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But do you need a slow turn on ? I didn't see anything in the data sheet that suggests the 6V6 can't handle a immediate B+ followed by a natural warm up of the heaters under ac power ? - certainly a LOT simpler.
Mine has run on both directly and indirectly heated rectifiers with the same CCS heater reg for 6V6's in many years and I have not experienced their ware out yet.
I am looking for a power supply for a 10. Killed one already just heating up the filament unfortunately. That's why the precaution 😉
Use determined current (CCS) for the heater, will be like having a bench supply with a securely set current limit.
Thank you Salas very muchi!! I will read and study Kmultiplier to choice the solution to reduce rail uhm.At the moment the pre work in a little wood box that Was a package for red wine so i expect a new supply stadium and a better package before show it.
thank you, last evening I solved the problem of hum due to ground loop and now the pre is very silent, howewer i want to add this cheaper circuit to verify improuvements in quality of sound.
Salas,
Is it a ridiculous notion to use the buffer version after the gain stage? This would allow the use of a line output transformer. I calculated its Zo as roughly 245
Is it a ridiculous notion to use the buffer version after the gain stage? This would allow the use of a line output transformer. I calculated its Zo as roughly 245
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Nothing is silly when it serves a purpose. Could sandwich the pot between stages and cut on first stage hiss even.
I am concerned as I will be running this to dual mono amps and might have a pretty good run of interconnect. Balanced is just so useful in this regard. If i put the pot in between stages, I would assume this would replace the 470k resistor? or would i just add it and increase the coupling cap to maintain desired bandwidth?
I would need a different reg for each filament, correct? Is it a better choice to have these regs powered by seperate transformers? or can I just use the secondaries that coem with main transformer. Also, I notice the cathoe follwer version has a B+ that is 10V less. Can i just insert a resistor in between the rail and plate of that tube to lower the voltage 10V?
Sorry for the questions. I want to do this right the first(second🙂 time and be done.
I would need a different reg for each filament, correct? Is it a better choice to have these regs powered by seperate transformers? or can I just use the secondaries that coem with main transformer. Also, I notice the cathoe follwer version has a B+ that is 10V less. Can i just insert a resistor in between the rail and plate of that tube to lower the voltage 10V?
Sorry for the questions. I want to do this right the first(second🙂 time and be done.
Those things are just about how separate PSUs and expensive you aspire your build to be. Common or separate power sourcing will basically work. If its CCS heaters got to be separate though else they will not balance Vh correctly. Not heater trafos, IhCCS circuits.
Using a pot in between its intuitive. You choose a Cout that can drive it well down to infra bass and you wire it instead of the output 470k as if the first stage was some source gear. Same stuff.
Same B+ will work OK.
Using a pot in between its intuitive. You choose a Cout that can drive it well down to infra bass and you wire it instead of the output 470k as if the first stage was some source gear. Same stuff.
Same B+ will work OK.
THanks. That is what I thought, but wanted to be sure. I will draw a schematic if you dont mind giving it a once over.
Salas,
Does the 470R resistor in the cathode need to change if I use a 200K pot? I assume this resistor sets the operating point of the stage.
Does the 470R resistor in the cathode need to change if I use a 200K pot? I assume this resistor sets the operating point of the stage.
Bias is bias, has not to do with the pot. Why you wanna use such a high value pot? There is still input capacitance in the tube even when not in gain mode, so much series R will truncate the bandwidth. See with a scope that it passes a 20kHz square nicely in any case.
was just trying to get as close to numbered values. Would you sugeest smaller, 50-100k, and larger cap?
50k pot and 2.2uF cap yields LF cutoff og 15hZ. I have bigger caps, but do not want to assume that bigger is better🙂
50k pot and 2.2uF cap yields LF cutoff og 15hZ. I have bigger caps, but do not want to assume that bigger is better🙂
Anyway use something sensible, 50K is good, you may wanna revert it to the first stage's input if you will not like it in the middle and there will be Miller too.
I will order stuff to try both ways, but like the idea of it being between the two circuits and attenuating noise.
Salas i Made some mesurement today: i have 300v on anode, 23mA , on cathode 90v and the grid Was -30v respect the configuration is cathode follower.
do you think the valve work in the correct zone? I observed a current variation of 0,3mA at max and a voltage variation of 3volt.
So other question is could the serial regulator improve something or i have to consider other action for seriously have result s on sound?
do you think the valve work in the correct zone? I observed a current variation of 0,3mA at max and a voltage variation of 3volt.
So other question is could the serial regulator improve something or i have to consider other action for seriously have result s on sound?
