Portable tube amp from china?

Discussion in 'Portable Headphone Amps' started by voodoo do-er, Sep 6, 2012.
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  1. choisan
    No, i set my onkyo to line out. On my B4, i only turned to 1/10 of volume.
    For the first impression, yes, you can tell the improvement. More level of detail and the sound quality is much clear.

    I will brun in more and update later on.
     
  2. jamonbread
    I just got my B4 this morning it sounds great and having more subtle control over the volume as apposed to digital volume is great. The tubes do seem to be adding something noticeably warm to the sound, I can detect very subtle background hiss when nothing at all is playing but the microphonics aren't as bad as a was expecting reading some comments. Well worth the extra pocket bulk for me.
     
  3. choisan
    You probably get a dual tubes version of Little Bear. Friend of mine who has it said the amp does required 1, 2 hours of warm up so as to have the performance. But once it is warm up, the sound is very nice.
    Mine is single tube, the reason i bought this is that it doesn't take long to warm up. Just few mins.
     
  4. choisan
    i am planning to change the cap inside as well. someone suggested to change and use some solid state, which cost very little but performance is noticeable
     
  5. jamonbread
    Yeah I got the 2 tube version and there's no charging indicator on the device its just the plug has one. I though it might have some LED's on the device but it doesn't. Its warms up pretty quickly.
     
  6. choisan
    Mine is having red light around the plug area when it is charging. It will turn blue upon fully charged.
     
  7. jamonbread
    I'm really happy with it overall, my only one concern is the headphone jacks seem a bit cheap and will likely suffer connection issues down the line. I really need to learn how to solder so I can at least replace the tubes when the finally crap out.
     
  8. jamonbread
    Well unfortunately mines developed a random static sound in the left channel, tapping the device sometimes makes it go away and sometimes its not there at all? Bit disappointed as I can't work out whats coursing it, and I can't apply contact cleaner to the volume pot to rule that out as there's no way to get it inside the pot itself.
     
  9. silverfishla
    IMG_0923.jpg
    What are you using as a source for it? It will pick up RF noise from a phone or if you are near a computer. Static, basically. Sometimes, it's absolutely clean sounding, but sometimes it will pick up some static noise. I usually can't hear it while the music is playing and doesn't affect my enjoyment of the amp. On another note, I changed out the capacitors on the amp and some of that noise was greatly reduced by doing that. Now I barely hear any static, and it's only there periodically. I think it's RF noise though, since I live near a radio tower.
    This is what mine looks like at the moment. I'm waiting for another capacitor in the mail, to see if I can fit it in so that I can put the lid back on it. Just experimenting. I find that this makes the Burson sound even better than the stock setup. Really wonderful clarity and great bass. Love it.
     
    Last edited: Aug 25, 2017
    aj_cal likes this.
  10. jamonbread
    I was using it with my Benjie MP3 player, there'e always been a small background hiss but it doesn't amplify at all (barley noticeable 99% of the time) This crackle/pop is new with the same setup and you can hear it over any audio volume (only in the one channel), but I've finally found out what the problem is, and its the volume pot. Tapping the volume pot lightly used to make it go away, and turning the pot past a certain point (too loud) it kicks in again permanently at higher volumes. Its now basically become permanent at all volumes in the same one channel (i can reduce it a bit by sweeping the pot up and down and tapping it). It has all the hallmarks of a crackly volume pot, and I've tried getting contact cleaner into the pot from all angles put I can't get any inside the pot itself.

    I managed to remove the knob and get the front off but I'm going to have to find a replacement 8pin 9mm 50k switched pot, and the same branded ALPS pots are out of stock everywhere. I also need to learn to solder my past attempts have ended in failure. I'm surprised the pot got dust inside in the first place as its a sealed unit. Same symptoms I have in the old Pioneer amp.
     
    Last edited: Aug 26, 2017
  11. cathee
    Anyone have more information on this IMS amp? Looks very interesting, but I can't seem to find any information any where. Their website doesn't have anything either...

    x
     
  12. magisterarus
  13. cathee
    Thank you for the quick reply. Apologies for bringing this OT, did not even realize they were from NZ!

    Also, have read Brooko's write up, unfortunately as detailed and thorough as it is, a data point of one is somewhat useless. Would love to read more about it, seems like a very interesting product.
     
  14. kukkurovaca
    I think this is the thread for it: https://www.head-fi.org/threads/wor...t-smaller-than-most-cellphones.764953/page-12
     
    golov17 likes this.
  15. Yobster69
    I could be very wrong, but I do not think this IMS amp is being made anymore. Please correct me if It is though???
    Link??
     
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