I have been given a bunch of voltage regulators -- 0D3, 0A3, 0B2, maybe a few others -- and have no real sense of how to use them or whether they are worth the effort. Anyone have any good links or suggested reading?
Attachments
Helpful applications are in the data sheets:
http://frank.pocnet.net/sheets/141/g/GL874.pdf
http://frank.pocnet.net/sheets/127/0/0C3W.pdf
Best regards
Andreas
http://frank.pocnet.net/sheets/141/g/GL874.pdf
http://frank.pocnet.net/sheets/127/0/0C3W.pdf
Best regards
Andreas
They are actually pretty easy to use - only a few considerations:
1. Need a little extra voltage above the operating point to light them off (depends on the type).
2. Use a current limiting resistor or current regulator to stay under the maximum current limit (the short term limit is well above the steady state limit) when the downstream stuff is not yet drawing current.
3. The general load recommendation I've seen, is that the load current should be within about half of the steady state limit, and the steady state current through the tube should be around half of the continuous maximum.
4. With series regs., you'll often see a high value resistor (200k or so) from the supply to the series connection between tubes. This helps light off the lower tube.
5. Keep the capacitance across each tube less than 100nF (even less to be on the safe side).
Sheldon
1. Need a little extra voltage above the operating point to light them off (depends on the type).
2. Use a current limiting resistor or current regulator to stay under the maximum current limit (the short term limit is well above the steady state limit) when the downstream stuff is not yet drawing current.
3. The general load recommendation I've seen, is that the load current should be within about half of the steady state limit, and the steady state current through the tube should be around half of the continuous maximum.
4. With series regs., you'll often see a high value resistor (200k or so) from the supply to the series connection between tubes. This helps light off the lower tube.
5. Keep the capacitance across each tube less than 100nF (even less to be on the safe side).
Sheldon
dsavitsk said:
However, main functionality is not so significant (Zeners are available) as their nice look, when they indicate presence of a plate voltage and it's variations:
http://www.diyaudio.com/forums/showthread.php?postid=1123419#post1123419
http://www.tpub.com/content/neets/14178/css/14178_148.htm theory and calcs
http://www.thermionic.org/types.html
http://www.mif.pg.gda.pl/homepages/frank/sheets/141/g/GL874.pdf
http://www.mif.pg.gda.pl/homepages/...s/137/0/0B3.pdf
http://www.audiophool.cjb.net/Misc/sylvr1.jpg
http://www.audiophool.cjb.net/Misc/sylvr2.jpg
http://www.diyaudio.com/forums/showthread.php?threadid=17471&highlight=
I've archived the following from the Net - not sure who the original authors were.
There is no "maxiumum input" as such. The tubes act like a zener, so whatever voltage you put into it, 150V will be dropped across the tube. That's why you need a dropper resistor, the rest of the voltage is dropped across is and this sets the current thorugh the tube. Without the resistor, even if you put 170V into it, without a resistor, it would blow up. You need to calculate the dropper resistor to drop the remaining voltage and give you a sensible current (5mA - 30mA for 0A2) through the tube. You also need to leave room for the current swing of the circuit you're powering. In theory, you could run them of kilovolts if you like, you would just need a *very* big resistor.Cheers, Pete P.S. The resistor can be replaced by a CCS.
Voltage Regulator (or VR) valves are ingenious devices designed to maintain a constant voltage across their terminals over a range of currents.Such valves have a cold cathode and contain gases at low pressure rather than the conventional high vacuum normally used in amplifying valves. The internal gasses are deliberately chosen to ionise (conduct) at a particular predefined voltage.
They work very well just like a zener.And they glow. Unlike mercury tubes they don't need to wait for the filament to light up, since they ain't got no filament. No mercury, either, just harmless argon. There's *neon* ones, too, which glow a cute pinkish or orange, like 0A3. Just don't force them to draw too much current (they only need a few ma to light up). Colour is entirely due to gas composition. Voltage drop is due to a combination of gas composition and cathode material. The level of intensity of glow is proportional to discharge current.
OD3 and 0A2(150V) are pink / lilac.
0C3 and 0B2 (105V) are also pink as far as I can tell (my 0C3s are almost entirely gettered)
I understand that 0B3 (90V) is a purple/indigo. Prettiest of the bunch IMO. thought ususally gettered into near invisibility.
0A3 and 0C2 (75V) are orange.
The confusion over colours possibly comes from the change in coding between the 0*3 (octal)and 0*2 (7-pin) series, where one went A to D with later letter higher voltage and the other went the other way. In addition there is the confusion added by the 85 Volt reference (low current high stability) 0E3 (octal) and 0G3 (7 pin).
Type OpV StrikeV min/max mA regV Pinout
0C2 75 115 (105) 5-30 4.5 7pin
0A3 75 105 5-40 6.5 Octal
0B3 90 110 Octal
0B2 105 133 (115) 5-30 4 7pin
0C3 105 133 (115) 5-40 4 Octal
0C3A " 127 " "
0A2 150 185 5-30 6 7pin
0D3 150 185 (160) 5-40 5.5
0D3A " 180 " "
0A4 Octal
0A5 7pin
Voltage Regulator 0A2 7 pin small
Maximum Supply Voltage ........................ 185 V
Regulated Voltage ............................. 150 V
Maximum Current ............................... 30 mA
Minimum Current ............................... 5 mA
Regulation (Min to Max Current) ............... 2 V
Voltage Regulator 0D3 octal
Maximum Supply Voltage ........................ 185 V
Regulated Voltage ............................. 150 V
Maximum Current ............................... 40 mA
Minimum Current ............................... 5 mA
Regulation (Min to Max Current) ............... 4 V
The 0A2, OB2, 0C2 tubes are all 7 pin minature base. The cathode of each is connected to pins 2,4,7. The plate is connected to 1 and 5. Pins 3 and 6 are listed as "internally connected" so don't connect anything to those pins.
The 0A3(a), 0C3(a) and 0D3(a) are all 8 pin octal bases, with a jumper between 3 and 7, often used to protect downstream electronics in case the regulator wasn't inserted, pin 5 as the plate, and pin 2 as cathode. The diagram snows pins 1 and 8 not connected.
http://www.thermionic.org/types.html
http://www.mif.pg.gda.pl/homepages/frank/sheets/141/g/GL874.pdf
http://www.mif.pg.gda.pl/homepages/...s/137/0/0B3.pdf
http://www.audiophool.cjb.net/Misc/sylvr1.jpg
http://www.audiophool.cjb.net/Misc/sylvr2.jpg
http://www.diyaudio.com/forums/showthread.php?threadid=17471&highlight=
I've archived the following from the Net - not sure who the original authors were.
There is no "maxiumum input" as such. The tubes act like a zener, so whatever voltage you put into it, 150V will be dropped across the tube. That's why you need a dropper resistor, the rest of the voltage is dropped across is and this sets the current thorugh the tube. Without the resistor, even if you put 170V into it, without a resistor, it would blow up. You need to calculate the dropper resistor to drop the remaining voltage and give you a sensible current (5mA - 30mA for 0A2) through the tube. You also need to leave room for the current swing of the circuit you're powering. In theory, you could run them of kilovolts if you like, you would just need a *very* big resistor.Cheers, Pete P.S. The resistor can be replaced by a CCS.
Voltage Regulator (or VR) valves are ingenious devices designed to maintain a constant voltage across their terminals over a range of currents.Such valves have a cold cathode and contain gases at low pressure rather than the conventional high vacuum normally used in amplifying valves. The internal gasses are deliberately chosen to ionise (conduct) at a particular predefined voltage.
They work very well just like a zener.And they glow. Unlike mercury tubes they don't need to wait for the filament to light up, since they ain't got no filament. No mercury, either, just harmless argon. There's *neon* ones, too, which glow a cute pinkish or orange, like 0A3. Just don't force them to draw too much current (they only need a few ma to light up). Colour is entirely due to gas composition. Voltage drop is due to a combination of gas composition and cathode material. The level of intensity of glow is proportional to discharge current.
OD3 and 0A2(150V) are pink / lilac.
0C3 and 0B2 (105V) are also pink as far as I can tell (my 0C3s are almost entirely gettered)
I understand that 0B3 (90V) is a purple/indigo. Prettiest of the bunch IMO. thought ususally gettered into near invisibility.
0A3 and 0C2 (75V) are orange.
The confusion over colours possibly comes from the change in coding between the 0*3 (octal)and 0*2 (7-pin) series, where one went A to D with later letter higher voltage and the other went the other way. In addition there is the confusion added by the 85 Volt reference (low current high stability) 0E3 (octal) and 0G3 (7 pin).
Type OpV StrikeV min/max mA regV Pinout
0C2 75 115 (105) 5-30 4.5 7pin
0A3 75 105 5-40 6.5 Octal
0B3 90 110 Octal
0B2 105 133 (115) 5-30 4 7pin
0C3 105 133 (115) 5-40 4 Octal
0C3A " 127 " "
0A2 150 185 5-30 6 7pin
0D3 150 185 (160) 5-40 5.5
0D3A " 180 " "
0A4 Octal
0A5 7pin
Voltage Regulator 0A2 7 pin small
Maximum Supply Voltage ........................ 185 V
Regulated Voltage ............................. 150 V
Maximum Current ............................... 30 mA
Minimum Current ............................... 5 mA
Regulation (Min to Max Current) ............... 2 V
Voltage Regulator 0D3 octal
Maximum Supply Voltage ........................ 185 V
Regulated Voltage ............................. 150 V
Maximum Current ............................... 40 mA
Minimum Current ............................... 5 mA
Regulation (Min to Max Current) ............... 4 V
The 0A2, OB2, 0C2 tubes are all 7 pin minature base. The cathode of each is connected to pins 2,4,7. The plate is connected to 1 and 5. Pins 3 and 6 are listed as "internally connected" so don't connect anything to those pins.
The 0A3(a), 0C3(a) and 0D3(a) are all 8 pin octal bases, with a jumper between 3 and 7, often used to protect downstream electronics in case the regulator wasn't inserted, pin 5 as the plate, and pin 2 as cathode. The diagram snows pins 1 and 8 not connected.
Hi,
I have read through all of this incl. the links and manuals.
I do have some questions still:
- Lynn used an OD3 here: http://www.nutshellhifi.com/IT-Triode-Amp.gif ...but why did he use the 330Ohm Resistor in this position ? He uses a CCS to feed the stage. The CCS allows only 60mA. So, even in warm up he would not need any resistor at all. It is notthe series resistor, it is between Anode of the OD3 and reg HV+ ?
- where is the OD3 allowed to be positioned in a PSU ? Always as last element of a passive filterchain or could as well between a pair of LC- legs ? Example: My current line amp has One 5u4g feeding into one LC, so choke input. For channelseperation, two LC in parallel are following, so we have LC-(LC*2).
Can i just have one OD3 after the first LC feeding into the two chokes following, so LC-OD3-(LC*2)? Or must it be two OD3, one per channel after the last LC of each channel feeding directly into the tubes, so LC-(LC-OD3)*2 ?
- in the discussion linked above, people talk about a start voltage of the OD3 of 180V. This confuses me. Looking at the data sheet I find as well 160V as starting voltage... https://frank.pocnet.net/sheets/137/0/0B3.pdf ...Currently I have only 172V on my PSU...
Can I interpret it like: New OD3 will start with 160V, but need more and more voltage once they age (up to 185V) ? Or will even a new one not start below 180/185V ? AND : For how long do we need the starting voltage ? Fractions of seconds ? I guess any transformer will deliver much more voltage as long as there is no real load as the main tubes need to heat up first...?
Thx for your help.
I have read through all of this incl. the links and manuals.
I do have some questions still:
- Lynn used an OD3 here: http://www.nutshellhifi.com/IT-Triode-Amp.gif ...but why did he use the 330Ohm Resistor in this position ? He uses a CCS to feed the stage. The CCS allows only 60mA. So, even in warm up he would not need any resistor at all. It is notthe series resistor, it is between Anode of the OD3 and reg HV+ ?
- where is the OD3 allowed to be positioned in a PSU ? Always as last element of a passive filterchain or could as well between a pair of LC- legs ? Example: My current line amp has One 5u4g feeding into one LC, so choke input. For channelseperation, two LC in parallel are following, so we have LC-(LC*2).
Can i just have one OD3 after the first LC feeding into the two chokes following, so LC-OD3-(LC*2)? Or must it be two OD3, one per channel after the last LC of each channel feeding directly into the tubes, so LC-(LC-OD3)*2 ?
- in the discussion linked above, people talk about a start voltage of the OD3 of 180V. This confuses me. Looking at the data sheet I find as well 160V as starting voltage... https://frank.pocnet.net/sheets/137/0/0B3.pdf ...Currently I have only 172V on my PSU...
Can I interpret it like: New OD3 will start with 160V, but need more and more voltage once they age (up to 185V) ? Or will even a new one not start below 180/185V ? AND : For how long do we need the starting voltage ? Fractions of seconds ? I guess any transformer will deliver much more voltage as long as there is no real load as the main tubes need to heat up first...?
Thx for your help.
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I am going to guess that he added the 330R resistor to swamp the negative slope resistance of the regulator valve. This avoids forming a relaxation oscillator with the decoupling capacitor. In this respect voltage regulator valves are different from zener diodes: zeners have a small positive slope resistance but VR valves have a negative resistance so cannot have too much capacitance placed across them.
Almost all valve audio circuits do not need voltage regulation. When present it is often there to impress journalists and customers by giving a superficial impression of precision. Personally I think it is quite silly to feed a valve stage via a series CCS and a shunt voltage regulator.
Starting voltage is a matter of age, sample variation, light level, local radiation sources, cosmic rays etc. Some military versions have a little radioactive gas inside to give a quick ignition under all conditions.
Where it does whatever you want it to do. If you know what you want to do then put it there. If you don't know what you want it to do then why do you think you need one?
Almost all valve audio circuits do not need voltage regulation. When present it is often there to impress journalists and customers by giving a superficial impression of precision. Personally I think it is quite silly to feed a valve stage via a series CCS and a shunt voltage regulator.
Starting voltage is a matter of age, sample variation, light level, local radiation sources, cosmic rays etc. Some military versions have a little radioactive gas inside to give a quick ignition under all conditions.
Thx...so I can position an LC-Leg behind thenm ? I understand that any capacitance bigger than 0.1uF will destroy the Reg tube...the question is, if the Choke is isolating the following C or if this is already to much for such a tube...never used them before...
Objectively you can reject quite a bit of power supply noise by doing this. Subjectively I believe it sounds better.
Even disregarding the bad grammar this is preposterous. This is diyAudio. Here we build amplifiers for our own use and don't need to impress anybody but ourselves. I find valve voltage stabilizers very useful and use them frequently. I'm sure that I'm not alone in this.
Driver stages in amplifiers often use a lower voltage than the output stage and a voltage stabilizer can conveniently be used to set the correct voltage. They kill ripple very effectively into the bargain. And they look good.
In the right circumstances they can also be used to get rid of those pesky cathode bypass capacitors. If you connect the voltage stabilizer from B+ to cathode you get a much higher current through the cathode resistor. If this results in a cathode resistor below 40 Ohms or so you will probably be able to omit the cap.
However, using a voltage regulator between two LC stages is not a good idea.
This is just plain wrong on so many levels.
Pentode finals operated as pentodes benefit from regulated screen supplies, especially active regulators that represent a Lo-Z return path.
Secondly, most journalists, and especially customers, are technological boobs. They wouldn't know the difference, and the vast, vast, vast majority of audio equipment made back in "the day" didn't include screen regulation. The one sample that did that I saw in the wild was a theatre amp that used gas tubes to stabilize the screens of the 807 finals, but no active regulation there either.
I include active screen regulation since I don't have to answer to any pencil-pushers from Accounting and I'm not trying for so-so performance for the masses who aren't really listening most of the time anyway.
I assumed that DF96 was referring to low level, line and driver stages. These are run in class A which do not generally benefit from B+ regulation. Instrumentation might have been an exception. Yes we all know about regulating power pentode screens as I'm sure DF96 also does. Many years ago I tried adding active series pass regulation to the input and driver stages of a pair of 6550A monoblocks using a dual dissimilar triode with a zener reference. And after critical listening I could not really hear any improvement in fidelity. So I tend to agree with it's non-importance for class A stages in audio. Using it to lower voltage is another topic. Also, I think there are more reviewers or journalists (in the sense that they write) that do understand basic electronics enough to appreciate regulation when used appropriately. At least more then they once used to.
Perhaps. The VR adds its own noise, though. Decoupling caps work quite well too.audiowize said:
The example given appeared to be a commercial circuit.boli46 said:
This results in wasting current and, unless the B+ rail is also stabilised, somewhat variable bias. Those who don't like cathode bypass caps could always use LED bias.
Yes, that is true. Regulated anode supplies, as shown in the example given, are rarely needed. Another place where voltage regulation is useful is a phono preamp, so mains voltage variations don't cause woofer flapping due to the bass boost.Miles Prower said:
I suspect that is why they are sometimes used where they are not really needed. I am happy to receive corrections to my grammar, although this might send the thread off-topic for a while. Obviously I don't take quite the same care about English when posting online in a technical discussion as I did when writing my thesis or producing software documentation for my employer.boli46 said:
zeners are a better alternatives as voltage reference. zeners + power fet makes
fine regulated B+ with minimal parts count and good stability.
One could have voltage regulator tubes for show however, but these are better
powered independently of the audio amp.
fine regulated B+ with minimal parts count and good stability.
One could have voltage regulator tubes for show however, but these are better
powered independently of the audio amp.
Well, I guess you guys saw this...
VinylSavor: The Ultimate Line Preamplifier
...and if I got it right, Thomas actually never uses any silicon, let alone a CCS...so as he used four ll1667 as shown on his web site, I though that there might ne some more substance behind the idea...bjt maybe he used a complete different circuit than a LTP...
VinylSavor: The Ultimate Line Preamplifier
...and if I got it right, Thomas actually never uses any silicon, let alone a CCS...so as he used four ll1667 as shown on his web site, I though that there might ne some more substance behind the idea...bjt maybe he used a complete different circuit than a LTP...
Sorry DF96, you ought to know that Lynn Olsen's designs are not commercial; you are long and often enough here 🙄🙄
I think voltage regulators work splendidly, especially with SE transformer coupled stages (that's how I use them). Looking good is a bonus, of course they have to work for a living.
Zeners were mentioned as a better alternative. I am in Lynn Olsons camp on this one. Let me quote from his article on the Amity amplifier: "A de luxe feature, which was easy to add, is is the Voltage Regulator (VR) tube shunt-regulation for the driver. I wanted to drop 270 volts, so why not regulate at the same time? The noise of VR tubes is only 1mV of broadband noise, while the more common Zener diodes have 3 to 5 mV of spectrally nonflat noise, occasional LF bumps and pops from "popcorn" noise, problems with temperature coefficients, and a huge amount of grossly nonlinear capacitance. Zener diodes need a lot of filtering and additional circuitry to isolate the problems. By contrast, VR tubes need no additional circuitry at all - just keep them away from capacitive loads". Nuff said.
Zeners were mentioned as a better alternative. I am in Lynn Olsons camp on this one. Let me quote from his article on the Amity amplifier: "A de luxe feature, which was easy to add, is is the Voltage Regulator (VR) tube shunt-regulation for the driver. I wanted to drop 270 volts, so why not regulate at the same time? The noise of VR tubes is only 1mV of broadband noise, while the more common Zener diodes have 3 to 5 mV of spectrally nonflat noise, occasional LF bumps and pops from "popcorn" noise, problems with temperature coefficients, and a huge amount of grossly nonlinear capacitance. Zener diodes need a lot of filtering and additional circuitry to isolate the problems. By contrast, VR tubes need no additional circuitry at all - just keep them away from capacitive loads". Nuff said.
I would also add that zener diodes get really, really hot, especially if you reduce the lead lengths on them when installing. I will generally run a 5W zener at no more than 1W dissipation to attempt to keep things somewhat reliable!
Cold cathode VR tubes, OTOH, can cook off a decent amount of heat without complaining, and that heat can be cooked off on top of the chassis! Win win!
Cold cathode VR tubes, OTOH, can cook off a decent amount of heat without complaining, and that heat can be cooked off on top of the chassis! Win win!