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Replacement Tube Suggestions

PhrygianPhan

Member
Messages
2
Recently my Crate V33 amp has been making a terrible shrieking noise. It'll play fine for about 10 minutes, then start to pop out for a few seconds, then just make a god-awful screaming noise. I've tried different channels and removing the inputs, and the noise persists. I've never replaced the power tubes after owning the amp for 10+ years, so I'm assuming they are starting to go out.

I pulled out 4 Sovtek EL84/6PQ5 tubes and they don't look so hot - there's a lot of scorching on the tip of every tube. I have two questions:

1) I see some numbers molded into the glass on the bottom of the tubes: 6, another 6, 18, and 21. They are molded from the inside, so they could just be related to production quality control, but I wanted to make sure they aren't important.
2) Can anybody recommend a good place online to pick up some decent EL84 tubes? thetubestore claims to have an exact match for my amp, but the online reviews worry me. I've looked on sweetwater and found a matched quartet of Genelux tubes (https://www.sweetwater.com/store/de...ex-gold-lion-el84-power-tubes-matched-quartet). Any input on this selection?

I'm open to other suggestions. I'd like to stay on the EL84 series if possible.
 

oneblackened

Member
Messages
1,140
The "scorching" you're seeing is normal - that's the getter flash.

I buy my tubes from Eurotubes generally speaking, but I just like JJs in general. For other brands, The Tube Store is a good choice.
 

lostpoet2

Member
Messages
3,280
I would suggest just buying a 12ax7 and trying it in each of your preamp tube slots. To me, the screeching issue sounds like you have a bad preamp tube (probably the first one) that makes noise once it warms up.
 

Glitch Magnet

Member
Messages
2,013
For new production tubes, my favorites are Tung Sol EL84, Svetlana 12AX7, and Sovtek 12AX7LPS.

I haven't liked any of the JJs, but I'm interested to try the new JJ E83CC.

As far as the squeal, I agree, if it's a failing tube, it's probably one of the 12AX7 preamp tubes.
 

Rod

Tone is Paramount
Gold Supporting Member
Messages
21,495
I like dealing with Tube Depot......going on 20 years
 

deepcove17

Silver Supporting Member
Messages
813
Recently my Crate V33 amp has been making a terrible shrieking noise. It'll play fine for about 10 minutes, then start to pop out for a few seconds, then just make a god-awful screaming noise. I've tried different channels and removing the inputs, and the noise persists. I've never replaced the power tubes after owning the amp for 10+ years, so I'm assuming they are starting to go out.

I pulled out 4 Sovtek EL84/6PQ5 tubes and they don't look so hot - there's a lot of scorching on the tip of every tube. I have two questions:

1) I see some numbers molded into the glass on the bottom of the tubes: 6, another 6, 18, and 21. They are molded from the inside, so they could just be related to production quality control, but I wanted to make sure they aren't important.
2) Can anybody recommend a good place online to pick up some decent EL84 tubes? thetubestore claims to have an exact match for my amp, but the online reviews worry me. I've looked on sweetwater and found a matched quartet of Genelux tubes (https://www.sweetwater.com/store/de...ex-gold-lion-el84-power-tubes-matched-quartet). Any input on this selection?

I'm open to other suggestions. I'd like to stay on the EL84 series if possible.
For your EL84's if you want late breakup go with JJ, early break go with Tung Sol and if you want something in-between go with Sovtek. I have no experience with Genelux.
As stated above you may want to start with trying a new 12AX7 before purchasing new power tubes.
 

pdf64

Member
Messages
7,058
I’ve known EL84 to start popping and develop an internal lightning storm, that sounds like the end of the world via the speaker cab.
So if the noise occurs with all the controls at minimum, maybe even go so far as to remove all other tubes, and check if it still manifests.
Assuming you can cope with the noise, don’t let such extreme faults carry on longer than momentarily; it’s probably putting the OT under stress.
 

easyed

Gold Supporting Member
Messages
2,486
I have a set of Russian 6p14p tubes that are great replacements for current production EL84 tubes. I got mine from member @PerryR. They sound better than the Sovtek EL84M's that they replaced and they will last longer. Perry is great to deal with.
 
Messages
304
Tubesandmore.com is my go to for tubes. But I second @lostpoet2 and try a preamp tube before you buy the pricey output tubes. If that isn't the problem it's not a bad idea to have some spare.
If money is no concern but a set of output tubes, too. It never hurts to have some on hand if you like the amp.
With output tubes the only thing that matters is the tube type, in your case el84. Beyond that you will just want to buy a matched set. You should be able to select that when selecting the tubes. Most preamp tubes are never matched unless you buy for hifi stereo.
The other thing is output tube bias and that is only a problem if the new set doesn't sound right or if they are red plating and then you will have to have the amp serviced.
 

PhrygianPhan

Member
Messages
2
Update:
Got some "Mid Level" power tubes from thetubestore. Shrieking has stopped, and it sounds exactly like the old tubes.
Thanks for all the suggestions! One question was unanswered, however:
The new tubes had the numbers casted into the bottom of the tubes. I really had no idea what to do, so I just went from lowest to highest starting from the transformer. Maybe it doesn't matter, maybe it does. Everything seems to be working, so I think I did it right??? Will update if there's any catastrophic developments.
 

jthomas666

Member
Messages
547
Update:
Got some "Mid Level" power tubes from thetubestore. Shrieking has stopped, and it sounds exactly like the old tubes.
Thanks for all the suggestions! One question was unanswered, however:
The new tubes had the numbers casted into the bottom of the tubes. I really had no idea what to do, so I just went from lowest to highest starting from the transformer. Maybe it doesn't matter, maybe it does. Everything seems to be working, so I think I did it right??? Will update if there's any catastrophic developments.
What numbers? Where?
 

easyed

Gold Supporting Member
Messages
2,486
TheTubeStore has a proprietary rating system for power tubes, like GT, Mesa, and others. It's a single number that they use for matching. I don't recall what measurements are involved.
 




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