Pavel,
Your boards are such beauties, I am dumb founded. I have no idea how you achieve such visual symmetry.
Man, you are a true artist.
Dinesh
Your boards are such beauties, I am dumb founded. I have no idea how you achieve such visual symmetry.
Man, you are a true artist.
Dinesh
dviswa said:
You just place components at the mirror image location on the other side of the board. Not too hard 😉
BWRX said:
Yeah, yeah, that's it... Just one solder plane accross the back ofthe PCB... That's the ticket....
Yes P-A, there are LME... 😉 ... Cca one dollar for single or two by dual one - do you know something better at this price cathegory ? There are more than fifty chips, 627 is too expensive... 😎
You have got emails twice but Yahoo is a problematic email provider.tobebu02 said:
You have got email 15th March and 6th April. Have you checked your spam filter .
I'll resend the last message.
Next step
Next step:
Recommended pre-amp (or DAC) to go with this amp?
How's the xover dcx2496 quality (digital input, for tri-amping)?
Next step:
Recommended pre-amp (or DAC) to go with this amp?
How's the xover dcx2496 quality (digital input, for tri-amping)?
Try New Dispre, designed by PMA - excellent measuring, excellent listening... For active boxes is this Behringer very good solution - one my friend use them in 3-way active ( one PA03 in bridge for bass, second PA03 for middle and treble ) with very good results....
Hi guys, I am here with one question: which transformer voltage to buy?
I am building two PA03 modules for bridge operation to 8 Ω. Building manual says ±35 V DC for 120 W do 8 Ω. But there is a lot of informations from the internet that ±35 V DC is too much for bridge configuration to 8 Ω and LM4780's will get too hot to run. According to the datasheet I should use only ±25 V DC for standard non-bridge configuration to 4 Ω.
So, am I supposed to buy 2x24 V AC (cca ±34 V DC) or 2x18 V AC (cca ±25 V DC) transformers for bridge to 8 Ω?
I am probably the last man in the world who builds this amp :-D
I am building two PA03 modules for bridge operation to 8 Ω. Building manual says ±35 V DC for 120 W do 8 Ω. But there is a lot of informations from the internet that ±35 V DC is too much for bridge configuration to 8 Ω and LM4780's will get too hot to run. According to the datasheet I should use only ±25 V DC for standard non-bridge configuration to 4 Ω.
So, am I supposed to buy 2x24 V AC (cca ±34 V DC) or 2x18 V AC (cca ±25 V DC) transformers for bridge to 8 Ω?
I am probably the last man in the world who builds this amp :-D
For bridged I wouldn’t use more than 2x20 v transformer for 8 ohms , but because some 8 ohms speakers will dip as low as 4 ohms , I would use 2x18v 160-200va transformer . Do you have any extra boards ? Thanks
I discussed it with Upupa Epops on our local forum and he didn't directly said 2x24 V AC is right or not, but said that everything in his building manual is correct and nobody ever complained. And in his manual is written this:
Basic parameters (valid for supply voltage ±35 V DC)
Output power:
2x 60 W into 4 Ω
2x 45 W into 8 Ω
120 W into 8 Ω – bridge circuit
120 W into 2 Ω – parallel operation
...so I believe him. In his manual he also highly recommends to have properly matched resistors to avoid too much offset and unnecessary heat for bridge solutions. So maybe this is the key how to not get LM overheating?
Unfortunately I do not have any extra boards. But if that will happen, that two bridged PA03 with proper heatsinks and matching will get some overheating with 2x24 V AC, I will sell them completed (and undamaged!) and full of Vishay, Wima and Panasonic components 🙂
Basic parameters (valid for supply voltage ±35 V DC)
Output power:
2x 60 W into 4 Ω
2x 45 W into 8 Ω
120 W into 8 Ω – bridge circuit
120 W into 2 Ω – parallel operation
...so I believe him. In his manual he also highly recommends to have properly matched resistors to avoid too much offset and unnecessary heat for bridge solutions. So maybe this is the key how to not get LM overheating?
Unfortunately I do not have any extra boards. But if that will happen, that two bridged PA03 with proper heatsinks and matching will get some overheating with 2x24 V AC, I will sell them completed (and undamaged!) and full of Vishay, Wima and Panasonic components 🙂
My recommendations are based on the Texas Instruments Lm4780 data sheet ,
If each half will see 4 ohms impedance then you need ±25V DC
If each half will see 6 ohms impedance then you need ±30V DC
If each half will see 8 ohms impedance then you need ±35 V DC
For ±35 V DC :
Output power:
2x 60 W into 4 Ω : each half of the chip will see 4 ohm impedance , NOT GOOD
2x 45 W into 8 Ω : each half of the chip will see 8 ohm impedance , GREAT
120 W into 8 Ω – bridge circuit
In this case each half of the chip will see 4 ohm impedance , NOT GOOD
120 W into 2 Ω – parallel operation
In this case each half of the chip will see 4 ohm impedance , NOT GOOD
If each half will see 4 ohms impedance then you need ±25V DC
If each half will see 6 ohms impedance then you need ±30V DC
If each half will see 8 ohms impedance then you need ±35 V DC
For ±35 V DC :
Output power:
2x 60 W into 4 Ω : each half of the chip will see 4 ohm impedance , NOT GOOD
2x 45 W into 8 Ω : each half of the chip will see 8 ohm impedance , GREAT
120 W into 8 Ω – bridge circuit
In this case each half of the chip will see 4 ohm impedance , NOT GOOD
120 W into 2 Ω – parallel operation
In this case each half of the chip will see 4 ohm impedance , NOT GOOD
Hi there! So my two PA03s are built, connected to two toroids with final ±35 V DC. In bridge mode into 8 Ω and with smaller temporary heatsinks it is not overheating even after 20 minutes of loudly played music. Talking about heatsinks and chips too. Looks like Upupa's design and knowledge are unbeatable 🙂
Now I am designing enclosure with bigger heatsinks and then I will test more.
Now I am designing enclosure with bigger heatsinks and then I will test more.
Some posts have been moved. R.I.P Upupa Epops.
https://www.diyaudio.com/community/threads/r-i-p-pavel-dudek-aka-upupa-epops.400369/
https://www.diyaudio.com/community/threads/r-i-p-pavel-dudek-aka-upupa-epops.400369/