Hello everyone, hope all is healthy and well.
So I've been doing some browsing, and came across this: https://www.headfonia.com/2013-spring-tokyo-headphone-festival-impressions/9/
I see that they are typical Cmoy tradition, sticking a headphone amp in a mint tin. But I've never seen something like this before. They appear to be hybrid amplification because there is 1-2 valves/tubes and then an op amp. From a general knowledge point of view, these tubes aren't powered like they usually would at around 200-300 volts, and instead by a couple of rechargeable double A's. Most of the amplification is probably done by the IC. I know that a few years ago a designer that goes by the name of FredsAmps built similar designs to this as a kit on his website, but is now shut down.
I was thinking of building one of these myself, as I would like to know what all the tube hype is about. What do you all think?
So I've been doing some browsing, and came across this: https://www.headfonia.com/2013-spring-tokyo-headphone-festival-impressions/9/
I see that they are typical Cmoy tradition, sticking a headphone amp in a mint tin. But I've never seen something like this before. They appear to be hybrid amplification because there is 1-2 valves/tubes and then an op amp. From a general knowledge point of view, these tubes aren't powered like they usually would at around 200-300 volts, and instead by a couple of rechargeable double A's. Most of the amplification is probably done by the IC. I know that a few years ago a designer that goes by the name of FredsAmps built similar designs to this as a kit on his website, but is now shut down.
I was thinking of building one of these myself, as I would like to know what all the tube hype is about. What do you all think?
Most use low voltage tubes like "hearing aid" tubes. The tube gives you the voltage gain, then an opamp buffer.
I built one commercially for a while - the schematic is attached. I used Li+ cell and a boost converter to get ~26V B+, if I remember right.
There is also a portable kit available using the Korg nutube: HA-S - NUTUBE HEADPHONE AMPLIFIER KIT | KORG (USA)
Pete
I built one commercially for a while - the schematic is attached. I used Li+ cell and a boost converter to get ~26V B+, if I remember right.
There is also a portable kit available using the Korg nutube: HA-S - NUTUBE HEADPHONE AMPLIFIER KIT | KORG (USA)
Pete
The FredsAmps kit uses a 12AU7 and runs off of 12 or 16 volts.
For example, if I wanted more output power could I just make an output stage that consists of maybe 2, 4, or 8 op amps after the buffer? Is that possible?
For example, if I wanted more output power could I just make an output stage that consists of maybe 2, 4, or 8 op amps after the buffer? Is that possible?
I had problems running 12ax7 off 12 volts.
I had to bias the grid a little positive to get it to conduct enough.
I had to bias the grid a little positive to get it to conduct enough.