Got a bunch of TV EHT rectifier and damper diodes here.
What kind are the most suitable for a power supply?
Ive got heaps of DY 802 and DY87, etc but it looks like they dont handle alot of current. I have some EY series damper diodes too.
Ive seen somewhere a pair of TV diodes used on a project but cant remember the type. Either way, its worth me keeping some for future if they are decent spec and is a cheaper option than going with GZ34 or other large rectifier tubes.
Am wanting to build an amp with 2 pairs of 807 in class AB and am looking at options for a decent tube rectifier that can handle enough current, looks like I will need at least 300mA.
Any part numbers to look out for would be great, ive got a few tubes to go through here. Winding a custom power transformer is not an issue if its got a 1.5V heater.
What kind are the most suitable for a power supply?
Ive got heaps of DY 802 and DY87, etc but it looks like they dont handle alot of current. I have some EY series damper diodes too.
Ive seen somewhere a pair of TV diodes used on a project but cant remember the type. Either way, its worth me keeping some for future if they are decent spec and is a cheaper option than going with GZ34 or other large rectifier tubes.
Am wanting to build an amp with 2 pairs of 807 in class AB and am looking at options for a decent tube rectifier that can handle enough current, looks like I will need at least 300mA.
Any part numbers to look out for would be great, ive got a few tubes to go through here. Winding a custom power transformer is not an issue if its got a 1.5V heater.
The 30,000V 1mA diodes are NOT going to feed audio power amps. The only "audio" chores I can imagine are electrostatic speakers and large CRT oscilloscopes.
Yeah ive figured they are just for low current applications for an HT supply on a CRT.
Ive seen people make x-ray tubes out of them lol.
I think it may have been PY88 that I was thinking of.
EY84 may be a better choice, since I can make use of a 6.3V heater?
Ive seen people make x-ray tubes out of them lol.
I think it may have been PY88 that I was thinking of.
EY84 may be a better choice, since I can make use of a 6.3V heater?
Don´t mix up CRT HV rectifiers (DY...) and booster/damper (EY... or PY...). The latter are perfect for power supply use.
Two EY88 can give you more than 400 mA of DC, two PY500 can give you more than 800 mA!
The drawback is the high heater power needed, but it comes with a nice glow. For the high heater-cathode peak voltage requirements the cathode is heated by radiation rather than thermal conduction.
Two EY88 can give you more than 400 mA of DC, two PY500 can give you more than 800 mA!
The drawback is the high heater power needed, but it comes with a nice glow. For the high heater-cathode peak voltage requirements the cathode is heated by radiation rather than thermal conduction.
Yes ive figured out that its damper diodes im after.
Thats nice to know, I will keep an eye out for these, I need to power 2 pairs of 807 tubes in class AB1 so will probably need around 400 mA power supply.
Looking at EY88 and these might be just what im after.
Datasheet doesnt even quote voltage drop or current, but the article quoted 550mA peak current.
http://www.r-type.org/pdfs/ey88.pdf
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Oh, i see, so the voltage drop is relative to current draw with these?
So if im running at 200mA, which I doubt I will even hit that, its a fairly modest voltage drop of only around 17V going by that graph.
Diode drop is always relative to the current draw. The only thing you‘re going to find with lower drop than a damper diode is something with silicon in it. If you are using them in a headphone amplifier, you could probably run them for 150 years before the emissions get low enough to even notice. Probably have more than 17 volts drop in the transformer winding. They probably provide just about he right amount of light to be able to change out the media (or flip the record over) during a late-night listening session.
Not true. Somewhere between a tube damper diode and an solid state is mercury vapour... Not that I would use or recommend using an MV rectifier these days, but they exist and fit in between.
Damper tubes are pretty good compared to a 5AR4 or 5U4GB, but I switched to HER*08 diodes because they work better, cost less, and I can use 4000µF of capacitance in the PSU.
Damper tubes are pretty good compared to a 5AR4 or 5U4GB, but I switched to HER*08 diodes because they work better, cost less, and I can use 4000µF of capacitance in the PSU.
Yeah - you can get MV rectifiers that can convert 220kV to DC for power transmission, as well as smaller ones. But no one in their right mind will use one in his audio amp. There are stashes of TV damper diodes around for those inclined to play with them - for less than a Sovtek 5**4. And they drop less voltage and contain no mercury.
I see tube rectifiers as something someone uses on the principle of the thing. Nothing wrong with a SS rectifier other than the fact that it’s SS. I use either 1N5408 or UF4007 depending on my current requirements and cap size - but that’s just because I haven’t built a tube project that’s supposed to be all tube with absolutely no silicon. I’m sure thats coming at some point - including the 6EW6’s in the LTP tails.
I see tube rectifiers as something someone uses on the principle of the thing. Nothing wrong with a SS rectifier other than the fact that it’s SS. I use either 1N5408 or UF4007 depending on my current requirements and cap size - but that’s just because I haven’t built a tube project that’s supposed to be all tube with absolutely no silicon. I’m sure thats coming at some point - including the 6EW6’s in the LTP tails.
I generally use HER108, 208, 308 for my projects, but for higher current I have FR607. For 60Hz, I have RL207.
Of course for low voltage/high current, I use MBR6045 with FWCT setup so there's only one diode drop instead of two.
Of course for low voltage/high current, I use MBR6045 with FWCT setup so there's only one diode drop instead of two.
Yeah that makes sense, ive always just gone to the datasheet on tubes to look at whats stated, but realise that its just the maximum current draw reading for voltage drop.
Looking at the specs, these damper tubes are about the same as a 5AR4/GZ34 at about 17V. I believe that the 5AR4 has pretty much one of the lowest voltage drops out of any rectifiers out there.
I was considering a MV tube, but the warm up times before applying HT are a pain, but they look awesome when running. A pair of 816 would look nice. 3B22 xenon rectifiers are probably a better choice and dont need as long a time to heat up.
Im the kind of person who just likes using tubes and only avoid SS simply because im wanting to build something as close to that era using the same technology, nothing more, other than all these old tubes need to be bought back to life! Ive used SS in guitar amps, but tube rectifiers are ironically better for guitar because the "sag" gives the guitar some nice compression as with tube rectifiers the voltage slowly rises in response to the load added to the transformer. SS doesnt give you that, its pretty much instant, so if anything would be an advantage to use SS in HiFi to give the amp a constant voltage.
I recently built a 3C24 amp with 866A MV tubes. I used a separate filament transformer for them that comes on when the mains power is switched on. Forty five seconds later an Amperite normally open tube relay closes and energizes the power transformer. Works nicely and was simple. I tried using the relay to switch the B+ but got more arcing than I was comfortable with.
Ive looked at some of those tube relays, from what I can tell, they are some sort of bi-metal activated switch that comes on when it heats up?
Exactly. They are available either normally open or normally closed. I use the NO60 ones and with the higher line voltage of 120V, they close at about 45 seconds which has been working well for the last 6+ months.
Thats pretty cool, i might look at using them on my next project. I am looking for some 816 tubes, I have tons of 866 but they are much larger and need more heater current, they are an overkill but look nice.
All the UV dangers are overblown, the glass blocks all of it. Thats why UV lamps are made of quartz - it allows the UV to pass.
Shoot, I just sold 4 816's as I like the larger bottle of the 866A or 866AX.
wow, they sure look nice dont they!
Is that an eimac transmitter tube youve got there?
I cant remember that part number but i think those are similar to the 35T but has the cathode lead on the side of the tube.
I nearly was going to work with some of those a while back, but your limited to class B and have to work with awkardly high voltages but they are supposed to sound good.