Last week, we have a nice blind test (or better we call as blind scoring) for high power triode Single Ended amplifier. The high power triode means a high voltage one. We are talking about at least 800 VDC voltage, (some could reach 1250 VDC)  which can be very lethal if treated not carefully. You never want to have a single contact with this when the circuit is on action. Physical skin damage could occur easily – at best, and at worst, could lead into serious injury (or death!). Before you have in mind to build one of these, better you know what you are doing. Never work in the working circuit and always measure the voltage before start tweaking here and there. Most of the capacitor at 800 VDC or more could store enough energy to hurt, shock, and kill anyone who dares to touch them. So beware! Always test all the point before, and never forget to use bleeder resistor to make sure no energy remains on the capacitors. Wait for awhile after powering down, to make sure the capacitor completely discharged. Well, enough all those silly theory, so enjoy the music and pics.

Below is a shoot of some amplifiers on action. As you can see below. The beauty of high power triode is their appearance. The light of thoriated tungsten is so sexy. Some of them use 10Y as driver stage, which also another thoriated tungsten which glows beautifully. This is hot amplifier, as the power dissipation is quite high. Forget about go green or any other power saving things. It’s time to get hot!

The setup. Source is Ayon CD-2S. Speaker is Quadral Platinum M4. Interconnect is Duelund 2.0 with Eichmann Bullet Plug RCA. Power cable is Acrolink. Speaker cable, IIRC, should be Kimber. This is direct setup from Ayon to Power Amplifier, set at High Gain. So the build-in preamp with digital volume control on Ayon will be used to match the volume.

The Ayon CD-2S. Quite promising sound. Probably a nice contender for Audio Research and Audio Aero. Which have chance for a session vs upgradeable CD7 and the Capitole.

Below is one of the contender, with 805 output triode, 300B as driver, and 3x tube rectifier, two of them are 5R4. I forget the red tube type.

Russian high power triode used in MIG jet, the 6C33. Low power, less risk, but the current is very high, up to 250 mA. Difficult to find the output transformer.

Factory made Audion 845. As a factory made amplifier, this Audion sounds quite balanced, with no extra emphasize on specific tones. The bass control is excellent. Probably you will not find delicate mids or highs, but overall. it sounds just right.

Another 845, driven by 10Y. Rectifier is RGN 2504 solid plate. I think 10Y as driver is one of the key to make the high power triode could “swing” the music better. Other keys will be explained later 😉

This amplifier reminds me of Consonance, but this one is 100% local made. It used 211 power tube. I forget the input and driver section, but probably 6SN7 or 6SL7.

Another 211 tubes, but this one is driven by 10Y. Another successful example about how to make high power triode to sing the music better.

This is the winner of the contest. Although this one doesn’t have 10Y as driver (but 5691 red base or also known as 6SL7), but this one has another winning factor: the RGN 2004 Mesh Plate and Jensen coupling capacitor. Configured in voltage doubler mode, the owner could operate the system in lower voltage, so RGN 2004 still can be used instead of the more expensive RGN 2504. Added with 5691 as driver, and another 6SN7 as regulator, this 211 really can sing very well.

I’m thinking now of 10Y, RGN, and Jensen or Duelund. Could be interesting… hmmm…

The winner took the photo together, also with the Indonesia High End Audio Club (IHEAC) senior member.

Below are some interesting shoot during the show. Sorry due to limited of my pocket camera, not all moments could be captured perfectly.

Giant 6C33 tube on action. I just wonder if this tube was used on MIG jet before. OMG, a tube on a jet? How much the pressure? How much the vibration? Also this tube has the most highest surface temperature (up to 250 degree Celsius or more). That’s why it has no base, just the glass and the pins.

This is the best design from my point of view. Well crafted amplifier and quite nice sound.

Another shoot of the amplifiers during the show.

Despite the risk (and the cost), I think high power triode is still interested project. But it does really need a serious handling to make it sounds good. Probably even more difficult than designing a low power triode like 2A3, EL34, or the famous 300B. But when you do really need a high power amplification to drive your heavy speaker (and has no interest to go into the Push Pull world), then this is probably the only choice. Remember, you can’t get both side of coins 😉