12B4 needs 320 volts. I can also get different regulator tubes....
I am using Brian Beck's 12B4 design
Thanks choky!
I am using Brian Beck's 12B4 design
Thanks choky!
fdegrove said:Hi,
Yes...............
Not SS or whatever. TUBE.
Cheers,
What is the single most important reason for shunt being superior? Is it because it's analogous to running class A (constant current draw)
Tube regulators look cool, MOSFET regulation small and efficient, so in my case I went for the latter.
ps.
Is there a thread on Shunt vs. Series pass?
Mark-there it is
with these values -even worst case scenario of minus 10% voltage from mains is covered; in your case-feeding with EICO this is irrelevant,but that's praxis........
btw-you really waste energy there burnin' 30mA in 6K25 anode resistor...
what you need is one nice plate choke ,and-tnx to low Ri of 12B4,that choke must not be enormous....in that case Ub will be around 150V,and just one OD will do the beeeezzzznissssss...
I'm not talking here about heat and pennies for electricity bill.....this is more measure of signal energy preservation.
with these values -even worst case scenario of minus 10% voltage from mains is covered; in your case-feeding with EICO this is irrelevant,but that's praxis........
btw-you really waste energy there burnin' 30mA in 6K25 anode resistor...
what you need is one nice plate choke ,and-tnx to low Ri of 12B4,that choke must not be enormous....in that case Ub will be around 150V,and just one OD will do the beeeezzzznissssss...
I'm not talking here about heat and pennies for electricity bill.....this is more measure of signal energy preservation.
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Hi,
I think that running in class A may well be one of the reasons, another may be the very short reaction time to changes in the rail voltage.
As Mark pointed out they're relatively noisier than series regs but in my experience, and apparently that from many other users as well, the noise is rather unobtrusive musically speaking.
It's not as if it's going to mask any detail in the music or something along those lines.
Subjectively shuntregs provide a tighter, more musical sound.
A hallmark of a low impedance supply, I reckon.
I'm sure there is one but that's quite a while ago already. I do remember all of us agreeing to the sonic superiority of the shuntreg....
On the downside it's obviously more wasteful especially so if you'd consider using that topology for higher current apps such as amps.
Ciao,
I think that running in class A may well be one of the reasons, another may be the very short reaction time to changes in the rail voltage.
As Mark pointed out they're relatively noisier than series regs but in my experience, and apparently that from many other users as well, the noise is rather unobtrusive musically speaking.
It's not as if it's going to mask any detail in the music or something along those lines.
Subjectively shuntregs provide a tighter, more musical sound.
A hallmark of a low impedance supply, I reckon.
I'm sure there is one but that's quite a while ago already. I do remember all of us agreeing to the sonic superiority of the shuntreg....
On the downside it's obviously more wasteful especially so if you'd consider using that topology for higher current apps such as amps.
Ciao,
frank, choky, I'm using series pass now on my 12B4. would like to try shunt.
Will this work? I used LTSpice to draw and simulate, but I really don't know if it is sound.
ps.
choky, you're right about the Ra. I have successfully used plate chokes on my 5842 and will be using the same for the 12B4. I'm having a couple of 150H 30mA plate chokes wound.
Will this work? I used LTSpice to draw and simulate, but I really don't know if it is sound.
ps.
choky, you're right about the Ra. I have successfully used plate chokes on my 5842 and will be using the same for the 12B4. I'm having a couple of 150H 30mA plate chokes wound.
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Choky,
Yes the resistor gets very hot and I believe its dissipating close to its rating. I have a Mills non-inductove in there and I really don't want to change much around in the actual circuit. Why mess with something that sounds as good as this? I would still like to run this at 320 volts input as it shows on Brian's link but for now the 300 volts will be a good experiment. what the heck... I always liked the glow of those regulator tubes! I can get what ever gas regulators we need to accomplish getting to 320 later on. A local surplus tube man has over 500,000 tubes in his warehouse... so what ever we need is not a problem.
Toobes anyone???????
Yes the resistor gets very hot and I believe its dissipating close to its rating. I have a Mills non-inductove in there and I really don't want to change much around in the actual circuit. Why mess with something that sounds as good as this? I would still like to run this at 320 volts input as it shows on Brian's link but for now the 300 volts will be a good experiment. what the heck... I always liked the glow of those regulator tubes! I can get what ever gas regulators we need to accomplish getting to 320 later on. A local surplus tube man has over 500,000 tubes in his warehouse... so what ever we need is not a problem.
Toobes anyone???????
Attachments
Yes,
I have built around 5 or 6 differnt versions finally settling on Brian's design as being best sounding. This is about as hard biased into class A as this tube can get and is wasteful of power... so be it, its not that much... not like a class A power amp. I use a CSS in the cathode as shown in the link to his design. Am certainly willing to try the gas toobes though.....
Also, I have purcashed pretty high end componenst for my 12B4. Mills and Vishay resistors, Multi-Cap coupling caps and Wonder film and Panasonic electrolytic bypass caps.
Perhaps Bill WW and Luckylyndy will chime in on how it sounds.....
More toobes anyone?
Mark
I have built around 5 or 6 differnt versions finally settling on Brian's design as being best sounding. This is about as hard biased into class A as this tube can get and is wasteful of power... so be it, its not that much... not like a class A power amp. I use a CSS in the cathode as shown in the link to his design. Am certainly willing to try the gas toobes though.....
Also, I have purcashed pretty high end componenst for my 12B4. Mills and Vishay resistors, Multi-Cap coupling caps and Wonder film and Panasonic electrolytic bypass caps.
Perhaps Bill WW and Luckylyndy will chime in on how it sounds.....
More toobes anyone?
Mark
Attachments
Mark A. Gulbrandsen said:
hehe-I don' care for your resistors (~5W of heat in each 6K25 resistor),but I care what's happening with poor signal with all that waste.....don't take me wrong-my WOT preamp is on same side of thinking- but I burn muuucho in PS and only what I must in da tube (in case of my EC8010 - 150V x 20mA) ......but this only tnx to use of OT .......
only when you hear choke ( or even xformer
) in place of anode resistor, you will know what I mean.......again-like broken record- "signal energy preservation".......but-good choke or good xformer and few other parts are even more critical than in case of R loaded stage
in your place (boots
?) I'll not care about that 20V difference , especially 'because I think that is hard to find gas tube combo for 320V....again-I urge you to try shunt reg,and thinking about your equipment around,I think that's easier way to try with gas stabs........
I don't have intention to claim that in your case sound must be better than with series reg.........
In my xperience -ALWAYS when i make good (enough ) shunt reg,no matter it is for SS or tube,sound is better to me...
jjust little edit:
I see difference between series and shunt reg in greater suspectibility to current delivering ,in case of shunt reg.........
dunno if my Engrish was good enough for that last sentence,but I hope that you all know what I mean....A class and B Class as difference was just allusion
Hi,
Not that I disagree with what Choky's saying but:
2*85A2 + 1*OA2 = 320VDC Reg.
Do you guys know there used to be single tube with multiple voltages references inside so you could tap say, 105V or 150V for instance?
Can't come up with a type number right now but browsing through the "glow discharge tubes" section of a tube manual should yield a few.
Cheers,
Not that I disagree with what Choky's saying but:
2*85A2 + 1*OA2 = 320VDC Reg.
Do you guys know there used to be single tube with multiple voltages references inside so you could tap say, 105V or 150V for instance?
Can't come up with a type number right now but browsing through the "glow discharge tubes" section of a tube manual should yield a few.
Cheers,
fdegrove said:Hi,
Not that I disagree with what Choky's saying but:
2*85A2 + 1*OA2 = 320VDC Reg.
Do you guys know there used to be single tube with multiple voltages references inside so you could tap say, 105V or 150V for instance?
Can't come up with a type number right now but browsing through the "glow discharge tubes" section of a tube manual should yield a few.
Cheers,
hehe-not to disagree with fdegrove,but my sentence
in fact lack just few words : "good for 30mA".........
85A2 is good for....10mA or so?
anyway-in tube world,when we are in ballpark of 300V,20 V difference is nothing........let's Mark now decrease with Eico knob (uups-with sheeeeety multiturn) 20 volts down and I can bet (even if I don't have that bad habit ) that difference will not be audible
edit-I can recall that gas tubes with (various purpose) aditionall taps,but-frankly I never see one..........local customs,don't you think?
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