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Finally got around to finishing this cool little amp and it sounds great!
A while ago I scored a box of 35-0-35 175VA EI transformers for <$5 each so I went dual mono for this build.
I used a star ground for the power and input, coax for the signal wires and the amp is dead silent without inputs connected! It was a nice surprise considering the amount of iron close to the signal.
Anyway, thanks Prasi for the board layout and Apex for the circuit!
A while ago I scored a box of 35-0-35 175VA EI transformers for <$5 each so I went dual mono for this build.
I used a star ground for the power and input, coax for the signal wires and the amp is dead silent without inputs connected! It was a nice surprise considering the amount of iron close to the signal.
Anyway, thanks Prasi for the board layout and Apex for the circuit!
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Sorry ,
just saw the post. hopefully not too late in answering.
here is a different format of drill file along with all other layers of gerber files.
let me know if its ok.
regards
prasi
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I've built plenty of AL125. They where discussed earlier in this thread or in another thread Prasi even designed a pcb using more modern devices. I used run them at 90v and used MJ15003 output devices. I still love the sound they give. A pile of vinyl, 2 x AL125 and a pair of Fane 12" speakers what could be better.
Any PS PCB's, Gerbers to go with Altona AL125? I've found schematics on this thread.. Thanks!
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No knowledge of AL125.
AX6 set for 70 v rail. Option 1 50 or 51 v transformer, no CT, >3.25 amp rating times number of channels. 50*1.4=70v. Follow by >=8 amp >=400 piv bridge rectifier (for 2 channels) followed by 3300 uf 100 v cap for 2 channels. I followed by 10 amp fuse.
My unit had 80 v as rectified 6.75 amp transformer, so I regulated to 70 v with 5 parallel TIP147 PNP darlington transistors with parallel .33 ohm 10 watt emitter resistors. Emitter resistors tie together to another 3300 uf cap. Bases driven by one stack of six 12 v 3 watt zeners 1n5327, lines up, protected from plus by 680 ohm resistor to keep zener current at 15 ma. All built point to point on Pentium II heatsink. Beware ON is subtituting TO220 case on fake TIP147, you have to download the datasheet day of purchase to catch them and not purchase the mislabeled cheaper part. IMHO buy ST, when I bought those they were real TO247.
MJL4281 is cheap, but On competes with themselves with MJL3281, MJW4281, MJW3281, NJL4281, NJL3281. there is also MJL21194 and MJW21196. I used white box MJ15003 since I had a heat sink drilled for TO3, sold as NTE181MP.
AX6 set for 70 v rail. Option 1 50 or 51 v transformer, no CT, >3.25 amp rating times number of channels. 50*1.4=70v. Follow by >=8 amp >=400 piv bridge rectifier (for 2 channels) followed by 3300 uf 100 v cap for 2 channels. I followed by 10 amp fuse.
My unit had 80 v as rectified 6.75 amp transformer, so I regulated to 70 v with 5 parallel TIP147 PNP darlington transistors with parallel .33 ohm 10 watt emitter resistors. Emitter resistors tie together to another 3300 uf cap. Bases driven by one stack of six 12 v 3 watt zeners 1n5327, lines up, protected from plus by 680 ohm resistor to keep zener current at 15 ma. All built point to point on Pentium II heatsink. Beware ON is subtituting TO220 case on fake TIP147, you have to download the datasheet day of purchase to catch them and not purchase the mislabeled cheaper part. IMHO buy ST, when I bought those they were real TO247.
MJL4281 is cheap, but On competes with themselves with MJL3281, MJW4281, MJW3281, NJL4281, NJL3281. there is also MJL21194 and MJW21196. I used white box MJ15003 since I had a heat sink drilled for TO3, sold as NTE181MP.
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Let me know where you found it, and if i did a layout, i will share gerbers.
I am getting old, so memory doesn't serve me anymore on what i did and what I didn't.🙂
I think you can use PSU 15R or PSU 10R. I posted a layout for these in Apex 100W thread.
100W Ultimate Fidelity Amplifier
100W Ultimate Fidelity Amplifier
Those are dual rail. I will make a single rail layout for PSU 10R if you are interested.
regards
prasi
