> Other option is to order twice as many through DK-Europe, <0.9 Euro/pr.
I am in for 40 pairs.
Are you in ?
Anyone else from Europe interested ?
Patrick
I am in for 40 pairs.
Are you in ?
Anyone else from Europe interested ?
Patrick
mosfets
Actually I've been thinking about getting the
Fairchild mosfets. What kind of matching
are we talking about here? Are we
talking about N and P devices with
similar Vgs?
I can help out on this side of the pond if there
is interest in a GB.
Cheers,
Dennis
Actually I've been thinking about getting the
Fairchild mosfets. What kind of matching
are we talking about here? Are we
talking about N and P devices with
similar Vgs?
I can help out on this side of the pond if there
is interest in a GB.
Cheers,
Dennis
😱 Matching P with N MOSFET's will be difficult.
The different Vgs at the operating bias (resulting in offset) can be trimmed.
And the proposed pairs have a rather different transconductance....
Matching will be important if you are paralleling FET's of same polarity, as in the F4.
Tino
The different Vgs at the operating bias (resulting in offset) can be trimmed.
And the proposed pairs have a rather different transconductance....
Matching will be important if you are paralleling FET's of same polarity, as in the F4.
Tino
Talking about the complementary pair....
Wouldn't the FQA17P10 be a much better complement? Looking at the transfer characteristics, I would think so.
100V instead of 200V, thats no problem for these amps (all with 18V secondaries 😀 )
The only drawback being the Junction-Case thermal resistance, which is higher (but in my opinion still ok, the junction being 15-20�C higher than the N-Channel part @30Watts per device as in the F5 case).
And in a F4 an absolute no brainer.
My 2 cents..
Tino
Wouldn't the FQA17P10 be a much better complement? Looking at the transfer characteristics, I would think so.
100V instead of 200V, thats no problem for these amps (all with 18V secondaries 😀 )
The only drawback being the Junction-Case thermal resistance, which is higher (but in my opinion still ok, the junction being 15-20�C higher than the N-Channel part @30Watts per device as in the F5 case).
And in a F4 an absolute no brainer.
My 2 cents..
Tino
It will work fine, but if you are tweaking distortion figures by balancing
the JFET/MOSFET gain products, you will find yourself doing so in
random directions with the original parts. If you use the 17P, you
will probably find yourself consistently trimming high on the + side
and low on the - side.
the JFET/MOSFET gain products, you will find yourself doing so in
random directions with the original parts. If you use the 17P, you
will probably find yourself consistently trimming high on the + side
and low on the - side.
If you go balanced (like the circuit Tino posted a while ago) and match left and right well, then the P-N match becomes less important, as one gets even order cancellation between left and right, in addition to constant current draw from power supply. But then I would be looking at +/- 16V rails (at the expense of somewhat higher capacitance at the FETs) and go for 2A bias per FET. This is my current thinking.
Dennis, very kind of you. Let's see how it goes. If the many interest in Europe, it is easier to order from Digikey.
So far we have :
40 pairs EUVL
100 pairs Jacco
100 pairs yggdrasil
20 pairs Yunick
190 pairs short.
I have opened a new thread at the Group Buy forum :
http://www.diyaudio.com/forums/showthread.php?s=&postid=1494775#post1494775
Please only post over there if you want to join, and NOT at this thread.
Patrick
Please note that Digikey price is excluding VAT, which is 19% in Germany (and in Holland I think). On top of that, Digikey charges a handling fee of something like 20-20 Euros, and we probably have to have 10% reject calculated in if we want matched quads (2Ns & 2Ps, but probably N-P with different Vgs, depends on what we get). On top of that postage to you (for 100 pairs by Small packet uninsured 7 Euros within the EU, Parcel / DHL insured 17 Euros. It will endup somewhere around Euro 1.50 per pair. Still a bargain.
Dennis, very kind of you. Let's see how it goes. If the many interest in Europe, it is easier to order from Digikey.
So far we have :
40 pairs EUVL
100 pairs Jacco
100 pairs yggdrasil
20 pairs Yunick
190 pairs short.
I have opened a new thread at the Group Buy forum :
http://www.diyaudio.com/forums/showthread.php?s=&postid=1494775#post1494775
Please only post over there if you want to join, and NOT at this thread.
Patrick
Please note that Digikey price is excluding VAT, which is 19% in Germany (and in Holland I think). On top of that, Digikey charges a handling fee of something like 20-20 Euros, and we probably have to have 10% reject calculated in if we want matched quads (2Ns & 2Ps, but probably N-P with different Vgs, depends on what we get). On top of that postage to you (for 100 pairs by Small packet uninsured 7 Euros within the EU, Parcel / DHL insured 17 Euros. It will endup somewhere around Euro 1.50 per pair. Still a bargain.
Those who subscribed to the Group Buy :
40 pairs EUVL
100 pairs Jacco
100 pairs yggdrasil
20 pairs Yunick
60 pairs Cfm
30 pairs Zinsula
30 pairs Tazzz
20 pairs Danny_66
Please send me a PM stating :
You full name, postal address, and whether you wish the transistors to be sent insured or uninsured.
http://www.diyaudio.com/forums/showthread.php?postid=1494854#post1494854
Till now, only Zinsula had mailed & confirmed payment details.
Patrick
40 pairs EUVL
100 pairs Jacco
100 pairs yggdrasil
20 pairs Yunick
60 pairs Cfm
30 pairs Zinsula
30 pairs Tazzz
20 pairs Danny_66
Please send me a PM stating :
You full name, postal address, and whether you wish the transistors to be sent insured or uninsured.
http://www.diyaudio.com/forums/showthread.php?postid=1494854#post1494854
Till now, only Zinsula had mailed & confirmed payment details.
Patrick