Hello all.
I have today received and soldered together one of those super cheap Chinese 'JLH' headphone amps, his 1969 design, so published the same year as his famous "simple 10 watt class A" amp.
Long ago I built the superb kit from Hart Electronic Kits in the UK, of his Chiara Headphone amp with its separate PSU.
This one, unlike the Chiara is all discrete and quite new to me.
I wondered as I was putting it together if it would be helpful to stop and share a scan of the board as a guide to some of the smaller components. These kits come with no instructions at all!
From other photos I have seen, the PCB has jumpers on the top surface where I have filled in the Plated-through holes. I think this is all that is required (?), and maybe not even this as they are PTH .
I hope (I'm out of practice) that I've put the diodes and the LED in the right way! (I did check).
I have today received and soldered together one of those super cheap Chinese 'JLH' headphone amps, his 1969 design, so published the same year as his famous "simple 10 watt class A" amp.
Long ago I built the superb kit from Hart Electronic Kits in the UK, of his Chiara Headphone amp with its separate PSU.
This one, unlike the Chiara is all discrete and quite new to me.
I wondered as I was putting it together if it would be helpful to stop and share a scan of the board as a guide to some of the smaller components. These kits come with no instructions at all!
From other photos I have seen, the PCB has jumpers on the top surface where I have filled in the Plated-through holes. I think this is all that is required (?), and maybe not even this as they are PTH .
I hope (I'm out of practice) that I've put the diodes and the LED in the right way! (I did check).
Attachments
Have fun building the kit. In stock form it is an ok but not great amp for phones down to about 120 Ohms impedance. There's a long thread on this forum about building and some mods. You'll definitely want to fix the grounding errors in the layout, shown in this post and described a few posts earlier:
JLH Headphone Amp
The supplied 100uF 'lytics are pretty cr@ppy, too.
JLH Headphone Amp
The supplied 100uF 'lytics are pretty cr@ppy, too.
Thanks for your reply. I have soldered it all together except for the final connection of the transformer and of course a pair of headphones.
As I have posted, I have not tried this circuit before. I did build the excellent "Chiara" headphone amp back in 1996 when I intended to use it as an input to a design by Jeff Macauly: his "Microreflex" active loudspeakers. (see WIRELESS WORLD: UK technical magazine 1913-2008, the PDF for June 1995)
That project never worked out - but I've been playing with active crossovers recently.
As I have posted, I have not tried this circuit before. I did build the excellent "Chiara" headphone amp back in 1996 when I intended to use it as an input to a design by Jeff Macauly: his "Microreflex" active loudspeakers. (see WIRELESS WORLD: UK technical magazine 1913-2008, the PDF for June 1995)
That project never worked out - but I've been playing with active crossovers recently.