Hi,
I'd rather choose two pairs (if they are TIP 125W darlington) - for a 4 ohm load.
For the my small AB100 I used 1 pair of MJ11015 / 16 200w transistors - output power approx. 55-60W @ 8 ohms and some 80-90W @ 4 at + - 37V DC ( 26,26 VAC ), so you can expect 60W @ 8 and 100@ 4 with +-39V rails.
I'd rather choose two pairs (if they are TIP 125W darlington) - for a 4 ohm load.
For the my small AB100 I used 1 pair of MJ11015 / 16 200w transistors - output power approx. 55-60W @ 8 ohms and some 80-90W @ 4 at + - 37V DC ( 26,26 VAC ), so you can expect 60W @ 8 and 100@ 4 with +-39V rails.
i haven't heard what ab100 sounds like with TIP transistors but internaly they are similar MJ has higher gain, but MJ NPN and PNP gain is identical at 1-2A instead of TIP.
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If I've calculated correctly it clips at about 120watts a side with 49V rails. I was expecting the good bass as others have said but I'm pleasantly surprised at the airy highs and imaging. A very listenable amplifier. Many thanks to Nelson for the circuit and to jwjarch for the boards.
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very nice diy amp ! I am also currently listening to my ab100 (Thievery Corporation
), I can't disagree about the sound. What is your bias level?
), I can't disagree about the sound. What is your bias level?I've set it at 50mA per device. I've got the heatsinks to go more but I'm a bit confused though after reading Self about biasing. Unless I misunderstood he advocates low biasing and even B class over AB?
thank you for information, these seems to be good for VA . DC offset values also outstanding IMHO.
sorry - another question from me: what is the gain of your AB100? 36dB as original or less ?
Mine has 25,2 dB gain (r3=100R). According to LTspice - distortion pattern will be the same - they all will be lower with lower gain.
But if we look at the first NP post - there is some differences in posted graphs ( see attachment - distortion 1Khz @ 2W)
With 36db I can't achieve it in the simulation - it's higher (0.01 or 0.02 @ 2W @ 1KHZ)
But with 25,2dB i can get these 0.006%...
It doesn't matter - it sounds great 😀
Mine has 25,2 dB gain (r3=100R). According to LTspice - distortion pattern will be the same - they all will be lower with lower gain.
But if we look at the first NP post - there is some differences in posted graphs ( see attachment - distortion 1Khz @ 2W)
With 36db I can't achieve it in the simulation - it's higher (0.01 or 0.02 @ 2W @ 1KHZ)
But with 25,2dB i can get these 0.006%...
It doesn't matter - it sounds great 😀
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Great job with those boards ZUM911! You’re very welcome! Glad to see some photos of them in a build. I like the added power supply caps as well. Did you point to point them or do you have additional power supply boards?
Hi Osscar, I increased r3 to 1K as you had suggested and I get 25 or 26db gain. I can't remember the exact number.
Hi jwjarch, I placed the extra caps on perf board. Overkill but I had them around. The channels share the first 30,000uF on each rail then I put 2 x 6800uF per rail on the boards.
Hi jwjarch, I placed the extra caps on perf board. Overkill but I had them around. The channels share the first 30,000uF on each rail then I put 2 x 6800uF per rail on the boards.
Anybody has used 2SC5171/2SA1930 for the VAS already? I have many of them im the drawer. As well as some 2SC3421 that I would like to use as VBE-multiplier... Anything that's against that?
Alternatively there are also some 2SC3423Y/2SA1360Y or 2SC2690A/2SA1220A here... What would be suitable for the VAS?
Thanks for your reply.
Alternatively there are also some 2SC3423Y/2SA1360Y or 2SC2690A/2SA1220A here... What would be suitable for the VAS?
Thanks for your reply.
IMHO 2SC3423Y/2SA1360Y will be very good for VAS. 200Mhz , Cob 1,8pf..
as VBE-multiplier - almost every transistor will work.
as VBE-multiplier - almost every transistor will work.
The distortion vs power curve has filters that take out most of the noise,
and the distortion vs frequency curve does not.
Most of us should admit that this is the less populated NP project ....I will not comment on the reasons to me are obvious .
Truly now the only thing that we are allowed to say to NP is a huge thank you for his work that he shared with us through so many years still this project should be excused from this picture .
I was expecting a touch of innovation and up to date technology for this project ....
Truly now the only thing that we are allowed to say to NP is a huge thank you for his work that he shared with us through so many years still this project should be excused from this picture .
I was expecting a touch of innovation and up to date technology for this project ....