# 63 Vibroverb Reissue tubes



## knight_yyz (Mar 14, 2015)

Hey guys, some of you know I grabbed a 63 VVRI brownface a while back and although I love the sound, I have no idea of the condition of the tubes. So I'm thinking of getting something better than the JJ's that are in there. 

When replacing tubes for better tone/sound, is it necessary to replace everything? My VVRI uses 8 tubes and if I bought "top of the line" NOS tubes I could buy another amp instead. LOL SED's would cost 90 each for the power side of things, than another 5 12AX7A's and then a 12AT7. Would i notice a big difference if I only replaced the power 6L6GC's and the 2 preamp tubes? ? 

Also I know nothing about tube tremolo/reverb except it sounds absolutely amazing. Assuming money is no object, is a high end tube going to make the tremolo and reverb sound better? Tremolo needs one tube, the reverb needs two. 

Or should I just replace the power and preamps for now? Oh, and i want headroom, I like the clean sound. If I need dirt I can move to the normal channel and add a stompbox. 

Power:............6L6WGC (Two)
Preamp:...........12AX7A (Two)
Phase Inverter:...12AX7A
Rectifier:........Solid State Diode
Tremolo/Vibrato:..12AX7A
Reverb Driver:....12AT7
Reverb Recovery:..12AX7A
Circuit:......6G16


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## ampaholic (Sep 19, 2006)

This might be useful. This is from KCA NOS tube website and is their opinion on a typical Fender circuit and where you'll get the most tone for your $ when changing preamp tubes.
They don't mention power tubes I suspect because it goes without saying that having the best power tubes you can afford will benefit tone.


https://www.kcanostubes.com/content/fender-amp-preamp-tube-layout-and-recommendations


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## epis (Feb 25, 2012)

If it sounds good tubes are good. You should change only phase inverter tube to 12AT7 for a bit more clean headroom.
Tremolo or reverb aren't gonna improve with "better" tubes. 
Most "improvement" would be a speaker change.
Cheers, Damir


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## knight_yyz (Mar 14, 2015)

Speakers are already upgraded. I'm pretty sure the tremolo tube is on the way out, it has quite the hum when I hit the pedal. I think I am just going to upgrade the power and pre amp and tremolo tubes. Still gonna cost a fortune. LOL


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## knight_yyz (Mar 14, 2015)

Found some good prices on NOS Sylvania 6L6GC's, a pair of NOS RTF 12AX7 for the preamp and a couple of new Mullard 4025's. For the non important stuff I will just mix and match. 

thanks for that fender link it helped quite a bit.


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## jb welder (Sep 14, 2010)

knight_yyz said:


> I'm pretty sure the tremolo tube is on the way out, it has quite the hum when I hit the pedal.


The signal does not pass through the trem tube at all, the trem only modulates the power tube's bias to give the effect. I doubt the hum is caused by the tube itself, more likely the circuit. You can check by swapping V1 and V5.
Looking at the rear of amp, tubes are from right, V1 through V8.

If you don't use the normal channel, then you don't need to worry about V1.
V2 will be the most critical preamp tube for the bright (rev.&vib.) channel.
V3 is reverb driver, effects reverb only.
V4 is reverb pickup and gain/mixer stage for vib. channel. It will affect vib.channel tone but not as much as V2.
V5 is trem tube and can not impact the tone.
V6 is phase inverter, see Epis comment about 12AT7 here.
V7 & V8 are power tubes, which will affect tone of both channels.

Edit: I see most of what I mentioned was in the link ampoholic posted in post #2. Doh!


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## knight_yyz (Mar 14, 2015)

This is what I will end up with

V1 jj tesla that came with
V2 RFT NOS 12ax7
V3 Mullard CV4024
V4 RFT NOS 12ax7
V5 jj tesla that came with
V6 Mullard CV4024
V7 Sylvania 1960 NOS 6L6GC short bottles clear top copper rods
V8 Sylvania 1960 NOS 6L6Gc short bottles clear top copper rods


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## knight_yyz (Mar 14, 2015)

Well, just got the amp back from Dan, and the new tubes made a huge difference. The power tubes run a little hotter than the old ones so now i have way more clean head room than before. Had the amp at 5 today and it was super clean at that volume. And it wasn't ear splitting loud which was also a bonus.


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## nonreverb (Sep 19, 2006)

Those Sylvania's must have cost you a small fortune...


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## knight_yyz (Mar 14, 2015)

Not nearly as much as a NOS set of black plate RCA'S!!


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## James (Jul 3, 2007)

hey there - I'm kind of late to the conversation - I too have a 63 VVRI that I bought new in the early nineties - still trying to get the tone a little sweeter though speaker changes have done a lot for that - I was all ready to order tubes (JJ) from eurotubes then I saw this post - are the JJ tubes not considered very good? I'd sure appreciate any feedback/opinions.
Thanks


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## knight_yyz (Mar 14, 2015)

Seems that you love them or hate them when it comes to Jj tubes. To me they are decent, but compared to NOS tubes, there is no comparison. They just dont make stuff like they used to.


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