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Input:
Question: IPlease, can you tell where is the headphone plug and the impedance of this amplifier?
Document: This is an all valve (in the signal processing circuits) amplifier. It sounds pretty neutral to me (but I just did a quick lash-up to check functionality). (There are solid-state components but they're in the power supply circuitry and don't affect the sound quality).
this wont work with headphones it has no jack!! ok they want 20 words well... it has lots of places where you could get electricuted if you touch it when it is plugged in that is if it came with a plug which it does not so my boy friend had to wire it for me!
This is a neat, compact kit, with very high quality components, thoughtfully arranged, and the vacuum tubes are very carefully packaged especially. I have not tested fully yet, as I am looking for the best box to fit it into for a clean look and ease of use. I am modifying the unit also so that it can drive either vacuum tube amplifier or PA style amplifier for live sound.
I'm using this tube buffer with a Tripath TK2050 based amplifier and it's a good match. Warms up the sound and tames the slight harshness of the amp. Detail and soundstage are good. Stock tubes are OK and holding up so far. Trying different tubes could improve things but I haven't tried any yet. A good cheap buffer for the DIY'er. Just make sure you get the wiring right.
I have a basic understanding of electricity.There are NO instructions on how to wire it. If not for the other comments I would have returned it.This is a safety issue and it appears  Amazon does not care about safety, only profit.It should be a 5 star item but as above. Also it does not come with a power plug, probably no warranty either. I could live without the led's too.Hooked up to headphones the volume is low but quality is good.
This is a tube buffer. It add that "warm", "analogue" and "vintage" sound everybody cashes in these days. It's a great product but you need to know your electronics. Be EXTRA careful when wiring the supplied transformer. Check and recheck voltages. Use a plug with an "ON-OFF" switch.As to the sound: after I placed my unit in a nice wooden box, I let lt run for a few hours to burn in.
Delivery and packaging were good. Notes:No instructions, but there were enough notes and previous comments that it wasn't difficult to put together.There is no headphone jack on the model I received. RCA phono in and out. Fine by me, I didn't need it. I'm using this as a preamp between my iPod and my receiver's CD input.Voltage gain of 3 into a 10k ohm load. About 10 dB voltage gain. Just enough.Clipping occurs at about 14 v rms output.
gotta admit it, the sound is pretty good and for $50 from ebay that's very competitive... I've gotten worst "tube preamps" from China for twice as much that were half as good.....now here's the catch....
Works perfectly.
This pre-amp is the best value that I have had in 40 years of audio.
Answer: There is no headphone jack that comes with the unit. You can buy a rca to 3.5 mm adapter from Amazon and plug it in to the output rca jacks. That is how I got mine to work. But even with low impedance headphones the volume is not all that loud. You would be better off with a headphone amp.2 x RCA Male, 1 x 3.5mm Stereo Female, Y-Cable 6-Inch