Not eye candy, but...
...it sure sounds great. This is a PP2A3 monoblock. Lots of Australian made iron! Output and interstage are made by Lancroft - the power supply iron is Black Art Audio.
I prototyped this for a friend. Input is 1/2 6SN7, driver is triode connected KT66. Fixed bias on the 2A3 outputs. Two choke input supplies.
It may be that I've been listening to chip amps too long, but this thing sounds beautiful in mono!
We were going to do the other monoblock with cathode bias (there's another power transformer winding for the extra voltage required) but I'm not sure we'll bother.
...it sure sounds great. This is a PP2A3 monoblock. Lots of Australian made iron! Output and interstage are made by Lancroft - the power supply iron is Black Art Audio.
I prototyped this for a friend. Input is 1/2 6SN7, driver is triode connected KT66. Fixed bias on the 2A3 outputs. Two choke input supplies.
It may be that I've been listening to chip amps too long, but this thing sounds beautiful in mono!
We were going to do the other monoblock with cathode bias (there's another power transformer winding for the extra voltage required) but I'm not sure we'll bother.
Attachments
thats overkill to me
Looks like lots of fun prototyping a tubeamp on a piece of plywood like that
Re: Re: Not eye candy, but...
Of course!
I think the KT66 is overkill, too, but I can't argue with the sound!
There are 2 power transformers, 4 chokes (two L-C-L-C supplies) plus the interstage and output transformers.
My only complaint is that it's short on gain for use without a preamp. That may not be a problem for the new owner.
planet10 said:
Of course!
Tekko said:KT66 for driving a 2A3 thats overkill to me. Looks like lots of fun prototyping a tubeamp on a piece of plywood like thatBut what on earth is all he transformers doing there ?chokes ?
I think the KT66 is overkill, too, but I can't argue with the sound!
There are 2 power transformers, 4 chokes (two L-C-L-C supplies) plus the interstage and output transformers.
My only complaint is that it's short on gain for use without a preamp. That may not be a problem for the new owner.
My new 45 oil tanker
My remodeled 45 stereo amp was completed yesterday. The circuit is based on the Sun Audio 2A3 design. I used 6J5 (single triode tube) instead of the 6SN7. Also, I used oil capacitors for the power supply and the cathode bypass of the 45 tube. The capacitors are rahter large in size and mounted underneath of the chasis. They seems like the gas tanks of a big truck.
I am rather surprised that the sound doesn't slow down by the oil capacitors at all. Instead, it sounds very nice to me especially it has lots of dynamic and energy.
73
Johnny
My remodeled 45 stereo amp was completed yesterday. The circuit is based on the Sun Audio 2A3 design. I used 6J5 (single triode tube) instead of the 6SN7. Also, I used oil capacitors for the power supply and the cathode bypass of the 45 tube. The capacitors are rahter large in size and mounted underneath of the chasis. They seems like the gas tanks of a big truck.
I am rather surprised that the sound doesn't slow down by the oil capacitors at all. Instead, it sounds very nice to me especially it has lots of dynamic and energy.
73
Johnny
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Pse2a3
"I also use oil tanks in my psu's"
As promised here's a photo of my latest prototypeSE 2A3 direct coupled driven by 6n7's in parallel.Psu consists of 3 10H chokes and absolutely minimal ripple.Sounds amazing,detailed,open and with bass to die for.Gonna do a decent looking version now I've ironed out the teething troubles.Balanced out at 115mA per channel on the output section and 5mA per channel on the 6n7's.DC filament supplies on the input AC with humpots on the output.Will post the schematic as soon as I've drawn it.
"I also use oil tanks in my psu's"
As promised here's a photo of my latest prototype
SE 2A3 direct coupled driven by 6n7's in parallel.Psu consists of 3 10H chokes and absolutely minimal ripple.Sounds amazing,detailed,open and with bass to die for.Gonna do a decent looking version now I've ironed out the teething troubles.Balanced out at 115mA per channel on the output section and 5mA per channel on the 6n7's.DC filament supplies on the input AC with humpots on the output.Will post the schematic as soon as I've drawn it.Attachments
Upupa Epops said:
No childern, but I do keep my tubes about 5 feet off the ground.
Safety in Canada? Sure ... the amp is grounded, the heaters run off of the mains (not the wall socket) and it is fused. The hot tubes are much safer to children (or cats) than an hot element on a stove or candle / scent pot on a table.
By stove child know, that it is hot, by tube probably not. Safety regulation for home electronic says ( and I hope that in Canada is it also the same ) : " Any by finger touchable part must not have temperature over 60 °C ". I recomend to you read some safety norms - they are not for joke .
Safety regulation for home electronic says ( and I hope that in Canada is it also the same ) : " Any by finger touchable part must not have temperature over 60 °C ". I recomend to you read some safety norms - they are not for joke .
Upupa Epops said:By stove child know, that it is hot, by tube probably not.
Well, a child will not know that a stove is hot unless he touches it or is told that it is hot. Obviously I will tell childeren that the tubes are hot. Most heating electronics such as stoves and heaters are hotter than 60C and touchable by a finger. Heck, a curling iron must be hotter than 60C...and that goes against your head!
Bas Horneman said:
Listening has been good so far. Becuase of the small OT, you do not get full bass extension. Mid-range and highs are very clean and clear. I really need to build a decent set of speakers. When I do, I will listen to my various amps critically and compare with my K-12M amp.
Indeed, the 50EH5 is not common. I have only seen two other 50EH5 amps on the internet thus far. You can link to them from my webpage. However, of the limited amount of old tube consoles and TVs that I have come across, the 50EH5 is the most common.