Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › M8161 Tube humming with Little Dot MK3
New Posts  All Forums:Forum Nav:

M8161 Tube humming with Little Dot MK3

post #1 of 9
2/24/10 at 1:31pm
Thread Starter 
Hi guys,

I received two pairs of Mullard M8161 and I hear a hum with both pairs. When I put back the stock tubes, the hum disappear.....

Am I doing something wrong ? or are the tubes defective ?

Thanks

Denys
Reply
post #2 of 9
2/24/10 at 3:34pm
If your stock tube is a 6ak5* (6J1) type you do need to install a jumper or throw a switch to use the EF92 EF91(M8161 or M8083) type tube.
Reply
post #3 of 9
2/24/10 at 4:11pm
Thread Starter 
Quote:
Originally Posted by Trapper32 View Post
If your stock tube is a 6ak5* (6J1) type you do need to install a jumper or throw a switch to use the EF92 EF91(M8161 or M8083) type tube.
Thank you for your answer...however...how do I do that ???

Where do I install a jumper...or throw a switch ??

Thanks again

Denys
Reply
post #4 of 9
2/24/10 at 5:36pm
The official manual is located here ..Google Docs

It explains how to do it. Basically turn the unit upside down and access the jumpers that way... You''ll have to use a narrow pair of needle nose pliers or some forceps to do the deed.
Reply
post #5 of 9
2/24/10 at 8:13pm
Thread Starter 
Quote:
Originally Posted by Trapper32 View Post
The official manual is located here ..Google Docs

It explains how to do it. Basically turn the unit upside down and access the jumpers that way... You''ll have to use a narrow pair of needle nose pliers or some forceps to do the deed.
Thanks.....I just looked and ther's no jumper at all...all three pins on both sides have no jumpers..l.... I believe I must buy some...

Denys
Reply
post #6 of 9
2/24/10 at 8:39pm
Quote:
Originally Posted by Denys View Post
Thanks.....I just looked and ther's no jumper at all...all three pins on both sides have no jumpers..l.... I believe I must buy some...

Denys
Yes, they're standard jumper pins...typically used on computer hard drives etc. A local computer store should fix ya up...
Reply
post #7 of 9
2/24/10 at 8:46pm
Thread Starter 
Quote:
Originally Posted by Trapper32 View Post
Yes, they're standard jumper pins...typically used on computer hard drives etc. A local computer store should fix ya up...
Thank you very much... I really appreciate your help...

Denys
Reply
post #8 of 9
2/24/10 at 9:11pm
If you purchased the amp from David (LD), he usually includes the jumpers in the bag with the stock RCA cables he provides.
Reply
post #9 of 9
2/13/12 at 5:42am

Hello

 

I have similar problem. I had 5654 tubes when my LDIII came. Few days ago I exchanged that tubes for golden pinned 6J1P-EV which is the same type of  tubes.

Some hum in background appears. Hum disappear when I touch enclosure, cables and ground connectors. Is something wrong with grounding in my LDIII or my tubes are broken?

 

Matt 

Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Headphone Amps (full-size)
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › M8161 Tube humming with Little Dot MK3