[ginetto61]

Hi to Everyone !
It has taken me a while to accept the evidence     but after having purchased an FX Audio TUBE-01 a put it between the dac and my solid state integrated amp i have to say that the sound really changes ... and for the better 
With this cheap preamp between my Cambridge Audio Dac Magic 100 and the amp the sound has more space and i like also the overall tone.  The sound stays clear by the way ... no haze or apparent distortion.
Problem is that i also get noise.  I think it must be a ground loop or similar even if it is high Hz sound not 50-60Hz hum ...   
So i have some questions.
1)  do any of you have direct experience of this preamp ? what is your opinion of it ?
2)  any suggestion about how could i eliminate that noise ?  i am using a cheap 12V smps to power it
3)  what would be a sensible step up ?  as i said above i like the added sense of space and the overall tone with voice.   
I would like to add that i have tried different integrateds downstream the fx audio all solid state, some very cheap and other more expensive,
nevertheless all benefits from its insertion in the audio chain. 
It seems to have a kind of magic touch that i cannot explain.
Usually i put the integrated volume to max and control the overall volume with the Fx Audio ...
Thanks a lot
Kind regards, gino   

[8T_BoCO]

I am using one between my DAC and class D power amp and like it a lot. 
I acquired it used and it came with a linear power supply.  I've read postings of a Pyramid regulated power supply having a positive affect on soundstage. 

I had awful 60hz noise in my system and it ended up being the PC source feeding my USB DAC (an old ASUS EeeBox).  A used Raspberry Pi 3 that replaced it is silent as a source.

I doubt it would affect 60hz hum, but have you tried different tubes? 
I thought the stock tubes were not as nice as GE, AEG and even Russian mil-spec tube equivalents.

[ginetto61]

I am using one between my DAC and class D power amp and like it a lot.

Hi !  thanks a lot for the very kind and valuable reply.  So i am not hearing things ... 
I needed a decent sound solution for the audio from my tv ... so i bought an Amazon Basic optical cable then > Cambridge Audio Dacmagic 100 (nice sounding) > FX Audio > different integrateds with the best one a Thule Audio IA100 quite decent sounding by itself.

I acquired it used and it came with a linear power supply.  I've read postings of a Pyramid regulated power supply having a positive affect on soundstage.

very interesting.  I would do it immediately but first i have to trace the source  of that noise ...

  I had awful 60hz noise in my system and it ended up being the PC source feeding my USB DAC (an old ASUS EeeBox).  A used Raspberry Pi 3 that replaced it is silent as a source.
I doubt it would affect 60hz hum, but have you tried different tubes ? 

not yet.  I am waiting for the cheap ones on ebay i bought.  I do not think they will provide a big improvement.  More than a hum is a higher Hz noise ... like something frying   

  I thought the stock tubes were not as nice as GE, AEG and even Russian mil-spec tube equivalents   

could you please provide any link to a specific tube ? 
As i said in the next days i will try to trace the source of the noise shorting inputs and moving upwards .... i have to check better.   
Still i am surprised by the sense of space to the sound ... maybe it is just added noise/distortion ? 
Thanks a lot again. 

[8T_BoCO]

ginetto61, this is the thread where I read about the EF95 tube family:

https://www.head-fi.org/threads/little-dot-tube-amps-vacuum-tube-rolling-guide.563884/

[ginetto61]

ginetto61, this is the thread where I read about the EF95 tube family:   
https://www.head-fi.org/threads/little-dot-tube-amps-vacuum-tube-rolling-guide.563884/   

Hi !  thank you so much for the very helpful link.  The guy did a great work indeed 
The choice is quite endless ... actually as i said i already bought some very cheap GE on ebay, actually too cheap  (fake ?  )
However as i am a little on DIY i am even thinking to take the guts of this little nice unit out of the case and try to upgrade it ... of course with a better power supply but also higher grade panel rcas and a nice attenuator with resistors. 
Imhe attenuators can have a big impact on sound ... like cleaning a window glass. 
I did some tests in the past.  After swapping an Alps Blue with an attenuator made with Holco resistors the image got much more defined ... more in focus.  I was quite surprised.
For now by the way i will try to do some tube rolling ... 
Thanks a lot  again
Kind regards,
gino   

P.S.  what about make it just a buffer for a dac by-passing the volume pot ?   

[8T_BoCO]

"P.S.  what about make it just a buffer for a dac by-passing the volume pot ?"

If you are confident modifying it, that could work for you, as you use an integrated.
I not only like the variable gain for my scenario, I do really need a volume control (power amp with fixed input).

I had the excellent $59 Nobosound passive pre (discussed in a separate C&C thread) in the signal chain as well, but eventually took it out.

[ginetto61]

    "P.S.  what about make it just a buffer for a dac by-passing the volume pot ?"

If you are confident modifying it, that could work for you, as you use an integrated. 
I not only like the variable gain for my scenario, I do really need a volume control (power amp with fixed input).
I had the excellent $59 Nobosound passive pre (discussed in a separate C&C thread) in the signal chain as well, but eventually took it out. 

Hi thank you very much indeed.  Unfortunately i have noise with the buffer in the chain even without music.  I need time to try to understand the reason of this noise. 
Kind regards, gino

[hifix]

1)  do any of you have direct experience of this preamp ? what is your opinion of it ?
2)  any suggestion about how could i eliminate that noise ?  i am using a cheap 12V smps to power it
3)  what would be a sensible step up ?  as i said above i like the added sense of space and the overall tone with voice.   
I would like to add that i have tried different integrateds downstream the fx audio all solid state, some very cheap and other more expensive,
nevertheless all benefits from its insertion in the audio chain.

Hi Gino,

I think its a nice unit and especially for the money.  I briefly ran mine with a linear power supply and the 5654w tube swap.  My existing system is built around a passive attenuator + amp combo so while i found  the tube-01 enjoyable,  the colouration from the unit didnt always help.  I am considering using it as part of another system.

When i was running the unit with its stock SMPS.  It was so electrically noisy that you could "see" the noise on my old TV.  The linear supply fixed it.  There is a big tread on AK for the tube-01.

[ginetto61]

Hi Gino, 
I think its a nice unit and especially for the money.  I briefly ran mine with a linear power supply and the 5654w tube swap.  My existing system is built around a passive attenuator + amp combo so while i found  the tube-01 enjoyable,  the colouration from the unit didnt always help.  I am considering using it as part of another system. 

Hi ! thank you very much indeed for your kind and very valuable reply.   Maybe i did not say that but i have been testing it in front of some cheap but decent integrated with the volume at max (the one on the integrated i mean) and found that indeed it adds some kind of space to the sound and stays transparent as well.  Main issue is with this noise ...

   When i was running the unit with its stock SMPS.  It was so electrically noisy that you could "see" the noise on my old TV.  The linear supply fixed it. There is a big tread on AK for the tube-01.

very very interesting ... i will try a linear asap .... I was skeptical about the buffer concept in general but then i have read about the B1 buffer by Nelson Pass and a friend of mine uses regularly with great satisfaction a Conrad Johnson PV10 in which the line stage is basically a tube buffer if i understand rightly.   I will try the linear supply before ditching it 
Thank you very much again
Kind regards, gino 

P.S.  thanks for the hint at the discussion on AK ... i have just read 3 posts and i am already amazed