Studio Reference Amplifier

[apexaudio]

Ok thanks,
which one is better, sanken or toshiba...? I bought toshiba transistors already ...my mistake...

Toshiba is OK

 

[apexaudio]

Hi Apex,

Im new here, almost read this thread from the beggining. It is so exiting to hear this stuff with my own work in the future.

I have here home made transfomer 800va but secondary output is quitly different 60 0 57 vac. After rectify by bridge diode it become +83.2 and -81.5 vdc.

Can this affect to supply class a/b amplifier? or is their other way to fix output dc to get balance?

DIY expert are welcome to reply.

an214q

Use regulated PSU from post #11 and set +/-75 vdc for SR200

 

[TonyTecson]

Hi Apex,

Im new here, almost read this thread from the beggining. It is so exiting to hear this stuff with my own work in the future.

I have here home made transfomer 800va but secondary output is quitly different 60 0 57 vac. After rectify by bridge diode it become +83.2 and -81.5 vdc.

Can this affect to supply class a/b amplifier? or is their other way to fix output dc to get balance?

DIY expert are welcome to reply.

an214q

no other way but to rewind you secondaries, this time do a bifilar wind, 2 copper wires wound at the same time, this is how i do all my traffos.....

if you do as i say you will never have to worry about balance voltages ever again...😀

 

[apexaudio]

no other way but to rewind you secondaries, this time do a bifilar wind, 2 copper wires wound at the same time, this is how i do all my traffos.....

if you do as i say you will never have to worry about balance voltages ever again...😀

No need to rewind secondaries, amp will work with this unbalanced rail voltages.

 

[AN214Q]

thank you Tony nice idea.

 

[JOHN BALI]

MJE on center also need same heatsink as the others, and this SanKen can be use instead Toshiba on same pcb.
Regards

Thanks,
I move it a little & ...
I believe this is not final layout, because it can be modified again latter to be better

No need to rewind secondaries, amp will work with this unbalanced rail voltages.

Will 300VA's trafo work for mono?
I'm planning to make my own trafo, maybe bifilar winding 🙂
Is this right :
55 Vac CT will work for non regulated PSU?
& 60 Vac CT will be OK for regulated PSU?

It will be my long... project 😎

Regards

 

[apexaudio]

Thanks,
I move it a little & ...
I believe this is not final layout, because it can be modified again latter to be better


Will 300VA's trafo work for mono?
I'm planning to make my own trafo, maybe bifilar winding 🙂
Is this right :
55 Vac CT will work for non regulated PSU?
& 60 Vac CT will be OK for regulated PSU?

It will be my long... project 😎

Regards

Use maximum 50 Vac CT for non regulated PSU, 300VA will work for mono.
Regards

 

[P_0815]

Dear Apex,
i build your PSU for my amp. Therefor i changed the values of a few parts (see picture) for DC output voltage from 34V to 42V. The PSU regulate the voltage really well, but after a few minutes the transistors MSPA42 and MPSA92 will be hot. Where is the mistake?

Regards

 

[comasus]

will SR200 amplifier work @ 4ohms load with 4 pairs of o/p transistors with +/-68vdc?

and how much output power i'll get?

sound difference between ax-14 and sr200?

 

[apexaudio]

will SR200 amplifier work @ 4ohms load with 4 pairs of o/p transistors with +/-68vdc?

and how much output power i'll get?

sound difference between ax-14 and sr200?

Yes and you will get 300W at 4ohms, I prefer sound of SR200.

 

[apexaudio]

Dear Apex,
i build your PSU for my amp. Therefor i changed the values of a few parts (see picture) for DC output voltage from 34V to 42V. The PSU regulate the voltage really well, but after a few minutes the transistors MSPA42 and MPSA92 will be hot. Where is the mistake?

Regards

What is the input voltage? Replace 1k2/1W with 2k2/1W or 3k3/1W.
Regards

 

[apexaudio]

and there is no mistake with 50 vdc on regulator input you have about 300mW on MPSA42/92

 

[comasus]

Yes and you will get 300W at 4ohms, I prefer sound of SR200.

Hi! Mile

then I am going to use this amplifier for PA speakers is that okay?
i think this will be better than b500 in highs as well as lows what do you say?

 

[apexaudio]

Hi! Mile

then I am going to use this amplifier for PA speakers is that okay?
i think this will be better than b500 in highs as well as lows what do you say?

Use SR200 for PA speakers and share your expirience,
Regards

 

[P_0815]

What is the input voltage? Replace 1k2/1W with 2k2/1W or 3k3/1W.
Regards

The input voltage is 50VDC. I changed the resistor from 1k2/1W to 3k3/1W and both transistors MSPA42/92 keeps cool. First of all i thought, if i change the value to 3k3, the current through the zener diode is too low.
Now, the PSU works fine and i can do the next step to integrate the PSU in the schematic of my amp.

Thanks a lot!

Regards

 

[nix]

..... Revised PCB this time , much better I hope ....🙂

Alex.

Hi Mr Apex Sir,
i try this pcb layout #145 but i have problem i got -48vdc at the output using 35 0 35 VAC trafo. I replace bc550 and bc560 to mpsa92/42 and mount in reverse position. sorry i dont have picture of my work. hope you can give me hint/clue on what could be the problem of my work if there is presence of high DC volts on output. thanks in advance.

regards,
nix

 

[44250]

just a lucky guess...

Have you placed all the jumpers? There is one in a lower left corner under the 2k2 2W resistors,easy to be forgotten and overlooked.

 

[apexaudio]

Hi Mr Apex Sir,
i try this pcb layout #145 but i have problem i got -48vdc at the output using 35 0 35 VAC trafo. I replace bc550 and bc560 to mpsa92/42 and mount in reverse position. sorry i dont have picture of my work. hope you can give me hint/clue on what could be the problem of my work if there is presence of high DC volts on output. thanks in advance.

regards,
nix

You must post pictures, there must be some mistake with this high DC on output.
Regards

 

[QQ12e5k1]

Top Side

Bottom will be upload later.

 

[apexaudio]

Bottom will be upload later.

Nice work, thank you for share this pcb design,
Regards