• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

The all DHT SET Headphone Amp

You can't get rid of the cap across the 4k3 resistor if you want the tube to properly amplify the signal. If you want to get rid of that cap you need a stacked supply. Then the 4k3 resistor also disappears. Which also makes the filament bias useless. So, if you want DC coupling then you either to the resistor plus cap, and the filament bias is useless IMHO, or you have a stacked supply, and the filament bias again brings nothing to the table.

Myself, not sure how much of a fan of DC coupling I am... is the effort and complications worth it?

It is exactly how I powered my last version of headphone amp, before the project had been postponed. Except the bottom PS was actually a shunt regulator, in series with upper 2 power supplies.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.
 
Last edited:
It is exactly how I powered my last version of headphone amp, before the project had been postponed. Except the bottom PS was actually a shunt regulator, in series with upper 2 power supplies.

Nicely folded aluplates there Anatoliy. I too is allergic to stupid smallish signal tubes sticking up for no reason and prevent decent stacking.

Nice looking toobs to be shown, the rest can rest.

Staffan
 
Last edited:
Nicely folded aluplates there Anatoliy. I too is allergic to stupid smallish signal tubes sticking up for no reason and prevent decent stacking.

Nice looking toobs to be shown, the rest can rest.

Thank you Stafan.

When I show tubes I always protect them somehow, like transformer box behind, cheeks on sides. Like here, for example:


Pyramid-VII-1.jpg
 
Sorry for OT. I follow the thread. My half nickel is that I am most curious about designs that meets designgoals, not just show excellent figures in relation to nothing (1 Mohm resistor so). Preamps, especially anodefollowers, for example. Most data is useless unless you know what you load it with.

Keep up, interesting thread!
Staffan
 
For military radio amplifiers. Originally were designed by Telefunken for their army and police.

http://tubedata.milbert.com/sheets/043/l/LS50.pdf

Telefunkens army and police. Sorry couldnt hold my breath. Ikoflexer, I'm sure the engineers will follow up on any schematic that is presented, as done already. The thread will end up in a state of the art thingy, if you just present the goals. You cant just up "headphones" since the standard there is not the common 4 or 8 ohms as in the speakerworld.

Merlin would like the lot choice. 600, 400, 200, 100, 50, 25. What does Sowter has to say about that?
 
I did a few listening test on my Beyer DT931. They are speced 600+ something. They are harch and twisty on that level and I prefer 200ish to my taste... Headphones is headphones. They are all designed (except some mentioned) to the common 200 ohm clausule.

Have anyone tried old tube radio OPTs? With maybe some lack in lower region I think they outperform newish stuff.

Staffan
 

iko

Ex-Moderator
Joined 2008
Staffan, I build things for myself, so my design goals are usually related to what I have. However, it's not too difficult to change a schematic to accommodate a higher impedance set of headphones. For myself I intend to wire my own output transformer if I can't find something reasonable to buy.

As for the topic, I think we're still on topic. As is the case with every thread, not every posting will be a schematic or comments on that schematic. Human nature...
 
As for the topic, I think we're still on topic. As is the case with every thread, not every posting will be a schematic or comments on that schematic. Human nature...

Topic is still The all DHT SET Headphone Amp I hope since it would be nice to build one. If it will be more expensive then a sandloaded one is not the topic, because it sure will be. If the data is worse then a sand loaded one, that is to live with. I am following the original topic. Tho its to much fishing about what to drive. Drive 200, and you can compare to standard.

/Staffan