2. amps-preamps
  3. 163493-5418

My really dumb tube mistake(s)

8 years ago, I bought a sweet sounding Line Magnetic amp for my office system which a few years ago died and had to go to the repair shop. $500 later it was back working, but then recently I noticed the sound was getting thin, I couldn’t bias the tubes and thought something else was wrong with it, arghh.

Then I noticed one newer tube was able to be biased and decided to replace all 4 KT-88 power tubes.
Presto, the amp sounded great again!

Like the boiled frog, the sound degradation had been so gradual my brain had gradually adjusted. But the new tubes brought it back to life.

So, then I thought, wow, maybe I should try the same thing in my primary system with my Primaluna monoblocks, switch out the Primaluna tubes for some new Gold Lions. Again - wow! What a difference. Like I bought new amps, much richer and fuller sounding.

Tubes wear out, even if they don’t blow out.
Yes, duh, it’s a good idea to replace them every 4 years or so and not wait eight.
cdc2
hshifi
572 posts
 
Hello,
I auditioned the Rouge RP7 preamp. So good. It is on my wishlist. If I bought a tube piece of equipment. I think I would buy a second set of tubes. Break them both in to have the perfect backup. I heard on the Rouge RP9 they have NOS Russian tubes. Is it good to buy an expensive piece that is setup to run in NOS tubes? What happens when there are no more NOS?
hobo1452's avatar
hobo1452
85 posts
 
elliottbnewcombjr
Similar obvious improvement: I just thoroughly cleaned the years old corroded rca jacks on my vintage McIntosh preamp. So old they are the close together ones, hard to clean but well worth it. I made a leather strap, put super fine steel wool on the inside of a loop, carried on like a professional shoe shine finale. Very glad I did it.

Don't just stop with the outside of the RCA's, clean the insides too! Power off and unplug the equipment. Spray DeoxIT or any other good, non-lubricant contact cleaner on a pipe cleaner, preferably white, and run it in and out of the plug until you can do it with a fresh one that comes out clean. It usually only takes a couple. You can grab the pipe cleaners at Hobby Lobby or just about any craft store.
sandthemall
544 posts
 
An overlooked advantage of tubes is that they start sounding great within 30/45 minutes of turning on the amp and preamp.

My solid state stuff needed to be on for at least a few (3) hours in order to sing. This really is a super duper convenience and worth every bit of the fussing.

But then I have a Primaluna power amp so it's pretty fool proof.


atmasphere's avatar
atmasphere
11,784 posts
 
The process is ongoing. The new tubes have about 75 hours thus far.


I’m hoping for the revelation to reveal itself soon.
@tvad 

If you're already at 75 hours, you're hearing it. Have you replaced the input tubes? They can have more effect than the output tubes.
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