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McIntosh MC275

Hi all. I recently purchased a used MC275 in very good condition. The original owner said he had it service not too long ago. The amp appears to work fine but the tubes are very dim. I had them tested and they are fine with about 1/2 life still on them. Not sure what to do. Do I need new tubes or is there an adjustment I need to make? If I need new tubes then could someone give me an idea what to get and where to place them on the amp (which slots)? I want quality tubes so please, ANY guidance would be appreciated. Thank you
ceborg999
jbeckley42
5 posts
 
If you really want to see the tubes glow, you can turn up your preamp as loud as it can go, and the power tubes do tend to glow a little brighter.

Seriously though, there are many amps and preamp out there that the tubes barely glow.  I have a Berning TF-10 that you can barely tell the tubes are on.  Tube brightness is no indication if they are "good" or not.  

2112oracle:  Have you tried any other KT-88's?  I was curious about the black treasures, but the cost at the time was a little steep for me.
tommaster
10 posts
 
+1 for just turn ‘em up!
ggc
178 posts
 
I concur with the assessment made regarding the dimness of the tubes not being an indicator on their performance. I know it can be confusing with all of the Tube Amp Porn Photos on the internet revealing as much light as a fireplace on each Amp. - Marketing

But most important is how they sound to you. If you do not like how they sound, then I suggest swapping out the Tubes. I have gotten some fantastic stuff from this site. 

http://www.audiotubes.com
fstary's avatar
fstary
18 posts
 
I have mac tube amps and the tubes last for a long time. If it sounds okay, do not worry. Mac does not push the tubes as hard as many other manufacturers do.
bac2vinyl
78 posts
 
they aren't light bulbs…you ay not even see but a di, light
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