It's very interesting. I knew there valve's designed to work at low voltages, but did not think as low as 6/12V. Live and learn 🙂
My only experience was growing up in Cuba in the '70s with old American cars from the fifties. And yes, my neighbour's Buick 52 radio had 6V6s for output, don't remember one or two.
The good old times.
My only experience was growing up in Cuba in the '70s with old American cars from the fifties. And yes, my neighbour's Buick 52 radio had 6V6s for output, don't remember one or two.
The good old times.
For those who want to learn more about these aforementioned car battery tubes and who read German, here's an interesting and informative site about them.
Best regards!
Best regards!
I can't read German, but Google can.😊
They have an app that you point the camera to the document and translates it😯. I use that for Russian Datasheets.
They have an app that you point the camera to the document and translates it😯. I use that for Russian Datasheets.
Does it also work with the scanned text, especially the very interesting one by Valvo, the German tube department of the Philips group? Then do it, please 😉 .
Best regards!
Best regards!
I have some other valves that have pentodes and tetrodes and wrote Pentode instead of hexode.
Yes it does work.🙂
I grab my phone and take a picture of the document and it translates it as you move your finger through the document.
Pretty amazing stuff.
Joe Sousa published measured plate curves for ECC81 on https://www.radiomuseum.org/tubes/tube_ech81.html
To pentode connect ECh81 heptode you use :
pin 1 as the screen
pin 2 as control grid
pin 3 as cathode
pin 6 as plate
pin 7 connected to pin 3 as suppressor
or pin 2 together with pin 7 as control grid.
The guys on https://www.radiomuseum.org/forum/ech83_qru.html also did extensive research and came to the conclusion that ECH81 and ECH83 are substantially equivalent including curves, internals, electrode spacing etc. They even found ECH81 with etch code of ECH83 and vice versa. At least for Philips, Valvo, Mullards ...
There were several German radios which used ech81 as phase splitter and driver for EL84 pp output stages like this one: https://www.diyaudio.com/community/threads/ech81-and-ech80.374846/
and an amplifier from France: https://www.diyaudio.com/community/threads/ech81-and-ech80.374846/
oh ... and a ECH81 heptode spice model : https://www.diyaudio.com/community/threads/vacuum-tube-spice-models.243950/page-143#post-6584084
To pentode connect ECh81 heptode you use :
pin 1 as the screen
pin 2 as control grid
pin 3 as cathode
pin 6 as plate
pin 7 connected to pin 3 as suppressor
or pin 2 together with pin 7 as control grid.
The guys on https://www.radiomuseum.org/forum/ech83_qru.html also did extensive research and came to the conclusion that ECH81 and ECH83 are substantially equivalent including curves, internals, electrode spacing etc. They even found ECH81 with etch code of ECH83 and vice versa. At least for Philips, Valvo, Mullards ...
There were several German radios which used ech81 as phase splitter and driver for EL84 pp output stages like this one: https://www.diyaudio.com/community/threads/ech81-and-ech80.374846/
and an amplifier from France: https://www.diyaudio.com/community/threads/ech81-and-ech80.374846/
oh ... and a ECH81 heptode spice model : https://www.diyaudio.com/community/threads/vacuum-tube-spice-models.243950/page-143#post-6584084
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I've tried yesterday the ECH83 pre-amp by Engel (reply 9 by @OldHector ), and connected via a cheap TDA2030A module from eBay and it works well. As I didn't have a pot for the gain control, I couldn't experiment with that though.
I've tried to connect the pre-amp to a JBL Flip 2 bluetooth speaker and it's ok too.
Just another piece of information. The 12DY8, despite not being designed for audio, works well too and for the guys in USA, they cost $3.95 + shipping at tubedepot.com .
Cheers,
Pedro
I've tried to connect the pre-amp to a JBL Flip 2 bluetooth speaker and it's ok too.
Just another piece of information. The 12DY8, despite not being designed for audio, works well too and for the guys in USA, they cost $3.95 + shipping at tubedepot.com .
Cheers,
Pedro
Hi guys,
As I wanted everything to be made with valves, I've tried a 6N16B in the power stage and the sound was very quiet but nice. But that kind of volume, I can get with the ECH83 alone. Tried a 6P30B-R and the sound was awful. Super distorted like a fuzz and the notes stop sounding after 1 second.
I had some hope that the 6P30B-R was going to work ... :-( The supply was 16V but, apparently doesn't work well with this one. Maybe one day I will try russian rod pentodes and either the 1P24B or 1J29B, maybe will do the trick.
Cheers,
Pedro
As I wanted everything to be made with valves, I've tried a 6N16B in the power stage and the sound was very quiet but nice. But that kind of volume, I can get with the ECH83 alone. Tried a 6P30B-R and the sound was awful. Super distorted like a fuzz and the notes stop sounding after 1 second.
I had some hope that the 6P30B-R was going to work ... :-( The supply was 16V but, apparently doesn't work well with this one. Maybe one day I will try russian rod pentodes and either the 1P24B or 1J29B, maybe will do the trick.
Cheers,
Pedro
Hi Pedro,
please don't forget you won't geht significant output power from tubes operating at such low voltages.
Anyway, the phenomenon you're describing lets me think of grid rectification. Not enough grid bias voltages? Too high bleeding resistance?
Best regards!
please don't forget you won't geht significant output power from tubes operating at such low voltages.
Anyway, the phenomenon you're describing lets me think of grid rectification. Not enough grid bias voltages? Too high bleeding resistance?
Best regards!
Hi,
I've rewired the 6P30B-R and, somehow, the problem disappeared. Then the ECH83 was replaced for an 6N16B and the sound is very nice with 16V of supply, but a bit quiet while connected to 12''speaker, but really nice. By the end, it's like a little champ. I know that I should use the 6N17B or the 6N21B instead to mimic the 12AX7, but I like the 6N16B better.
It's amazing how the 6N16B works so well at low voltages. Nevertheless I am a bit stubborn, so I will come back to the ECH83 and 12DY8, and make them working ! Don't kill me, but I prefer the 12DY8. It works well, same volume and easier to read datasheet curves, since it is a triode/pentode, not triode/heptode.
Next step -> Increasing the voltage to, let's say, 50V. That should improve the amp for quite a bit.
Next project -> I will increase the supply to 170V and build a subminiature champ. :-D
Cheers,
Pedro
I've rewired the 6P30B-R and, somehow, the problem disappeared. Then the ECH83 was replaced for an 6N16B and the sound is very nice with 16V of supply, but a bit quiet while connected to 12''speaker, but really nice. By the end, it's like a little champ. I know that I should use the 6N17B or the 6N21B instead to mimic the 12AX7, but I like the 6N16B better.
It's amazing how the 6N16B works so well at low voltages. Nevertheless I am a bit stubborn, so I will come back to the ECH83 and 12DY8, and make them working ! Don't kill me, but I prefer the 12DY8. It works well, same volume and easier to read datasheet curves, since it is a triode/pentode, not triode/heptode.
Next step -> Increasing the voltage to, let's say, 50V. That should improve the amp for quite a bit.
Next project -> I will increase the supply to 170V and build a subminiature champ. :-D
Cheers,
Pedro
@Sorento
I've read the thread you posted and it is amazing.
I've discovered this one too: https://www.radiomuseum.org/tubes/tube_ech83.html
In this thread, they say that both tubes are the same, but some were chosen for low-voltage operation.
To be honest, the curves look almost identical to me. They've swept the voltage of both tubes up to 300V and the results are very close.
So, I believe I can use the curves from the ECH81 to design an ECH83 amp.
I am expecting a significant increase in volume when going from 12V to 50V. Let's see.
Cheers,
Pedro
I've read the thread you posted and it is amazing.
I've discovered this one too: https://www.radiomuseum.org/tubes/tube_ech83.html
In this thread, they say that both tubes are the same, but some were chosen for low-voltage operation.
To be honest, the curves look almost identical to me. They've swept the voltage of both tubes up to 300V and the results are very close.
So, I believe I can use the curves from the ECH81 to design an ECH83 amp.
I am expecting a significant increase in volume when going from 12V to 50V. Let's see.
Cheers,
Pedro
They should have put an extra winding in the alternator for a 150v b+ a simple solution.
Dual 6v6 at 12v wouldn't put out more then 100mW.
Dual 6v6 at 12v wouldn't put out more then 100mW.
Alternators didn't appear in cars until the mid 60's. Older cars had generators with brushes that needed frequent replacement. By the mid 60's all the car radios were running on silicon. Back in the 40's we had mechanical vibrators to turn 6 volts into 300+ volts. These were the first real SMPS's with a mechanical SPDT switch swinging back and forth at about 25 Hz. The really old drug store tube testers even had sockets to test the vibrators.
