Thanks Patrick. I can understand where Bigun is coming from but I must say that your initial comments at the start of the thread made it quite clear that you were 1. providing, for free, the gerbers plus 2. your rational behind the changes to the circuit
...and that it was possible to build either version...either the REAL JHL design or your updated one.
I can not see any issue.
I am really looking forward to future posts and thanks again for your efforts.
The next posts will come from the Beta tester, when he has finsihed with his build.
Then the Gerbers.
Patrick
Then the Gerbers.
Patrick
single power supply would require a output cap. if single power supply is what you want, build a nerfed 1969 😉
> if single power supply is what you want,
You can find out in the other "JLH Headphone Amplifier" thread :
JLH Headphone Amp
This is precisely what we do not want to build, with input and especially output coupling caps.
I am afraid you are at the wrong place here.
Cheers,
Patrick
You can find out in the other "JLH Headphone Amplifier" thread :
JLH Headphone Amp
This is precisely what we do not want to build, with input and especially output coupling caps.
I am afraid you are at the wrong place here.
Cheers,
Patrick
I will probably use it with LM317 regulated PSUs with tl431 as voltage reference 
and most likely a fat capacitor bank before it
and most likely a fat capacitor bank before it
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Many Thanks for the replies. I have the original JLH amp with me.(1969)
My interest at present is to know whether it is possible to have single power supply amp with this symmetrical topology !(with its advantages and disadvantages)
My interest at present is to know whether it is possible to have single power supply amp with this symmetrical topology !(with its advantages and disadvantages)
> whether it is possible to have single power supply amp with this symmetrical topology
I admit I do not understand why single supply is important, as it hardly safes you any cost.
But in theory you can do a couple of thing to create a dual supply from a single one.
1. Virtual Ground from a single 30V supply
Virtual Ground Circuits
2. Use something like the Jan Didden Silent Switcher to create dual supply from single using a SMPS chip, followed by linear regulators.
For the latter, make sure the chip is capable for the power requirements.
And for me, these are more complicated solutions than a dual supply, with no benefits.
Patrick
I admit I do not understand why single supply is important, as it hardly safes you any cost.
But in theory you can do a couple of thing to create a dual supply from a single one.
1. Virtual Ground from a single 30V supply
Virtual Ground Circuits
2. Use something like the Jan Didden Silent Switcher to create dual supply from single using a SMPS chip, followed by linear regulators.
For the latter, make sure the chip is capable for the power requirements.
And for me, these are more complicated solutions than a dual supply, with no benefits.
Patrick
Symmetrical amps cannot be operated on a single supply I mean you could, with a virtual ground but virtual ground requires a super beefy opamp and at these operating currents it is very much out of the question. Or you'll get a lot of asymmetrical distortion.
Trying to use a single supply or turning a single supply into dual supply is more trouble than it's worth
I have done virtual Gnd for a power amp decades ago.
So it is possible.
But we should end this discussion here.
There are other threads in DIYA for virtual Gnd.
For this particular circuit, only symmetrical rails make sense.
See article re DC offset, etc.
Cheers,
Patrick
So it is possible.
But we should end this discussion here.
There are other threads in DIYA for virtual Gnd.
For this particular circuit, only symmetrical rails make sense.
See article re DC offset, etc.
Cheers,
Patrick
One last question:
Instead of creating a virtual ground, can this topology be adopted ?
Recommendation for 5-10W amp.
Instead of creating a virtual ground, can this topology be adopted ?
Recommendation for 5-10W amp.