# when to retube



## deadear (Nov 24, 2011)

Can you test tubes rather than run out and buy new ones because you feel it is time. Seems like the guys selling like to replace often.


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## nonreverb (Sep 19, 2006)

You can test them for emission by way of a tube tester. Otherwise, if they have really bad microphonics or they sound dull and farty, then it's probably time for a change.


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## LydianGuitars (Apr 18, 2013)

+1 on what nonreverb said. 

I'd add volume drops and fuses blowing for no apparent reason.


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## Wild Bill (May 3, 2006)

deadear said:


> Can you test tubes rather than run out and buy new ones because you feel it is time. Seems like the guys selling like to replace often.


I must have half a dozen tube testers around my shop. If you only need a couple tested I do them no charge. If you have a bunch I might have to charge you a half-hour of shop time.

If you bring a basketful I have one of those old-fashioned drug store self-service tube testers and you can do them yourself!

Many music stores seem to advise you to change all the tubes in your amp because they really have no idea what may be wrong! They may be fooling themselves as well. It's easy to tell if a crook is trying to fool you but it's a lot harder when the guy is sincere and believes his own bullcrap. You can't help but wonder when they push you into buying a complete new set and don't even give you the old tubes to use as spares. What are the odds that ALL your tubes went bad at once?

Anyhow, if you need some tested just let me know and I'll be glad to help!

Wild Bill


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## dcole (Oct 8, 2008)

It seems a lot of players themselves believe in replacing all the tubes when they do a tube swap. I had a fellow bring in a Peavey 5150 II as it was not as loud as he thought it should be. I checked all the power tubes and they were good on my tester but I only measured 19 ma of current on one side and none on the other when checking the bias. So after checking the screen resistors I found 3 blown, replaced them and everything was good, yet he wanted to replace all the power tubes and pre-amp tubes on top of it. If you want to through money at things willy nilly go right ahead!


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## parkhead (Aug 14, 2009)

dcole said:


> It seems a lot of players themselves believe in replacing all the tubes when they do a tube swap. I had a fellow bring in a Peavey 5150 II as it was not as loud as he thought it should be. I checked all the power tubes and they were good on my tester but I only measured 19 ma of current on one side and none on the other when checking the bias. So after checking the screen resistors I found 3 blown, replaced them and everything was good, yet he wanted to replace all the power tubes and pre-amp tubes on top of it. If you want to through money at things willy nilly go right ahead!


I would agree that 80% of customers want to replace all of the tubes at once... 
I usually walk them through the amp and suggest that if they gig and play regularly they should replace the power tubes with reliable new production, keep a spare 12ax7 handy 
and get on with it. 
Less regular players should change their power tubes when they replace their car tires ie every few years. 

If your amp lights up and does not blow fuses your rectifier tube is good ...
& most of your pre amp tubes are not working that hard unless you have a high gain amp 

personally I have lots of cool old amps that have fresh filter caps and original old tubes... 
this is the number 1 thing on anything made prior to 1978 ... get fresh filter caps and leave the tubes, many older tubes are better than what you can buy now 


to sum up 
Pre amp tubes are like Light bulbs ... they work or they are busted 
Power tubes are like car tires they actually wear out over a period of years 
Filter caps are like your car battery... the less you use the amp the less they hold their charge at 10+ years they are expired 
at 20 years they are sounding bad and you don't know it 
at 30 years they are looking to take out other components when they fail 



p


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