Hi Patrick,
first I also agree.
Thanks for your efforts in this GB. I had to back out a bit in the last few weeks and could not keep track on diyaudio regularly, therefore my late reply.
I will be home to receive the parcel, but it seems I will need another three or four weeks until I will find the time to start things working.
Greetings,
Chris
first I also agree.
Thanks for your efforts in this GB. I had to back out a bit in the last few weeks and could not keep track on diyaudio regularly, therefore my late reply.
I will be home to receive the parcel, but it seems I will need another three or four weeks until I will find the time to start things working.
Greetings,
Chris
In fact it was 3 o'clock (summer time), I just came back from the "Gentse feesten" a party that lasts for 10 days, we're half way 
http://www.gentsefeesten.be/eCache/DEF/52.html
http://www.gentsefeesten.be/eCache/DEF/52.html
So finally I heard from everyone. All have received their FETs and seemed to be happy. I have arranged the donation of 71 Euros to Unicef to be done this week. So a satusfactory end to the group buy.
I have not received all the money from those who reserved the "left-over" FETs yet. So that part of the donation still to follow.
Happy soldering and group buy declared closed,
Patrick
I have not received all the money from those who reserved the "left-over" FETs yet. So that part of the donation still to follow.
Happy soldering and group buy declared closed,
Patrick
> For a pair of F5´s and some just in case,
Balanced or single ended ?
> 6-8
6-8 of each type (N & P), or 6-8 in total ?
All matched to same Vgs or just in pairs ?
> I don´t know how well matched they usualy are...
The ones from the group buy is 10mV at room temperature.
If you want something more accurate, they need to be matched at temperature (say 60 degC) and working dissipation (say 32W per FET).
And if you want to be really demanding, then they also want to be matched for transconductance.
>The price?
Depends on what you want, see above.
If you want something simple, you should really buy from Tech-DIY. If you want something fancy, you could contact me.
Patrick
Balanced or single ended ?
> 6-8
6-8 of each type (N & P), or 6-8 in total ?
All matched to same Vgs or just in pairs ?
> I don´t know how well matched they usualy are...
The ones from the group buy is 10mV at room temperature.
If you want something more accurate, they need to be matched at temperature (say 60 degC) and working dissipation (say 32W per FET).
And if you want to be really demanding, then they also want to be matched for transconductance.
>The price?
Depends on what you want, see above.
If you want something simple, you should really buy from Tech-DIY. If you want something fancy, you could contact me.
Patrick
Hi Patrick, after a post i spent some time and find store where i bought couple hundreds
http://www.onlinecomponents.com/buy/FAIRCHILD/FQA19N20C/
thay are quite cheap at 1,19 and 1,79usd/each but still I know I will not have time to match them for maybe.. never its quite time consuming process- I still painfully remember my last irfp240 maching- bought 700psc and mached them on bench meter with 0,0001v accuracy, i tried this on 25v rails and 0.3A as mosfets heated i did way i felt best put fet on special lock and after 60sec fixed value. I was not able to mach 50 of them to very close (more than 0,001V) sextets because when I retested next day 0,0001V mached fets they showed diferent values and was close as much as 0,001v. then i just mountened them at small heatsinks and redone maching on working conditions. it tooked some seriuos time and two person work, so i do not want to go throught this again- I rather pay someone to mach them for me. or just buy what ever i need at current amp projects. that would be 2 psc stock F5, I am also considering buz900 version or yours toshiba balanced version. but again no time for scrubing PCB.. do you have mached P to P on working conditions fairchild or toshiba devices and pcb ?
http://www.onlinecomponents.com/buy/FAIRCHILD/FQA19N20C/
thay are quite cheap at 1,19 and 1,79usd/each but still I know I will not have time to match them for maybe.. never
its quite time consuming process- I still painfully remember my last irfp240 maching- bought 700psc and mached them on bench meter with 0,0001v accuracy, i tried this on 25v rails and 0.3A as mosfets heated i did way i felt best put fet on special lock and after 60sec fixed value. I was not able to mach 50 of them to very close (more than 0,001V) sextets because when I retested next day 0,0001V mached fets they showed diferent values and was close as much as 0,001v. then i just mountened them at small heatsinks and redone maching on working conditions. it tooked some seriuos time and two person work, so i do not want to go throught this again- I rather pay someone to mach them for me. or just buy what ever i need at current amp projects. that would be 2 psc stock F5, I am also considering buz900 version or yours toshiba balanced version. but again no time for scrubing PCB.. do you have mached P to P on working conditions fairchild or toshiba devices and pcb ?
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So you do want very fancy matching.
But as you said, it is way too much work.
I only do fancy matching (curve traced) for a large batch like 200 FETs, for myself and our DIY group members.
Unfortunately I do not have any "left overs" right now. Else you can have a set or 2.
And 1mV match at working condition under steady state is IMHO not realistic.
The devices are just way too thermal sensitive than even room temperature change will pull it off.
So even if you have a large enough pool of transistors to get to 0.001V match, I would not trust those value anyhow if they were not matched within 2 minutes when bolted onto a common sink, like in post #47.
But for the F5, you only need good match for Toshibas, as the Fairchilds Ns & ps are not complementary anyway.
Suggest you buy from this online place.
Sorry,
Patrick
But as you said, it is way too much work.
I only do fancy matching (curve traced) for a large batch like 200 FETs, for myself and our DIY group members.
Unfortunately I do not have any "left overs" right now. Else you can have a set or 2.
And 1mV match at working condition under steady state is IMHO not realistic.
The devices are just way too thermal sensitive than even room temperature change will pull it off.
So even if you have a large enough pool of transistors to get to 0.001V match, I would not trust those value anyhow if they were not matched within 2 minutes when bolted onto a common sink, like in post #47.
But for the F5, you only need good match for Toshibas, as the Fairchilds Ns & ps are not complementary anyway.
Suggest you buy from this online place.
Sorry,
Patrick
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