I have a 6N6P 2 channel preamplifier that uses a single 6N6P tube it does work but the bass is virtually non existent.
and it has no tube warmth.
I suspect a too low bias point as I have already tried to find many possible causes for this.
The tube runs at 122 V on the Anode B+ is 162 V
Anode resistor is 5k12 voltage drop is 40V so current is 7mA
Cathode resistor is 565 Ohm voltage on Cathode is 4.4 V
Input impedance is 47k Ohm
Output capacitor is 1µF load is 40k Ohm it is a transformer.
Can someone please help me make this thing sing?
Thanks!
and it has no tube warmth.
I suspect a too low bias point as I have already tried to find many possible causes for this.
The tube runs at 122 V on the Anode B+ is 162 V
Anode resistor is 5k12 voltage drop is 40V so current is 7mA
Cathode resistor is 565 Ohm voltage on Cathode is 4.4 V
Input impedance is 47k Ohm
Output capacitor is 1µF load is 40k Ohm it is a transformer.
Can someone please help me make this thing sing?
Thanks!
Did you run a frequency response to see how the low end fares?
Can you post a schematic? One picture being worth a 1000 words ...
For instance, how is the transformer load 40k? Is that the load at the secondary transformed to the primary?
Jan
Can you post a schematic? One picture being worth a 1000 words ...
For instance, how is the transformer load 40k? Is that the load at the secondary transformed to the primary?
Jan
Frequency response measurement can clearly confirm if this really is the case.
What tests have you done?
1.Run 6n6p with 110v Anode voltage, -3V V GK , 180 ohm cathode resistor thus 16 mA anode current .That its his first sweet spot and most linear.
2. Use 100uF output capacitor.
2. Use 100uF output capacitor.
If you want real tube sound with 6n6p go for 55v Anode and tie the cathode to ground .6n6p is one of the most neutral tube possible when used right.
http://klausmobile.narod.ru/testerfiles/6n6p.htm
http://klausmobile.narod.ru/testerfiles/6n6p.htm
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First, post the schematics. Second, tube warmth comes from heater, check that.
Hello Jan, thanks for your reply, I only have a hand drawn schematic so far and the design is not mine.
The transformer is the input transformer of my poweramp, my other preamplifier that uses 2 12au7 in parallel does not have
a weak bass.
Thanks Adison yes the warmth surely comes from the heater!
There is not much more to the schematic than what I have written in my OP , cathode bypass is 470µF and not drawn in the schematic.
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Specifications of transformer are needed (Please).
Primary DCR
Primary Impedance
Primary Inductance
Primary DC current rating
Secondary DCR
Secondary Impedance
And . . .
Load Impedance that the Secondary has to drive
It is beginning to sound (seriously; and pun intended too), like your transformer as it reacts to your surrounding circuits (tube and load on transformer output) are the cause of the sound quality.
What is the transformer manufacturer name and model number?
Thanks!
Primary DCR
Primary Impedance
Primary Inductance
Primary DC current rating
Secondary DCR
Secondary Impedance
And . . .
Load Impedance that the Secondary has to drive
It is beginning to sound (seriously; and pun intended too), like your transformer as it reacts to your surrounding circuits (tube and load on transformer output) are the cause of the sound quality.
What is the transformer manufacturer name and model number?
Thanks!
Yes, its such a simple circuit that it has to work. I see no heater supply. Is it ac or dc? Post the full schematics, including power supply.
Hi Adison I can't post the full schematic yet and the design is not mine , I am waiting for the original designer to reply.
Btw, here is similar stuff, read it.
https://diyaudioprojects.com/Tubes/Universal-Tube-Preamplifier/
https://diyaudioprojects.com/Tubes/Universal-Tube-Preamplifier/
Thank you dreamth, this is the kind of information I was looking for, what about the anode resistor or do I only change the cathode resistor?
If it is driving a transformer it is most likely the transformer can't pass the low frequencies as it's inductance there is to low.
