twitchie said:Thank you ZM 😀
Actually what I meant to ask was how much bias can the 510/9510 take? Should I just let the heatsinks decide?
(previous post should have been bias adjustment, not gain)
Let your ears/heatsinks decide 😉
Magura 🙂
twitchie said:Thank you ZM 😀
Actually what I meant to ask was how much bias can the 510/9510 take? Should I just let the heatsinks decide
(previous post should have been bias adjustment, not gain)
presuming that your hphones aren't too hungry - 150 to 200mA will suffice .
Magura said:
always nutty Metaldanske
but - speaking wise ......
thanks Magura, thanks ZMSo let my ears decide? Just keep turning the pot until I hear it pop right?
Just kidding
there are limits to even my own stupidity
twitchie said:..........
ya lucky bstrd ;
there are no limits for my own ......
( increase bias step by step and listen ; when you hear no more quality increase , back a little ..... and enjoy )
it's alive!
Currently running at 125mV or about 250mA and the heatsinks don't actually feel very hot until you squeeze them between your fingers for about 5 seconds and then they are hot, but not too hot to continue holding.
Had them hooked up to LM317/337 regulated supply at first, but it was unstable so I suspected it was drawing more than the regulators could handle.
Right now, it's running on super-overkill psu held down to 15V with a variac
I need to figure out a permanent solution for the psu since I don't have any 'appropriate' transformer.
Anybody have a good recommendation on minimum VA for the transformer? 10VA enough? I was thinking of a 12V (AC) through hole Pulse transformer from digikey
http://www.pulseeng.com/products/datasheets/LT2006_27.pdf
What would the min VA recommendation be? I have a few of the 15V 2.3VA ones:
http://www.pulseeng.com/products/datasheets/LT2006_10.pdf
Here's what it looks like so far:
with the psu:
Currently running at 125mV or about 250mA and the heatsinks don't actually feel very hot until you squeeze them between your fingers for about 5 seconds and then they are hot, but not too hot to continue holding.
Had them hooked up to LM317/337 regulated supply at first, but it was unstable so I suspected it was drawing more than the regulators could handle.
Right now, it's running on super-overkill psu held down to 15V with a variac
I need to figure out a permanent solution for the psu since I don't have any 'appropriate' transformer.
Anybody have a good recommendation on minimum VA for the transformer? 10VA enough? I was thinking of a 12V (AC) through hole Pulse transformer from digikey
http://www.pulseeng.com/products/datasheets/LT2006_27.pdf
What would the min VA recommendation be? I have a few of the 15V 2.3VA ones:
http://www.pulseeng.com/products/datasheets/LT2006_10.pdf
Here's what it looks like so far:
An externally hosted image should be here but it was not working when we last tested it.
with the psu:
An externally hosted image should be here but it was not working when we last tested it.
Re: it's alive!
2x15V DC means that you can use 2x 12Vac ( 24Vac ct.) xformer
well - 2x15V x 0,25A x 2(channels) = 15W of pure dissipation ;
use at least 3x that as xformer power .
45VA is ok , 60VA even better
twitchie said:
2x15V DC means that you can use 2x 12Vac ( 24Vac ct.) xformer
well - 2x15V x 0,25A x 2(channels) = 15W of pure dissipation ;
use at least 3x that as xformer power .
45VA is ok , 60VA even better
Supply trannie
Twitchie,
Go nuts and really do it right - won't cost the earth.
Suggest a 30V centre tap, 100VA to give you a "raw" rails about +/-20 volts, and then simply reg it down to the 15V rails - a couple of Toole shunts (boards available soon) look to be perfect for this, or any other GOOD supply. (317/37 will take more than 1/4 amp, but easy to slave as Teddy-Power Reg for example)
Phones are much more critical, long term, than speakers.
[... then you can also try it on the DOA, just for fun!]
Twitchie,
Go nuts and really do it right - won't cost the earth.
Suggest a 30V centre tap, 100VA to give you a "raw" rails about +/-20 volts, and then simply reg it down to the 15V rails - a couple of Toole shunts (boards available soon) look to be perfect for this, or any other GOOD supply. (317/37 will take more than 1/4 amp, but easy to slave as Teddy-Power Reg for example)
Phones are much more critical, long term, than speakers.
[... then you can also try it on the DOA, just for fun!]
I finally finished the second F4 for monoblocks. Now all I need is that Pumpkinhead to give them the full juice...
tms0425 said:
that's fugly!
blast those fronts with few augmented smilies ......
this way they look too serious
Nah, they just need pumpkin 😉Zen Mod said:
that's fugly!
blast those fronts with few augmented smilies ......
this way they look too serious
I love 'em. Sometimes not being too tricky is best..
Of course for Zen Mod , fugly is the highest compliment 😀
Of course for Zen Mod , fugly is the highest compliment 😀
I am building a pair of SE Mono F4's and would like opinions.
I have 2 pair of the Conrad Heatsinks from the group buy.
Would mounting 3 Mosfets per heatsink and running a higher bias current to get 50 deg C be better than all 6 Mosfets on 1 heatsink at a lower current?
What bias current would each allow for.
rigma
I have 2 pair of the Conrad Heatsinks from the group buy.
Would mounting 3 Mosfets per heatsink and running a higher bias current to get 50 deg C be better than all 6 Mosfets on 1 heatsink at a lower current?
What bias current would each allow for.
rigma
Starting to stuff my boards and realized:
I ordered FQA12P20-ND but received FQAF12P20-ND
There are differences according to the spec sheets (links below)
Could someone with more knowledge than me let me know if the FQAF12P20-ND is OK in F4
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=FQA12P20-ND
http://parts.digikey.com/1/parts/1018029-mosfet-p-ch-200v-11-5a-3pf-fqaf12p20.htm
I ordered FQA12P20-ND but received FQAF12P20-ND
There are differences according to the spec sheets (links below)
Could someone with more knowledge than me let me know if the FQAF12P20-ND is OK in F4
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=FQA12P20-ND
http://parts.digikey.com/1/parts/1018029-mosfet-p-ch-200v-11-5a-3pf-fqaf12p20.htm
rigma said:
The FQAF12P20 is TO3PF package, will dissipate 70W and the FQA12P20 is TO3P will dissipate 150W -- see
http://mouser.com/catalog/637/513.pdf
The FQAF12P20 isn't on Fairchild Semi's website, or at least it isn't this Saturday morning.
ND just means "number digikey"
rigma said:
The PF stands for fully insulated plastic package, unsuitable for high thermal exchange purposes.
jacco vermeulen said:
Naah Grünschnabel, I think you made a typo, no?
The P in TO-3P is as opposed to a regular TO-3, which is a metal can.
So, we have TO-3P(lastic).
The F is as you describe the designation for "Fullpack", as in fully insulated.
For the F4, I would not worry too much about it, 70W per device is still plenty.
Magura 🙂