100W Ultimate Fidelity Amplifier

[bigaudioscotto]

I am running at 34v on rails,
It is dead quiet zero hum.
Cannot hear a thing 12 inches from tweeter at idle.


QUOTE=xrk971;6142316]Wow, nice monblock setup for the FH9 there! How many volts are you running and is the setup quiet and hum-free?[/QUOTE]

 

[bigaudioscotto]

Apex FH9 Gerber

Here is the Gerber file for FH9
I had it modified to have nice thru hole
Solder pads on both sides.
Nice little boards for any of you guys that are wanting
To build these.
I had pcbway make them.

 

[xrk971]

Thanks for the new updated Gerbers, Bigaudioscotto! I might have to make another set of these to have in hand. You can build one of these in an hour really. Parts are basically all in the parts bin already as common stuff.

 

[hassan4119]

What is the max safe PSU voltage for FH9 if is BD139/140 used? On that sch is +/-50V? Thanks,

hi
in post number 12329 i put my fh11 with 3 pair irf640n/9640n
pcb is very compact and nice....12*6 cm
sound be good.instead of 150 ohm mr mile tell me put 330 ohm.
but when i power on for 2 seconds i have a few hum with +50/0/-50.after 2 seconds every thing be ok.whats problem?

 

[44250]

What is the max safe PSU voltage for FH9 if is BD139/140 used? On that sch is +/-50V? Thanks,

if they are rated to 80V,rail voltage should not exceed 40V at worse. those transistors at their place in schematic would see almost rail to rail voltage at maximum power.

 

[jorgovanko]

Does anyone made sim for FH9 to be shure about voltages and BD transistors? We currently have two conflicting opinions.

 

[andrewlebon]

Use KSC3503/1381 for best results
warm regards
Andrew

 

[bullittstang]

hi
in post number 12329 i put my fh11 with 3 pair irf640n/9640n
pcb is very compact and nice....12*6 cm
sound be good.instead of 150 ohm mr mile tell me put 330 ohm.
but when i power on for 2 seconds i have a few hum with +50/0/-50.after 2 seconds every thing be ok.whats problem?

Do you have gerber files you could post? Did you only allow spacing for TO-220 devices, or is there room for TO-247 (IRFP240/9240) devices?

 

[xrk971]

Use KSC3503/1381 for best results
warm regards
Andrew

Yes, that’s what I used and it worked well. If you plan on taking it above 40v, switch the drivers to be on the safe side. They cost no more really. I suppose you could chance it and if they blow out, you just replace them but you might get some magic smoke.

100W Ultimate Fidelity Amplifier

 

[alain98]

Hi xrk,
Do you have a link to an Aliexpress seller for the IRF240 and 9240?
Thanks

 

[hassan4119]

Do you have gerber files you could post? Did you only allow spacing for TO-220 devices, or is there room for TO-247 (IRFP240/9240) devices?

no pcb designed with to220 pac.but i can change this for to247

 

[bullittstang]

I think most people have IRFP240/9240 in their bin (I do), which is why I was asking. I would appreciate posting either the current gerbers (TO-220) or modified gerbers (TO-247).

 

[jorgovanko]

OK, i made simulation and receive those results for FH9:

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

PSU +/-45V


So, BD139/140 are safe? Actualy, they are on the half of the max Vce voltage in this situation.
But when one is active at the moment, the other sees the full power supply voltage (45+45)...


KSC2690AYS and KSA1220AYS are also very good (Vce=160V)


More simulation pics can be found here:

SC409 — ImgBB
SC414 — ImgBB
SC413 — ImgBB
SC412 — ImgBB
SC411 — ImgBB
https://ibb.co/z5Bn35K

 

[channini]

OK, i made simulation and receive those results for FH9:

PSU +/-45V


So, BD139/140 are safe? Actualy, they are on the half of the max Vce voltage in this situation.
But when one is active at the moment, the other sees the full power supply voltage (45+45)...


KSC2690AYS and KSA1220AYS are also very good (Vce=160V)


More simulation pics can be found here:

SC409 — ImgBB
SC414 — ImgBB
SC413 — ImgBB
SC412 — ImgBB
SC411 — ImgBB
https://ibb.co/z5Bn35K

what program do you use to simulate

 

[Siva Kumar]

Sir
I built apex a14p. The bias voltage is 13v to 15v across the emitter resistors. I checked all the components with their polarities and positions thoroughly. Please kindly ny one help me in this regard.

 

[44250]

*...bias voltage is 13v to 15v across the emitter resistors." that is almost impossible!

 

[jorgovanko]

what program do you use to simulate

Microcap 12 which is now free.

So, regarding FH9 and to be on the safe side, please do not use BD139/BD140 with PSU higher than ~ +/-35V. For bias BD139 is OK.

 

[xrk971]

Thanks, Jorgovanko,

FFT looks good with mostly monotonically descending higher order distortion and dominant H2/H3. Which is why this amp sounds good.

Slight rise in 8th order but that level is relatively low.

 

[clpk]

AX11 does not polarize

Good morning, I can't adjust my AX11 bias. In the tests the lamp remains on and biases with 350mV and each emitter. I've already changed all the transistors, i installed a 5k pot (in place of 4k7), checked for short circuits, but it didn't work, rotate the pot but do not change bias.
I made some measurements:

Differential pair: BC546
BxC=1,95V, 2,03V
CxE=1,31V, 1,37V
BxE=595mV, 594mV

BC546
BxC=2,70V
CxE=630mV
BxC=2,07V

BC639 and BC640
BxC= 2,03V, 1,95V
CxE= 1,37V, 1,31V
BxE= 594mV, 595mV

BD139 and BD140
BxC= 1,98V, 2,07V
CxE= 2,65V, 2,71V
BxE= 630mV, 639mV

BC517
BxC=2,72V
CxE=3,38V
BxE=661mV

2SC5200 and 2SA1943
BxC=2,65V, 2,68V
CxE=3,30V, 3,35V
BxE=672mV, 694mV

I forgot to measure mpsa92, if necessary I will do the measurement.

To help is welcome, thank you.
(I'm testing the amplifier on the right)

 

[Siva Kumar]

*...bias voltage is 13v to 15v across the emitter resistors." that is almost impossible!

And also the output transistors are getting hot