Voltage and Power Compatibility

[minions]

Hello,

I was planning on buying a Weber 6A20 (Weber's version of the Fender Deluxe Reverb) with 120-220-240 Line Voltage. Someone told me replacing two of the 6V6s with EL84s would not work because the voltages are not compatible. But if I did choose the 120-220-240 option (EL84s and 220V are British power), would this work?

Thanks.

[sumgai]

minions,

Your source is so incorrect, I don't know where to start..... sigh.

Suffice it to say, if the website says it's for sale in Country X, and it will work in multiple countries, then that should be a good enough indicator that the amp will work, when and where you want it to. After all, if the designer were to be so grossly wrong, they'd be liable for beaucoup damages, when everybody who believed them started finding out differently.

But Weber's been around for 25 years, maybe longer, and they haven't caused anyone any problems yet (of this nature, anyways). I think you can safely buy what you want, and they will deliver the goods that you request of them.


As for that source, I can only say, he or she should go back to school and take Remedial Elementary Electricity, they're very lacking in knowledge about things electronical......

HTH




sumgai

[minions]

Haha thanks. But I think what he said was that the two voltages (that of EL84s and that of 6V6s) are not compatible with each other. Does the same still hold true?

[sumgai]

minnie,

I should reiterate, but I won't.

The deal is, the EL84 is simply the European designation for a 6BQ5, a nine-pin miniature receiving tube. (Old school terminology.) So far as I know, the 6V6 has no such "over the pond" designation. But more importantly, it's an 8-pin octal tube, much larger in physical size, and commensurately more powerful in output capacity.

(Warning! Techno-mumbo-jumbo ahead!)
The two tubes, and indeed all tubes, operate on DC that is handled by the power supply. The only AC voltages seen by the tube are the signal being amplified (your guitar signal) and the heaters (or the filaments, same thing). And at that, the heater voltage is still being controlled by the power supply.

The bottom line is, there is a difference between the tube types you mention, in terms of the maximum voltages they can handle, but that's about it. They're both meant to be power amplifiers (output tubes), but they were designed and made for different purposes, meaning different output levels (wattages). They also have different distortion characteristics, but that's not really at issue here, so we'll leave that for another day.

Your take-away from all this is that the power supply is in charge, and if the amp in question is meant to travel from one country to another, then said power supply has to be able to handle the destination country's normal "wall socket" voltage - nominally 110-120 vAC for North America, 100 vAC for Japan, 220-240 vAC for Europe, and other voltages to be found around the globe. Consult your favorite internet search engine to learn what voltage is normal for the country you intend to visit/gig in, and make sure the power supply is designed for that voltage.

It's not that hard to make a power supply handle several voltages, but doing so usually involves a larger transformer than might otherwise be necessary. I say that only because it's more expensive, and it weighs a helluva lot more than the single-voltage transformer designated for just any one single country. Other than that those factors, the transformer operates exactly the same no matter where you use it, and the tubes in the amplifier circuit will see exactly the same voltages that the designer wanted them to see, and all will be well in minions-land.

But you do know, don't you, that without a conversion socket, the 6V6 and the EL84 are not direct substitutes for each other? You'll need something called a YellowJacket (from THD) to make it happen.

Just so you know.

HTH



sumgai

[minions]

Jan 17, 2010 4:44:22 GMT -5 sumgai said:

But you do know, don't you, that without a conversion socket, the 6V6 and the EL84 are not direct substitutes for each other? You'll need something called a YellowJacket (from THD) to make it happen.

Thanks, that is exactly what I wanted to know. So would I use one Yellow Jacket on each tube or only on the EL84(s)?

Thanks again .

[sumgai]

minions,

Only on those EL84's that you're gonna use to replace any 6V6's.

HTH




sumgai

[minions]

Oh, okay. Thanks!

[stevo58]

Hi, I'm new here, but I'm just curious, what do you expect to gain by replacing 6V6s by EL84s? There will be no power reduction, the amp will still be around 18-22 watts; the two tubes are very comparable in power output, and you can't hear a difference of a few watts. It won't sound much diffferent either unless you drive it very hard. There is much more to the tone of an amp than what power tubes are used.

I also have to say if you are planning on building this amp yourself, and you ask this sort of question, then you better do some more studying, because a blackface Fender is not a beginner build. Sorry, but you are showing that you don't have a shimmer of what goes on in an amp, and that is literally a potentially fatal mistake. I don't want to be a jerk about this but you could hurt yourself. Furthermore, Weber kits don't include ANY instructions, you get a schematic and a layout, which is enough if you have a few builds under your belt, and woefully inadequate the first time.

As far as your question about the voltages goes, it's like this: there is high-voltage DC on the anodes of the tubes. The Deluxe Reverb puts extremly high voltages (for a 6V6) on the anodes; more than 400 volts, as a matter of fact. The maximum anode voltage for a EL84 is 300 volts, so let's say you can drive it safely (meaning faster burn-out) at 350 volts; so even if you pull out the octal sockets and put 9-pin in there and make a couple of other changes you will have extremely short tube life, at more than 100V over design maximum.

The wall voltage doesn't have much to do with anything; that is fed into a transformer right off the bat and turned into something else. You have to pick the right wall voltage so the transformer has the right source voltage to change into something else - in a DR, that would be 5V, 6.3V, -50V, and 330V.

Yellow jackets will work, but I'll bet you don't notice much change.

steven

[newey]

Stevo-

Hello and Welcome!

Your points about working on amps and/or building an amp kit are well taken. We have posted warnings about this at the top of this forum, but such cautions always bear repeating.

Minions didn't say he was planning on building this, and I think we assumed that he was either buying one already built or having it built for him. But his link is to the kits, so he may be planning to build one.

THD's site claims their yellow jacket adapters result in a total transformation of the amp, tone-wise. Of course, that's marketing-speak. You sound like you have some experience, so I'm wondering if you have tried this type of mod (and found little difference, sonically)?

[stevo58]

Hello Newey -

Using the yellow jackets will change the amp from fixed to cathode bias. There will be a change in the sound due to that. I'm trying to think of two well-known, similar amps, one fixed, one cathode, but can't think of anything. The DR and Tweed Deluxe are completely different animals, so that won't work. If he buys the triode-strapped Yellowjackets, there will be a significant drop in power, but also a significant change in tone which not everybody likes.

My point, other than hoping he wasn't going to build this himself, is that there isn't as big a difference between the sound of an EL84 and a 6V6 (in the same amp) as people think. It won't sound like an AC30, for example, or a Marshall 1974. It will still sound pretty much like a deluxe reverb. In my test amp, I can run either an EL84 or a 6V6, and you really have to turn it up into heavy saturation before you hear a difference.

I can't comment on the marketing hype from YellowJackets. I would suggest that they are expensive, so if he can find a pair to borrow, or if he return is guaranteed, it would be worth a try. It could be the difference from the cathode biasing is just what he is looking for. I don't know, this is why I asked what he wants from it. He offered a solution without stating a problem.

On the other hand, if he is having this amp built for him, it would be easy to add a fixed/cathode bias switch, which is the way I would go. You could also add a switch to take out the negative feedback. If you are having an amp built, there are countless easy (read: inexpensive) ways to add things to change the tone.

As far as a DR goes, the voltage on the preamp anodes is important in that amp; it is lower than in the larger BF Fenders (from memory I'm thinking 80 volts lower). This reduces the headroom and contributes a lot to the famed tone.

Oh, and yes, I've tried yellowjackets, but it has been years and years and all I remember is I sold them right away, they weren't for me.

steven

[limbe]

I hope that you won´t mind if I point out a few things.
If you buy or build an amplifier with the voltage specs being 120,220 and 240 it will work everywhere though you have to wire the power transformer differently for 120 or 240 volt.These transformers are called export transformers as opposed to domestic transformers which only will work with one voltage.
sumgai,you are right in assuming that there is no european equivalent to 6V6.
stevo58,EL84 is rated for a maximum of 300 volts on the anode and the 6V6 315 volts in some data books and 350 in others.I wouldn´t put EL84s in an amp with 400 volts on the plates either.I also made a single ended amp with two sockets.One for a 6V6 with the right cathode resistor and one for an EL84 connected as a triode.I honestly can say that I couldn´t tell which tube was in it´s socket.So much for "tube character". Limbe signing off

[minions]

Okay this is lot to absorb.

First of all, I'm not as naive as to think that putting a single EL84 in an amp with automatically transform it into a Vox.

I do plan do drive the amp pretty hard most of the time, but now that you've mentioned that EL84s don't sound much different to 6V6s, I might not use one. I was looking into the cathode/fixed bias switch and the negative feedback switch, too.

Let me get this straight. The only thing a Yellow Jacket does is convert a fixed bias amp to a cathode biased amp? If that is the case, I think I can forget about the Yellow Jacket and the EL84 and just stick with the bias/neg fb switch.

As for maximum anode voltage, THD has this to say:

"When the Yellow Jacket Converters are installed in larger amplifiers intended for 6L6s or EL34 output tubes, the high plate and screen voltages are reduced as well as current limited to protect the EL84 and to drop output power."

Although, this may be completely different, I don't know.

Newey was right to assume I wouldn't be building this myself, I'm aware that Weber offers in-house building as well as sending parts to third-party assembly companies.

Stevo-
Yes I know I have a lot to learn, and this is going to be more of a long-term project for me. I'm not planning on starting it until I have a great deal of knowledge under my belt, and I have even considered buying Weber's So Watt! beginner's amp kit to get the hang of modding an amp and such.

My whole point for being a part of such forums like this one and many others like it is to learn all I can, and while I know that is a bit selfish, maybe in due time I'll be the one answering other members questions (but one step at a time!) I appreciate all of your help with this, even you Stevo Haha, I guess I should say especially you. And don't worry about insulting me, it's all good.

- Minions

[D2o]

Feb 20, 2010 17:05:08 GMT -5 minions said:

Yes I know I have a lot to learn, and this is going to be more of a long-term project for me. I'm not planning on starting it until I have a great deal of knowledge under my belt, and I have even considered buying Weber's So Watt! beginner's amp kit to get the hang of modding an amp and such.

My whole point for being a part of such forums like this one and many others like it is to learn all I can, and while I know that is a bit selfish, maybe in due time I'll be the one answering other members questions (but one step at a time!) I appreciate all of your help with this, even you Stevo Haha, I guess I should say especially you. And don't worry about insulting me, it's all good.

- Minions

That's the GN2 spirit! +1 for both you and Stevo!

D2o