250W+250W power amp build

[Aniket]

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.

Amp modules

Power amp modules. 4 pair 2SC5200/1943, TEF output stage.

Power transformer

0-220::40-0-40, 8A Secondary 640VA

Soft Start & Protection

Speaker protection and soft start integrated on a single PCB.

PreAmp & Power supply

Simple preamp based on TL074 opamp, and 20000uF capacitance per rail.

 

[reubensm]

good going, neat mounts on the PCB, that's one monster tranny

on another note, the circuit design (in relation to the output transistors) looks similar to my NAD 216thx, http://dymas.ii.uam.es/~jga/nad216thx/nad-216-sch.jpg

 

[kanwar]

Nice build Aniket

 

[Aniket]

good going, neat mounts on the PCB, that's one monster tranny

on another note, the circuit design (in relation to the output transistors) looks similar to my NAD 216thx, http://dymas.ii.uam.es/~jga/nad216thx/nad-216-sch.jpg

yes reubensm,

that too is TEF( Triple emitter follower) output stage. interesting circuit.

Regards,
Aniket

 

[spirovious]

Good DIY skills,well done.

 

[Mano]

Good work Aniket, would like to know if the PCBs are available for others. Are the 2SC5200/1943 Toshibas and would be interested to know the cost break up after you are done. Good luck.

Cheers

 

[Hiten]

Nice build Aniket.

 

[hydrovac]

Nice work Aniket,

Which driver and bias transistors are used, and set bias current? You want to bias this amp in class A or otherwise?

The power supply shown is for a 56V. The bridge rectifier should be a 400V/35A chassis mount type, and should be properly chassis mounted using heatsink compound.

Filter capacitors (63WVDC) can preferably be rated higher. If possible, use 105C rated caps, and join the earthed terminals very solidly to form the star earthing point.

Cheers.

 

[Aniket]

Good work Aniket, would like to know if the PCBs are available for others. Are the 2SC5200/1943 Toshibas and would be interested to know the cost break up after you are done. Good luck.

Cheers

Hello Mano,

I have 6 more PCB's to spare. the 2SC5200/1943 aren't available here in Delhi. i'm using Toshiba's TTC5200/1943, these are replacements for 2SC5200/1943, you could check them on the Toshiba semiconductors website. these have similar specs to the originals, and are somewhat better. I would be using Onsemi's NJW0281/0302 instead of the 5200's in future projects as these have much better SOA and above all these are available in Delhi for 200INR a pair.

Regards,
Aniket

Nice work Aniket,

Which driver and bias transistors are used, and set bias current? You want to bias this amp in class A or otherwise?

The power supply shown is for a 56V. The bridge rectifier should be a 400V/35A chassis mount type, and should be properly chassis mounted using heatsink compound.

Filter capacitors (63WVDC) can preferably be rated higher. If possible, use 105C rated caps, and join the earthed terminals very solidly to form the star earthing point.

Cheers.

Hello Hydrovac,

It's a triple output stage with MJE15032/33 drivers and MJE340/50 predrivers. the bias transistor is a BD139.
the bridge rectifier is rated at 1000V/35A, and i wanted to keep the connection between the bridge and the caps shortest, so I mounted it on the PCB itself, would use a heat sink for the bridge.
as for the filter caps, I used only 20000uF per rail, so under load the rail would sag and would keep the caps within safe limits. Nichicon, Rubycon, Panasonic weren't available here for anything above 50V, so had to use these Samwha caps that too were available upto 63V. earlier i was planning 4 10000uF80V caps per rail, but sadly these weren't available.
The terminals are connected using 2.5mm electrical copper wire and the main caps are bypassed with 0.1uF250V caps soldered under the PCB, star ground is made under the PCB on the copper side.

Regards,
Aniket

 

[diesel engine]

Re: Power transformer

0-220::40-0-40, 8A Secondary 640VA

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?

 

[GeorgeO]

Nice build, good to see diyers doing such projects..

 

[Mano]

Hello Mano,

I have 6 more PCB's to spare. the 2SC5200/1943 aren't available here in Delhi. i'm using Toshiba's TTC5200/1943, these are replacements for 2SC5200/1943, you could check them on the Toshiba semiconductors website. these have similar specs to the originals, and are somewhat better. I would be using Onsemi's NJW0281/0302 instead of the 5200's in future projects as these have much better SOA and above all these are available in Delhi for 200INR a pair.

Regards,
Aniket

Hello thanks Aniket, can you PM me your contact info so we can take it from there.

Cheers

 

[faizal]

Re: Amp modules

Power amp modules. 4 pair 2SC5200/1943, TEF output stage.

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

 

[omishra]

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

Yes, that's possible. I experienced same with Pass F5 turbo V2 Amp. There is audible difference between Fairchild MOSFETs and IRF replacement devices. People should not blame the design unless they use original recommended parts.

 

[linuxguru]

It's a triple output stage with MJE15032/33 drivers and MJE340/50 predrivers. the bias transistor is a BD139.

It's derived from Douglas Self's Blameless, but with a triple-darlington output stage. It can be improved further by operating the pre-driver and driver stages in Class-A (i.e. Self Type-II Emitter Followers), rather than Class-AB as shown. Most of the Emotiva/Sherbourn monoblocs also use 4x 2sc5200/2sa1943 in triple-darlington, but with drivers and pre-drivers in Class-A.

 

[Aniket]

It's derived from Douglas Self's Blameless, but with a triple-darlington output stage. It can be improved further by operating the pre-driver and driver stages in Class-A (i.e. Self Type-II Emitter Followers), rather than Class-AB as shown. Most of the Emotiva/Sherbourn monoblocs also use 4x 2sc5200/2sa1943 in triple-darlington, but with drivers and pre-drivers in Class-A.

Yup,

It could be improved a lot more, not only driver stage. but the CCS for the LTP and VAS also. another thing would be cascoding LTP and VAS, and using high gain low noise transistors in the LTP (eg BC550, MPSA18), and the excellent KSC3503/1381 in the VAS and predriver stages. but sadly I had the PCB's long ago, would surely redesign and improve the circuit later, and design new PCB's.

Edit:
finally assembled all the modules of the amp, got the cabinet yesterday, it took the whole day playing with jigsaw and drill, cutting circles for the fan, connectors, terminals, screw holes, on all sides, drilling holes that too in 1.5mm steel is bit lengthy . the cabinet alone weighs 6.5kgs.
But, at last could relax now listening to some hip-hop and feeling some bass. of course this amp is a beast, but sounds great. crisp and clear highs, smooth mids and the bass is so so powerful, great control and authority, it just punches in the chest. A thing that high power amps have so much control over the cone movement, it bottoms out an 8" 60W woofer so easily. pity on the woofer. This amp is begging for the right speakers, would connect my main speakers tomorrow( which are 2 way, with a 400W 12" Pioneer TSW1208D2 sub and a 4" 50W AudioPro tweeter which covers the midrange as well). couldn't do this at night, or my neighbors would go mad. Anyways, would post more pics and updates later.

Cheers!!,
Aniket

 

[sarith]

This amp is begging for the right speakers, would connect my main speakers tomorrow( which are 2 way, with a 400W 12" Pioneer TSW1208D2 sub and a 4" 50W AudioPro tweeter which covers the midrange as well). couldn't do this at night, or my neighbors would go mad. Anyways, would post more pics and updates later.

Cheers!!,
Aniket

Well done! After setting up the right speakers, would you mind uploading a video? Curious

 

[Aniket]

Well done! After setting up the right speakers, would you mind uploading a video? Curious

Sure,

Some earlier videos :
2 Pioneer TSW1208-D2 shattering my house - YouTube

2* Pioneer TSW1208-D2 creating havoc. - YouTube

These were powered by my 150+150 W amp.

 

[keith_correa]

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!

 

[sarith]

Sure,

Some earlier videos :
2 Pioneer TSW1208-D2 shattering my house - YouTube

2* Pioneer TSW1208-D2 creating havoc. - YouTube

These were powered by my 150+150 W amp.

Saw it..subscribed..Awesome vdos..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?

Hoping that you will upload vdo of 250+250 amp too.
A.R Rahman Maahi Ve Full Song (Audio) Highway | Alia Bhatt, Randeep Hooda | Imtiaz Ali - YouTube this ARR song seems to have nice bass.