Info on this pair of A1943/C5200

[RishiGuru]

Hello this is rishiguru. I am a newbie and have very little knowledge about DIY. My friends audio amplifier is broke we have opened the cabinet and found that a pair of A1943/C5200 is used per channel of the two channel amp.

Now, one of the C5200 is burnt, so below is the image of the other pair(which seems ok).

[url=https://www.freeimagehosting.net/2c95f]**broken link removed**[/URL]

Can anybody tell the name of the manufacturer & the specs like power output, voltage and current ratings of this pair. The amp is rated 125 watts X 2. the transfo outputs +/-30V to this two pair of transistors. Is the current rating 5A (not quoted on the transfo)?

It also have 4, 4700uF, 50V capacitors used as ripple filters

Also cannot find CKT brand name? Where we can buy this exact pair?

Kindly help. Thanks in advance.

 

[ronsimpson]

I found them at digikey.com
2SC5200
2SA1943

 

[RishiGuru]

I found them at digikey.com
2SC5200
2SA1943

Are the above transistors from Toshiba?

 

[ronsimpson]

If you go to digikey you will see that there are choices.
Toshiba, Fairchild Semiconductor, STMicroelectronics

 

[RishiGuru]

If you go to digikey you will see that there are choices.
Toshiba, Fairchild Semiconductor, STMicroelectronics

Will having left speakers of CKT brand and Toshiba ones on right can produce different sound signatures in the speakers?

Can any one tell me where I can get this specific pair (Same brand & model)?

 

[ronsimpson]

I found the 2sc1943 at all of these but not from CKT.
Newark, Farnell, Mouser Electronics, TTI, Avnet Express, arrow, MCM Electronics, Quest Components
Maybe someone will have old stock. Good luck

If you can hear the difference between CKT and Toshiba then there may be something else wrong.

 

[RishiGuru]

I found the 2sc1943 at all of these but not from CKT.
Newark, Farnell, Mouser Electronics, TTI, Avnet Express, arrow, MCM Electronics, Quest Components
Maybe someone will have old stock. Good luck

If you can hear the difference between CKT and Toshiba then there may be something else wrong.

thanks, ronsimpson

 

[RishiGuru]

well the amp is rated:

125W X 2 @ 4ohms
100W X 2 @ 6ohms
80W X 2 @ 8ohms

The transformer is sizebale. From what i heard you need a minimum of 300Va tranfo to pump out 250 watts of power @ 4 ohms. So, i was thinking +/-30V, 5A from the transfo. (ampere not quoted on the transfo)

the transfo have two secondaries +/-30V to the power amps (two sets of the above transistors) & +/-15V to the op amp circuit.

Below is the link to amplifier internal (hope it helps):
**broken link removed**

The op amps (3 units) are Texas Instruments TL072CP. Are they dual op amps. Just out of natural curiosity is the transfo 300+ VA?

 

[colin55]

It looks like a 150VA transformer 150VA = 2.1kgm

 

[RishiGuru]

It looks like a 150VA transformer 150VA = 2.1kgm

well all i can say is the amp weighs 9 kilos.

The transformer have a diameter of 11 cm and a height of 5.5 cm

 

[colin55]

The transformer has a diameter of 11 cm and a height of 5.5 cm - it's 150VA

 

[RishiGuru]

Well here is the info i was able to gather regarding the amp. And yes this CKT A1943/C5200 transistors belong to Taiwan. Do not know the manufacturer yet.

1: the primary fuse rating. :T3AL250V.EI

2: the physical dimensions of the transformer.: Diameter: 11 cm, Height: 6 cm

3: the rating of the secondary rectifier diodes:
i) Secondary +/- 30V --> Diodes used is two pairs of 6A4 MIC, Caps: two pairs of 4700uF, 50V --> goes to power amp
ii) Secondary +/- 15V --> Diodes used is two pairs of "MIC", Caps: two pairs of 1000uF, 25V --> goes to pre amp

4: the amplifier module fuse ratings: Each of these A1943 or C5200 have one T3AL250V.EI fuse. Total 4 fuse for four transistors.

Transformer pics:

**broken link removed**

**broken link removed**

**broken link removed**

Diodes at +/-30V rails:
**broken link removed**

Internal layout:

**broken link removed**

**broken link removed**

Heatsink:
**broken link removed**

I am very curious to find out the true power output of the amp. Also the VA rating of the toroid.

Thanks in advance

 

[RishiGuru]

Hi guys, here is the update. My friend have bought the pair of transistors. Also the multimeter.

We will be starting to do our DIY on the amplifier by tommorow.

Also, i got the toroid transformer specs.The transformer is a 5 amp for 30-0-30, and 350 Ma for 15-0-15 winding.

60 X 5 = 300.00 VA [goes to Power amps]
30 X 0.35 = 10.50 VA [goes to Pre amps]
---------------------------
Total = 310.50 VA

Any idea about its true continuous power output per channel for this amp?

 

[audioguru]

You said the power supply is plus and minus 30V which is a total of 60V. Then the output swing is aboput 54V p-p which produces about 91W into 4 ohms at clipping. Maybe the output is 56V then the output power is 98W into 4 ohms.

I think the amplifier manufacturer is lieing about how much output power.