Hum

MartinLogan Audio Owners Forum

Help Support MartinLogan Audio Owners Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
M

Mantana

Well-known member
Joined
Feb 10, 2009
Messages
267
Reaction score
0
Location
Centennial, CO
I just borrowed a Butler 5151 amp from my dealer and hooked it
up to my Musical Fidelity A5 integrated through the pre-amp out.
When first turning on the Butler, there is no hum coming through
my Spires. After about 10 seconds, once the tubes kick in, there
is an audible hum from the speakers i can hear from 15 feet
away. Is this normal from tube amps ? It doesn't bother me
while playing music, but it seems odd.
 
Last edited:
Mantana said:
I just borrowed a Butler 5151 amp from my dealer and hooked it
up to my Musical Fidelity A5 integrated through the pre-amp out.
When first turning on the Butler, there is no hum coming through
my Spires. After about 10 seconds, once the tubes kick in, there
is an audible hum from the speakers i can hear from 15 feet
away. Is this normal from tube amps ? It doesn't bother me
while playing music, but it seems odd.
Click to expand...

nope, not normal. hum is quite often a ground loop problem. have you cable TV hooked up to anything in the system? try unhooking that. cable TV is often a source of hum.
 
i do have my cable tv linked, but it was hooked up before
into my A5 and i had no problem at all until i added the Butler
amp.
 
Get everything video out of the system and see if the hum is still there. That is, not connected - even if it is off! - the earth loop can still travel through the RCA cables of turned off and unplugged appliances. Then plug them in one by one and you'll soon find it. Little doubt it'll be your antenna connection.

There's an easy way to find out if it is a problem with the Butler and that is if the hum is there if everything else is turned off.........if there is no hum then it can't be the Butler. If the hum is coming from the MF then you'll hear it through its speaker level outputs as well in 99% of cases.
 
well, you're right about the cable creating the hum. I unhooked
both cables from my TV cable box and my DVD player to my
MF A5 and there was no hum. I didn't isolate if it was the TV cable box
or the DVD, but i'll do that next. Regardless, i never had a hum problem
when cable and DVD were just being driven by the A5... only when
i added the Butler and bypassed the A5 amplifier and used
the A5 as a preamp. Since i definitely want to play my TV &
DVD audio through my speakers, do you know how to correct
this or should i just forget the Butler and go with the A5 ?

Just checked again....it's not the DVD, but the hookup from the cable TV box
into the A5, SACD input. I have the DVD connected to the tape input of the A5...
 
Last edited:
Mantana said:
well, you're right about the cable creating the hum. I unhooked
both cables from my TV cable box and my DVD player to my
MF A5 and there was no hum. I didn't isolate if it was the TV cable box
or the DVD, but i'll do that next. Regardless, i never had a hum problem
when cable and DVD were just being driven by the A5... only when
i added the Butler and bypassed the A5 amplifier and used
the A5 as a preamp. Since i definitely want to play my TV &
DVD audio through my speakers, do you know how to correct
this or should i just forget the Butler and go with the A5 ?

Just checked again....it's not the DVD, but the hookup from the cable TV box
into the A5, SACD input. I have the DVD connected to the tape input of the A5...
Click to expand...


cable grounding is horrid. bar none. a simple fix is to drop in an isolation transformer. you can buy them from a couple of places but what i did was end-to-end attach a 75Ohm to 300Ohm transformer with a 300Ohm to 75Ohm transformer. then i put this inline on the cable feed. the two transformers create a 75Ohm to 75Ohm isolation transformer. rat shack or similar will have the parts for a few bucks.

while the Butler might show up the problem, the problem isn't neccesarily the fault of the Butler :)
 
thx for the suggestions, guys....

actually, i was getting hum from both the cable hookup and the DVD
when i added the Butler to the mix. I wonder why i have no
problem with the MF A5 when hooked up alone. Anyway, i can't
justify the cost of adding the Butler. It is a good amp and seems
to eliminate the edge or glare that is evident with just the A5.
Remember, the A5 is a great match with the Montanas, but
not so great with the Logans. I still like an integrated over
separates. I hate having all those extra boxes, so i'll continue
my search. I'm still considering the Sim I7, but the Butler is a
smooth amp and seems well made.
 
I ended up taking the Butler back. As an FYI, it was a good
amp. It gave the Logans some bloom and took away some
of the glare i sometimes experience with the A5. The bass
was not as tight, nor as detailed. I'd have to say the Butler
gave it a fatter, softer sound, but wasn't
quite as detailed as the MF. The Butler might have been a
little more 3 dimensional. Not sure on that point... I needed
more time with the amp to confirm that. It did take away
that edginess which is important to me. It's built very well,
extremely solid.

I plan to listen to other amps....still like the ease of an
integrated, though.

No more hum once i switched back to the A5...
 
You must log in or register to reply here.

Similar threads

Peter Robbins
11As or 13As?
2
Replies
30
Views
2K
Lightloopy
Lightloopy
Ishaansuri
ESL 9 hissing and levels
Replies
16
Views
2K
Ishaansuri
Ishaansuri
C
Solid State Power Amp for Impression 11A speakers
2 3 4
Replies
65
Views
6K
Big Dog RJ
Big Dog RJ
ejspain
Just Wondering....
2
Replies
24
Views
4K
Brazillnut
B
B
Just picked up a pair of Odysseys - fulfilling a 25 year goal
Replies
6
Views
581
Paul172
Paul172

Latest posts

Back
Top