Bare Knuckle Pickups Forum
Forum Ringside => Guitars, Amps and Effects => Topic started by: steve on May 19, 2006, 09:43:55 AM
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Does anyone know the difference in tone going from el34's to 6550 power amp valves. Cheers.
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can yu even plug them in the same socket? or yu need yellow jackets?
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You can plug them in the same sockets, and you could probably run them without modding anything. When Marshall switched over to 6550's, they changed the 220k bias splitter resistors in the power amp to 150k's. So you might want to do that too if you're switching Steve.
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You'll need to re-bias though - you can't just swap them over and play...
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You were asking for tonal differences. In my univalve where I can swap tubes like I want, 6550/KT88 have more clarity and punch, pretty similar to 6L6/5881 but a little more body, they can break up in a quite rude way and you need to be easy on treble/presence when cranking the amp, whereas EL34s are smoother in general, but with scratchy/crunchy upper mids that make the tone cut through well.
I would say 6550 are generally better for cleans and Recto / Soldano kinda sound, whereas EL34s are better for 60s to 80s style rock.
In my opinion the ideal is two guitars played with both styles of sounds, that's why I like playing parts twice for recording and swapping tubes to fill a different frequency range with each take.
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Cheers guys, i have a late 90's trace elliot speed twin and it takes el34,6550 and 6l6. I was considering chucking a set in a seeing what they do.
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If your amp can take EL34s, then you should also try KT77s and 6CA7s. These valves are a sonic hybrid between big bottles (like the KT88) and the EL34, while still being beam tetrodes. 6550s have a really big, full sound, not as midrange peaky as an EL34, but less upper frequency detail. (What you would call 'air', or 11kHz or above) EL34s, however, can sound really 'beamy', which is why I love the 6CA7 -- it has the midrange and upper midrange clarity of the EL34, as well as the robust bottom end of a KT88. I have a set of KT77s at home, but haven't had time to try them yet. (Too busy messing with the Holy Diver in my M1)
It's all an organic mix, depending on guitar, playing style, and overall tone. Try them all!!
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I have KT77s in my amp right now (also a Speed Twin). I changed the EL34s that were in it to 6L6s at the recommendation of Bob at Eurotubes, but I didn't really like the sound. I found it more balanced, but less full, and I preferred the fatter sound the EL34s gave.
Then I got the KT77s and I'd say that they're right smack in the middle, sonically. I don't mind them. They're good for cleans--better than the EL34s--but I think I still like EL34s a little better overall, especially for lead guitar playing and riffing. Of course, that's my subjective opinion. And the original tubes were nice tubes, but not the same brand as the JJs, so that might interfere with the comparison too.
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6550s require more bias voltage than EL34s so you will need to make sure your bias circuit will cope with that (most can't and require modification).
tonally 6550s will give you more clean headroom, lower/deeper bass & more highs while having more high-mid focus rather than the low-mids of EL34s.
I personally prefer 6550s in high-gain amps & also prefer an ECC81 phase inverter valve.
:twisted:
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You'll need to re-bias though - you can't just swap them over and play...
Actually going from a EL34 to a 6550 you wont NEED to rebias, but you will definitely want to so it sounds good!
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If your amp can take EL34s, then you should also try KT77s and 6CA7s.
There are also KT66s which will be warmer and KT88s which will be cleaner, both of which are acceptable alternatives as well. KT88s are military versions of the 6550s and tend to take more of a beating and at the same time be warmer.
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The 6CA7s are the tubes favored by Eddie Van Halen in his old Marshall, from what I have heard. If that's the case another good reason to try them.
Though I will give this disclaimer. I'm not positive Eddie ever knows what the hell he is using or has used. He looks like a homeless person lately.
Maybe Ben's endorsement of them should be enough now that I think about it.
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Actually going from a EL34 to a 6550 you wont NEED to rebias, but you will definitely want to so it sounds good!
well you don't NEED to rebias but the bias range that EL34s operate within is FAR too hot for 6550s so they will redplate and you'll ruin a new set of 6550s. if that sounds like fun to you then go ahead. checkout the datasheets, 6550s require considerably more bias voltage than EL34s
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Actually going from a EL34 to a 6550 you wont NEED to rebias, but you will definitely want to so it sounds good!
well you don't NEED to rebias but the bias range that EL34s operate within is FAR too hot for 6550s so they will redplate and you'll ruin a new set of 6550s. if that sounds like fun to you then go ahead. checkout the datasheets, 6550s require considerably more bias voltage than EL34s
Wait. You first said that EL34s require more bias voltage than 6550s and then that 6550s require more than EL34s. Which is it?
It's been my understanding that just like 6L6s, 6550s require more voltage so at the lower EL34 voltages they will just sound too cold but not to any damage.
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Wait. You first said that EL34s require more bias voltage than 6550s and then that 6550s require more than EL34s. Which is it?
no I didn't, read my post again - both times I said that 6550s require more bias voltage than EL34s.
It's been my understanding that just like 6L6s, 6550s require more voltage so at the lower EL34 voltages they will just sound too cold but not to any damage.
If you're very lucky, then maybe. In most cases I think it's safe to say that putting 6550s in an amp setup for EL34s will result in the 6550s being over-dissipated.
:twisted:
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The 6CA7s ... Maybe Ben's endorsement of them should be enough now that I think about it.
Yes, listen to Ben ... whoever he is!!!
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no I didn't, read my post again - both times I said that 6550s require more bias voltage than EL34s.
I quote you "but the bias range that EL34s operate within is FAR too hot for 6550s so they will redplate and you'll ruin a new set of 6550s."
What does less voltage run hotter?
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EL34s typically operate with around -45 to -25 on the grids
6550s typically operate with around -65 to -45 on the grids
as the bias voltage is adjusted towards 0v, the output valves will run hotter.
I've actually done this procedure on amps many times, this is not just something I've read on the internet and taken as gospel.
If anyone wants to plug 6550s into their EL34 amp without modification then go right ahead, it'll end up in the hands of a tech like myself requiring a new set of valves and possibly replacement of burnt out screen resistors and arced sockets (worst case scenario of course).
What does less voltage run hotter?
I don't know how to answer that question, it makes no grammatical sense.
:twisted:
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EL34s typically operate with around -45 to -25 on the grids
6550s typically operate with around -65 to -45 on the grids
as the bias voltage is adjusted towards 0v, the output valves will run hotter.
I've actually done this procedure on amps many times, this is not just something I've read on the internet and taken as gospel.
If anyone wants to plug 6550s into their EL34 amp without modification then go right ahead, it'll end up in the hands of a tech like myself requiring a new set of valves and possibly replacement of burnt out screen resistors and arced sockets (worst case scenario of course).
What does less voltage run hotter?
I don't know how to answer that question, it makes no grammatical sense.
:twisted:
You just answered it. Having less current makes tubes run hotter. I always thought more current made tubes run hotter and I know 6550s require more current.
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where do you guys all get your amps biased, or do you do it yourself? I'm dreading having to change my valves because i'll never be able to bias my amp and i don't know anybody who can do it for me offhand. Do music shops do it? Sound Control etc.?
Actually i could just get the amp serviced by the marshall factory, but I'm thinking that might be overly expensive?
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There's no point bickering over whether the tubes need rebiasing if you switch to 6550's, as even if you changed simply to a different pair of EL34's you still should be rebiasing. Just set the bias trimpot to minimum, pop the new tubes in and bias to whatever the recommended bias range is for the new tubes.
indysmith - biasing an EL34 amp isn't as hard as some people might like to make out. All you need to do is install 1ohm resistors in the power tubes (join pins 1 and 8 and put the resistor inbetween those pins and ground), then measure the current either side of the resistor, turning the trim pot to get in the range you want.
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There's no point bickering over whether the tubes need rebiasing if you switch to 6550's, as even if you changed simply to a different pair of EL34's you still should be rebiasing. Just set the bias trimpot to minimum, pop the new tubes in and bias to whatever the recommended bias range is for the new tubes.
Dude, I don't know all the stuff you do. I've always thought voltage = heat with tubes just like solid state. I know some of the basics, as much as 6550s require more voltage than a EL34, and I have some understanding of electronics, but I haven't learned how to bias an amp yet. I would like to, but I don't know how/where to do that.
where do you guys all get your amps biased, or do you do it yourself?
A friend recommened a semi-local tech. I brought him my '69 Major which needed some repairs and when I got it back, it was so incredibly warm - now I understand why some people say the Majors are the best sounding Marshalls ever. But aside from doing great work, he's a really nice guy as well!
Ask friends who play, and ask Bainzy I'm sure he'd do it for the right price. You heard what he did with his Marshall right? ;)
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indysmith - biasing an EL34 amp isn't as hard as some people might like to make out. All you need to do is install 1ohm resistors in the power tubes (join pins 1 and 8 and put the resistor inbetween those pins and ground), then measure the current either side of the resistor, turning the trim pot to get in the range you want.
Whats a 1ohm resistor look like? which pins are which? what's ground? THE ground? how do yu measure current? whats a trim pot? Where's a trim pot?!
I think you can probably see that the chances of me biasing my amp are close to zero, but thanks for your help
I'm a race driver, not a pit mechanic
Ask friends who play, and ask Bainzy I'm sure he'd do it for the right price. You heard what he did with his Marshall right? ;)
I don't know anyone around here with a valve amp; how depressingly rubbish. Unfortunately Bainzy is a few hundreds of miles north of me... :P Yeah his marshall was definately sweeet 8)
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You just answered it. Having less current makes tubes run hotter. I always thought more current made tubes run hotter and I know 6550s require more current.
voltage and current are not the same thing and are not interchangeable terms. increasing the idle current DOES make the valves run hotter.
I have some understanding of electronics, but I haven't learned how to bias an amp yet. I would like to, but I don't know how/where to do that.
hmmm, never biased an amp in your life yet you're willing to argue the point with someone :roll:
:twisted:
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Simmer down folks :)
Electrical 101 (gawd, going back to my Apprentiship days). VERY first thing ya learn.
Voltage is NOT what will Kill Ya, Current i.e. AMPS is what'll do it.
Just a premiss, and NOT directed at ANYONE in particular, but :), lot's of SILLY confrontations lately on this board with people arguing the fact when they have NO training/experience on what they are arguing about.
People, listen and learn. Ask and be courteous with thankyou's and responses. Being an I Know Everybloodything about guitars/music etc. but A.am still in school or B.Never opened my amp or guitar backplate or C.never listened to what music you are discussing is getting OLD!
This is an Excellent board to participate in the above;
H-C lol
Rant over :)
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Heavier Than Hell has dished out some very sage advice. I've recently made the change to 6550's in one of my amps and the tech explained about the differences between them and EL34's (the chap I use as a tech is well respected in the industry, if he has advice for me more often than not I listen!).
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where do you guys all get your amps biased, or do you do it yourself? I'm dreading having to change my valves because i'll never be able to bias my amp and i don't know anybody who can do it for me offhand. Do music shops do it? Sound Control etc.?
Actually i could just get the amp serviced by the marshall factory, but I'm thinking that might be overly expensive?
Indy
Go to the Marshall factory
You are already in Bucks - so distance is easier for you
They are really helpful and they do it cheaply as they like to have Marshalls running well -
And you get to look around the factory or the museum and get a feel for a bit of rock tradition
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There's no point bickering over whether the tubes need rebiasing if you switch to 6550's, as even if you changed simply to a different pair of EL34's you still should be rebiasing.
Sound advice Bainzy!!
biasing an EL34 amp isn't as hard as some people might like to make out. All you need to do is install 1ohm resistors in the power tubes (join pins 1 and 8 and put the resistor inbetween those pins and ground), then measure the current either side of the resistor, turning the trim pot to get in the range you want.
Once again - correct and sound stuff but possibly beyond the skills and inclinations of many who post here.
It is ok NOT to do all your own tech work
Do indeed consider guitar techs and amp techs to be like F1 pit crew if you like the racing car driver analogies.
Find one who you trust and who communicates well with you, & Value them and don't begrudge paying them their fees - especially if they are not being extortionate.
Then get on with enjoying playing guitar
there is nothing wrong with understanding how things work or go together and still chose to delegate the work to somebody more experienced.,
I know how to do DIY and gardening and stuff but sometimes I still employ the services of a decorator I trust simply because they can do the job quicker and more efficiently than me , with minimal mess and few complications , leaving me free to do what I like doing best
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Heavier Than Hell has dished out some very sage advice. I've recently made the change to 6550's in one of my amps and the tech explained about the differences between them and EL34's (the chap I use as a tech is well respected in the industry, if he has advice for me more often than not I listen!).
Don't like the 6550s much? (I prefer EL34s too).
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Don't like the 6550s much? (I prefer EL34s too).
I actually really like them and they give me a different flavour to play with which is great. Having 3 EL34 powered heads meant that I was hearing more or less the same sound when I used them. I mentioned to the tech that I wanted to try something else and he suggested them.
With yet another EL34 powered amp coming into the fold (I have a Marshall 30th Anniversary head and cab heading my way), I may have one of the other amps switched to 6L6's (is 7 amps too many?!).
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With yet another EL34 powered amp coming into the fold (I have a Marshall 30th Anniversary head and cab heading my way), I may have one of the other amps switched to 6L6's
I'd be interested to know how you get on with the 30th Anniversary Marshall - I had one & just couldn't get on with it - the 2nd channel is by far & away the best (lots of JCM800 and JCM900 tones in there)
If you want a change from EL34s and already have an amp with 6550s, try some (Chinese) KT66s or some (Russian) EH 6CA7s.
(is 7 amps too many?!)
heh, you can never have 'too many' amps - I used to carry a spare for every amp in my collection at one point (20+ heads excluding combos) :lol:
:twisted:
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With yet another EL34 powered amp coming into the fold (I have a Marshall 30th Anniversary head and cab heading my way), I may have one of the other amps switched to 6L6's
I'd be interested to know how you get on with the 30th Anniversary Marshall - I had one & just couldn't get on with it - the 2nd channel is by far & away the best (lots of JCM800 and JCM900 tones in there)
If you want a change from EL34s and already have an amp with 6550s, try some (Chinese) KT66s or some (Russian) EH 6CA7s.
(is 7 amps too many?!)
heh, you can never have 'too many' amps - I used to carry a spare for every amp in my collection at one point (20+ heads excluding combos) :lol:
:twisted:
20+ heads! The only word I can use to describe that is eeeek! Sir, you fully deserve your login name!
I certainly let you know what my impressions are when it arrives, although I will not be getting my mits on it until August, it's a done deal but I have to collect it from Spain first!
I've played a combo version and compared to other Marshalls I have tried or owned my impressions were certainly more favourable. I share your opinion of channel two, in combo form it was certainly the best sounding - some very organic tones could be obtained here.
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Don't like the 6550s much? (I prefer EL34s too).
I actually really like them and they give me a different flavour to play with which is great. Having 3 EL34 powered heads meant that I was hearing more or less the same sound when I used them. I mentioned to the tech that I wanted to try something else and he suggested them.
With yet another EL34 powered amp coming into the fold (I have a Marshall 30th Anniversary head and cab heading my way), I may have one of the other amps switched to 6L6's (is 7 amps too many?!).
I prefer El34s, but having so many EL34 heads, I'd do the same thing ;)
I have 2 heads and 2 combos, and no place to store them all, but if you got room for them, more power to ya!
There's a guy on the forums at plexipalace.com with something like 10 or 12 Marshall Majors ;) And then there is this guys collection - http://www.plexipalace.com/va/showroom.html