 or 25 days and then started to built my amplifier. This Boards used the transistors 2SC5200 & 2SA1943 from toshiba.

BOM:
Transformer is 50-0-50 AC / 600 VA “R-Core” Shielded from Shilchar. Soft-start & all connectors from diyaudiocrafts, Capacitor Bank & speaker protect pcb was given my our FM @Aniket , Heatsinks are from Akash Enterprise HS 300 model machined at a local engineering shop as per my dimensions. The complete enclosure is from aluminum sheet 3 mm laser cut and anodized as per my requirement. Face plate is 12.7 mm (1/2") thick machined at a local engineering shop as per my dimensions.

As I have mentioned above... This is indeed one of the best sounding amplifier and dead silent (zero hiss or hum). Enough of write up and sharing some photos of built. I will not be sharing the complete built just the highlights.

Below are the Boards and components provided by my friend Mr Muthukrishnan. Many FM from our forum may know him
View attachment 51072

Assembly of his Boards
View attachment 51073

Below are the PCBs from JLC. I liked the white color
View attachment 51074

View attachment 51075

R-Core from Shilchar.
View attachment 51076

Testing & Bais setting. I managed to blow one cap due to my own mistake. the polarity was reversed, you can also see the green LED besides the capacitor is not glowing. I had to replace all the small transistors to get this PCB running again. (Always there is a lesson to learn) so lesson learned No over-confidence.
View attachment 51077

Now coming to the enclosure. The aluminum plates were plain, I was trying for brush finish but ended with this beautiful pattern. I am loving it. The Owner of the anodizing plant said its the problem of material that is why it got its texture.
View attachment 51078

View attachment 51079

View attachment 51080

Layout
View attachment 51081

Wiring. One of my cleanest wiring i can say.
View attachment 51082

Today i have given the face plate for machining. Tomorrow i will get it done. Will update more once i am finished with face plate.
Great project Sadik. I was planning to build something similar. And I am really excited to find your project, very well done! I was wondering if you have the boards left over which you bought from JLC, if yes I would like to buy 2 of them from you.
 
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