Back from the bench, calling the smart people 🙂
No matter what combination I try to wire the output transformer, I can't make it work.
For a given input of 25mV from the DAC, I either get 260mV or 117mV at the output transformer and the speaker side is attenuated.
This is the color code from Sowter:
Hugo
No matter what combination I try to wire the output transformer, I can't make it work.
For a given input of 25mV from the DAC, I either get 260mV or 117mV at the output transformer and the speaker side is attenuated.
This is the color code from Sowter:
Hugo
Just want to mention that we found a good solution for the output transformer for the Hiraga Nemesis Push-Pull.
https://www.diyaudio.com/community/threads/the-jean-hiraga-nemesis-quadrige.401114/post-7397229
I tend to believe it can be used also for the Zeus with lateral MOSFETs.
Patrick
https://www.diyaudio.com/community/threads/the-jean-hiraga-nemesis-quadrige.401114/post-7397229
I tend to believe it can be used also for the Zeus with lateral MOSFETs.
Patrick
Thanks Patrick.
My prototype was with toroids and it worked great but now I have the Sowters and I'd like to make them work.
I'm sure I did something wrong but I can't find the mistake.
Hugo
My prototype was with toroids and it worked great but now I have the Sowters and I'd like to make them work.
I'm sure I did something wrong but I can't find the mistake.
Hugo
Very elegant design and outstanding measurements. But too late, I build the Zeus...
Note that for the dual chamber output transformers, it is important to have each primary winding using one section from each bobbin section.
Also each secondary is one pair of windings, one from each bobbin section. These secondaries can be connected either in parallel or series, depending on load (I normally use all in parallel).
It's important to get the phases right, otherwise they will cancel out!
Here's a pic from my notes.
Also each secondary is one pair of windings, one from each bobbin section. These secondaries can be connected either in parallel or series, depending on load (I normally use all in parallel).
It's important to get the phases right, otherwise they will cancel out!
Here's a pic from my notes.
Yes, primary side is how it should be.And for the primary side I assume this is the correct schematic, independent of 4 or 8 ohm:
Secondaries all in parallel or series-parallel.
P.S. After three and a half years of shielding, including FFP3 masking, and being super careful - I have caught my first Covid-19 infection, and now my partner has it too.
This will have been contracted from work as I cycle-commute, and we don't go out to public places.
Oh, Susan, take good care, both of you! Paracetamol helps.. but you probably know that.
I'll try to find out about the windings but its strange that I need to put more power into the amp than I get out of it.
For the moment I'll connect the speakers to the primaries, at least these give me some output.
Thanks, Hugo
I'll try to find out about the windings but its strange that I need to put more power into the amp than I get out of it.
For the moment I'll connect the speakers to the primaries, at least these give me some output.
Thanks, Hugo
Here's some more data:
Balanced output DAC: 100mVAC 1kHz
Voltage across secundary of input transformer: 1000mVAC
Voltage across sources of mosfets: 421mVAC
Output transformer wired parallel to speaker: 48mVAC (no load)
Power supply +30VDC
Bias 0.6A
Hugo
Balanced output DAC: 100mVAC 1kHz
Voltage across secundary of input transformer: 1000mVAC
Voltage across sources of mosfets: 421mVAC
Output transformer wired parallel to speaker: 48mVAC (no load)
Power supply +30VDC
Bias 0.6A
Hugo
I escaped for nearly 2 years before it got me. 2 months before vaccines became available. It was 6-7 days of 103F.
I hear it’s much less severe after vaccination.
I added the third mosfet and the schottky diode but that didn't help.
I think the voltage at the sources should equal the voltage at the gates.
But all mosfets are OK.
Hugo
I think the voltage at the sources should equal the voltage at the gates.
But all mosfets are OK.
Hugo
If one follows Sowter's color code in a logical order, it won't work. With Susan's notes it works.
Many thanks, Susan. I hope you are not too affected by covid.
Hugo
Many thanks, Susan. I hope you are not too affected by covid.
Hugo
It's not pleasant, like a middling with spikes of bad flu for me - my partner who is immunocompromised is having a rougher time.
Thankfully, we have both be able to have the vaccines; fingers crossed it isn't going to get worse.
The transformer windings may seem complicated, but it was the best way to get the configurations and performance.
Winding in a more conventional method, with separate bifilar-primary and bifilar-secondary layers, the output DC resistance is double that of the dual-quadfilar wound cores, and the connections are even more fiddly to join everything up!
Thankfully, we have both be able to have the vaccines; fingers crossed it isn't going to get worse.
The transformer windings may seem complicated, but it was the best way to get the configurations and performance.
Winding in a more conventional method, with separate bifilar-primary and bifilar-secondary layers, the output DC resistance is double that of the dual-quadfilar wound cores, and the connections are even more fiddly to join everything up!
Yes, fingers crossed. Take care.
The Sowter is confusing (for me at least) because Sowter's color codes don't match with your notes. The connections flip from top to bottom and from primary to secundary. I still don't get it but hey, it works.
Hugo
That is a real puzzle, and no colored wires at all...
The Sowter is confusing (for me at least) because Sowter's color codes don't match with your notes. The connections flip from top to bottom and from primary to secundary. I still don't get it but hey, it works.
Hugo
I will have a look at this when I am feeling better - nudge me if I forget! 🙂
I hope everyone is keeping well.
I have been testing out a new output-transformer, this one wound using an amorphous toroid core (one of a set of four I got some time ago).
Sadly I now know how long it will take me to make the second one!
3 layers of bifilar wound 0.80mm magnet-wire, by hand sitting on a sofa and dropping the two wire-spools through the centre hole without getting them too tangled up each time (that was the aim anyway). Each layer took 2 hours, so I wound one layer per evening after getting back from work.
Completed transformer and the second core waiting for it's windings! The core (in its case) is 143mm OD, 96mm ID, and 30mm high.
And the test setup...
Playing music - source is a MOTU M2 box.
With a quick test driven from a Sig-Gen's 50ohm output it goes from below 10Hz to over 150kHz.
I have been testing out a new output-transformer, this one wound using an amorphous toroid core (one of a set of four I got some time ago).
Sadly I now know how long it will take me to make the second one!
3 layers of bifilar wound 0.80mm magnet-wire, by hand sitting on a sofa and dropping the two wire-spools through the centre hole without getting them too tangled up each time (that was the aim anyway). Each layer took 2 hours, so I wound one layer per evening after getting back from work.
Completed transformer and the second core waiting for it's windings! The core (in its case) is 143mm OD, 96mm ID, and 30mm high.
And the test setup...
Playing music - source is a MOTU M2 box.
With a quick test driven from a Sig-Gen's 50ohm output it goes from below 10Hz to over 150kHz.
Attachment link is broken.
Looking at the winding... six wires in, six wires out, huh?
Does it make any difference if the layers of winding start/stop at the same place on the core? Would it be better to spread them out, in this case spread the layers like 120 degrees apart around the core?
Looking at the winding... six wires in, six wires out, huh?
Does it make any difference if the layers of winding start/stop at the same place on the core? Would it be better to spread them out, in this case spread the layers like 120 degrees apart around the core?
Hi Susan,
Looks pretty impressive - would be interested to hear how it sounds once the other one is finished.
Also if the technical spec is significantly different from the original ones.
mike
Looks pretty impressive - would be interested to hear how it sounds once the other one is finished.
Also if the technical spec is significantly different from the original ones.
mike
Winding toroids is always a thundering pain in the bottom. If you have an idea as to how much wire you need, you can decant it onto an improvised shuttle made of PCB material. Otherwise, it's pain all the way...