Dirty DC power for heaters can be worse than AC, noise could be injected via Cfk, and/or Rfk, the LM317 is a poor choice, IMHO, try an OPAMP+MOSFET+Voltage reference.
From a modest CA3130 to the wonderful NE5534 work very well, an LM329 as voltage reference and an IRF540 also work very well.
I don't want a "sound" in my valve amps/preamps, and DC works very well to me.
Don't forget RF chokes, see "Morgan Jones- Valve Amplifiers" for a good aproach.
This circuit with some mods could work OK, try LM317 instead of 78XX, a simple zener also could do the job, here is acceptable, only to power the OPAMP and voltage reference.
http://www.diyaudio.com/forums/tubes-valves/212175-heaters-filaments-ac-vs-dc-12.html#post3045237
The cleanest the DC, the cleanest the sound...
Edit: With clean DC you will lose some 50Hz(60Hz)/100Hz(120Hz) information, and its harmonics, but this is a "sound" that don't belong to the musical material, fireworks..."coupe d'effet" for audiofools.
From a modest CA3130 to the wonderful NE5534 work very well, an LM329 as voltage reference and an IRF540 also work very well.
I don't want a "sound" in my valve amps/preamps, and DC works very well to me.
Don't forget RF chokes, see "Morgan Jones- Valve Amplifiers" for a good aproach.
This circuit with some mods could work OK, try LM317 instead of 78XX, a simple zener also could do the job, here is acceptable, only to power the OPAMP and voltage reference.
http://www.diyaudio.com/forums/tubes-valves/212175-heaters-filaments-ac-vs-dc-12.html#post3045237
The cleanest the DC, the cleanest the sound...
Edit: With clean DC you will lose some 50Hz(60Hz)/100Hz(120Hz) information, and its harmonics, but this is a "sound" that don't belong to the musical material, fireworks..."coupe d'effet" for audiofools.
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Dirty DC power for heaters can be worse than AC, noise could be injected via Cfk, and/or Rfk, the LM317 is a poor choice, IMHO, try an OPAMP+MOSFET+Voltage reference.
From a modest CA3130 to the wonderful NE5534 work very well, an LM329 as voltage reference and an IRF540 also work very well.
I don't want a "sound" in my valve amps/preamps, and DC works very well to me.
Don't forget RF chokes, see "Morgan Jones- Valve Amplifiers" for a good aproach.
This circuit with some mods could work OK, try LM317 instead of 78XX, a simple zener also could do the job, here is acceptable, only to power the OPAMP and voltage reference.
http://www.diyaudio.com/forums/tubes-valves/212175-heaters-filaments-ac-vs-dc-12.html#post3045237
The cleanest the DC, the cleanest the sound...
Edit: With clean DC you will lose some 50Hz(60Hz)/100Hz(120Hz) information, and its harmonics, but this is a "sound" that don't belong to the musical material, fireworks..."coupe d'effet" for audiofools.
Popilin I use this board as regulator
Link
I dont know if is good or bad the borad but listen Mozart feel good
but my surprise have been how the sounds details changes, for next week will use a swich to test both ac and dc to the heater, will be more clear what happen
If Mozart sounds good, it's good.
If you hear some harsh in mids/treble, maybe a sign of ripple/RF, maybe your circuit need an update.(Triode strapped pentodes?)
Don't search for the fifth leg of the cat with micro-detail unless you can listen the same piece of Mozart in a concert hall.
BTW, 6C33 is current hungry, nevertheless you can also power filaments with DC.
Mains frequency IM also affects power amps, a few less than preamps.
Sky is the limit...
Edit: Heaters must always be referenced to some potential from ground, even better, elevate the heaters about 40V from ground in normal topologies.
If you hear some harsh in mids/treble, maybe a sign of ripple/RF, maybe your circuit need an update.(Triode strapped pentodes?)
Don't search for the fifth leg of the cat with micro-detail unless you can listen the same piece of Mozart in a concert hall.
BTW, 6C33 is current hungry, nevertheless you can also power filaments with DC.
Mains frequency IM also affects power amps, a few less than preamps.
Sky is the limit...
Edit: Heaters must always be referenced to some potential from ground, even better, elevate the heaters about 40V from ground in normal topologies.
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Does true Mr Popilin, can you show the circuit?
Hi Guys, can you show the electric diagram of the board?
The best for you.
Popilin I use this board as regulator
Link
I dont know if is good or bad the borad but listen Mozart feel good
but my surprise have been how the sounds details changes, for next week will use a swich to test both ac and dc to the heater, will be more clear what happen
Hi Guys, can you show the electric diagram of the board?
The best for you.
If Mozart sounds good, it's good.
If you hear some harsh in mids/treble, maybe a sign of ripple/RF, maybe your circuit need an update.(Triode strapped pentodes?)
Don't search for the fifth leg of the cat with micro-detail unless you can listen the same piece of Mozart in a concert hall.
BTW, 6C33 is current hungry, nevertheless you can also power filaments with DC.
Mains frequency IM also affects power amps, a few less than preamps.
Sky is the limit...
Edit: Heaters must always be referenced to some potential from ground, even better, elevate the heaters about 40V from ground in normal
topologies.
Heaters must became some positive from ground respecting the differential cathode-heater, we speek about DC but in AC better is 0 volt.
One thing I making a OTL with 20 6AS7 (a la atmasphere) and I using a Switching DC PS. 6.3volt 50amp. What do you think about?
Best Regards
Heaters must became some positive from ground respecting the differential cathode-heater, we speek about DC but in AC better is 0 volt.
One thing I making a OTL with 20 6AS7 (a la atmasphere) and I using a Switching DC PS. 6.3volt 50amp. What do you think about?
Best Regards
Hi Dady, good to see you around here !
I think to elevate heaters is almost mandatory, even with AC, there is a junction diode formed between heater and cathode, if you elevate heater reference, the diode is reverse biased or whatever must said it (Tarzan English)
20 6AS7 !!! beautiful stove, not suitable for these latitudes, except some winters.
I'm designing a 100W class A hybrid that disipates almost 240W/ch...close ah?
Big hug from Argentina
CAT5?
Just a thought, but CAT5/6 network cable contains multiple twisted pair wires all encased within a metalic shield. Not sure about the current carrying capability, but would it be feasible to use them all (making sure that one wire from each twisted pair are connected together) for the filament heaters, grounding the shield at one end?
Just a thought, but CAT5/6 network cable contains multiple twisted pair wires all encased within a metalic shield. Not sure about the current carrying capability, but would it be feasible to use them all (making sure that one wire from each twisted pair are connected together) for the filament heaters, grounding the shield at one end?
I just looked up the specs, and CAT5 specifies wire no thinner than 24AWG. The cross-section area of 24AWG is .205mm, so using 4 of them together yields an area of .82mm, which is about equal to the cross section area of 18AWG (.823mm). Since we're only dealing with 6.3 (or 12.6) volts, insulation wouln't seem to be an issue.
An externally hosted image should be here but it was not working when we last tested it.
Looks pretty tight to me. Seems like connecting all the solids and all the stripes would have to be as effective as any hand twisting of 18Gauge wire....
Practical points to consider...
Single solid cores have little flex and are likely to break off in time.
Also, the insulation is not intended for soldering applications and will shrink during soldering.
Finally, you need to consider the amplifier as a system and while the heater wires carry only 6.3 or 12.6 volts, these wires could come into contact with B+ voltages.
Your best bet for all wiring in Tube amplifiers is the appropriately rated (voltage and gauge) stranded silver plated teflon insulated wire which isn't terribly expensive when compared with audiophool grade interconnect and speaker wire. You can easily twist this wire using an electric screwdriver/drill.
Single solid cores have little flex and are likely to break off in time.
Also, the insulation is not intended for soldering applications and will shrink during soldering.
Finally, you need to consider the amplifier as a system and while the heater wires carry only 6.3 or 12.6 volts, these wires could come into contact with B+ voltages.
Your best bet for all wiring in Tube amplifiers is the appropriately rated (voltage and gauge) stranded silver plated teflon insulated wire which isn't terribly expensive when compared with audiophool grade interconnect and speaker wire. You can easily twist this wire using an electric screwdriver/drill.
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The paper "Predicting the Magnetic Fields from a Twisted-Pair Cable", by MOSER & SPENCER, 1968, includes a graph showing the reduction in external field with the twist pitch as a function of distance from the cable. Related thread was:
http://www.diyaudio.com/forums/tubes-valves/182540-heater-wiring-coaxial.html
http://www.diyaudio.com/forums/tubes-valves/182540-heater-wiring-coaxial.html
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