switching from EL34s to 6550s - what to expect?

[Neeklaus]

I was looking for a resource online that gave GENERAL descriptions for tube types. I understand each brand and each tube for that matter may have it's own nuances.

Is there a "quick reference" guide to what each tube type sounds like: EL34, 6L6, 6550, KT88, etc etc etc?

 

[Neeklaus]

none of you tube experts can chime in?

 

[CaseyCor]

I've been looking for this same thing for some time now.

 

[Motorpud]

I saw something like this at either thetubestore.com or tubedepot.com I can't remember but if you go look around they have reviews of the differences between tubes. I'd find it but I'm on my phone right now so it could take forever

 

[D-Rock]

I was with a friend and we were swapping the EL34's out of his amp for 6550's. With his amp you could do bias adjustments on the fly so not much time passed between swaps.
The 6550's made for a stiffer feel to the amp. Not as lively or warm as the EL34's. More headroom with the 6550's, but there wasn't really a lack of headromm with four EL34's, so that wasn't beneficial IMO.
The lowend was tighter with EL34's, but they were also a bit brighter than the 6550's.
The 6550's had a deep punch and the lowend wasn't loose, but I found it wasn't as defined as the EL34's.
Both of us prefered the EL34's in the end.

 

[Devilinside]

Yeah 6550's=boner

 

[glpg80]

I was with a friend and we were swapping the EL34's out of his amp for 6550's. With his amp you could do bias adjustments on the fly so not much time passed between swaps.
The 6550's made for a stiffer feel to the amp. Not as lively or warm as the EL34's. More headroom with the 6550's, but there wasn't really a lack of headromm with four EL34's, so that wasn't beneficial IMO.
The lowend was tighter with EL34's, but they were also a bit brighter than the 6550's.
The 6550's had a deep punch and the lowend wasn't loose, but I found it wasn't as defined as the EL34's.
Both of us prefered the EL34's in the end.

This - all of it. same experiences i have with 6550's.

 

[Ventura]

Really depends on the amp too, and what sort of preamp stage you've got driving into the power section. It's a yin-yang thing. It's really hard to say "all things being equal", because it's really amp and preamp specific.

I love EL34's for the grinding, chewy, middy, rich, full, looser (careful here folks, I use this term conservatively), more aggressive crunching tones. In to the higher gain ranks, it's good, it's harmonically rich and has some of that swirly edge to it.

I went with 6550's in my VH4S - the amp is my high gain beast...and it SCREAMS with the 6550's. It's thick, potent, hot, full of sizzle, and handles the compression fairly well...if that makes any sense. They like to be driven hard, and their response to clean to mean is very linear - whereas the EL34's tend to have different echelons of break up along the way.

Further note: Although "power valve saturation" is a highly overused term and concept around here, EL34's do sound nice (to my ears) when getting driven into the dirt than the 6550's do. But conversely, the 6550's take more of a beating and therefore don't saturate as easily, so it's kind of a moot point.

V.

 

[droptrd]

6550s have a big, extended top and bottom end. It almost makes it sound slightly scooped. Very bright too. I dont like em personally. If they were the shit, you'd see more manufacturers designing amps around them

 

[glpg80]

6550s have a big, extended top and bottom end. It almost makes it sound slightly scooped. Very bright too. I dont like em personally. If they were the shit, you'd see more manufacturers designing amps around them

i didnt get the extended bottom end as in it adds more, if anything the top end has alot going on and the slightly scooped thing is true too

IMHO i dont like them at all. they seem bland to me, much prefer smaller bottle tubes like 6L6's.

 

[MississippiMetal]

I changed out 6550's for EL34's in a 1985 Marshall 2204 and it definitely made the amp sound warmer and less harsh. I'm doing a re-cap on this amp as we speak, so I can't attest to the bottom end response as it still has the original LCR's in it, and the intended lowend of the amp is all but gone. I'll report on it once i get the new supply caps in and the rest of the amp wired up and running.

I'm also replacing the main board with a JMP style turret board, 1 and 2 watt resistors and Mallory caps. Should be interesting to hear how it sounds after the caps are formed and the bias set.

 

[Schaf]

I was with a friend and we were swapping the EL34's out of his amp for 6550's. With his amp you could do bias adjustments on the fly so not much time passed between swaps.
The 6550's made for a stiffer feel to the amp. Not as lively or warm as the EL34's. More headroom with the 6550's, but there wasn't really a lack of headromm with four EL34's, so that wasn't beneficial IMO.
The lowend was tighter with EL34's, but they were also a bit brighter than the 6550's.
The 6550's had a deep punch and the lowend wasn't loose, but I found it wasn't as defined as the EL34's.
Both of us prefered the EL34's in the end.

This - all of it. same experiences i have with 6550's.

Me, too. I would describle the high end as more brittle sounding.

 

[joepete77]

i have 0wned many 70s and 80s marshall jmps and jcms which many came st0ck with 6550 in usa, in uk they still had el34. I always preferred the el34 as I prefer the extra crunch and they are easier t break up. The 6550 have m0re headr00m but in a n0n master amp this isnt always a g00d thing , especially in my case. If y0ur amp is m0re 0f a m0dern higher gain preamp type , then u may like the 6550 . I like t0 swith my jmps 0ver t0 el34.

 

[racerevlon]

I think it's all about frequencies. When switching my VH4 from EL34s to 6550s I found the same as most--I noticed slightly more perceived gain, but really just different frequencies emphasized. Better low-mids and not as edgy high-mids. More sizzle. Love 'em. (In the VH4--not sure how they'd do in other amps...)

 

[charveldan]

I've got the best of both worlds, my 6550 amp is like an EL-34 amp on steroids, but some can sound on the cold side, depends on the tubes, plus i have my tech bias my amps a "little hot."

The EL-34 JMP is at Dave Friedman's shop getting the Kitchen Sink mod, the mid-range on that amp just turns to butter the more you turn it up.

 

[MississippiMetal]

Great amp porn Dan! Although if I ever get ahold of a JMP for myself, the first thing I'm doing before any tone mods or whatever, is replacing that built-in mains cord with an IEC receptacle.

 

[glip22]

Try a quad of Gold Lion KT77. Great tubes!! More power than a 34. Musical breakup. More soundstage and dimension. More complex mids. Killer low and high end. Perfect compression. Not glassy at all. My new favorite new production tubes.

 

[charveldan]

Great amp porn Dan! Although if I ever get ahold of a JMP for myself, the first thing I'm doing before any tone mods or whatever, is replacing that built-in mains cord with an IEC receptacle.

Thanks dude they are kinda a pain, love your avatar, i grew up with the original SNL cast, did you know Belushi actually cut Buch Henry on the face with a Samari on live TV, Buck was lucky it was just a nick.

 

[steve_k]

I usually see how quick I can get 6550's replace with 34's and keep a stock of bias resistors for that purpose. They are a little stiff for me - except in one amp, and that is my 20th Anniversary Shiva. They melt like butter in that amp. Marshall amps though, I like my 34's.

Steve

 

[glip22]

I usually see how quick I can get 6550's replace with 34's and keep a stock of bias resistors for that purpose. They are a little stiff for me - except in one amp, and that is my 20th Anniversary Shiva. They melt like butter in that amp. Marshall amps though, I like my 34's.

Steve

You havn't put those KT77's in yet.