These both sound great, the EL34's seem, in the recording, to be brighter and edgier where the KT66 seemed warmer and rounder, I can see how a two guitarist band would sound huge by having one guitarist load his Marshall with KT66's while the other uses EL34's! THX!
I agree. The KT66's have a bit less "clank" compared to the EL34's. I can think of situations where the EL34's WOULD be preferable (like doing AC~DC covers, for instance), but overall I think I prefer the KT66's. They're just a little sweeter.
I reckon they're temperature dependent! There's a definite shift depending on whether I'm playing it in the cold or in summer. But, it could be pickups as well. They change a bit depending on the temperature.
@Explexador Yeah, you should see it here in Australia. The nominal 240VAC can be anywhere between 220VAC-265VAC at any time of the day! I've got a 240V breakout board for when I test 240V devices/modules (because I test everything sent from ebay, you can't trust 'em) and I can hook up a meter for the input.
I’ve had kt66 tubes in a few amps and I’ve always really liked the soft, round mids. I actually like el34s but there’s just something about the big sound of the kt66 that I like. I find 6L6s can be a little too bright in some amps and the kt66 is a great way to fix it.
KT66 has beautiful mids Johan, it sounds more full! I love your channel, I have a Vox AC30, you're the only one who makes a AC30 sounds like it should sounds!
The KT66s sounded a bit more "high fi", with a lot of note definition in the mids. For full-tilt rock, I still liked the EL34s, with the additional saturation and overtone.
Great vid. I have for a long time switched out el34s to kt77 tubes. The plate voltages do not need to change. They are a direct replacement. In most amps I find the kt77s to be rounder and warmer while still being aggressive sounding. Basically just fills out the bottom better than an el34. There have been a couple of amps where I did not like the kt77s over the el34 tubes. I guess it depends on the circuit 2 that come to mind are a friends JCM 800 and all 3 of my old Carvin x100b amps. ( original, not reissue) but my old Deizel Einstein was night n day better with kt77s. After using them I tried el34s again and absolutely hated it then. Every amp is different but in many the kt77s are almost a blend of the good points of the el34 and good points of the kt66. Try it for yourself.
KT 66 have a huge sound that carries over a long distance and its a big sound indeed ! Johan does the most interesting test of anyone and Kudos to ya for what you do Johan !
I had a Marshall Vintage Modern 100 watt head years ago with KT66s and it was my favorite amp ever. I'm sold on buying a 50 eat combo now with the KT66s in it. Such good tone.
My take: The KT66s sound a little softer and slightly more organic and musical. The EL34s sounded brighter with a sort of hard edge to them. You make everything you play sound good. Thanks for these videos!
El34 for me. I love that grit and that cut. When you're a neck and bridge pickup switcher like me, it's great to hear the difference and EL34 does a great job of that.
Wow! what a difference here! No doubt the difference in impedance between EL34 and KT66 on the same transformer contributes to tonal change. I like both, but those KT66's blew me away - crunchy or clean, they had a really wonderful sound! Cheers, Johan! ^_^
Johan's videos are refreshing to my ears, especially the Marshall sounds because he is one of the few who never seem to have crossover spikes in the output tubes. Well done my friend 👍
Nice comparison vid Johan. The KT66 in its large form is a killer valve and shapes the amps tone so well. My own JTM45 MKII gold script logo / cream back plate from early '66 is powered by two 60's era brown based KT66's (1 GEC, 1 Pinnacle) and 52 years on, it still sounds the business. So for me KT66 wins this one ... but I am a little biased (valve humour) 😆
Two winners here - both sound awsome! The KT66 seem to sound a little bit warmer and rounder. The EL34 a bit more agressive and harsh (but not in a bad way). Great compare, Mr. Segeborn :-)
That was great Johan! Man, I would of really liked to hear those KT’s cranked up a little more. They are fantastic tubes in a 1987 circuit. Tell you what, you send me a plane ticket and I’ll stop by and put a bias resistor in there so we can do just THAT!!! Tremendous video my friend ;-)
I’ve tried the nos mullard xf2’s el34’s and nos amperex xf3’s el34’s and always liked those nos gec kt66’s WAY better. Another great tube for Marshall’s that I’ve liked better than el34’s is nos sylvania 6ca7’s. Killer tubes. Thanks for the awesome vids
I have been building and listening to vacuum tube amplifier for a lot of years and this is the first time I can definitively say I hear a difference. I assume nothing had been changed but the bias to set it at something like 50mA for the KT66 and 60mA for the EL34. Of course this changes the load impedance that the output tubes want and the EL34 "wants" a little lower impedance in the transformer, just to split hairs", so this means that the EL34 is operating into a OPT with a impedance a small amount higher than the KT66. This is not a problem and is not going to harm anything. I have a feeling that has something to do with it, not necessarily the "tube" but the circuit the tube is working into. That is just my thoughts on it, for what it might be worth. Very nice demonstration. Thank you.
Waiving a hand here from Canada,, I use the Gold Lions KT66 tubes,,,, from The Route 66 “Dr Z” right to few of my vintage YBA “ PTP “Bassmaster” from Traynor,,,,,with those they sound fantastic,,,,,thanks for all your good videos and keep up the good work👍
Please do the same but with KT88’s that would be great. Jimmy page put 88’s in his plexi’s in 1973 and that TSRTS tone is one of the best i’ve ever heard. Cheers, thanks.
Thanks Johan! They both have their advantages, but the KT's are definitely fuller sounding. Years ago I decided I must just not like Marshalls, but I later figured out that it was the EL34's I didn't like. With KT's, Marshalls are basically perfect!
I'm hearing a bit more of a warmer fuller tone with the KT66s. The EL34s are a bit more biting and direct. Possibly a bit more breakup with the EL34s as well?
The primary impedance for the 1987x I think is around 3.2 or 3.6k, the JTM45 that ran KT66 's was either 6.6 or 8k, is my understanding. So you would be running the KT66's at a reduced load which I think results less clean/grittier output (maybe?). Anyhow I find manufactures choice of primary output impedance fascinating (high nerd factor). For instance the Trainwreck Express runs 2 EL34's @ 6.6k while Marshall runs them at 3.6k. Most manufacturers run a pair of EL84's at 8k while Matchless runs them at 4k. At some point I may understand this enough to design something of my own. Great work BTW, most people probably don't realize the effort it takes to make comparison videos that have any meaningful content which you Sir do on a regular basis!
matching the transformer to the value used on the tube charts for a particular map, produces the maxim power.head room/clairity. mis-matching the 'correct' impedance high or low reduces output power.. higher impedance compresses and reduces the output nicely, in a very useable form, the tone gets slightly fuller/warmer, and overall it sounds very much like the same except for lower volume. excellent way to rewduce volume of tube amps and retain athe tone ( plug 16 ohm cabinet into 8 ohm jack) Running the plate plate primary much LOWER than designed also limits the power but adds a more raw distortion. I assume that's why 8K primarty used in some 50watt marshall combos-(like 2266)- the designer is reducing the power , in part, with transformer primary- -probably because combo amps only have two (25watt) speakers, lots of amps are intentionall4 'mismatched' to start with, so modifying the impedanced on those amps could be moving it closer, or farther, from normal.- so if the amp is already running at half its drawing-board impedance, reducing it further would be excessive. these vidoes are great, but this comparison isn't good- running one pair excessivle 'hot' becuase you didn't have enough bias range, . throws off all- the comparrisons ..Plus, someone persuauded Johann to belive running the amp at 'middle power' would reduce the stress on the under-biased KT66's. and might seem logical but it's wrong. On guitar amps the MAXIMUM plate currentr is right aoerun half-volume.- so this actually put MORE stress on the tube and amp... Nice videao as usual, lots of work, but really shoudldn't go by this one. harmonic design usa
To me it takes out the harshness some people detest in Marshalls. It makes them smoother and IMHO much better sounding and versatile, since you get rid of the usually crappy and tinny clean tones. Had I known that, I wouldn't have sold my JCM, I hated the harshness.
More separation and width, & articulation in the KT66 the EL34 seem to cut through and have a solid punch. Live I'd use the EL34, studio KT66 Tough call.
Hello Johan! I recently built an amplifier for the scheme Marshall JTM45 on KT66. Test run and first time worked on the Soviet 6p3s-e ("analogue" EL34). When I put the KT66, the sound changed greatly. The sound became bass, less readable or something. In the end, I liked the lamp 6p3s-e. But now when you change the lamps you can significantly change the nature of overload.
I believe the EL34s sounded brighter because of the correct impedance matching. The KT66s were getting loaded down by the 4 k primary. They want to see 8K. Just set the impedance selector to half of what the speaker load is to match. Correct me if I'm wrong.
Hmm, I think I like the KT66's just a little bit more. Really depends on what/how you're playing, though. I could see the KT66's being good for higher gain because they seem to retain a lot of clarity whereas the EL34's are a bit more distorted. Idk I'm not an expert or anything, just my opinion based on what I heard. Cheers!
Johan the KT66s sounded like most other valves that are being run into half their required primary impedance, and with a DC bias current of 150%. They just sound strained. The EL34 sound good and would sound great cranked a little more, as they do. Cheers
I like the tightness of the EL34. The KT88 can sound too loose sometimes, but sounds great crunchy. Maybe I'm just so used to EL34s. It's the sound in my head.
Fascinating! I much prefer the KTs. I’ve always wondered about this as my amp’s vintage is exactly at that time they switched from 6550s to EL34s, about 1969, purportedly because 34s were “easier to source”. That’s manufacturing code for cheaper. This is a lot to think about…
Don't fool yourselves, we all know the magic tone comes from the Crocs :p Kidding aside, both sound pretty good, although I'm more of a fan of the crunchy EL34's in this one. I wonder if Johan or anyone has experience with running 5881's in an amp like this. I'm tempted to try those out in my Marshall Haze 40 (slightly modded to JCM800 specs), since I love them in my JCM900 clone and am curious as to how those would sound in a more classic Marshall. Big thanks to Johan for keeping up the high quality content, these videos are like a library of how so many great Marshalls through the years sound and compare to each other.
nice tones! the EL34 sounds higher headroom and more dynamic... a bit more hifi. the KT66’s sound more compressed. i’m curious how KT77’s would stack up here?
Impedance match is very important! 2xEL34 will usualy have 3.4k ohm but 2xKT66 ask for 8k ohm, so that's double. When playing through KT66 you should connect 16 ohm cabinet into 8 ohm socket in amp, or 8 ohm cabinet into 4 ohm socket. What a pitty not to hear 2xKT66 at correct matching.
Paul kossoff would often be using the kt66 equipped pa heads, he seemed to mix it up sometimes with orange. You got some great tones there. The other thing is with a variac or 'brown box' device it could lower the mains voltage and hence bring the voltage down a bit and as an experiment hear what it sounds like with a closer bias voltage. But its not advice, im sure you know what you are doing inside an amp. Lol
Interesting! Sort of what I expected to hear. The EL34's have a stronger midrange with less lows and chimey highs, but with a more vocal quality. The KT66's have a wider sound with lower lows and higher highs. In this case with a 4x12 closed-back cab, I think I prefer the EL34's. I have a 1984 4104 that I had modified to accept KT77's. That change alone produced more low end, but also some annoying ice-picky highs. Further mods included removal of the bright cap and experimentation with different speakers eventually settling on the Limited Edition X35 Anniversary Celestion speakers. This combination makes the open-back combo sound fairly close to a closed-back cab characteristic. I think it has a lot to do with the heavier Pulsonic cone of those particular speakers. Anyway, I my case the KT77's sounded more to my liking.
I agree with Curtis Chavez in his comment below. The EL34s are edgier, so it's up to the individual player as to what they want in their Marshall. I prefer the KT66 sound as with the vintage JTM45s so have changed to these in my SV20H.
I read an article about Jimi Hendrix using K.T.66-s alot...even in the studio..he blew alot of Celestions..Any speaker stretches after awhile.. Angus Young told me that in the late 80-s..HE was very right!!!;
Any chance of a kt77 vs e34l vs 6ca7 in a marshall clean and cranked. I'm lacking a little bit of bass and find the midrange a little much on my clean channel of a el34 amp and wondered if kt77 might just be the right choice.
I thought they both sounded great, but I preferred the round, warm tones of the KT66's. Thanks for another constructive video. I've been wondering whether my 1987x could be tubed with the 66's.
I'm more accustomed to the EL34 sound than the KT66, but both sound good in their own right. I prefer the tone of the EL34 a bit more. Have a great week bro and God Bless!
In this particular amp, the KT66s sound significantly better to me. They are fuller and rounder without muddiness. But, a more interesting comparison would be the original JTM45 circuit with KT66s, and then with EL34s with both transformers
the hotter BIAS really comes through with the KT's. I still think it would be noticeable with the BIAS modifications made on the board to reign in the voltages.
These both sound great, the EL34's seem, in the recording, to be brighter and edgier where the KT66 seemed warmer and rounder, I can see how a two guitarist band would sound huge by having one guitarist load his Marshall with KT66's while the other uses EL34's! THX!
i had pretty much the same thought. thanks for confirming my bias :D
I agree. The KT66's have a bit less "clank" compared to the EL34's. I can think of situations where the EL34's WOULD be preferable (like doing AC~DC covers, for instance), but overall I think I prefer the KT66's. They're just a little sweeter.
@@OgamiItto70 "clank" thats exactly how I describe the Marshall high end! Lol
@@mikieknight6607 Great minds and all that, doubtless.
The KT66 is such a beautiful power tube.
Damn, those KT66 tubes really add some depth to the sound. I love EL34s but these really round out the tone in the right spots. Outstanding.
My Marshall sounds different every day depending on what color of panties I wear, strange.
It's a Marshall !
I reckon they're temperature dependent! There's a definite shift depending on whether I'm playing it in the cold or in summer. But, it could be pickups as well. They change a bit depending on the temperature.
@Explexador Yeah, you should see it here in Australia. The nominal 240VAC can be anywhere between 220VAC-265VAC at any time of the day!
I've got a 240V breakout board for when I test 240V devices/modules (because I test everything sent from ebay, you can't trust 'em) and I can hook up a meter for the input.
I bet it sounds well odd when you ware your wifes :-)
Dad?
I hear a 400-500hz push with kt66, and slightly less treble. I love it!
I’ve had kt66 tubes in a few amps and I’ve always really liked the soft, round mids. I actually like el34s but there’s just something about the big sound of the kt66 that I like. I find 6L6s can be a little too bright in some amps and the kt66 is a great way to fix it.
KT66 has beautiful mids Johan, it sounds more full!
I love your channel, I have a Vox AC30, you're the only one who makes a AC30 sounds like it should sounds!
The KT66s sounded a bit more "high fi", with a lot of note definition in the mids. For full-tilt rock, I still liked the EL34s, with the additional saturation and overtone.
They both sound great, but I especially liked the KT-66 cleans. I just love that pushed to the ragged edge clean sound!
Great vid. I have for a long time switched out el34s to kt77 tubes. The plate voltages do not need to change. They are a direct replacement. In most amps I find the kt77s to be rounder and warmer while still being aggressive sounding. Basically just fills out the bottom better than an el34. There have been a couple of amps where I did not like the kt77s over the el34 tubes. I guess it depends on the circuit 2 that come to mind are a friends JCM 800 and all 3 of my old Carvin x100b amps. ( original, not reissue) but my old Deizel Einstein was night n day better with kt77s. After using them I tried el34s again and absolutely hated it then. Every amp is different but in many the kt77s are almost a blend of the good points of the el34 and good points of the kt66. Try it for yourself.
KT 66 have a huge sound that carries over a long distance and its a big sound indeed !
Johan does the most interesting test of anyone and Kudos to ya for what you do Johan !
Thank you Mr. Segeborn for posting your unending quest for tone, the guitar world thanks you!
I had a Marshall Vintage Modern 100 watt head years ago with KT66s and it was my favorite amp ever. I'm sold on buying a 50 eat combo now with the KT66s in it. Such good tone.
My take: The KT66s sound a little softer and slightly more organic and musical. The EL34s sounded brighter with a sort of hard edge to them. You make everything you play sound good. Thanks for these videos!
El34 for me. I love that grit and that cut. When you're a neck and bridge pickup switcher like me, it's great to hear the difference and EL34 does a great job of that.
Wow! what a difference here! No doubt the difference in impedance between EL34 and KT66 on the same transformer contributes to tonal change. I like both, but those KT66's blew me away - crunchy or clean, they had a really wonderful sound! Cheers, Johan! ^_^
I don’t think it’s a transformer mismatch. The KTs were always regarded as a lower-distortion tube.
Johan's videos are refreshing to my ears, especially the Marshall sounds because he is one of the few who never seem to have crossover spikes in the output tubes. Well done my friend 👍
Nice comparison vid Johan. The KT66 in its large form is a killer valve and shapes the amps tone so well. My own JTM45 MKII gold script logo / cream back plate from early '66 is powered by two 60's era brown based KT66's (1 GEC, 1 Pinnacle) and 52 years on, it still sounds the business. So for me KT66 wins this one ... but I am a little biased (valve humour) 😆
I've got KT66 tubes in my Astoria. Absolutely love that amp! :)
Great Variety of Riffs! Both sound great and very useable! Thanks for sharing brother!
Both sounded good. But I preferred the 34.
@@inTheBandTree me too in my amp i use el34b love the sound
Me3
Didja now?
66's all the way! Much Fuller, warmer sounding.
+ Cooler looking!
EL34s all the way for me, especially noticed the difference when you played the octaves.
your content is o helpful notonly for guitar player, but for tech and guitar engineering, thank you for your passion and commitment to the tone
Two winners here - both sound awsome! The KT66 seem to sound a little bit warmer and rounder. The EL34 a bit more agressive and harsh (but not in a bad way). Great compare, Mr. Segeborn :-)
KT 66 plus those bottles look great in your amp
That was great Johan! Man, I would of really liked to hear those KT’s cranked up a little more. They are fantastic tubes in a 1987 circuit. Tell you what, you send me a plane ticket and I’ll stop by and put a bias resistor in there so we can do just THAT!!!
Tremendous video my friend ;-)
Great video! I would love to see the KT 66 comparison in the JTM45 Reissue vs stock tubes 👍
I love listening to Johan play
I’ve tried the nos mullard xf2’s el34’s and nos amperex xf3’s el34’s and always liked those nos gec kt66’s WAY better. Another great tube for Marshall’s that I’ve liked better than el34’s is nos sylvania 6ca7’s. Killer tubes. Thanks for the awesome vids
I have been building and listening to vacuum tube amplifier for a lot of years and this is the first time I can definitively say I hear a difference. I assume nothing had been changed but the bias to set it at something like 50mA for the KT66 and 60mA for the EL34. Of course this changes the load impedance that the output tubes want and the EL34 "wants" a little lower impedance in the transformer, just to split hairs", so this means that the EL34 is operating into a OPT with a impedance a small amount higher than the KT66. This is not a problem and is not going to harm anything. I have a feeling that has something to do with it, not necessarily the "tube" but the circuit the tube is working into. That is just my thoughts on it, for what it might be worth. Very nice demonstration. Thank you.
I respect your opinion a lot, but is 60 mA for an EL-34 not a little bit on the high side? I think they are normally run on 40 - 45 mA in guitar amps.
Johan, that riff at 3:55 is heaven! Love that tone with the EL34's!
Zach C if you ever listened to Jimi Hendrix, you would know the roots :-)
I’ve KT77 in my 50 W plexi clone and I just love it. Fuller and less compression. More open.
Waiving a hand here from Canada,, I use the Gold Lions KT66 tubes,,,, from The Route 66 “Dr Z” right to few of my vintage YBA “ PTP “Bassmaster” from Traynor,,,,,with those they sound fantastic,,,,,thanks for all your good videos and keep up the good work👍
Please do the same but with KT88’s that would be great. Jimmy page put 88’s in his plexi’s in 1973 and that TSRTS tone is one of the best i’ve ever heard. Cheers, thanks.
Yes
KT88s demand about twice as much from your transformers though.
Page's amps were modded for 6550 or KT88, whichever. I think for KT88 you'd need different transformers, etc.
Yeah. I think you might be able to use the same transformer on some 100w amps if you only use two kt88s.
@Thomas Jefferson We are talking about KT88s read the comments again
Thanks Johan! They both have their advantages, but the KT's are definitely fuller sounding. Years ago I decided I must just not like Marshalls, but I later figured out that it was the EL34's I didn't like. With KT's, Marshalls are basically perfect!
Definite difference, hard to put into words. Almost sounds like your changing from a open to closed back speaker cab on my end. Cool experiment Johan
I'm hearing a bit more of a warmer fuller tone with the KT66s. The EL34s are a bit more biting and direct. Possibly a bit more breakup with the EL34s as well?
Have always used el34 and 6550 tubes since 1972, both work well and sound great. Your friend in tone, Norman Mozley Mr Analog
The primary impedance for the 1987x I think is around 3.2 or 3.6k, the JTM45 that ran KT66 's was either 6.6 or 8k, is my understanding. So you would be running the KT66's at a reduced load which I think results less clean/grittier output (maybe?). Anyhow I find manufactures choice of primary output impedance fascinating (high nerd factor). For instance the Trainwreck Express runs 2 EL34's @ 6.6k while Marshall runs them at 3.6k. Most manufacturers run a pair of EL84's at 8k while Matchless runs them at 4k. At some point I may understand this enough to design something of my own. Great work BTW, most people probably don't realize the effort it takes to make comparison videos that have any meaningful content which you Sir do on a regular basis!
matching the transformer to the value used on the tube charts for a particular map, produces the maxim power.head room/clairity. mis-matching the 'correct' impedance high or low reduces output power.. higher impedance compresses and reduces the output nicely, in a very useable form, the tone gets slightly fuller/warmer, and overall it sounds very much like the same except for lower volume. excellent way to rewduce volume of tube amps and retain athe tone ( plug 16 ohm cabinet into 8 ohm jack) Running the plate plate primary much LOWER than designed also limits the power but adds a more raw distortion. I assume that's why 8K primarty used in some 50watt marshall combos-(like 2266)- the designer is reducing the power , in part, with transformer primary- -probably because combo amps only have two (25watt) speakers,
lots of amps are intentionall4 'mismatched' to start with, so modifying the impedanced on those amps could be moving it closer, or farther, from normal.- so if the amp is already running at half its drawing-board impedance, reducing it further would be excessive.
these vidoes are great, but this comparison isn't good- running one pair excessivle 'hot' becuase you didn't have enough bias range, . throws off all- the comparrisons ..Plus, someone persuauded Johann to belive running the amp at 'middle power' would reduce the stress on the under-biased KT66's. and might seem logical but it's wrong. On guitar amps the MAXIMUM plate currentr is right aoerun half-volume.- so this actually put MORE stress on the tube and amp... Nice videao as usual, lots of work, but really shoudldn't go by this one.
harmonic design usa
The primary impedance have to fit the plate voltage. You can´t just take the impedance out of the equation alone.
I definitely prefer the KT66 tubes. Great post as always 👍
To me it takes out the harshness some people detest in Marshalls. It makes them smoother and IMHO much better sounding and versatile, since you get rid of the usually crappy and tinny clean tones. Had I known that, I wouldn't have sold my JCM, I hated the harshness.
More separation and width, & articulation in the KT66 the EL34 seem to cut through and have a solid punch. Live I'd use the EL34, studio KT66 Tough call.
Indeed wow. Kt 66-s all the way for me Johan!!!
I love how you do this stuff so I don't have to blow my stuff up trying it out... Rock on mate, your a legend.
EL 34 all the way for me! Cheers Johan! \m/
Simply best channel on RUclips. You reached my dream guitar tone with KT66.
Hello Johan!
I recently built an amplifier for the scheme Marshall JTM45 on KT66.
Test run and first time worked on the Soviet 6p3s-e ("analogue" EL34).
When I put the KT66, the sound changed greatly. The sound became bass, less readable or something. In the end, I liked the lamp 6p3s-e. But now when you change the lamps you can significantly change the nature of overload.
This was a good video. Simple and to the point. Thanks.
I believe the EL34s sounded brighter because of the correct impedance matching. The KT66s were getting loaded down by the 4 k primary. They want to see 8K. Just set the impedance selector to half of what the speaker load is to match. Correct me if I'm wrong.
It is an interesting subject. I have build amps with both tubes, but never calculated the load impedance side by side.
Hmm, I think I like the KT66's just a little bit more. Really depends on what/how you're playing, though. I could see the KT66's being good for higher gain because they seem to retain a lot of clarity whereas the EL34's are a bit more distorted. Idk I'm not an expert or anything, just my opinion based on what I heard. Cheers!
Most informative video. Learn something new all the time.
for me a Marshall between 6 and 7 brings everything i like a bout the el34 to life,, i haven't found anything that beets that,
YES Johan! I've wanted to know this for years! KT66's for me
In a live setting, it would be cool to A/B them. The KT66 for rythmn and EL34 for leads.
Johan the KT66s sounded like most other valves that are being run into half their required primary impedance, and with a DC bias current of 150%. They just sound strained.
The EL34 sound good and would sound great cranked a little more, as they do. Cheers
I can't help my self to love the EL34 Sound witch I'm so familiar with😍
Thank you, I was just looking for this exact tube comparison yesterday ^^
I like the tightness of the EL34. The KT88 can sound too loose sometimes, but sounds great crunchy. Maybe I'm just so used to EL34s. It's the sound in my head.
Fascinating! I much prefer the KTs. I’ve always wondered about this as my amp’s vintage is exactly at that time they switched from 6550s to EL34s, about 1969, purportedly because 34s were “easier to source”. That’s manufacturing code for cheaper. This is a lot to think about…
Both sound good. but for all the bias and other changes, I don't think its a large enough difference. I like the edgier EL34s. Good playing!
I swear every time the KT66 were on I could hear your amp saying “help me” but I must be hearing things 😵
Don't fool yourselves, we all know the magic tone comes from the Crocs :p
Kidding aside, both sound pretty good, although I'm more of a fan of the crunchy EL34's in this one.
I wonder if Johan or anyone has experience with running 5881's in an amp like this. I'm tempted to try those out in my Marshall Haze 40 (slightly modded to JCM800 specs), since I love them in my JCM900 clone and am curious as to how those would sound in a more classic Marshall.
Big thanks to Johan for keeping up the high quality content, these videos are like a library of how so many great Marshalls through the years sound and compare to each other.
I rather like the sparse broken up chimeyness of the KT66's. Really enjoyed this comparison. Thanks for your hard work in setting up these demos.
nice tones! the EL34 sounds higher headroom and more dynamic... a bit more hifi. the KT66’s sound more compressed. i’m curious how KT77’s would stack up here?
What sounds really great here is Mr. Tone Tendrils himself....JOHAN !!!
Nice video/comparison.
Great!
Now I know why people say EL34 are more mid range...
Nonetheless, whatever tube is in, it sounds great!
Cheers,
Wow...like it ....rocking good music
Impedance match is very important!
2xEL34 will usualy have 3.4k ohm but 2xKT66 ask for 8k ohm, so that's double.
When playing through KT66 you should connect 16 ohm cabinet into 8 ohm socket in amp, or 8 ohm cabinet into 4 ohm socket.
What a pitty not to hear 2xKT66 at correct matching.
Ivan Horvat actually the primary impedance of KT66 is 6.6k
LPCustom3 it's very similar, but less than 4k isn't good, according to datasheet
Exactly what I was aiming for!
Paul kossoff would often be using the kt66 equipped pa heads, he seemed to mix it up sometimes with orange. You got some great tones there. The other thing is with a variac or 'brown box' device it could lower the mains voltage and hence bring the voltage down a bit and as an experiment hear what it sounds like with a closer bias voltage. But its not advice, im sure you know what you are doing inside an amp. Lol
Interesting! Sort of what I expected to hear. The EL34's have a stronger midrange with less lows and chimey highs, but with a more vocal quality. The KT66's have a wider sound with lower lows and higher highs. In this case with a 4x12 closed-back cab, I think I prefer the EL34's. I have a 1984 4104 that I had modified to accept KT77's. That change alone produced more low end, but also some annoying ice-picky highs. Further mods included removal of the bright cap and experimentation with different speakers eventually settling on the Limited Edition X35 Anniversary Celestion speakers. This combination makes the open-back combo sound fairly close to a closed-back cab characteristic. I think it has a lot to do with the heavier Pulsonic cone of those particular speakers. Anyway, I my case the KT77's sounded more to my liking.
Great video Johan 🎉
I agree with Curtis Chavez in his comment below. The EL34s are edgier, so it's up to the individual player as to what they want in their Marshall. I prefer the KT66 sound as with the vintage JTM45s so have changed to these in my SV20H.
Love the Alice Cooper riff at 2:51. I play that song all the time. It's my favorite Coop tune.
There you go , you got yourself ACDC Sound 🔥
Would love to hear a KT 88 demo but I think using those tubes require a mod .
Wonderful playing and a great demo !!! KT66 for me 😁👍
I like both, I don't think I would want to go through a bias to run the the kt66's, nice comparison.
I read an article about Jimi Hendrix using K.T.66-s alot...even in the studio..he blew alot of Celestions..Any speaker stretches after awhile.. Angus Young told me that in the late 80-s..HE was very right!!!;
I prefer the high end and higher mid of the EL34s. That and they sound louder and more clear. My taste. Thanks for the comparison!
Thanks for this vid Johan !!
KT66 sounded amazing, less piercing and it seems like they had a little more headroom to offer, even if they were biased hot
Johan, I love that you are a discerning tone guy. The KT66's are my choice, less harsh than the EL34's.
I agree with Zach C on the riff at 3:55. Hendrix heaven. Similar to the wind sighs Mary. I think that was the tune.
What tune is that around 4:00?very nice Johan. This comparison is a toss up both sound nice.
I have a Budda that has KT66s and it sounds similar. The EL34s have more bite and the KT66 is more mellow. I prefer the EL34. Maybe do a EL34 vs KT77?
Any chance of a kt77 vs e34l vs 6ca7 in a marshall clean and cranked. I'm lacking a little bit of bass and find the midrange a little much on my clean channel of a el34 amp and wondered if kt77 might just be the right choice.
KT66's sound warmer/bigger! The EL34's are a bit harsh and have a bright topend.. KT66's have been my fave large output valves for decades!
Someday, in another life we'll all have access to a super lead AND a 45/100!!!
I thought they both sounded great, but I preferred the round, warm tones of the KT66's. Thanks for another constructive video. I've been wondering whether my 1987x could be tubed with the 66's.
EL34s are the clear winner for me here!
It’s like Keith Richards vs Malcom young.
Both are awesome.
Great job!
That's what I thought too haha, kt66s were almost more of a tweed sound
Still like the sound of the EL34s best!
May the 4s be with you!
I hear the EL34's just a tad more chimey and the KT66 a bit fuller (more mids) but this is all avery subtle difference... Cheers
Loves the EL34's tone, very warm yet bright. Could please say which mics did you use? Sounds great! Thanks a lot
"Today I'm gonna play my Morshall"
KT66 sound fuller and warmer, less brittle and fizzy to my ears. Also EL34s seem to have less headroom, right?
I'm more accustomed to the EL34 sound than the KT66, but both sound good in their own right. I prefer the tone of the EL34 a bit more. Have a great week bro and God Bless!
You need a blend knob. I like both sounds.
In this particular amp, the KT66s sound significantly better to me. They are fuller and rounder without muddiness.
But, a more interesting comparison would be the original JTM45 circuit with KT66s, and then with EL34s with both transformers
the hotter BIAS really comes through with the KT's. I still think it would be noticeable with the BIAS modifications made on the board to reign in the voltages.