Hello, does anybody here build a tube headphone amp with balanced output? I have new JVC HP-DX1000 phones modified for balanced operation I would like to build an amp to drive them in balanced configuration. I think that LittleDot has a model with balanced output (tube) so something similar.
Any ideas or recommendations?
Thanks
Petr
Any ideas or recommendations?
Thanks
Petr
Have you check this?
Papa Rusa Headphone Amplifier – wauwatosa tube factory
If you removed the ground on the opt secondary, the output is balanced. The Parafeed feature is important since you are removing the ground from OPT secondary. Do make sure you use tiny leakage 4.7uf high voltage film capacitor. It also help if you use OPT that can handle tube higher voltages. High voltage to head is a bad idea.
Papa Rusa Headphone Amplifier – wauwatosa tube factory
If you removed the ground on the opt secondary, the output is balanced. The Parafeed feature is important since you are removing the ground from OPT secondary. Do make sure you use tiny leakage 4.7uf high voltage film capacitor. It also help if you use OPT that can handle tube higher voltages. High voltage to head is a bad idea.
Build a tube amp that has an output transformer that has 0, 4, 8, 16 Ohm output taps.
Ground the 4 Ohm tap. That causes: 0 and 16 to be the balanced output.
I can not think of a simpler solution.
And it could be safe, the output secondary is grounded. It can not rise to a high voltage, if the grounded 4 Ohm tap is connected to Earth, such as the ground of a 3 wire mains (only some locations have this kind of power) . . . But then you can not wear nor touch the phones if you will also contact any voltage source that is referenced to ground.
Hope that makes sense.
Ground the 4 Ohm tap. That causes: 0 and 16 to be the balanced output.
I can not think of a simpler solution.
And it could be safe, the output secondary is grounded. It can not rise to a high voltage, if the grounded 4 Ohm tap is connected to Earth, such as the ground of a 3 wire mains (only some locations have this kind of power) . . . But then you can not wear nor touch the phones if you will also contact any voltage source that is referenced to ground.
Hope that makes sense.
I wanted to build a Papa Rusa, but the cost of 6C45P tubes stopped me, they are about $30 each and to get a matched pair I'd probably have to buy several (I have a curve tracer to do matching with). Pre matched sets go for about $140! Probably because I hear there is a wide range of differences in making this tube so finding two that match requires more tubes to test out. Most of the Russian sellers are all ran-out on NOS too.
Does anyone know of a good substitute for 6C45P without a whole lot of changes to this circuit? So this simple amp can be built much cheaper and with a tube that is more readily available. I understand the 6C45P is a difficult tube to manufacture and there are not very many hair-wire screen grid tubes that might work as substitutes? It's too bad I love simple circuits that work well, if just to breadboard them.
Have you not tried ebay?
Brand New Factory Matched Pair (2) Sovtek 6C45Pi Audio Guitar Vacuum Tubes | eBay
6c45pis are cheap and plentiful. You should be able to find other matched pairs for fairly cheap. You could also try a 417a/5842 or a triode connected d3a. But both of those should be more expensive than the 6c45Pi tubes.
Brand New Factory Matched Pair (2) Sovtek 6C45Pi Audio Guitar Vacuum Tubes | eBay
6c45pis are cheap and plentiful. You should be able to find other matched pairs for fairly cheap. You could also try a 417a/5842 or a triode connected d3a. But both of those should be more expensive than the 6c45Pi tubes.
6e5p ?
Here's an option: https://www.diyaudio.com/forums/tub...ns-parafeed-headphones-amp-2.html#post4037465 Just don't ground the output side of the transformer, add a pair of 1k resistors from + and - to gnd.
Here's an option: https://www.diyaudio.com/forums/tub...ns-parafeed-headphones-amp-2.html#post4037465 Just don't ground the output side of the transformer, add a pair of 1k resistors from + and - to gnd.
Thanks, usually I do try ebay. This is less than half the matched pair price of the sellers that came up for me. The Sovtek had more followers than the EH so this is good. The Russian store I shop at has been all out of NOS.
From the same site as the Papa Rusa amp project there is a PP balanced input headphone amp project:
The Bad Hombre in a few different versions...
El Bad Hombre “Balanced” Headphone Amplifier – wauwatosa tube factory
The low gain version gives you a capacitor-less signal path. My DAC has balanced outputs (188 ohm, 12v swing) so a balanced input headphone amp is just the thing.
The output here is not balanced, but I don't have my balanced headphones anymore. Sound-wise they never made any difference anyway. However having a balanced output DAC paired with a balanced input headphone amp is a huge advantage for me. Because it lets me run a 16 foot cable from my stereo rack DAC to a headphone amp on a living room side table where I sit and need to get at the headphone volume control a lot. Running single ended cables 16 to 20 feet long has never gone well for me (hum, ground loop and rolloff problems). Equally running a 16 foot headphone cord back to the DAC headphone amp is not good either.
I saw this project several months ago and made a mental note to begin bread boarding it, but it fell through the cracks. The WTF site is very cool too. I have to get this one in the work queue.
I think you have to ask why you need balanced headphones if you are only using a comfortable 6 foot headphone cord? Were you going to install this balanced output headphone run 16 feet away where its volume control would now be across the room and un-useable without a remote?
I would recommend putting something together that can run off a 2v rms input. Most sources these days will output 2vrms, so if you ever decide to upgrade your dac or use a different source entirely, you wont be stuck trying to find an odd ball source that outputs 12v.
Also FYI, you do not have to build a PP headphone amp just so that you can run a balanced cable. You can use that same input transformer WTF amps is using as a balanced to single ended converter.
Both single ended and PP amps have their own pros and cons, but I just wanted to let you know that you have more options than you think you do.
Also FYI, you do not have to build a PP headphone amp just so that you can run a balanced cable. You can use that same input transformer WTF amps is using as a balanced to single ended converter.
Both single ended and PP amps have their own pros and cons, but I just wanted to let you know that you have more options than you think you do.
Thanks, I think I may have 2v, not sure. I cant make sense out of the XLR output specifications for max output level, about half way down this page: For XLR they give 2v (fixed), 4v (+6db), and 12v (variable) specs. So I guess I really have 2v fixed? I understand about being able to use either SE or balanced at the end of my long cable, I was just thinking to keep it balanced so I wouldnt need any coupling capacitors or inverter stage. I guess I'm at 2v fixed output though, the specs are confusing to me where they mention 12v.
UD-503 | TEAC
What the length of cables have to do with headphone level signal and balanced/unbalanced drive? Even when headphones are not shunted by output impedance of the amp, can you hear any picked up interference by a 16 feet cable? What it has to do with volume control?
I see what you mean at headphone levels balanced or unbalanced makes no difference with cable length. But at line level it does. One of the snake-oil selling points of balanced headphones is cable length.
As for the volume control...
For me the whole issue with the volume control and headphone listening is that I always want the volume control to be at my chair-side, analog knob. Even if my headphone amp has a motorized volume control and is on the other side of the room, I'd rather not have to pick up a remote. Also I dont want a 16 foot cord coming off my phones.
The ideal headphone amp setup for me is to have the DAC residing in the entertainment center where it needs accessibility to all the source inputs. Then have a line level balanced feed going across the room to the listening position, where the headphone amp is right next to me with the volume knob a comfortable reach away.
this +1
balanced dynamic h.p. are bullsh*t.
literally same driver, but with little different wiring... this is definition of snakeoil.for example stax must be balanced, because you have front and rear stator..
but there is nothing similar inside of typical dynamic headphones..
you still have only one voicecoil LOL
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