Twin reverb reissue tube question

I own a 65 twin reverb re issue and I’m wondering if I can change the tubes to make it so the amp can produce a natural dirty sound instead of its infinite amount of headroom. The amp is loud enough already and I’ve been having trouble getting a good lead sound, I think having a pushed amp and then a pedal on top of that would make for a good lead tone, any thoughts?

Hashwagon said:

any thoughts?

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Buy a smaller amp! The twin reverb is a high powered amp that is renowned for clean tones and having loads of clean headroom, changing valves will have little or no effect on this, if you want something that breaks up at lower volumes then the only real answer is a different amp.

AFAIR you can remove half of the power tubes for an earlier breakup.

It is indeed possible to remove 2 output valves which will half the output power, however this will not have as much effect as you might expect and will only result in a -3dB reduction in sound pressure level. This will of course allow you to turn the volume control up a bit more for more distortion at lower volume levels but ultimately it is still a twin reverb which is well known for being a clean amp.

It's also important to note that removing 2 of the output valves will change the impedance loading, the amp is designed to run into a 4 ohm load, if you remove 2 valves it should ideally be run into an 8 ohm load to ensure the output transformer is not damaged.

Why not put a boost or distortion pedal in front of it....?

As already said, the twin is too much amp.

there is a way... Yellow Jackets!

with yellow jackets you can use EL 84 power tubes.

Or: Sell the Twin and get a Deluxe Reverb!

fakejake said:

Or: Sell the Twin and get a Deluxe Reverb!

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Exactly! Having the right amp for your needs is an infinitely better option than having the wrong amp and attempting to make it something it isn't!

Wilko said:

As already said, the twin is too much amp.

there is a way... Yellow Jackets!

with yellow jackets you can use EL 84 power tubes.

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“ In a 100 watt amp like a Twin Reverb or Marshall 100, either two or four Yellow Jackets™ can be used. If only two are used and the other two sockets are left empty, the output is dropped to about 20 watts. With four in place, the amp puts out about 40 watts and takes on a whole new warmth and richness.

Will they hurt my amp?

No! Yellow Jacket™ converters are safe for all amplifiers and transformers. As all Yellow Jacket™ Converters internally limit voltage and current they put no extra strain on amplifiers' power and output transformers or internal components. Using the Yellow Jackets™ in higher powered amplifiers actually reduces the strain on the transformers and internal components because it reduces the overall wattage of the system. Furthermore, the heater (or filament) current of the EL84 is lower than that of the 6L6, EL34 or 7591, so the Yellow Jacket™ will reduce the strain on the filament windings of the power transformer as well. ”



found this info, true ?

garywright said:

“ In a 100 watt amp like a Twin Reverb or Marshall 100, either two or four Yellow Jackets™ can be used. If only two are used and the other two sockets are left empty, the output is dropped to about 20 watts. With four in place, the amp puts out about 40 watts and takes on a whole new warmth and richness.

Will they hurt my amp?

No! Yellow Jacket™ converters are safe for all amplifiers and transformers. As all Yellow Jacket™ Converters internally limit voltage and current they put no extra strain on amplifiers' power and output transformers or internal components. Using the Yellow Jackets™ in higher powered amplifiers actually reduces the strain on the transformers and internal components because it reduces the overall wattage of the system. Furthermore, the heater (or filament) current of the EL84 is lower than that of the 6L6, EL34 or 7591, so the Yellow Jacket™ will reduce the strain on the filament windings of the power transformer as well. ”



found this info, true ?

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Firstly a caveat, I have no first hand experience of using them but as someone who builds and repairs valve amplifiers for a living I do have an understanding of what they are and how they work.

As with many of these things the answer to your question if it is true is probably "sort of...... maybe..... not quite!" The claim that they put no extra strain on the transformers is the one I find particularly suspect, in the case of the power transformer that is probably correct as the amp will be likely to be drawing less current but in the case of the output transformer the impedance reflected back is likely to be not optimal and could put extra strain on the output transformer. In practice it is probably not going to cause any problems (obviously if they were regularly causing output transformers to fail they would not have a very good reputation!) but to claim that they put less strain on the output transformer is very suspect. The other point I noticed is that they make a point of saying the heater current will be less and put less strain on the filament winding - this is very true but what they don't say is that this reduced load on the filament winding will cause the filament voltage to be higher and this could potentially reduce valve life. One other claim they make on the website is that they operate in class A, this is total bullshit, they are cathode biased but that does not necessarily mean they are class A. Unfortunately class A has developed into something of mythical status and is often used as a marketing term to suggest that it is somehow better than class AB which is what the vast majority of push-pull guitar amps really are, almost all of the amplifiers that are quoted as being examples of class A (Tweed Deluxe 5E3, Vox AC30 etc.) are not true class A (OK class A rant over )

My personal view of these is that the likes of Fender and Marshall put a lot of time and effort into designing their amps to use a particular type of valve and all of the components in the amp will be optimized to run those particular valves, using different valves is always going to result in something being less than optimal. Of course many people do use them and in reality they are probably not going to cause any significant damage but my advice would always be if you want a cathode biased EL84 amp there are plenty to choose from that were designed to run that way

I've used Yellow jackets in my 135 watt UL twin. It got me breakup at reasonable levels, but the sound is less than stellar. A twin uses a SS rectifier and sounds thin already compared to a Super Reverb anyway. Add to that the fizzy sound of EL84s and you a whole other animal.

It is fun to do, but as mentioned, the right amp for the volume you need is a far better option in many cases.

I've used the Yellow Jackets in the Twin Reverb, Super Reverb (1966), Hiwatt Custom 50 (1972). Didn't do it very often and have opted for the smaller amps as they sound better.

Like many before me, I've sold off almost all of by big amps. That 135 watt twin was the first to go. I gig mainly with either Princeton Reverb with a Celestion Blue, or a 1964 Deluxe Reverb. I sometimes use an 18 watt Marshall clone or 1965 Vox Cambridge reverb. The point being, small amps give up the goods.

I use a Weber Mass Attenuator with my 65 twin reverb reissue with no issues... it works fine, but I prefer a pedal in front to tame it, my current favorites being a Van Weelden Royal Overdrive or Tanabe DUM+ZEN Twin Custom.

Pedal in front means your hearing a pedal.

Yeah you can get a lot different sounds from pedals. At that point the amp matters less and less. Twins are great for that! Too much distortion from an amp softens the sparkle and immediacy of the pedals.

The right amp meshing well with the right pedal can be magical, too.

Ah, the tone quest.

I've experimented with yellow jackets in both vintage 50watt and a '97 35th anniversary Marshall plexi.
The breadth and depth of tone lost with the yellow jackets wasn't compensation for earlier, reduced volume overdrive.
I'm not saying that they have no place, but reported results in smaller wattage amps have been more positive in offering a workable alternative, such as a one or two 6v6gt amp for example.

My brother has been wedded to his twin reverb for 25 yrs and after much switching and swapping has found 4 or 5 pedals that give him incredible drive tones, from subtle to 'run for cover', if you know what I mean.

We live in a golden age where pedals are concerned I've no doubt you will find all you need to put your music across.

I tried everything and more. Here's a trick that did work: low efficiency speakers. I went from stock speakers with 99 db sensitivity to 89 db sensitivity. I also shaved 14 pounds in the process. Its very controllable now.

musekatcher said:

I tried everything and more. Here's a trick that did work: low efficiency speakers. I went from stock speakers with 99 db sensitivity to 89 db sensitivity. I also shaved 14 pounds in the process. Its very controllable now.

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Out of curiosity which speakers did you use? It is unusual to find 12 inch guitar speakers with sensitivity that low.

Going from 99 dB to 89 dB speakers would certainly make a big difference, a 10 dB cut will effectively halve the perceived volume level whereas pulling 2 valves and halving the wattage will only result in a 3 dB cut which wouldn't be significantly noticeable. In fact to achieve the same halving of volume by reducing wattage alone you would need to reduce it by a factor of 10 and go from a 100 watt amp to a 10 watt amp.

There is no reason to alter that amp. It is a mighty Twin Reverb, renowned as one of the greatest amps of all time. Can't wack it up to patent pending to get that great pushed Blackface growl 'cause it's a high power, high headroom behemoth and you for sure, ain't playing arenas? You bought a muscle car and drive in school zones and you want to floor it?

What were you thinking?
Why didn't you get a Deluxe Reverb or Princeton Reverb you could make angry and howl and growl away with all the natura tube amp overdrive you need?

'Cause they are not mighty Twin Reverbs with harmonicly rich, bold full sounding, amazingly tactile, shimmering tone that rings like a cathedral bell and grand piano at room filling volume without falling apart, that's why, and it is a good damn reason!!

So what can you do?

Don't fret, Uncle Al has some proven strategy's that work.

First, don't remove tubes, don't put in crappy speakers, don't, DO NOT DETWINALISE IT!! If you don't like it replace it. Sell it and get a Blues or Hot Rod Deluxe. Me? I'd keep it, put in better speakers, ( Weber Silver and Blue alnico 50watt light dope pair works for me), and good tubes.

Now, SRV and a bazillion others push the front end with a Tube Screamer with Level raised, Drive low and Tone set for full, warm tone, [around noon, halfway], where it sounds right. THIS WORKS! Set your levels and rock out.

As some have suggested, if you have a specific overdrive sound in mind, that is a lead drive tone, there is a pedal that will sound exactly how you want. The right pedal of your choosing will allow you to retain all the Twins tonality and allow you to switch to a lead tone, with the responce and tone you want. THIS WORKS!!

Now, when your ol' Uncle Al does it, it's done with a $70 EH Soul Food boost pedal. I can push the front end with the VOL. control to get the level of natural overdrive I want, I adjust the TREBLE to perfectly match the bypassed tone and keep the DRIVE turned down for a natural, transparent boost overdrive tone. It really sounds like my Twin on 10. I can exceed that if I wish by further raising the VOL., add more drive by adding DRIVE to where I'd like, while lowering VOL. to keep overall volume to balanced levels and, if I wish, change the character of the lead tone with the TREBLE. THIS REALLY WORKS!! for me.

Point is, you have lots of options with pedals that really work and is exactly how most folks do it. It is cheap, easy and effective.

:hee :salude

Detwinalise! Great word!

(oh yeah, love the pull- boost!!!)

A good (original) BF Twin is a beautiful thing, maybe my favorite BF amp, but Yellow Jackets don't replace that awkward handle and the amps back breaking 85lbs.

I also agree that the right pedal or pedals with a Twin can be a remarkably great setup. A lot of opinions about other amps being "pedal friendly," but Twin amps are still king in that department.