Hi, this is for now last post on this amp.
It is not so relevant, it is about main PS, while I had this opened I wanted to see how PS works in max currents, if anyone is interested:
I opened connection between one bridge rectifier and capacitor filter, 0R1 1% resistor was inserted in series so I can measure microvolts that translate in PS currents, my multi-meter has 1ms and 100ms peak and hold , so I used only this, not scope. This is how it looks:
1. Inserted additional chokes (all very high current rated) in series making effectively L-C filters:
a. With "small" choke; filtered voltage remained pretty much the same; 30V. Continuous average current little bit decreased and 1ms peaks (ripple) went just a bit down (8.16A comparing to 8.5A) .
b. With "large" choke; filtered voltage dropped significantly to 21.6V, 1ms ripple peaks also reduced a lot to 4.6A.
2. Without any choke, PS as is; bridge rectifier followed by 100,000 microF capacitors:
a. Continuous DC current: 2.44 A (corresponds close enough with 1.12 A I measured per +- leg earlier in post #5
b. 1ms peaks (ripple) 8.5 A
c. Switch on (switch on mains with empty capacitors) 1ms peak 70 A, with 100ms peak its averaged 19A
New F&T specification for GM series 100,000 microF /40V capacitors (mine are much older and little bit bigger than new products) declares:
So seems all its fine without additional chokes.
(PS these huge electrolytic have generous film and close to load decoupler small capacitor helpers)
For now, that's it from me on this subject, I'm closing the amp and releasing workbench,
Cheers,
Drazen
It is not so relevant, it is about main PS, while I had this opened I wanted to see how PS works in max currents, if anyone is interested:
I opened connection between one bridge rectifier and capacitor filter, 0R1 1% resistor was inserted in series so I can measure microvolts that translate in PS currents, my multi-meter has 1ms and 100ms peak and hold , so I used only this, not scope. This is how it looks:
1. Inserted additional chokes (all very high current rated) in series making effectively L-C filters:
a. With "small" choke; filtered voltage remained pretty much the same; 30V. Continuous average current little bit decreased and 1ms peaks (ripple) went just a bit down (8.16A comparing to 8.5A) .
b. With "large" choke; filtered voltage dropped significantly to 21.6V, 1ms ripple peaks also reduced a lot to 4.6A.
2. Without any choke, PS as is; bridge rectifier followed by 100,000 microF capacitors:
a. Continuous DC current: 2.44 A (corresponds close enough with 1.12 A I measured per +- leg earlier in post #5
b. 1ms peaks (ripple) 8.5 A
c. Switch on (switch on mains with empty capacitors) 1ms peak 70 A, with 100ms peak its averaged 19A
New F&T specification for GM series 100,000 microF /40V capacitors (mine are much older and little bit bigger than new products) declares:
- Ripple current 18.3A
- ESR 4mOhm
So seems all its fine without additional chokes.
(PS these huge electrolytic have generous film and close to load decoupler small capacitor helpers)
For now, that's it from me on this subject, I'm closing the amp and releasing workbench,
Cheers,
Drazen
Dear Ggetz and Tamra,
Thanks for your kind suggestions but I gave up on any unobtainable components usage, besides for this I would need 2 matched pairs which is even more impossible to get.
After buying counterfeits 2 times (both times at least I got money back but spent days looking for them, testing, returning to seller... complete waste of time and energy) I figured 3rd time will be my mistake, so I stop and decided to use only excellent components that are available widely. I think that decision is also good for social environment as one less searcher for them means less business for thief.
This project is also closed for the moment as I opened few other ones, I put the lid on and use amp as is, it is still excellent piece. Might be one day I will open it again, by then better mosfets will come on my door by their own, it always happens like this if I'm patient 🙂
Thanks for your kind suggestions but I gave up on any unobtainable components usage, besides for this I would need 2 matched pairs which is even more impossible to get.
After buying counterfeits 2 times (both times at least I got money back but spent days looking for them, testing, returning to seller... complete waste of time and energy) I figured 3rd time will be my mistake, so I stop and decided to use only excellent components that are available widely. I think that decision is also good for social environment as one less searcher for them means less business for thief.
This project is also closed for the moment as I opened few other ones, I put the lid on and use amp as is, it is still excellent piece. Might be one day I will open it again, by then better mosfets will come on my door by their own, it always happens like this if I'm patient 🙂
Hi Zen,
Yes, agree! I learned to trust into members of this site, and I think it is also because the site is very well managed and moderated. That's why I donated 50€ to site instead of buying 4 transistors (cost almost the same with p&p). I think it is money much better spent 🙂
Reason for not going for Toshiba mosfets is different, I changed philosophy because firstly I think perfect circuits can be made from abundance of available components. Than making these obsolete parts "an object of desire" supports counterfeiters and similar criminals, if nobody wants them they are out of the business. That's my small contribution to fight against it. Further is availability, if one part burns in one year, who knows if I will find it again. Price is also not negligible.
Besides, seems industry is catching up, I see more and more new jfets and lateral power MOS being produced, not to mention better and better bjt-s. Only these mid size linear mosfets are not available, , yet. But I think this will come too.
I also have pile of nice old parts, keep them for repairs , for myself and if someone else needs them. Might be I use some in new design, but only if similar available replacement is existing. This is not the case with 2Sk2013 , yet 🙂
Cheers,
Drazen
Yes, agree! I learned to trust into members of this site, and I think it is also because the site is very well managed and moderated. That's why I donated 50€ to site instead of buying 4 transistors (cost almost the same with p&p). I think it is money much better spent 🙂
Reason for not going for Toshiba mosfets is different, I changed philosophy because firstly I think perfect circuits can be made from abundance of available components. Than making these obsolete parts "an object of desire" supports counterfeiters and similar criminals, if nobody wants them they are out of the business. That's my small contribution to fight against it. Further is availability, if one part burns in one year, who knows if I will find it again. Price is also not negligible.
Besides, seems industry is catching up, I see more and more new jfets and lateral power MOS being produced, not to mention better and better bjt-s. Only these mid size linear mosfets are not available, , yet. But I think this will come too.
I also have pile of nice old parts, keep them for repairs , for myself and if someone else needs them. Might be I use some in new design, but only if similar available replacement is existing. This is not the case with 2Sk2013 , yet 🙂
Cheers,
Drazen
I really spent to much money on Fake parts, However, there are way to identify these Toshiba parts may this helps.
