JLH Class A headphone amplifier

[Angry Fat Cat]

OPA1656 (dual) and OPA1655 (single), 2.9nV / sqrt(Hz) noise and 0.000029% THD, 24V/usec slew rate, and 100mA capable.

Yep, good op amps. I did use them in I/V stage of my reserve AD1853 DAC.

 

[jamesfeline]

Always start to populate pcb from smaller/lower components (resistors, IC) to bigger (electrolytic capacitor, radiators, etc.)

Hello .. yep I know that as I have enough building experience to construct in any method or order of procedure that I feel like
But for me building electronic circuits since the age of 15 I am confident to make how I like in my workshop and what ever takes my fancy on the day etc
But do agree this is the best advice and best practice

But in my work shop I have no rules .. except good practice for safety etc
and SMD is banned or kept at a minimum if I can help it
all the best

 

[jamesfeline]

Hello Kuzmenko

As said you are correct in your post .. as I get older you sometimes slip into bad habits
My next build will use the lowest Hight components 1st .... then on to the highest .. agree this is the best practice

all the best

 

[jamesfeline]

anyway some of my other construction skills .. purely done by feel and the good old fashion eye ball
A EL34 valve power amp one channel shown as they are mono-blocks

1st 15w in pure class A

 

[jamesfeline]

one more

 

[jamesfeline]

And today purchased some component spacers .....

 

[jamesfeline]

few more pics of my progress for the JLH class A headphone Amplifier

 

[jamesfeline]

Hello All

So have added PCB spacers (4mm)

 

[jamesfeline]

Plus also fitted the 1st TIP41 power transistor heatsink

 

[jamesfeline]

Pic from underneath the PCB so you can see how the heatsinks are attached
3mm stainless steal cap heads

 

[jamesfeline]

ok folks

Matched the output transistor today

 

[jamesfeline]

picked out 4 with the same hfe .. managed to find 4 at 63

 

[jamesfeline]

and the B184B and 2 power transistors with heatsinks fully mounted (all matched) just waiting for some more components to arrive from RS and Rapid .. plus mouser etc

 

[jamesfeline]

Hello gang

headphone amp nearly complete .. quick update on the main headphone amp

 

[penn07]

I still have my original Chiara headphone amp /preamp. I built mine when the kit was first published. I used original PCB from JLH kit. The 2 cases on the top shelf are JLH Chiara Headphone / preamp and power supply installed in my DIY cases.. The two items below it are a pair of ESP Audio P3A power amp mono blocks again in my DIY cases. I am a retired Electrical technician I used to work at a very large Pharmaceutical site in UK. All the enclosure heatsinks were made using materials from scrap Motor Drive VSD cabinets the rest of the aluminium came from scrap production machinary.

 

[jamesfeline]

Hello penn07

Many thanks for posting .. great post this is exactly how I make my amps, always trying to reuse big heatsinks from old equipment
I love the Chiara its a great headphone amplifier that is why I invested lots of man hours to reproduce the pcbs's etc with new gerber files
would love some internal pics if possible

all the best

 

[jamesfeline]

Hello penn07

Any pics of the internals ? if possible
regards