a 6c19p linestage. (Petite Lowmu)
I needed a linestage since I am planning to finally start playing lp's again. Normally I just have one source. I use picoreplayer for my lms. And control volume with my remote (phone).
Anyway. So I built a 6p1p based linestage. But in my main system it was meh.
Then I thought about the other options I have and one of them was a 6c19p...a quick glance showed that I would only have to relocate one resistor (cathode) and change the value of that. For the rest I was good to go. Half an hour later I had it soldered up and started playing some tunes.
Long story short. If looking for a linestage. And you have this tube in your parts bin. Definitely worth trying...it might be just the ticket. Very neutral and open.
ps B+ around 285. Draws around 25mA per channel. Heaters AC. Elevated. Dead silent.
Edit a couple of weeks later. There appears to be a slight hardness in the sound....especially noticeable with female voice and piano.
I needed a linestage since I am planning to finally start playing lp's again. Normally I just have one source. I use picoreplayer for my lms. And control volume with my remote (phone).
Anyway. So I built a 6p1p based linestage. But in my main system it was meh.
Then I thought about the other options I have and one of them was a 6c19p...a quick glance showed that I would only have to relocate one resistor (cathode) and change the value of that. For the rest I was good to go. Half an hour later I had it soldered up and started playing some tunes.
Long story short. If looking for a linestage. And you have this tube in your parts bin. Definitely worth trying...it might be just the ticket. Very neutral and open.
ps B+ around 285. Draws around 25mA per channel. Heaters AC. Elevated. Dead silent.
Edit a couple of weeks later. There appears to be a slight hardness in the sound....especially noticeable with female voice and piano.
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I like the simplicity Bas!
What impedance is the output capacitor designed to drive? 600R?
I have some 6S19P to try, and so I might skip the "HV regulator like Maida" and replace it with a suitable Active load instead, and maybe diode bias the cathode.
I wonder if the output has high 3rd harmonic as I have read in comments by other members here, claiming that fault of the 6C19P triode.
What impedance is the output capacitor designed to drive? 600R?
I have some 6S19P to try, and so I might skip the "HV regulator like Maida" and replace it with a suitable Active load instead, and maybe diode bias the cathode.
I wonder if the output has high 3rd harmonic as I have read in comments by other members here, claiming that fault of the 6C19P triode.
Not needed. At least I did not give it conscious thought. But the 21st century Maida boards I have. Have a 'thingy' incorporated. (Thingy is what Morgan Jones called it) The thingy's use itself has been thought of as not being anything better than a voltage divider. However....since the thingy was there. I used it.
Text from link below:
Elevation means referencing the heater supply to a DC voltage other than ground or zero volts. The heaters still operate at 6.3V or whatever, but this floats on top of the elevation voltage. Some valve stages such as cathode followers require the heater supply to be elevated to avoid exceeding the valve's Vhk(max) rating.
But even when not explicitly needed, elevation can reduce hum in AC-heated circuits by reducing or saturating the leakage current between heater and cathode.*
*See: Cooper, C. E. (1944). Valve Hum. Electronic Engineering, (July), pp72-5.
The DC voltage is applied to a transformer centre tap, artificial centre tap, humdinger, or whatever reference connection the heater supply would normally have.
The elevation voltage can be taken from a potential divider across the HT (it doesn't matter where you position the divider), and an elevation voltage around 30 to 60V is typical. The divider should have a fairly high resistance so as not to waste current, although the lower arm (R2) should not be excessively large or Rhk(max) may be grossly exceeded, so it is advisable not to make it greater than 100k. The elevation voltage should be decoupled/smoothed with an arbitrarily large capacitor (C1), say 10uF or more.
Another convenient source of elevation voltage is the cathode of a cathode-biased power valve. No current flows ‘into’ the heater supply from here, so the power valve bias is not affected.
Here is the link:
The Valve Wizard.
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Basically it was the best quality cap in my partsbin. The 6p1p linestage was based around Salas 6V6. Which uses a biggish 0,68uF
Sounds like a good idea!
If you can measure it. I'd love to know. I found no harshness at all.
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In this article, I see a contradiction between fig. 3, its descripition and the text.
Now that I've listened a bit longer...I think I've noticed a little hardness in female voices and piano. Perhaps that is 3rd harmonic?
Why the highish (and probably electrolytic) 1500 uF cathode capacitor?
A 47 uF film type of your choice would give a ~ 2 Hz pole; should do...
A 47 uF film type of your choice would give a ~ 2 Hz pole; should do...
Hi Daan,
Leftover from the Salas 6V6 where I used a 6p1p in lieu of a 6V6.
I'll get rid of them and see if I can get a film type in there.
Thanks for the suggestion. I'm still so happy with it I have not even thought about finetuning.
Leftover from the Salas 6V6 where I used a 6p1p in lieu of a 6V6.
I'll get rid of them and see if I can get a film type in there.
Thanks for the suggestion. I'm still so happy with it I have not even thought about finetuning.
Agreed. With all due respect to Jan, that was a very weird article. A lot of opinions with contradictions and unclear statements. And no experimental data to support any of it.
Indeed! I'll do that first....remove the cap out of the circuit...and then have a listen.
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