100W Ultimate Fidelity Amplifier

[karachay]

You can use f100 psu.

hi mr. mile is it normal i getting 1vdc at outl and outr pins on f100 psu?

i test it witouh connect my amp and read dc voltage at where amp out pins.

thank you for answers...

 

[kandimba]

The other way to do the same APEX AF14

 

[kandimba]

APEX AF14

 

[karachay]

hi friends,

i finish f100 psu and put on ax14 . its working nice and good not hot but warm. but there is one little problem i have and cannot fix it.

when there is no sgnal i getting humm. but if i connect my radio and put volume half on it that humm going away or i dont feel cause of the music i dont know. maybe humm coming from bad grounding i check it but cannot see any problem. it can take noise from air?

or maybe my schematic wrong one?

please help any idea can be important..

dc ofset 2.6mV
power + - 47VDC
bias at 0,33ohm resistor is 10mV

where do i need to look for that problem?
note: yes i did make input gnd to psu gnd, out gnd to psu gnd,

 

[karachay]

that caps on psu are 15000uf maybe i need biger one?

 

[bullittstang]

Measure AC voltage on the speaker output, that will probably tell you how large the hum is. Then you can carefully move wires to find where it is lowest. Even try shielded input signal wires.

 

[r_jik45]

I had to enlarge it some.

Is there not a missing connection within the lower 10k trimmer pins (look like the middle pin is not connected, leaving a fixed resistor)?

 

[still4given]

Is there not a missing connection within the lower 10k trimmer pins (look like the middle pin is not connected, leaving a fixed resistor)?

Good catch.

 

[karachay]

Measure AC voltage on the speaker output, that will probably tell you how large the hum is. Then you can carefully move wires to find where it is lowest. Even try shielded input signal wires.

ty i will try that to day.

 

[prasi]

The other way to do the same APEX AF14

NICE !

 

[kandimba]

My contribution for APEX AF14 with 2SK1530 - 2SJ201 , different pinouts. Thanks Prasi.

Regards

 

[prasi]

here is a version of above quoted crc with either CT trafo or dual secondary trafo. though slightly larger at 95 mm x 99mm, it can now take up 35mm caps, 6 x 3W resistors or 2 x 5W resistors.
The center bridge to be used only when CT trafo is to be connected.

regards
prasi

Having some fun with Autodesk Fusion to create 3D models, here are some images. Earlier 3D's from sketch-up were too drab.

its the compact CRC PSU PCB with ability to use either CT trafo / dual secondary trafo of the quoted post

regards
Prasi

 

[Yurik_V]

I modified the circuit board a bit, added thermal pads to make it easier to solder.

 

[andrewlebon]

FX11

Hello
greetings lockdown time decided to try to improve FH 11

1 INPUT TRS 2SC1845
2 Driver trs 1381/3503
3 Offset preset added
4 T6- 2sc1381
5 2 in4148 diodes added
6- MPSA92 in series as suggested by apex audio
Warm Regards
Andrew

 

[andrewlebon]

Hello Apex audio
greetings i have little doubt on the second MPSA92 does the base
go to ground in input section i have added 10 ohms 1 watt ground
lift resistor
warm regards
Andrew

 

[ballisticz4]

Bridge rectifier has incorrect orientation. As done here, its gonna have to go underneath the board. I wil ltry and rectify it this evening when I get home from work

 

[r_jik45]

Plenty of fine posts in this looooong thread. Read about the first 200 pages then moved to the last 10 ones.
Wondering how many amplifiers were build during these 10 years.

 

[avtech]

Underneath the board would allow you to mount the rectifier case in contact with the chassis to help with heat dissipation.

 

[ballisticz4]

Underneath the board would allow you to mount the rectifier case in contact with the chassis to help with heat dissipation.

Exactly what I thought, hence me not chaning my board. But for ease of swapping it out

 

[karachay]

hi friends,

i finish f100 psu and put on ax14 . its working nice and good not hot but warm. but there is one little problem i have and cannot fix it.

when there is no sgnal i getting humm. but if i connect my radio and put volume half on it that humm going away or i dont feel cause of the music i dont know. maybe humm coming from bad grounding i check it but cannot see any problem. it can take noise from air?

or maybe my schematic wrong one?

please help any idea can be important..

dc ofset 2.6mV
power + - 47VDC
bias at 0,33ohm resistor is 10mV

where do i need to look for that problem?
note: yes i did make input gnd to psu gnd, out gnd to psu gnd,

still cannot fix it

if i short input then humm going away i find its coming from input cable i change and use shilded cable too but still same just drop noise a little. i remember i was have same problem 1 year ago again on same amp i think there is some thing i doing wrong.

what can i do please any help can be powerfull.

thank you.