250W+250W power amp build

[diesel engine]

Re: Amp modules

Recently in Kerala i am not getting original 2sc 5200 and 2sa 1943 pair,i can here audible difference between original n fake one,now in our market we are getting T T I 5200 and TTC 1943:sad:
i tested with original(IMO) Vs fake,there is a huge audible difference in in overall tone and quality

Please post some photos of the original and fake

 

[kanwar]

2SC5200 & 2SA1943 && TTC5200 & TTA1943 are both genuine from Toshiba. TTC/TTA are newer versions from new process.

 

[Aniket]

Hi Aniket, do you have fans on the chassis opposite both ends of those heat sinks? Are those sinks hollow or solid?

That's a hell of a transformer!

Hi,

there's only one fan at the rear of the cabinet to exhaust hot air. heat sinks have horizontal fins and they form a tunnel the way they are placed.

2SC5200 & 2SA1943 && TTC5200 & TTA1943 are both genuine from Toshiba. TTC/TTA are newer versions from new process.

Exactly,

both have similar specs and SOA, except for, the TTC's have a bit higher gain and lower COB than 2SC's, so techically as far as the datasheet says TTC's should sound better.

Nice build this is buddy.
to be on the safe side, you should have used at least 75V filter capacitors.
BTW, what is the tounge width and stack height of this transformer?

Hi diesel engine,

that's a cool name. my car too has a diesel engine.
anyways, I planned to use 80V caps earlier, but sadly those weren't available here, had to use 63V caps. So, to be on the safe side, i used only 2 10000uF caps per rail as the rails sag under load and keep the caps within safe limits. The caps sees ~56-57V max at no load.

the transformer is 4.5" tall, 5" wide, 4" deep, weighs around 10Kgs.

.btw, that 8" woofer you have seems good. I like white colour cone and the surround is inverted it seems. It's written 'Power' on the dust cup. Is 'Power' good? How much did it cost you?

Hi Sarith,

"Power" It's was local brand here in Delhi, Gurgaon, I have 2 of these and are around 10yrs old. I mostly use them for testing purposes, sure they look good, and yes the surround is inverted. They costed me only 150 INR a piece 10yrs ago. Don't know if these would be available or not nowadays.

 

[anurag.lodha]

Hello Guys,

sharing some pics of my current project, a 250W+250W amp with integrated tone controls. design and schematic is by me and PCB's are by Mr. AlexMM from DIY Audio. the chassis is under construction at a local sheet metal shop, would be ready by tomorrow.

Cheers!!
Aniket

Hi Aniket,
Thanks for sharing. Could you please share a high resolution pic of the schematic as not able to clearly make out the exact value of each component.

Also would be good if you share the overall cost incurred for components, PCB, chasis, etc.

Could we please connect offline as I need to understand where can I get all these stuff locally in Delhi and would also appreciate some tech guidance to build this monster
Please ping the contact details.

Thanks,
Anurag

 

[Aniket]

Hi Aniket,
Thanks for sharing. Could you please share a high resolution pic of the schematic as not able to clearly make out the exact value of each component.

Also would be good if you share the overall cost incurred for components, PCB, chasis, etc

Thanks,
Anurag

Hello Anurag,

I had attached high resolution pic of the schematic on the first post, but it has been downsized automatically.
other thing is the attachment quota is only about 250kB, i was attaching the updated and improved schematic in pdf that too only 64kB, it says you exceed your quota by 9kB. Pity.:sad:

Hi Ankit,
Could we please connect offline as I need to understand where can I get all these stuff locally in Delhi and would also appreciate some tech guidance to build this monster
Please send the contact details on [email protected]

Thanks,
Anurag

The cost of the whole amp came around 8~8.5K INR. for the rest i would email you.

Regards,
Aniket

 

[omishra]

Upload image to imageshack.us and share that direct image link between post by choosing insert image button at above this reply box - rising sun from mountain.

 

[Aniket]

Created my account on Imageshack. Thanks omishra.

Here's the link to the original schematic. https://imageshack.com/i/n8x5j8j

Updated schematic. https://imageshack.com/i/nhx26qj

Updated PCB. https://imageshack.com/i/fksl2hg

Simulated the updated schematic in Multisim, used NJW0281/0302 as output devices. Performance is same as before, THD figures are 0.001% @ 1kHz and 0.01% @ 20kHz @ 330W into 4 ohms. DC offset 0.4mV. Improved the Constant current sources for the LTP and VAS. Predrivers operate in Class A with 4mA current. Although I used NJW0281/0302 outputs, a number of other output transistors could be used, such as 2SC-TTC5200/A1943, 2SC5949/A2121 from Toshiba, MJL3281/1302, MJL4281/4302, NJW3281/1302, MJL21193/21194 from On semiconductors, 2SC6011/A2151, 2SC6145/A2223, 2SC3263/A1294 from Sanken. 2SC4793/A1837 could also be used as drivers. and if you could get use 2SC-KSC3503/A1381 in the VAS stage for even more improved performance and lower THD figures.

Regards,
Aniket

 

[omishra]

Original -

Updated -

 

[Aniket]

Thanks again.

I tried the image URL option but, the image didn't showed up.
Updated PCB.

It did this time.

 

[quad]

Should Q1 and Q2 be back to back on the board for better thermal
coupling (zip tie or heat shrink)? Something like Q5, Q4 here (some pic found on net) -

 

[faizal]

actually i got relocated to saudi arabia last week,and i am not having the components with me,and i am not having the photos of fake and genuine transistors right now,i heard the audible difference between TTC and 2sc series transistors, in which 2SC is best

please go for Alcon Capacitor 100v working range,available from DIY audiocart,very good component with life upto 5000hrs,

2SC5200 & 2SA1943 && TTC5200 & TTA1943 are both genuine from Toshiba. TTC/TTA are newer versions from new process.

Dear Kanwar,
I got 2 amps,one with 2SC5200 & 2SA1943 and one with TTC5200 & TTA1943. The former amp having good base and the latter having reduced base.i interchanged inputs,speakers, power connections, swapped the whole amp but the same problem

 

[Aniket]

Should Q1 and Q2 be back to back on the board for better thermal
coupling (zip tie or heat shrink)? Something like Q5, Q4 here (some pic found on net) -

Hi,

If your question is for me, regarding the placing of Q1 and Q2 on the new PCB, then here's the answer.
Q1 and Q2 are part of small signal circuitry, the input stage here. these operate at less than even 1mA and have around 45~50V across C-E. these dissipate close to nothing thermally, i.e they remain cold always.
thermal coupling is required where the transistors get warm, or hot and need thermal contact with other device to track temperature for compensation, here in case of Q1 and Q2, if they were to get warm they would have required thermal coupling to maintain linearity, gain also the DC offset.

Regards,
Aniket

 

[kanwar]

Are the 2 amps same?

 

[faizal]

Are the 2 amps same?

exactly same,differ only in final power transistors ie TTC & 2SC

 

[kanwar]

Are the TTC genuine?

Can you post some pics of both the amplifiers?

 

[faizal]

Can you post some pics of both the amplifiers?

I am not sure whether it is genuine(poor marking of part number) and i didint find any original TTC and TTI in our market .Currently i am relocated to Saudi Arabia so i am not having any images of the same and soon i can post as i reaches my home

 

[Aniket]

After a long time, I made my version of this amp with some upgrades.
Used a 45-0-45, 750VA toroid with 3X15000uF100V caps per rail for the power supply.
In the amplifier modules, used Onsemi NJW3281/1302 in place of 2SC5200/A1943 in the output stage, and KSC3503/A1381 in place of MJE340/350 in the VAS stage.
With these mods the amp puts out 300W+ per channel. Finally after a long time I made an amp for me

Here are some pics:

Regards,
Aniket

 

[spirovious]

Aniket ,the amp looks super cool and hifi. Congrats.

 

[Mano]

Hello Aniket the amp looks very good with a clean layout. Congrats.

Cheers

 

[omishra]

Looking good!