• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Hybrid Tube Headphone Amp

> nothing wrong with what you have already.

But there are, IMHO :
better output devices than IRF510
better current source than LM317
better circuits without output coupling caps, better PSRR, and more headroom for 600R phones.

The Borbely posted above is quite the opposite to the NP-100v12.
It has LTP input, has NFB, needs dual rail supplies, but is DC coupled.
So depends on your personal choice.


Patrick
 
I am scratching my head on my project. I have tried 5 SMPS and all gave me hum, thus I kinda want to give up on this amp. As a last resort I am currently waiting on a LM317 stepdown converter and a dc power filter to eliminate the hum. Any thoughts on what else that could help?
 
> nothing wrong with what you have already.

But there are, IMHO :
better output devices than IRF510
better current source than LM317
better circuits without output coupling caps, better PSRR, and more headroom for 600R phones.

The Borbely posted above is quite the opposite to the NP-100v12.
It has LTP input, has NFB, needs dual rail supplies, but is DC coupled.
So depends on your personal choice.


Patrick

How will the sound differ? What are the pros and cons of using an output coupling cap?
 
There's always the old Caveli SOHA

From years back on the long-gone HeadWize site. Not fancy, uses a 12AU7 at low voltages for gain and an opamp to power the 'phones. 12AU7s and various equivalents can be rolled for desired sonic effect. Only one cap in the signal path and it can be rolled too. I build 3 or 4 for friends years ago and they were all quiet. Parts list shows fancy PS diodes but 1N variety or inexpensive bridges will work as well.

Should fit your budget.

S.
 

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From years back on the long-gone HeadWize site. Not fancy, uses a 12AU7 at low voltages for gain and an opamp to power the 'phones. 12AU7s and various equivalents can be rolled for desired sonic effect. Only one cap in the signal path and it can be rolled too. I build 3 or 4 for friends years ago and they were all quiet. Parts list shows fancy PS diodes but 1N variety or inexpensive bridges will work as well.

Should fit your budget.

S.

Do you have a pcb eagle file so that I can try and order it from JLCPCB?
 
If you are making a basic build and watching your budget probably not worth the extra. If you are going to glam it up a bit with better coupling caps and an NOS tube perhaps, maybe go with the more expensive pot. Your choice. Don't go with a cheap carbon pot though. They have notoriously poor tracking, especially at the low volume end.

S.
 
I've not built a NP-100v12. Few headphone amps can drive speakers without the signal first being sent through a power amp. Was that what you were asking?

NOS tubes? Some of the more obscure ones like a 5963 can often sub for a 12AU7 and depending on the circuit sound decent and they usually don't cost a lot. The SOHA is quite amenable to tube rolling. It's gentle with tubes so if you get one you like it should last a long time.

S.