First attempt at mu follower for headphone amp.
2 x 6N6P.
Voltage on bottom anode is 100V - led bias at about 2.0V across it.
18-20mA??
top cathode has 120 ohm resistor (1.9V-16mA) follower by 10K with bootstrap of 220K.
Small bypass cap connected to bottom anode.
Turn is up a little a it distorts quite a bit.
32 ohm phones.
For me the voltages and currents look ok.
Strange.
2 x 6N6P.
Voltage on bottom anode is 100V - led bias at about 2.0V across it.
18-20mA??
top cathode has 120 ohm resistor (1.9V-16mA) follower by 10K with bootstrap of 220K.
Small bypass cap connected to bottom anode.
Turn is up a little a it distorts quite a bit.
32 ohm phones.
For me the voltages and currents look ok.
Strange.
32 ohms is a pretty impossible load for a valve. I think you would need a pretty special circuit with lots of feedback. Think about the problems of designing OTL amps.I think EC8010 probably knows a lot about this kind of thing judging from some of his posts.
Isn't 32 ohms the impedance of the smallest headphones??
Mt SRPP drove them really well. And I expect the 300 ohm phones such as Sennheiser.
FYI- I have a 220uF output cap.
Mt SRPP drove them really well. And I expect the 300 ohm phones such as Sennheiser.
FYI- I have a 220uF output cap.
If I understand your schematicless description right, you have a voltage drop of 160V over the 10k. So with 100V over the upper tube you need just over 350V B+. Do you have that?
I have 325V.
Where am I going wrong? Do I need to lower or increase the upper cathode resistor or the 10K plate resistor?
The mu follower should have lower distortion than the SRPP.
Where am I going wrong? Do I need to lower or increase the upper cathode resistor or the 10K plate resistor?
The mu follower should have lower distortion than the SRPP.
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I think that the load impedance you're trying to drive is way too low for that valve....🙁
32 ohm is VERY low impedance for a 6N6p....🙄
Try a higher impedance headphone, around 300 ohm....
Or you could replace the top valve with a MOSFET a la Allen Kimmel....
32 ohm is VERY low impedance for a 6N6p....🙄
Try a higher impedance headphone, around 300 ohm....
Or you could replace the top valve with a MOSFET a la Allen Kimmel....
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Maybe I got confused with the load.
These phones are standard small headphones. Easiest to drive.
300??
Why does the SRPP with 6N6P's perform flawlessly?
These phones are standard small headphones. Easiest to drive.
300??
Why does the SRPP with 6N6P's perform flawlessly?
Hmm...
You say, 'small and easy to drive'....
What is the actual Impedance of these phones...?
That type used fro MP3 players etc are usually below 50 ohms, and not a good load for any small Valve circuit!
You say, 'small and easy to drive'....
What is the actual Impedance of these phones...?
That type used fro MP3 players etc are usually below 50 ohms, and not a good load for any small Valve circuit!
😕
Big error on my behalf. I thought they were easier to drive.
Come to think of impedance I couldn't have been so wrong.
Yes small maxell phones.
The SRPP worked great with them. Quite superb. Guess I'll go back to my original design.
Mu followers IMLE in most cases don't drive low impedances very well as compared to say a properly trimmed white cathode follower (WCF) or even SRPP - A properly designed WCF is inherently PP and the SRPP if designed to match the headphone impedance range will also work in PP. Mu followers work great for voltage gain in applications where the load impedance is relatively high.
I drive 32 ohm and lower impedances quite effectively with a pair of 5842 in a WCF - you only need a few mW typically for ear splitting levels with most headphones.
You need to choose a topology designed to deliver power to low impedance loads, the mu follower is great for providing voltage gain, not quite as good providing high current to a load.
I would think the 6N6P would be ideal in a WCF..
I drive 32 ohm and lower impedances quite effectively with a pair of 5842 in a WCF - you only need a few mW typically for ear splitting levels with most headphones.
You need to choose a topology designed to deliver power to low impedance loads, the mu follower is great for providing voltage gain, not quite as good providing high current to a load.
I would think the 6N6P would be ideal in a WCF..
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Had built one of these but my psu was too noisy. maybe a cascode DN2540 would filter out the noise on the plate.
Sorry no chokes available here.
My SRPP was dead quiet.
That's because SRPPs rock, and you are a splitter for thinking of using anything else 😉
my wife who listened to my design thought that too. gave her goosebums cuz mark anthony was so sureal.
spent days tweaking it to see which gave the best sound.
not sure on the dn2540 on the upper cathode or resister split(broskies idea), is best yet.
spent days tweaking it to see which gave the best sound.
not sure on the dn2540 on the upper cathode or resister split(broskies idea), is best yet.
AGGGHHHHH!!!!
True story: my sister-in-law was a groupie. Followed them from city to city. Had a child by the lead singer.
True story: my sister-in-law was a groupie. Followed them from city to city. Had a child by the lead singer.
No. Apparently, neither can his biological father (though I'll admit to total ignorance of their music- I'm very pop-averse).
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