AB100 Class AB Power Amplifier

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#1,222
Hello friends,
I once considered this project, but now I've come back to it again. Although the topology is quite outdated, even nowadays still sufficient quality for home hifi.
A lot of people have asked in the thread what maximum voltage to choose for this amplifier. If you look at the SOA characteristics of the TIP142/147 transistors, I would go to a maximum of 45V DC, but prefer less. In my case I chose a toroidal transformer 2x25V AC / 300W. Since I live pretty close to a transfo-station, I measured 237V AC on my network, which gave me 28V AC on my transformer. (28x1,41=39,5V, ...when we cut off the loss on the diodes I get to 36,5V). With this voltage I can easily reach 100w/4 ohm, which is plenty enough for me at home!

Since I'll be powering the amp with a lower voltage than you all, I'll use a low-noise bc550c on the input stage (T1, T2). The main filter capacitors will be Mundorf 6800uF/40V, 4 pcs per channel. The small capacitors will be Audio Note from the Kaisei series. The ceramic capacitors will be Charcroft and the foil capacitors I will use Amtrans. Resistors probably Vishay Dale.

The enclosure will be from Slim Line 2U Modushop series and the whole amplifier will be inside on massive SK56/75/SA heatsinks from Fischer Elektronik. The top cover on the box will be fully vented. PCBs are already at home, so I'll slowly start building.

Do you like my idea?

IMG_20221227_211452.jpg
 
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#1,225
HRDSTL said:
Hello friends,
I once considered this project, but now I've come back to it again. Although the topology is quite outdated, even nowadays still sufficient quality for home hifi.
A lot of people have asked in the thread what maximum voltage to choose for this amplifier. If you look at the SOA characteristics of the TIP142/147 transistors, I would go to a maximum of 45V DC, but prefer less. In my case I chose a toroidal transformer 2x25V AC / 300W. Since I live pretty close to a transfo-station, I measured 237V AC on my network, which gave me 28V AC on my transformer. (28x1,41=39,5V, ...when we cut off the loss on the diodes I get to 36,5V). With this voltage I can easily reach 100w/4 ohm, which is plenty enough for me at home!

Since I'll be powering the amp with a lower voltage than you all, I'll use a low-noise bc550c on the input stage (T1, T2). The main filter capacitors will be Mundorf 6800uF/40V, 4 pcs per channel. The small capacitors will be Audio Note from the Kaisei series. The ceramic capacitors will be Charcroft and the foil capacitors I will use Amtrans. Resistors probably Vishay Dale.

The enclosure will be from Slim Line 2U Modushop series and the whole amplifier will be inside on massive SK56/75/SA heatsinks from Fischer Elektronik. The top cover on the box will be fully vented. PCBs are already at home, so I'll slowly start building.

Do you like my idea?

View attachment 1123630
Click to expand...
I think you will be pleasantly surprised. It sounds pretty good for old technology. My heatsinks are a little small, I put everything inside an old Proton D1200 case and hooked up the watt meters. It looks good and sounds good. Currently using it in my main system for 200Hz and up. I'll be replacing it with two Wolverine monoblocks and a stereo Honey Badger for the 200Hz and down.


20220113_183508.jpg
 
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#1,228
Bc550/560 have the same pin layout as bc547/557, just look at the datasheet. TTA004/TTC004 have the same pinout as KCS3503/KSA1381 but only 1,5W and I'm not sure if they would be enough to build full performance of TIPs 142/147.

KCS3503/KSA1381 is a better choice!
 
#1,232
I browsed the web a bit and read that TIP142/147 are not very suitable for audio applications. I don't know how it is with the newer types with the G suffix.
Admittedly these older 142/147 types also had an integrated audio analugue puccini amplifier in them, and sounded very good!

In any case, ...my version will have the SANKEN 2SB1560/2SD2390 - designed for audio.
 
#1,233
HRDSTL said:
I browsed the web a bit and read that TIP142/147 are not very suitable for audio applications. I don't know how it is with the newer types with the G suffix.
Admittedly these older 142/147 types also had an integrated audio analugue puccini amplifier in them, and sounded very good!

In any case, ...my version will have the SANKEN 2SB1560/2SD2390 - designed for audio.
Click to expand...
If you read the entire thread, you will find this is the Analugue Puccini design.
 
#1,234
Friends, my AB100 boards are almost ready, ...equipped with Nichicon (4x 6,800 uF) from the KG series. I'm only waiting for small capacitors ELNA (100uF) and ceramics from Charcroft Silver mica.

IMG_20230116_171730.jpg
I am going to use sanken 2SB1560/2SD2390 transistors. Have any of you used anything other than the TIP142/147?

At the moment I'm going to install parts for the SSR protection 🙂
IMG_20230116_171958.jpg
The whole amplifier will be designed as dual mono, 2x toroid, 2 power supply (4x 10.000 uF) in a 3U box from Modushop.
 
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#1,239
HRDSTL,

Reasons why you should replase TIP142/7? Meybe it because of that:
''I BROWSED THE WEB A BIT AND READ THAT TIP 142/7 ARE NOT VERY SUITABLE FOR AUDIO APPLICATIONS"? Don't listen to them. Merry pranksters🙂. The result depends on the person who doing it. Bet on Mr. Pass. Osscar uses MJ11015/6 /#284/. Very, vey successfully. The Sankens are 50/55MHz. I don't exactly know, but........ be careful. Sometimes it becomes a fun indoor activity :redhot:.
Good luck.
 
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