JLH 1996 based class A amplifier about 10 watts.
Using a +/-15VDC SMPS to power it.
Sounds excellent through my pair of Fane 12-250TC's
I used the JLH96 as basis for this, however the first CCS variable resistor was too small and I couldnt get zero volts on output.
I increased the 220r to 1K and it works fine now.
Using a +/-15VDC SMPS to power it.
Sounds excellent through my pair of Fane 12-250TC's
I used the JLH96 as basis for this, however the first CCS variable resistor was too small and I couldnt get zero volts on output.
I increased the 220r to 1K and it works fine now.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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I am sure this amp sounds better the longer I listen to it.
This is my first class a amp.
I was always convinced all amps sound the same but this one is very detailed.
This is my first class a amp.
I was always convinced all amps sound the same but this one is very detailed.
Nice work - a great idea and an unusual use for a sensitive PA speaker too!
It's hard to beat most true class A amps for critical, personal listening. We might believe the differences are all in the mind now, in 2020 but allegedly inaudible crossover distortion in most commercial class AB amps still results in audio that is inferior when played at the same SPL. Also, it would be interesting to compare at high SPLs, such as used for entertainment in public spaces but really, who wants that much sound in the home?
If you follow the JLH69 thread, you may find and read some of John Ellis' comments on the design and specifically on Q4 as I think you designate it (the phase splitter-VAS transistor Q3 of the original schematic) in particular. Other transistors in the design are non-critical and may be "jelly bean" types but this one needs something better, as in better Ft than MJE 340 though I guess some production will be better than others of that generic type. A BD139-16, 2SD669 or 667 wouldn't be bad and are widely available at good prices etc.
It's hard to beat most true class A amps for critical, personal listening. We might believe the differences are all in the mind now, in 2020 but allegedly inaudible crossover distortion in most commercial class AB amps still results in audio that is inferior when played at the same SPL. Also, it would be interesting to compare at high SPLs, such as used for entertainment in public spaces but really, who wants that much sound in the home?
If you follow the JLH69 thread, you may find and read some of John Ellis' comments on the design and specifically on Q4 as I think you designate it (the phase splitter-VAS transistor Q3 of the original schematic) in particular. Other transistors in the design are non-critical and may be "jelly bean" types but this one needs something better, as in better Ft than MJE 340 though I guess some production will be better than others of that generic type. A BD139-16, 2SD669 or 667 wouldn't be bad and are widely available at good prices etc.
Welcome to JLH-land, I have been stuck here for a while now 🙂
Built some variations of the JLH, and there are differences even between them, and that's not to mention the difference to the class AB, B & D I built and tried.
You're welcome to post your findings (or questions) in the massive JLH thread.
Built some variations of the JLH, and there are differences even between them, and that's not to mention the difference to the class AB, B & D I built and tried.
You're welcome to post your findings (or questions) in the massive JLH thread.