JLH Headphone Amp

[MilesCampbell]

Picture List

1. Rectifier Diodes and LED

Comments

1. The 1N4007 has a sliver band which denotes the cathode and this band can also be found on the PCB,
2. It is VERY important the 1N4007 are fitted the correct way around in the PCB
3. The LED has a very tiny flat on the side of the round case with a longer leg this again denotes the cathode. This is the - or negative connection of the LED.

Tip : Please double check the 1N4007 direction

[badgerboy]

Miles, this SbS is so good even a newbie like myself is (so far) having no trouble at all. Diodes are in, resistors are in, and as my workbench is also my office I've put the heatseaks on so it sits on the bench and there's no hot stuff resting on the bench. Looking forward to the next installment...

[MilesCampbell]

Hello Steve

I have to admit that I didn't think anyone would be interested..
It's kind of my own journey into JLH and his designs ..
So I'd better get on with the next installment

Thank you very much for your feedback

Miles

p.s. I'm a bit worried about having the heatsinks on already, but let see how we go ..
p.p.s. Pattie in a Bread cake, oooowwww how I miss them I really enjoyed my time in Hull ..

[badgerboy]

If you only knew how many arguments my girlfriend and I have had.. Her being a Geordie, bread cakes are bread 'buns', patties as I know them don't exist, and a hundred and one other differences! English as a common language.. HA!
PS When were you in Hull? Things don't change much around here...

Steve.

[badgerboy]

I think the journey you're on is an interesting one. For me, it's a learning process for my next kit, a PANDA headphone amplifier. Saying that, I may prefer the JHL, at which point I may well follow you further, and pass the PANDA to my girlfriend's son. He's looking for a good amp, so whatever happens I think he's on to a winner. When I do things I always mean to document things, but then I start and... well, you can guess
I'm still finding cables from my home and office rewire, and wonder where the other end is

[MilesCampbell]

Picture List

1. Capacitor 330pF - 2 off
2. Capacitor 0.1uF - 14 off
3. Capacitor 220pF - 14 off
4. Capacitor 470nF - 2 off
5. Capacitor 100uF - 8 off BEWARE OF POLARITY

Comments

1. I would strongly suggest that the build order above is followed, otherwise the small capacitors would become a real pain to fit.
2. Either side of the potentiometer the board requires a capacitor of the value 105 which is shorthand for 10^5 or 1uF or 1000nF or 1,000 000pF These are NOT included in the kit of parts but 0.47uF or 470nF I believe has been substituted.
3. The 100uF capacitors are marked on one side with a minus sign and a shorter leg. The PCB is marked with a smile and this is the negative leg.
4. Failure to insert any electrolytic capacitor with the correct polarity can lead to CATASTROPHIC consequences.

Tip : Solder ONE leg of a capacitor first. Then re-melt that soldered leg pushing the cap against the board. This makes sure the capacitor doesn't wobble .. Then proceed to solder the other leg in the normal manner.

[MilesCampbell]

Originally Posted by badgerboy

I think the journey you're on is an interesting one. For me, it's a learning process for my next kit, a PANDA headphone amplifier. Saying that, I may prefer the JHL, at which point I may well follow you further, and pass the PANDA to my girlfriend's son. He's looking for a good amp, so whatever happens I think he's on to a winner. When I do things I always mean to document things, but then I start and... well, you can guess
I'm still finding cables from my home and office rewire, and wonder where the other end is

Hello Steve

The Deep had just been started when I left after a wonderful 5 years there .. Is Spiders still there ??

Now the panda is an interesting beast ... Reading the extensive threads, there is not much to add. Was this another ebay purchase?

Right that's enough for one day

Miles

[badgerboy]

The Panda was an ebay purchase, it's due in a week or three. Should be a fun second project. Hopefully I'll learn something from the JLH and Panda threads and your geat SbS will help too. I've recently rebuit my Beyer DT990s and need a good amplifier.
Spiders will be there when the sun flickers and goes out. I know it's been going for at least 30 years, and is still the same (so I'm told by those young or strange enough to go).

[MilesCampbell]

Picture List

1. Vin Connector
2. Voltage Regulators assembled on to heasinks (See tips)
3. Voltage Regulators mounted onto the PCB (See tips)
4. Capacitors - Smoothing 2200uf 4off (Pre-Regulator) BEWARE OF POLARITY

Comments

1. There is a slight misalignment between voltage regulator and the heatsink alignment holes on the PCB. The regulator pins are not quite straight when all is complete.
2. The 2200uF capacitors are marked on one side with a minus sign and a shorter leg. The PCB is marked with a smile and this is the negative leg.
3. Failure to insert any electrolytic capacitor with the correct polarity can lead to CATASTROPHIC consequences.
4. The voltage regulator part numbers are very similar, 7912 and 7812 care is required at this stage. The 7912 is require for the negative -12V supply and mounted to the left of the board as shown with VIn at the top. To the right is 7812 which is the positive +12V supply.

Tips

1. Soldering the Vin connector it is very easy to have a gap UNDER the connector to the board. Simple trick is to solder the centre pin of the connector first, check to see if the connector is flush to the PCB and solder the outer two legs..
2. Can I suggets that the voltage regulators are mounted onto the heatsinks with the screws LOOSE...
3. Solder the middle pin of the regulator first, then check to see if the assembly is mounted square and flat to the PCB. Now solder the other legs of the regulator and the heatsink. Finally tighten the screw on the heatsink.
4. The large power supply smoothing capacitors are another component which it can be easy to leave a gap between to the PCB. Again solder one leg and check that the component is tight to the PCB.
   
   PCB = Printed Circuit Board
   VReg = Voltage Regulator

Next the power supply of the board needs to be tested.

[fj12centauro]

Hello
I have just finished and tested my headphone amp with my HD600 ' after controls of course), it works fine but the level is too high.
where are the resistors to change to reduce the gain?
Thanks