Need some help please.
1.For Q1/Q2 use KSA992/KSC1845-- Gain 150-500
2. Or use 2n5401/2n5551-- Gain 50-240
I am currently using number 2 and it works good. Will there be an advantage to use option 1 with the higher gain devices ?🙂
1.For Q1/Q2 use KSA992/KSC1845-- Gain 150-500
2. Or use 2n5401/2n5551-- Gain 50-240
I am currently using number 2 and it works good. Will there be an advantage to use option 1 with the higher gain devices ?🙂
Jan,
You can use A992/2N5401 for Q1, but you are advised to use KSC1845 for the VAS, Q2, which needs higher beta and better Cob than 2N5551.
Most of the components in the BOM are easily procured around the world (though increasingly most people buy their genuine parts componies like RS, Element14, Digikey and Mouser because so many small suppliers are holding fakes.
Hugh
You can use A992/2N5401 for Q1, but you are advised to use KSC1845 for the VAS, Q2, which needs higher beta and better Cob than 2N5551.
Most of the components in the BOM are easily procured around the world (though increasingly most people buy their genuine parts componies like RS, Element14, Digikey and Mouser because so many small suppliers are holding fakes.
Hugh
Funky Phunk boards received
So, I have been following this thread for a while, and finally got around to ordering a run of PCB. I decided on the lovely Phunk POD layout, as the compact form factor fits well in an old (dead) Toshiba amp I can use for testing 🙂
I received the boards yesterday, but they turned out a bit more "Phunky" than I was expecting: Bottom is blue, but the top is just plain FR4 🙄 Also just single sided pads. Which is fine of course, I am just so used to seeing through plated holes.
Phunk > I much appreciate your work (and others who made their layout available here), so please don't take this as criticism. I didn't really check the Gerbers before sending off, so not sure if the color issue stems from the files, or if PCBway made a mistake. Will have to check up on that... Silkscreen looks quite good though, and the boards are fine otherwise.
I really look forward to trying this design, but it may be a few weeks before I have it up and running. I think I have most of the components, and will likely use MJL4281 and IRFP250 as outputs. I plan to do a fair bit of objective testing on varying voltages and loads, before moving on to listening and general use.
In the meantime, to give something back to the community:
If someone would like a set of these unique two-tone PCB, I will send you a set for free. I can spare 4 boards, so can send out 2 free stereo sets.
And last but certainly not least: Big thanks to Hugh (Aksa) and Ranchu32!
So, I have been following this thread for a while, and finally got around to ordering a run of PCB. I decided on the lovely Phunk POD layout, as the compact form factor fits well in an old (dead) Toshiba amp I can use for testing 🙂
I received the boards yesterday, but they turned out a bit more "Phunky" than I was expecting: Bottom is blue, but the top is just plain FR4 🙄 Also just single sided pads. Which is fine of course, I am just so used to seeing through plated holes.
Phunk > I much appreciate your work (and others who made their layout available here), so please don't take this as criticism. I didn't really check the Gerbers before sending off, so not sure if the color issue stems from the files, or if PCBway made a mistake. Will have to check up on that... Silkscreen looks quite good though, and the boards are fine otherwise.
I really look forward to trying this design, but it may be a few weeks before I have it up and running. I think I have most of the components, and will likely use MJL4281 and IRFP250 as outputs. I plan to do a fair bit of objective testing on varying voltages and loads, before moving on to listening and general use.
In the meantime, to give something back to the community:
If someone would like a set of these unique two-tone PCB, I will send you a set for free. I can spare 4 boards, so can send out 2 free stereo sets.
And last but certainly not least: Big thanks to Hugh (Aksa) and Ranchu32!
Attachments
Jan, be aware that the A992 and 2N5401 have different pinouts so I would opt for whatever device matches the board layout.
Thanks JV!
Christian and I designed it from the POV of easy, low count components, conventional in terms of the topology, but one difference; npn for quasi, and nmos for upper device. It had to be cheap, small, and perform very well sonically. We were not too concerned about the THD, which is around 0.06% but mostly H2 and H4.
Many years ago there was a very good quasi produced by an Adelaide guy, Con whom I later met. It was excellent, designed for high power, and elegantly designed and drafted. It was, like most forum guys realise, an archetypal Oz design; practical, inexpensive, powerful, reliable and conventional. We wanted the same, but a bit more care with the harmonic profile, and since so many pcb were created for this, I think about four of them, all very good artwork, it must have been built all over the world.
I design a lot of amps, but keep the best for my commercial products. But Christian and I have been pretty happy with the Simple Quasi. We'd noticed that complex, low THD difficult amps were magnificent designs, but most people did not build them, too difficult to get 'em going. I design simple amps because I am not smart enough to design complex, low THD machines, although I have a good repertoire of topologies.
Enjoy Phunk's artwork, he did a paisley job, didn't he?
Cheers,
Hugh
Christian and I designed it from the POV of easy, low count components, conventional in terms of the topology, but one difference; npn for quasi, and nmos for upper device. It had to be cheap, small, and perform very well sonically. We were not too concerned about the THD, which is around 0.06% but mostly H2 and H4.
Many years ago there was a very good quasi produced by an Adelaide guy, Con whom I later met. It was excellent, designed for high power, and elegantly designed and drafted. It was, like most forum guys realise, an archetypal Oz design; practical, inexpensive, powerful, reliable and conventional. We wanted the same, but a bit more care with the harmonic profile, and since so many pcb were created for this, I think about four of them, all very good artwork, it must have been built all over the world.
I design a lot of amps, but keep the best for my commercial products. But Christian and I have been pretty happy with the Simple Quasi. We'd noticed that complex, low THD difficult amps were magnificent designs, but most people did not build them, too difficult to get 'em going. I design simple amps because I am not smart enough to design complex, low THD machines, although I have a good repertoire of topologies.
Enjoy Phunk's artwork, he did a paisley job, didn't he?
Cheers,
Hugh
Yes Phunk's Pod design is quite a work of art! A shame it won't be visible once the boards are mounted.
- Also, I can imagine those gently curving tracks will make the amp sound much smoother and rounder, than with ordinary angular sharp cornered tracks - those can really give rise to uneven high-order harmonics you know..
- Also, I can imagine those gently curving tracks will make the amp sound much smoother and rounder, than with ordinary angular sharp cornered tracks - those can really give rise to uneven high-order harmonics you know..
The unusual coloration is the result of not having through hole pads on the top. This it is a single layer board and the color comes from the solder mask. As there is no solder, no mask. I would ask layout artists to please generate Gerbers with top side pads to make it "double sided" in the future. Then colors should all work out. I had same issue with Thiago's board. I suppose one could have requested a solder mask on top side despite one sided. However, having pads on top increases durability of solder joints and nice to have. Costs nothing extra.
Looks like Thiago substituted BC560 for 2N5401 and BC550 for KSC1845, and BD140 for KSA1381. Not sure why (maybe the usual parts harder to get locally?) but he says it has been tested. I think KSA1381 has special properties and may sound better than BD140. They are pin compatible at least.
Yay! Free lunch!.😀
I would like a pair please, if you dont mind sending me one.😉
I shall pay shipping and other charges that you may incur.
Thanks for posting it here. likewise I had also appreciated phunk's layout when he posted it here. and its a shame the art wont be visible once built and mounted. electrons will have a joy ride while moving thro his PCB🙂.
Regards
Prasi
Hi Yay !
PM sent for the second pair PC board.
Would be interested to build these amp
Greetings gabor
PM sent for the second pair PC board.
Would be interested to build these amp
Greetings gabor
Another victim of sterile online Chinese board houses, read the advice here
JLH 10 Watt class A amplifier, rest assured, it will work fine.
regards
Prasi
