100W Ultimate Fidelity Amplifier

Member
Joined 2018
Paid Member
Apex XRK FH-9

the height is only 70mm, so you wont be able to fit it , you need to go for some other design or cut the pcb right down the middle but that would be a hassle.

another design for Apex XRK FH-9 is shown (attached) , although shown as side mounted, you can mount transistor vertically on heatsink.

pr like Terry says go for FX-8, its one sweet sounding amp in 50 x 50 mm size , you find gerbers and stuff somewhere in the thread, but uses lateral mosfets which are hard to source or costly.

There are many more apex amps , compact but great sounding like FX-11 or AX 14 etc. with BJT instead of mosfet

Hi! prasi, can you share the gerber file for mono versuin of Apex XRK FH-9?

Thanks
 
Hi! prasi, can you share the gerber file for mono versuin of Apex XRK FH-9?

Thanks

Hi Nick,
here are the files:). be very careful in soldering as components are in close proximity due to compactness of pcb.;)

Another thing, if you want quickly the pcbs for this amplifier but different pcb design/size, xrk 971 has already his version of pcb in his store , have a look at GB section or his store here FH9HVX Amp PCB | Etsy

regards
prasi
 

Attachments

  • GERBERS-APEX FH-9 XRK-MOD-COMPACT-side fet-fh9vx_2021-05-17-MONO.zip
    309.6 KB · Views: 357
  • APEX FH-9 XRK-MOD-COMPACT-side fet-fh9vx-SCH.png
    APEX FH-9 XRK-MOD-COMPACT-side fet-fh9vx-SCH.png
    44.1 KB · Views: 1,240
  • APEX FH-9 XRK-MOD-COMPACT-side fet-fh9vx-LAY.png
    APEX FH-9 XRK-MOD-COMPACT-side fet-fh9vx-LAY.png
    90.7 KB · Views: 1,268
Member
Joined 2018
Paid Member
Question about Apex NE555 DC Protect

I have a couple of questions about the APEX NE555 DC Protect circuit,

Apex NE555 DC Protect schematic.jpg

APEX DC Protect NE555 LAY6 FOTO.GIF

Here is a link to a build,

Click here for link to build of this circuit

Halfgaar has some pretty dramatic footage of relays arcing and failing here,

Click here to see vids of relays arcing and failing

And I was wondering if that is a possible issue with the APEX NE555 DC Protect circuit?

Would upgrading the Omron relays to Amplimo relays make a difference?

Click here for to see Amplimo relay

Does this APEX NE555 DC Protect circuit lend itself to adding the "relay ground" that Halfgaar talks about, or is it not necessary?

Thanks, David.
 
Last edited:
I have a couple of questions about the APEX NE555 DC Protect circuit,

View attachment 954960

View attachment 954961

Here is a link to a build,

Click here for link to build of this circuit

Halfgaar has some pretty dramatic footage of relays arcing and failing here,

Click here to see vids of relays arcing and failing

And I was wondering if that is a possible issue with the APEX NE555 DC Protect circuit?

Would upgrading the Omron relays to Amplimo relays make a difference?

Click here for to see Amplimo relay

Does this APEX NE555 DC Protect circuit lend itself to adding the "relay ground" that Halfgaar talks about, or is it not necessary?

Thanks, David.

In order to work, we have marked in red the changes that need to be made:
-turns the diode backwards
- joins pin 4 with 680K resistance
 

Attachments

  • APEX DC Protect NE555 LAY6 FOTO.jpg
    APEX DC Protect NE555 LAY6 FOTO.jpg
    387 KB · Views: 809