Fender Twin Reverb late 70s Silverface Tubes

orson198305

orson198305

New member
Hello everyone, i am wanting to replace my tubes in my old twin reverb, it's starting to get noisey etc. I asked fender what tubes i should replace the old ones with, they replied with tube numbers i cant locate to buy eg a 6L6 Groovetube - 099 4001 204, i can find 099 4001 with other ending numbers, will this make a difference, i don't want to damage my amp.

Also, what is with the fender colour coding on tubes? white red etc

Thanks
 
I am not sure if this is what you are after:There should be a tube chart on the inside of your cabinet that will tell you what you need and where they go. But off the top of my head looking from the back of your amp left to right, you will need 4 6L6s those are the large Power Tubes. Next to them should be a 12AT7 that is your phase inverter tube, that tube should be changed every time you change your power tubes. Then comes a 12AX7 then a 12AT7 then 3 more 12AX7's. The first 12AX7 from the right is your channel 1 preamp tube, if you do not use this channel you do not even need to put a tube in that socket. The next tube from the right is your channel 2 (reverb,trem) the one every one uses, that is another 12AX7 then comes another 12AX7. If you are not sure what brand name to buy I would suggest Groove Tubes only because they are fairly consistent in their production. Good Luck new tubes make a big difference
 
The exact numbers like those you have listed,... are the year, and batch numbers those particular tubes were made,.....

It is not THAT critical that you get the numbers exact,....


as long as it is a 6L6 tube, it will work,....



However,......



Those amps are a bit touchy when it comes to their power tubes,.... it likes them to be pretty well balanced to sound the best,.... and it should really be done at a reliable shop so it can be biased when you replace the power tubes......



You can change your own Pre-amp tubes with no harm to the amp,.....

and no adjustments are required with those.....

they are usually numbered as a 12AX7, or, 12AT7, and are the smaller of the types used in your amp.....


Groove Tubes are one manufacturer that tests, and numbers its tubes acording to how clean/dirty they sound,.... from 1, to 10,.... and I think, if I remember correctly,.. it is lower is clean,... higher is dirty,.... and what they mean by that, is I think the higher numbers depict earlier breakup,....


U can get that info right from the groove tube site...



Steve
 
Yeah, i'm kind of new to all of this, i did find the sticker depicting which valves go in which sockets. What i found was 3x fender 6L6GC's and one "national electronics" 6L6GC which is pretty wierd. Obvousley not matched. I am operating on a budget, but i was thinking mabye electro-harmonics matched power quad? any ideas for power and preamp manufacturers.

Thanks
 
Thanks everyone for being so helpful, fender's support wasn't very helpful.

this is what is listed in my amp;

(Socket 01) - 6L6GC
(Socket 02) - 6L6GC
(Socket 03) - 6L6GC
(Socket 04) - 6L6GC
(Socket 05) - 12AT7
(Socket 06) - 12AX7A
(Socket 07) - 7025
(Socket 08) - 12AT7
(Socket 09) - 7025
(Socket 10) - 7025
 
Just so you know a 12AX7 and a 7025 are the same tube, 7025 is just the industrial code for a 12AX7. The short of it is: A long time ago when tubes ruled the world the industrial tube was a better tube. Here is a chart on preamp tubes, notice that the same tube can have different designated names. My preferance for the 2nd preamp tube (socket 9) is a 5751 it has a little less gain, but I prefer the sound.

Pre-amp Tubes
Standard-----Industrial-----European------Gain
12AX7A------7025---------ECC 83---------100
N/A----------5751---------N/A-------------70
12AT7-------6201----------ECC 81---------60
12AZ7-------N/A---------------------------60
12AY7-------6072----------N/A------------44
12AU7-------5814A---------ECC 82--------19
 
Excellent, thanks for that, i actually thought the user before me installed some wrong preamp valves and was worried about the stain it might have had on the amp.
 
If that amp is thirty somthing, it may also need to be "re-capped". Some of that noise may be comming from old caps breaking down.
 
Yes Capacitors. They tend to break down with time, especically electrolytic caps. If there are paper electrolytics they have a tendency to dry out with a lot of years. The amp may become noisy, hum and the tone and power will be affected too.

Years ago I had a Fender Bassman that I used for guitar because I liked the sound ... it began to sound weak and crappy and noisy as hell so I replaced the tubes ... it sounded better but was still not great. I took it to a shop and they recapped it and after that it sounded great. Now I an sorry that I gave it away.
 
I recently retubed one of my Twins with Electro Harmonix, they soud great, they are made in Russia but if you want USA manufactured tubes try this site www.tubesandmore.com they have "New Old Stock" which means they purchased a whole heap of tubes ex-US military. These were made back in the 60's and were held in a govt. warehouse. They are top quality and never been used. They are what your amp would have had when new.

Clive
 
Groove Tubes is now manufacturing 6L6's in CA on the original GE equipment salvaged from Owensboro KY.

Look for GT 6L6-GE's. They're about $72/pair on Ebay.

You'll need to have the amp rebiased too.
 
What do you mean by re-biased? I have a hum balance pot and an output balancing pot. I thought if you buy any matched 6L6 tube Quads i wouldn't need to tamper with anything.

I will be able to recap the amp myself (i'm an inst. tech and have built effects before). But what will i have to watch out for when substituting capacitor types?

I live in the uk aswell so i have to pay quite a bit more for the tubes.
 
orson198305 said:
What do you mean by re-biased? I have a hum balance pot and an output balancing pot. I thought if you buy any matched 6L6 tube Quads i wouldn't need to tamper with anything.

I will be able to recap the amp myself (i'm an inst. tech and have built effects before). But what will i have to watch out for when substituting capacitor types?

I live in the uk aswell so i have to pay quite a bit more for the tubes.
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You can always buy off the internet from the USA. I have been buying gear from the USA since the 70's and have only been stuffed around twice, once by Sam Ash and they eventually sorted it and I got my pedal and once by Music Toyz who were slack but again I got the order and I saved. And that's 2 out of many over 25 years. Most beat the post from my own state in Australia by days.
 
Groove Tubes is now manufacturing 6L6's in CA on the original GE equipment salvaged from Owensboro KY.
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I have a quad, and they aren't even close. This is a vastly overpriced tube, and isn't even in the same league as the tube it is designed to replace. I would know...I have 3 quads of the originals.

I personally think that the Winged C version of the Svetlana tubes is superior to this particular Groove Tube. Don't even get me started on their Mullard reproduction.
 
For what it's worth,.... I have a bunch of used older Bottle shaped RCA 6L6 tubes,.... and all but one have tested at 85% or above,... and after using a very long list of NOS, and current GT, among others,.... I gotta say,... that there is sumpthin about the old stuff that none,... at least none I have tried,.... comes close to what they can do,......it must have been the people makin em...



those RCA tubes have more of everything you want a tube amp for,.....


and I bet if you really pushed them,... I mean like gigs every weekend,... or more,..... you would get at least two times the life..., and maybe more , compared with lesser sounding new stuff......



My point,.... you know your own sound, ...
your guits,
your amps,...
your sound,...

and you may be perfectly happy with the sound you get with the cheapest tubes you can find,.....

but if you are picky,... and want the guits, and amp, to make your sound,.... then it might be wise to shop the internet for some tubes,....

I'd just google 'Vacuum Tubes'

many reliable dealers among the top ten on page one.....


and you can always Ebay it,... I have been doin it for years,....


some bargains,... some not......


Shopping is key,..... just as anywhere,......


Steve
 
edgarallanpoe said:
I have a quad, and they aren't even close. This is a vastly overpriced tube, and isn't even in the same league as the tube it is designed to replace. I would know...I have 3 quads of the originals.

I personally think that the Winged C version of the Svetlana tubes is superior to this particular Groove Tube. Don't even get me started on their Mullard reproduction.
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What's up with the Mullard re-issue???
 
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