[CJG888]

I always use low gain wherever possible. The hiss is not affected by the gain setting, however. I presume it is background noise from the tube preamp circuit. The output stage should be quiet (high quality opamp).

 

[vkung]

I will check for you. 

 

[CJG888]

Thank you.

 

[vkung]

Please email info@elekit.co.jp attn: Mrs Tamura for your issue.

 

[py61]

I have this item too. When I turn on there is no hiss - background noise for 2 seconds, after it begins, I stopped listening classic music because of this problem, it hurts your ears when you listen music which goes slow.Otherwise great amp.

 

[py61]

update,
 
I emailed elekit, and they said this issue caused by the op-amp.(white noise) so whatever you do if you are using a high sensitive iem you will hear the white noise.One and only solution is changing iem to low sensitve.
 
Maybe 75 Ohm Earplug will work too, but I think it will change the character of iem.

 

[vkung]

All tube headphone amps prefer low impedance headphone.. In fact,  low impedance headphone sounds better with tube amp... 

 

[CJG888]

I have just ordered a Hifiman HM-650. Together with this and the DT48Es, this amp should make the centrepiece of a fantastic OTG rig...

 

[CJG888]

Have ordered a MUSES02. Should make for an interesting setup.

 

[KT66]

did the op amp change make any difference?

 

[ClieOS]

  did the op amp change make any difference?

 
Of course. Not much of a point to roll the opamp if it didn't.

 

[HaypurTiryading]

I bought this amp yesterday amd I want to do some modifications. Now I'm using with opa2604. First, I need different opamps like muses01-02. How can I get best of them in single purchase? I like warm but punchy, colorized but organic, tube like sound. I'm searching different but efficient sub-miniature tubes. Do you know any replacement tubes directly or similar tubes? Last of all, I am going to change input/output capacitors with elna silmics or wima mkps. Is it worth?

 

[ClieOS]

I bought this amp yesterday amd I want to do some modifications. Now I'm using with opa2604. First, I need different opamps like muses01-02. How can I get best of them in single purchase? I like warm but punchy, colorized but organic, tube like sound. I'm searching different but efficient sub-miniature tubes. Do you know any replacement tubes directly or similar tubes? Last of all, I am going to change input/output capacitors with elna silmics or wima mkps. Is it worth?

 
Don't just buy opamp without knowing whether they can be used or not. Read the section on opamp rolling in my review about what opamp can be used.
 
Secondly. sub-miniature tubes are rather limited in variety and therefore it won't be easy to find a direct replacement. Also, the tubes in TU-HP01 is mount on flex circuit to avoid vibration. It will be a pain to desolder them as they can be easily melted with a bit too much heat. Care must be taken.
 
Lastly, there is no input or output caps used on TU-HP01, so there is really nothing for you to change there.
 
If you ask me, I'll say TU-HP01 isn't exactly a good choice if the intended purpose is modding.

 

[HaypurTiryading]

   
Don't just buy opamp without knowing whether they can be used or not. Read the section on opamp rolling in my review about what opamp can be used.
 
Secondly. sub-miniature tubes are rather limited in variety and therefore it won't be easy to find a direct replacement. Also, the tubes in TU-HP01 is mount on flex circuit to avoid vibration. It will be a pain to desolder them as they can be easily melted with a bit too much heat. Care must be taken.
 
Lastly, there is no input or output caps used on TU-HP01, so there is really nothing for you to change there.
 
If you ask me, I'll say TU-HP01 isn't exactly a good choice if the intended purpose is modding.

Ok, I prefer Muse 01/02 and Opa2604 for tube like sound and I won't buy others. Because my budget is a bit limited. Flex circuit is not problem, I am planning to buy 6418 or similar tube. (nearly 1.2V filament / 30V plate / 0.01a current, if I can find.) I'm planning recabling tubes with silver cabling instead of flex cable for more efficient results.
 
I'm adding capacitors photo. If you help me for caps' function in pcb, i would be very happy.
 
Thanks.
 

 

[NNewman]

Hello. Can anybody advice me if this amp can "soften" the midds of a Beyerdynamic t5p? Aune b1 is n a good pair...