I build my F3 and I used in a biamping configuration with an F7 for bass and the F3 handles upper frequencies from 800Hz and up, a horn loaded tweeter.
From F3 I connected the Twitter before the capacitors but I left the 1uF and a 100ufFmuses cap for the feedback. I think you still need those for the feedback.
You can remove the 15000uf cap. Am I right?
From F3 I connected the Twitter before the capacitors but I left the 1uF and a 100ufFmuses cap for the feedback. I think you still need those for the feedback.
You can remove the 15000uf cap. Am I right?
How can I tell if my Lu1014 are genuine? The amp sounds very good but I am still not sure if they are genuine. I got them from Jim's audio.
I did some measurements based on the original F3 schematic
With R5 at 2.6 ohms I got 1.156v at the Lu's source the schematic shows 1V
but at the drain I have 4.5V compare to schematic 3.5V.
Both channels have higher Drain voltage than original schematic .
Do you think the Lu's are good?
I did some measurements based on the original F3 schematic
With R5 at 2.6 ohms I got 1.156v at the Lu's source the schematic shows 1V
but at the drain I have 4.5V compare to schematic 3.5V.
Both channels have higher Drain voltage than original schematic .
Do you think the Lu's are good?
Hi together,
as I had to build another F3 for my Dad (yes, again a fugly one
), due to the minimum order value I have a bunch of PCBs left. For now I have 3 to 4 sets (left channel, right channel, double PSU and bridge) left, for which I would be happy to give it to somebody willing to build an F3. Just bare in mind that shipping under some circumstances might surpass the PCBs itself.
Also some working LU1014 are left. I cannot tell, whether these are genuine or not, but in the 2nd F3 they're working good with similar measures compared to the original ones from NP. Some are from Jim's Audio, some from other "Distributors". I took the risk and ordered from almost any source I was able to find with let's say "varying results directly correlated to the price and increasing distance to sender".
If someone's interested, just leave me a message.
as I had to build another F3 for my Dad (yes, again a fugly one
), due to the minimum order value I have a bunch of PCBs left. For now I have 3 to 4 sets (left channel, right channel, double PSU and bridge) left, for which I would be happy to give it to somebody willing to build an F3. Just bare in mind that shipping under some circumstances might surpass the PCBs itself.Also some working LU1014 are left. I cannot tell, whether these are genuine or not, but in the 2nd F3 they're working good with similar measures compared to the original ones from NP. Some are from Jim's Audio, some from other "Distributors". I took the risk and ordered from almost any source I was able to find with let's say "varying results directly correlated to the price and increasing distance to sender"
. If someone's interested, just leave me a message.
So should I adjust P1 until I get 3.5V figure?
Output voltage will drop lower then 21V
Hi folks, working on getting my F3 built up and fired up the first channel today. Everything is OK, but I'm not getting the rails where I expected only 41V on a 2x35V torrid.
So my voltages are off everywhere, getting 18V instead of 21V @ R9. Getting 1.3V at R3/4/5. I can adjust R6/7/8 to get 21V, but temps seem very high. I did set R5 low (1.5R) based on my measurement of LU and am getting 4.6V at the drain with 21V and about 3.2V with 18V, so I assume I need to increase R5?
So my voltages are off everywhere, getting 18V instead of 21V @ R9. Getting 1.3V at R3/4/5. I can adjust R6/7/8 to get 21V, but temps seem very high. I did set R5 low (1.5R) based on my measurement of LU and am getting 4.6V at the drain with 21V and about 3.2V with 18V, so I assume I need to increase R5?
Hi,
I assume you don't get more than 19V, even with adjusting the pot to max? Had a 2x34V toroid in the beginning with similar rail voltage, but nevertheless was able to adjust to 21V. Did it like described in the ZV9-article:
BTW: sounded better to me, even with lower UB when adjusted to 21V.
However, my starting point would be to check whether there's an extensive current draw and what is the behavior when adjusting the pots.
One of the experts will have an more educated answer, for sure. Just thinking loud ...
I assume you don't get more than 19V, even with adjusting the pot to max? Had a 2x34V toroid in the beginning with similar rail voltage, but nevertheless was able to adjust to 21V. Did it like described in the ZV9-article:
BTW: sounded better to me, even with lower UB when adjusted to 21V.
However, my starting point would be to check whether there's an extensive current draw and what is the behavior when adjusting the pots.
One of the experts will have an more educated answer, for sure. Just thinking loud
...
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Thank you. Plays music and sounds fine on cheapo shop speakers with 4x220uF paralleled on output for now. I am able to adjust to 21V with P1. Voltage between Q3 and Q5 is 37V. Little confusion on my side as I was using the Jeff Young boards that have P1 labeled as offset. Vds on LU is about 1.6V when I adjust up to 21V. Vds on LU is about 1.9V when adjusted to 18.5V (1/2 of 37V). V across R3/4/5 is pretty consistent at 1.1V. Need to go back and reread ZV8 and ZV9 articles.
Replaced the SIL-Pad on Q3 and Q5 with Keratherm and temps are 25C cooler on the case of the device, so that is better. Overall bulk heatsink temp is 25C over ambient as normal. Not that I know what I'm doing, but I settled on setting P1 to give me ~18.5V. That gives me Ids on Q1 of 1.8A, but Vds is still low at ~1.9V.
If I tweak the equivalent resistance of R6/7/8 to .36R, I can bump up to 2A and hit all the voltages, e.g. 21V and Q1 Vds of ~2.5V.
I'm sure this does not matter, but should I be trying to hit Vds or Ids across Q1? I recognize I am somewhere between the ZV9 and F3 operating points, and I should probably just let it go....
If I tweak the equivalent resistance of R6/7/8 to .36R, I can bump up to 2A and hit all the voltages, e.g. 21V and Q1 Vds of ~2.5V.
I'm sure this does not matter, but should I be trying to hit Vds or Ids across Q1? I recognize I am somewhere between the ZV9 and F3 operating points, and I should probably just let it go....
Just put together f3. It works, sounds fine on test speakers. Few questions though.
While lu is just warm, and current source mosfets relatively hot, the Q2 cascode mosfets gets very hot. Much hotter then others. I adjusted voltages with p1 just fine, p2 does not seems to affect much.
How do i verify i made no mistake? Do others have Q2 hotter then rest?
Yeah i should read 92 pages, but i thought i will ask first.
While lu is just warm, and current source mosfets relatively hot, the Q2 cascode mosfets gets very hot. Much hotter then others. I adjusted voltages with p1 just fine, p2 does not seems to affect much.
How do i verify i made no mistake? Do others have Q2 hotter then rest?
Yeah i should read 92 pages, but i thought i will ask first.