buzz. you know me
heatsinked man i'll use 2x10.080 profiles 6"long pr side. and drive them to maximum
acording to latest numbers. i will get the heat spread maximum over this field so i guess i'm good only the bias will tell
i will however run it on a BIT higher rail voltage. +/-51V or there about and still maintain about 2.6A bias
heatsinked man i'll use 2x10.080 profiles 6"long pr side. and drive them to maximum
acording to latest numbers. i will get the heat spread maximum over this field so i guess i'm good only the bias will tell
i will however run it on a BIT higher rail voltage. +/-51V or there about and still maintain about 2.6A bias
Last edited:
Yep they are the Antek ones.
I'm using them at 8" high for my F5 now biasing at 1.6A
They get hot but I can put my hand on it for at least 20s
I think the last time I checked they run at 50C at 25C room temp
When you start adding the amp board to it what voltage drop do you get? 4-5V? or about 45-46V rail?
I'm using them at 8" high for my F5 now biasing at 1.6A
They get hot but I can put my hand on it for at least 20s
I think the last time I checked they run at 50C at 25C room temp
When you start adding the amp board to it what voltage drop do you get? 4-5V? or about 45-46V rail?
Last edited:
Hmm so this means to get the final 50Vpk loaded, I will need about 55Vpk unloaded
which means 55V = 1.3 x 42Vsec from the transformer.
This will mean that : 50Vpk /1.414 =35.36V and solve P=V^2 /R(8ohm) I should get 156Watts?!
What about efficiency factor ....?
Are the sinks from heatsink USA more appropriate? You can order them as tall as you like.
yes. sort of. they have more spacing between the fins but they come only in raw aluminium
I think this is correct now. Comments?
Prms is the Watts RMS output.
I^2 = Prms/8R0
Irms = Sqrt(I^2)
Vrms = Irms * 8
Vpk = Vrms * 1.414
Vrect = Vpk + 5.6 V
Vac = 1.3 * Vrect
Loss/droop of 5.6 volts. This is Class A.
Prms I^2 Irms Vrms Vpk Vrect Vac
20 2.5 1.581 12.649 17.885 23.486 18.066
50 6.25 2.5 20 28.28 33.88 26.062
100 12.5 3.535 28.284 39.993 45.593 35.072
150 18.75 4.330 34.641 48.98 54.582 41.986
As far as the VA for each transformer, that is a different story.
Please note, I take no responsibility that these will work in your amp, as I'm just trying to learn this stuff and could be very wrong.
AudioSan,
The table suggests you are going to get 135 Watts from a 40 V transformer. In real life, a little less.
The table also suggests that 50 V caps should be OK for a 100watt amp.
Prms is the Watts RMS output.
I^2 = Prms/8R0
Irms = Sqrt(I^2)
Vrms = Irms * 8
Vpk = Vrms * 1.414
Vrect = Vpk + 5.6 V
Vac = 1.3 * Vrect
Loss/droop of 5.6 volts. This is Class A.
Prms I^2 Irms Vrms Vpk Vrect Vac
20 2.5 1.581 12.649 17.885 23.486 18.066
50 6.25 2.5 20 28.28 33.88 26.062
100 12.5 3.535 28.284 39.993 45.593 35.072
150 18.75 4.330 34.641 48.98 54.582 41.986
As far as the VA for each transformer, that is a different story.
Please note, I take no responsibility that these will work in your amp, as I'm just trying to learn this stuff and could be very wrong.
AudioSan,
The table suggests you are going to get 135 Watts from a 40 V transformer. In real life, a little less.
The table also suggests that 50 V caps should be OK for a 100watt amp.
Last edited:
Personally, I think your first equation is Irms^2= Prms/8R0,
But this is backwards???
SqRt (Irms^2) *1.414=Ipk
Ipk*8R0=Vpk
Vpk+(2V MOSFET Drop)= powersupply DC
DC/1.3=Secondary Vrms
You could experience MOSFET drop closer to 4V but it depends on your VAS drive and or other factors.
Depending on the load and the rectifier Vf I ussually see about 2.5V drop from the unloaded condition. YMMV
I ussually use schottky rectumfriers with about .3-.4Vf @ load.
But this is backwards???
SqRt (Irms^2) *1.414=Ipk
Ipk*8R0=Vpk
Vpk+(2V MOSFET Drop)= powersupply DC
DC/1.3=Secondary Vrms
You could experience MOSFET drop closer to 4V but it depends on your VAS drive and or other factors.
Depending on the load and the rectifier Vf I ussually see about 2.5V drop from the unloaded condition. YMMV
I ussually use schottky rectumfriers with about .3-.4Vf @ load.
Last edited:
The PCB's are ordered and should be in the store within the month. We got expedited shipping and production.
I know this has been an incredibly long time, but we don't have full time people helping here at the forum or at the store and I have been swamped with work at my "real Job" Also, there were issues with getting the order right with the maker, which is really important !
I know this has been an incredibly long time, but we don't have full time people helping here at the forum or at the store and I have been swamped with work at my "real Job" Also, there were issues with getting the order right with the maker, which is really important !
Personally, I think your first equation is Irms^2= Prms/8R0,
But this is backwards???
SqRt (Irms^2) *1.414=Ipk
Ipk*8R0=Vpk
Vpk+(2V MOSFET Drop)= powersupply DC
DC/1.3=Secondary Vrms
You could experience MOSFET drop closer to 4V but it depends on your VAS drive and or other factors.
Depending on the load and the rectifier Vf I ussually see about 2.5V drop from the unloaded condition. YMMV
I ussually use schottky rectumfriers with about .3-.4Vf @ load.
It does not really matter when you do the calculation for Vpk, just so that you do it somewhere.
My guestimate for 5.6 needs some looking at.
A great read, from page 64 and on.
http://www.onsemi.com/pub/Collateral/HB206-D.PDF
- Home
- Amplifiers
- Pass Labs
- F5 Turbo Builders Thread