Studio Reference Amplifier

[Arif Budiyanto]

Dear Mr. Apexaudio,
I use one my regulated psu 10 to feed my amp (using 2 pairs of toshiba 5200, 20mV bias set up on R 0,22 Ohm 5 W). 32 Vac from 5A EI resulted 40Vdc.
After plays 5 songs, the bridge dioda (50 A) will be warm tends to hot, zener dioda is 8V.
If I set bias for 5mV, bridge dioda only warm after playing more than 20 songs.
May I have your advice to solve the problem?
Thank you so much.
Best Regards.
Arif

[JOHN BALI]

Hi Mr Arif,
I guess it is still normal condition, did you put a small heatsink on that bridge rectifier?
I found that our local bridge diode can't handle its ratted current, that bridge dioda without plastic case is better.
I use that marked MIC RU AC KBPC3510 on traffo 32 VAC 10ABE*T on my AX, only warm witout heatsink
How about your new PCB SR200 V2, do you already worked on it?

Regards

[Arif Budiyanto]

Originally Posted by JOHN BALI

Hi Mr Arif,
I guess it is still normal condition, did you put a small heatsink on that bridge rectifier?
I found that our local bridge diode can't handle its ratted current, that bridge dioda without plastic case is better.
I use that marked MIC RU AC KBPC3510 on traffo 32 VAC 10ABE*T on my AX, only warm witout heatsink
How about your new PCB SR200 V2, do you already worked on it?

Regards

Hi John Bali....How are you?
I see, maybe because of the diode built quality. I use the Mexico one...maybe needs to be put heat sinking on. I used the MIC before but some friends told me that Mexico is the better one.
I order the pcb, never build that one (lack of capability..hi hi hi) ... I am still thinking about what color I will take for that pcb and the pcb maker still full of tasks. So I have to be patient waiting for my pcbs.
Thanks for your input...
Best Regards..

[Arif Budiyanto]

Dear John Bali,
sorry my mistake, wrong posting on local diy forum, the right one is I set bias 1 V on r10Ohm instead of fuse. I tried to set up to 1,2 up to 1,3 but the HS was too small. So the amp will hot soon. For the safety reason I prefer to have 1V bias setting.
Best Regards.

[JOHN BALI]

Originally Posted by Arif Budiyanto

Dear John Bali,
sorry my mistake, wrong posting on local diy forum, the right one is I set bias 1 V on r10Ohm instead of fuse. I tried to set up to 1,2 up to 1,3 but the HS was too small. So the amp will hot soon. For the safety reason I prefer to have 1V bias setting.
Best Regards.

Hi, I'm fine thanks.
I have use Mexico diode, they are hotter. I have 2 grade, one of them marked JPN but not really good diode. They only good at lower voltage...
for bias I will say
No, 1 volt on 10 ohm resistor will be 333mA per output tranie (very hot )
Apex suggest 30-60mA per output.
Now let see what the other comment

Originally Posted by shreya

Hello Andrew

I mean in sr200 amplifier

capacitors voltage must be?

Hi Shreya,
I was ask similar question but nobody answer it yet.

Originally Posted by JOHN BALI

Hi Apex,
For C1, C8, C9, C10, C11 it is also 50V or higher?
if we use max +/-75VDC, what is the minimum allowed(safe) for these caps rating?

I guess 50V ratted caps will be okay, except on
C8 220nF, C9 22nF, C10 & C11 100pF
I don't know the safe ratting of these caps, maybe they fail if we use 50V ratted caps since total from rail will be more than 100V
So anybody give us some clue, please...

@Arif Budiyanto, what your caps ratting that you used?

Regards

[apexaudio]

Originally Posted by Arif Budiyanto

Dear Mr. Apexaudio,
I use one my regulated psu 10 to feed my amp (using 2 pairs of toshiba 5200, 20mV bias set up on R 0,22 Ohm 5 W). 32 Vac from 5A EI resulted 40Vdc.
After plays 5 songs, the bridge dioda (50 A) will be warm tends to hot, zener dioda is 8V.
If I set bias for 5mV, bridge dioda only warm after playing more than 20 songs.
May I have your advice to solve the problem?
Thank you so much.
Best Regards.
Arif

Use fast diode instead bridge like in post #52

[JOHN BALI]

Dear Apex,
that will be more time to source the fast diode, hard to find in my local city.
any fast diode will work? Any diodes type that recommended?

and sorry if this one just a silly question
but please your guidance because I'm not sure yet

Originally Posted by JOHN BALI

I guess 50V ratted caps will be okay, except on
C8 220nF, C9 22nF, C10 & C11 100pF
I don't know the safe ratting of these caps, maybe they fail if we use 50V ratted caps since total from rail will be more than 100V
So anybody give us some clue, please...

Thanks in advance

[Arif Budiyanto]

Many thanks Mr. Apex for your advice...
and
Thanks to Mr. John Bali,
I do have the same problem in finding the fast diode. I will try to find those fast diodes by internet order..
Best Regards..

[carlmart]

I think On's MUR diodes can be a good choice too and easier to find.

[comasus]

which type of capacitor i have to use (SR200) for C1 10uf & C4 1uf

can i use electrolyte polarized type??