I changed the loudspeakers and I didn't like the sound anymore, hence I just skip the UL tap and connect the sceen to AT+, and the system sounds better than before.
Tube is 6L6GC-STR in S.E.
So, question is, why and when someone should prefer "tetrode" mode instead of ultralinear mode?
Tube is 6L6GC-STR in S.E.
So, question is, why and when someone should prefer "tetrode" mode instead of ultralinear mode?
I have experienced your situation. I have found that different tubes, transformers, circuits,voltages, bias, type of music and speakers all affect the final sound. What matters is what sounds good to you. What I have read over the years is that UL is a compromise between pentode (Power with more distortion) and triode (Less power less distortion).
I like my Sansui AU717/TU717 Combo. And my Eico Tuners playing thru a 3W SE 6AU6/6AQ5 in a fully integrated amp.
Ella Fitzgerald is on the local Jazz station as I type this. Both systems are more than passable for my use as primarily background.
Pushing more Tonnes of snow today, making space for the next dump!
Ella Fitzgerald is on the local Jazz station as I type this. Both systems are more than passable for my use as primarily background.
Pushing more Tonnes of snow today, making space for the next dump!
Attachments
ygg-it,
What was the first speaker model you were using UL;
Then what was the second speaker model you were using that you did not like UL?
When you say 6L6GC in Tetrode mode, I believe you mean Beam Power mode, Right?
Can you post a schematic of the amplifier that you first had in UL, and then switched it to Tetrode?
Details, please?
A mystery without knowing any of the "players" is still a mystery.
Thanks!
What was the first speaker model you were using UL;
Then what was the second speaker model you were using that you did not like UL?
When you say 6L6GC in Tetrode mode, I believe you mean Beam Power mode, Right?
Can you post a schematic of the amplifier that you first had in UL, and then switched it to Tetrode?
Details, please?
A mystery without knowing any of the "players" is still a mystery.
Thanks!
If it sound different there is a measurable difference. Maybe the difference only occurs with
the speaker connected. If you really want to know, then start measuring.
ygg-it
The differences between Ultra Linear mode versus Pentode / Beam Power mode, partly depends on the amount of negative feedback that includes the output tube(s) (this applies to both single ended and push pull).
(Ultra Linear is negative feedback; but I am talking about any Additional* negative feedback: global, Schade, output plate to driver cathode, output secondary to output tube cathode, etc.)
At one extreme
No Additional* negative feedback . . . the damping factor is very different, the frequency response is very different, the distortion is very different, and the output power is somewhat different.
All the way to the other extreme
Lots and Lots of negative feedback . . . the damping factor is similar, the frequency response is similar, the distortion is similar, and the output power is fairly close.
Also, pentode / beam power modes have more gain, versus Ultra Linear mode (on the same tube type).
So, a driver has to output more volts to get the same watts out (and the driver might be distorting long before the driver output is putting out peaks that are almost 2x the bias volts (even if you did not change the bias volts from pentode/beam power mode to UL mode).
This is not just a function of maximum power out differences versus the operating mode, it is a function of low and medium power out.
Do you have a driver that has early distortion?
Are you using negative feedback?
If your loudspeakers have a wide range of impedance versus frequency, then damping factor may or can be important.
With such a loudspeaker, and an amplifier with low damping factor, then the combined frequency response of the system may not be good.
That is why I requested that you post the amplifier schematic, and tell us the two different loudspeaker makes and models.
It is not fair to blindfold the archer, and then ask him to hit the bulls eye.
The differences between Ultra Linear mode versus Pentode / Beam Power mode, partly depends on the amount of negative feedback that includes the output tube(s) (this applies to both single ended and push pull).
(Ultra Linear is negative feedback; but I am talking about any Additional* negative feedback: global, Schade, output plate to driver cathode, output secondary to output tube cathode, etc.)
At one extreme
No Additional* negative feedback . . . the damping factor is very different, the frequency response is very different, the distortion is very different, and the output power is somewhat different.
All the way to the other extreme
Lots and Lots of negative feedback . . . the damping factor is similar, the frequency response is similar, the distortion is similar, and the output power is fairly close.
Also, pentode / beam power modes have more gain, versus Ultra Linear mode (on the same tube type).
So, a driver has to output more volts to get the same watts out (and the driver might be distorting long before the driver output is putting out peaks that are almost 2x the bias volts (even if you did not change the bias volts from pentode/beam power mode to UL mode).
This is not just a function of maximum power out differences versus the operating mode, it is a function of low and medium power out.
Do you have a driver that has early distortion?
Are you using negative feedback?
If your loudspeakers have a wide range of impedance versus frequency, then damping factor may or can be important.
With such a loudspeaker, and an amplifier with low damping factor, then the combined frequency response of the system may not be good.
That is why I requested that you post the amplifier schematic, and tell us the two different loudspeaker makes and models.
It is not fair to blindfold the archer, and then ask him to hit the bulls eye.
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