Off Topic Valves/tubes

[Jonny Dubai]

Hey there tone hounds i need a bit of advive on the "dark art" of tubes. I am feeling my Engl Blackmore is getting a bit "tired" sounding and i may need to replace some tubes. Took the back off the head and the
4 x 6L6's dont match. the 2 outside ones are different!!!! Should your output valves be matched? Will this make a difference?

Also

going to replace the preamp valves. I need "thicker" gain and compression as i feel the tone is a bit fizzy and the high gain notes dissapears too quickly from under my fingers. What are the best high gain pre amp vales to get for this?

Hope this makes sence and thanx in advance.

Jonny

 

[joe web]

JJs preamp tubes make a thicker sound with a nice gain structure. ECC803s could be a good tube for you.
in my mesa amps i prefer the Tung Sol in V1 which makes a great cleansound and a nice overdrive as well, but not so compressed.
i would recommend to just order both kind of tubes and check out which you like best in V1.

don´t know if the engl amp needs matched pairs or if this amp has an auto-bias for each tube.

 

[peterd79]

when i ordered new tubes for my Z i was shocked when they recommended a mix-matched set for the tubes...

JJ for this position
Tung Sol for that position
off brand for here
and a mullard for there

so i figured if it really didn't need to match i'd do my own mixing and matching to find what sounds best to my ear and came up with a good combo.

I'd say spend some time reading about what each type of tube is known for (they're usually right) and start by making small changes to the tube layout and you should find someting that works great for you.

 

[Jonny Dubai]

Cheers chaps much appreciated. I have contacted Watford Valves here in the UK. They have a great reputation so will see what they say too.

J

 

[DrKev]

Definitely change the tubes. It's just like strings - old ones won't sound as good.

I have no great experience with different brands of tubes but I've always been very happy with JJ tubes. I won't pay the extra for NOS tubes. I think it's a rip off.

As far as matching goes, I'd stick with the same brand and type for the power tube pairs. Different brands of similar tubes can run very differently. That said, doing so won't harm your amp, but may (or may not) sound great and could shorten the lifespan of one or two of the tubes (because some could be running nicely in spec but others too hot or too cold).

I don't think that matched pairs are necessary for two reasons: 1) components in your amp are not matched, they'll have probably 10% or 20% variance between individual components on the push and pull sides of the power amp, as is often the case for the two sides of the 12AX7 phase inverter and the two sides of the output transformer. Nothing else matches, so why should we care about the power tubes?; 2) tubes that start out matched won't stay that way for long. I once installed a set of matched tubes that biased identically but were 11% out after three weeks and stayed that way ever since.

That said, power tubes are often only available as matched pairs and it's no real disadvantage in my opinion, though I'm not sure I'm happy about paying the extra when I have no way of knowing if the truly were matched. Some people swear that matched pairs sound better and some swear not matching them sounds better. Nobody has produced any hard evidence either way so relax and rock out!

For preamp tubes, you can do whatever you like without any issues whatsoever.

And yes, Watford do have a great reputation. I used Tube-town.de in the past and been very happy.

 

[Spudmurphy]

I spent an hour yesterday with my mate an amp tech, and took my old MM amp down for valves. Only have two output valves, and these were definitely matched - he has the old gear/punch cards to check - yeah the technology is that old.
We replaced the valves and checked the bias and the bias showed two different results for the valves - as Dr K says the internal components will be a factor. It was biased following the instructions of Mike Baugh a guy who worked for MM. I fired the amp up last night and it was great.
Once again there are opinions for and opinions against getting the two values spot on. He has built a number of Trainwreck/Liverpool amps and they are awesome - he is not one who advocates them both reading spot on.
But hey JD - yeah, it's best to have all the valves the same make - and new valves will add zing I am sure.

 

[Jonny Dubai]

Sweet. Cheers lads. Will get on this ASAP.

 

[TNT]

Ah Tubes - what a joy!!!

Yes, you can pretty much roll the tubes just about anyway you want. I agree with the above comments too. Pop a Tung-Sol in V1 & v2, as far as the power tubes go, well it's a preference there. I prefer Winged C, & Svetlana as "matched" (in my Marshalls).

And, since I bias my own amps (about as often as I change my guitar strings which is quite regularly), the thing perpetually "purrs like a kitten", with the rpm's up, just begging for the green light!!!!

 

[auxren]

In an push-pull scenario, like in your amp, the inner two tubes and the outer two tubes have to match. Those two sets form two amplification stages. People play games with those two stages and have different output tubes to try to achieve different things. The purpose of having matched tubes in each set is for the pushing and the pulling. Imagine you have a sine wave and the amplification is pulling the wave higher in the positive direction and lower in the push direction in a disproportional mannor; you would have some sort of funky wave that isn't representative of the input wave. This can introduce all sorts of unwanted harmonics.

 

[DrKev]

you would have some sort of funky wave that isn't representative of the input wave. This can introduce all sorts of unwanted harmonics.

Correct! But some people argue that exactly that distortion is a good thing. After all, guitar amps are not simply amplification devices, they are also tone shaping devices. But people have been arguing this for decades so who knows?! What we do tend to forget is that back in the 50's, 60's, and 70's, people were a lot less picky about bias and matching, often just shoving a new set of tubes in there and off they went!

 

[auxren]

Thats true. I wonder how many times Hendrix got his Marshalls biased....

 

[Spudmurphy]

in the 50's, 60's, and 70's, people were a lot less picky about bias and matching, often just shoving a new set of tubes in there and off they went!

yup ... .... .... that was me !!!!

 

[Jonny Dubai]

It's a "dark art". A bit like recording!

 

[luke2joey]

[I]In an push-pull scenario, like in your amp, the inner two tubes and the outer two tubes have to match. Those two sets form two amplification stages. People play games with those two stages and have different output tubes to try to achieve different things. The purpose of having matched tubes in each set is for the pushing and the pulling. Imagine you have a sine wave and the amplification is pulling the wave higher in the positive direction and lower in the push direction in a disproportional mannor; you would have some sort of funky wave that isn't representative of the input wave. This can introduce all sorts of unwanted harmonics.[/I]


This is very true. With matched tubes, you have the best performance of your amp, with the least trouble. If the ignition of your car is not properly adjusted, when one cylinder has more power than the others, your car will not run very well.
I have very good results with JJ. I am using no other brand anymore, since I discovered them some 10 years ago. They made my Boogie 'sing'.
Besides that, JJ uses colour codes, for Mesa anyway, which is very helpfull to choose the kind of tubes you need for your playing style, e.g. blue is medium hard, green is medium.
Good luck

 

[DrKev]

I didn't know JJ had colour codes though I know Mesa apply their own to tubes they sell. I never knew Mesa used the JJ power tubes either. (preamp tubes, yes, it seems).

I can't stand the prices that Mesa or Groove Tubes charge. I once paid through the nose for Mesa branded tubes and they rattled louder than anything I've ever used, ever. Very disappointing. So much for better quality control. BTW, never leave a store without a receipt!

 

[Jonny Dubai]

Just had a good look at the Watford Valves site. They have a specific pre amp set for my engl, and they are on sale. Going to have to give them a go. Now to the problem of the power valves (6L6)!!!!!

 

[welshboyo]

IIRC, the Blackmore is a 5881 amp (a military spec 6L6), as many others have said, matched valves are the best and get the amp re-biased (6L6 will be fine too - just mention to the valve peeps that the amp is a 5881 model)

Any respectable valve supplier ( I use Karltone and Hot Rox ) will be able to recommend suitable replacements.

The Winged C Svets are probably the best you can buy outside of the NOS arena.

 

[Jonny Dubai]

Cheers Welshboy. Thanks for the advice.

 

[Jonny Dubai]

Valves purchased. For the power section I went for Harma 6L6. It's what MarshalllBoogie sounded like in the 80s and 90s. For the pre amp section I went for some electro harmonix 12AX7 high gain valves. Can't wait to get em in. The guy at watford Valves was super nice and too time to help me get the right ones.

Cheers
J