JLH Class A headphone amplifier

[jamesfeline]

I currently use TIP41C as I have loads of them for Q1 and Q2

 

[jamesfeline]

Data Sheet attached (Tip 41C)

 

[xrk971]

My current favorite audio opamps are

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

Or

OPA1642 (dual) and OPA1641 (single)
5.1nV / sqrt(Hz) noise and 0.00005% THD, 20V/usec slew rate 36Vpp, and 36mA capable.

The former has MOSFET inputs and latter JFET inputs. Both sound superb and capable of driving a lot of current.

 

[jamesfeline]

nice one .. thanks for the update ?
are you using the same circuit as me ??

 

[jamesfeline]

 

[jamesfeline]

and we are talking about the opa 627

 

[jamesfeline]

Hello all

Mounted the 2 burr brown OPA627AP op amps on a brown dog adapter .. this was fiddly to say the least next time will get them pre made from the supplier

 

[jamesfeline]

would you believe this represents just over a £100 in cost !! for these 2 little chips

 

[jamesfeline]

 

[EUVL]

In my personal experience, using lateral MOSFETs such as 2SK1058 / 2SJ162 not only simplifies the circuit considerably.
It also gives you a much more powerful and controlled sound, especially with low impedance phones.
Not related to JLH though, if that is important.

Dual OPA627 are best done with SMD packages.


Patrick

 

[EUVL]

Also attached the Spice file to play with.


Patrick

.

 

[jamesfeline]

Hello members
I just wanted to note that this thread that I originally started many years ago was dedicated to the JLH Chiara class A single ended design. There have been some posts that are a different design to what I make . .which is all OK just wanted to stop any confusion as JLH did complete numerous designs in his career and some versions are re hashed designs from China.

little back ground info below

 

[jamesfeline]

a few diagrams to help potential constructors
the brown dog adaptor

 

[jamesfeline]

And the 2 OP Amps that I use currently .. any better ones that people have used successfully then please let me know as would be interested to see what other people are up to ??

 

[jamesfeline]

Hello

Just started to populate my new design PCB
Have added the IC (op amp) socket and the copper wire links (couple of pics below)

 

[jamesfeline]

one more

 

[jamesfeline]

headphone sockets added

 

[jamesfeline]

few more pics

 

[jamesfeline]

a few more components added

 

[Kuzmenko]

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