Have you solved the heater? 6N6P draws 750mA, which is a lot, and should be very hot. When I was working on my tube preamps, I avoided 6N6P just for that reason, even it sounds good. If you do not have proper heater supply, it will not perform well. Its based on thermionic phenomenon.
https://www.diyaudio.com/community/threads/6n1-6n2-6n11-6dj8-in-pre.380485/
The 6N6 and the sister 6H30 are a very good tubef IF correctly selected to get the two setion equals. The selection needs to have a good batch of tubes, unfortuntely.
The costs are reasonable for 6N6 but no so good for 6H30.
When properly set in a circuit both give a high level results.
Of course the filament current is high but can't be a problem.
I using the 6H30 also for a long tail phase splitter, not so easy to trim but very linear and great swing ( keep almost at the limit of specs)
Walter
The costs are reasonable for 6N6 but no so good for 6H30.
When properly set in a circuit both give a high level results.
Of course the filament current is high but can't be a problem.
I using the 6H30 also for a long tail phase splitter, not so easy to trim but very linear and great swing ( keep almost at the limit of specs)
Walter
I've tested about 30 x 6n6p.None of them had the matching offered by ANY ADZAM e288cc. Yet they are ok...You won't hear differences between channels.
Hi all and thanks again.
I have just measured the 6N6P circuit with and without the transformer load and apart from a very small loss of signal
there is no bandwidth difference at all so no explanation here!
The output impedance of the 6N6P circuit is according to the designer 1k5 Ohm could this explain that on dynamic bass swings the tube runs out of current?
I have just measured the 6N6P circuit with and without the transformer load and apart from a very small loss of signal
there is no bandwidth difference at all so no explanation here!
The output impedance of the 6N6P circuit is according to the designer 1k5 Ohm could this explain that on dynamic bass swings the tube runs out of current?
We know really nothing about that transformer of yours...ca you show some photos? I have no ideea of what circuit you're talking anymore...
The 6n6p tube can go by itself with no transformer down to 1k5 anode impedance and below 100 ohms in cathode follower connection...What's that transformer even doing there?
The transformer is there because the input impedance of the poweramp stage is around 2k2 Ohm.
Then use two more 6n6p cathode followers and you're done! We use 6n6p to drive 32 ohms headphones...
You are not a lucky man 🙂
The graph of Sofia I sent show the real test on this tube; it is not easy to match the 6N6 but no impossible.
The tube is very good and, my opinion, a little sacrifice can be done.
Walter
The trafo is a 4:1 ratio so with the 2k2 on amp impedance give a reflected Zin of 35kohm that is enough.
The problem is to check the real Zin at 20 Hz. But it will be fine
But if the freq response is similar with 0ro without trafo some erron exist on circuit.
This is my opinion
The problem is to check the real Zin at 20 Hz. But it will be fine
But if the freq response is similar with 0ro without trafo some erron exist on circuit.
This is my opinion
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Hi waltube, thanks I think that in this case the source impedance is too high causing in combination with the Zin of the transformer the bass rolloff
that would explain the loss of bass I hear.
If I remember correctly the specs on the transformer state a 600 Ohm source impedance.
The measurements I did were on the output of the preamp not the poweramp so that might be next to do.
Hi Jan on the scope put on the output of the preamp there is no loss of bass I have not measured on the output of the poweramp or output of the transformer yet...