MESA BADLANDER EL34 VS 6L6 TUBE COMPARISON

Подписаться 874 тыс.

Просмотров 95 тыс.

50% 1

Trying out the Mesa Badlands again, this time comparing Power amp tubes and also boosting with a Maxon ST9 Pro.
Signal path -
Solar Guitar
Maxon ST9 Pro+
Mesa Badlander
Direct To Audio interface
------------------------------------------------------------------------
I'm Ola Englund and welcome to my channel. A channel dedicated to guitar related gear with a focus on metal. I also play in the metal bands The Haunted & Feared and run a guitar company www.solar-guit...
My Pages
► My Music - www.olaenglund....
► Merch - www.olaenglunds...
► Website - www.olaenglund.com
► Twitch - / olaenglundofficial
► Facebook - www.olaenglund....
► Instagram - / olaenglund
► Feared - www.fearedband.com
► Want to interact more with me? Join My Discord Channel and Become a RU-vid Member for VoiceChat and more. Click the Join button above. Link To Discord - olaenglund.com...
►List of things I use to make my video(affiliated links)
www.amazon.com...
Edited by OrionVP

Опубликовано:

16 окт 2024

Ссылка:

Скачать:

Готовим ссылку...

Добавить в:

Мой плейлист

Посмотреть позже

Комментарии : 537

@OlaEnglund 3 года назад

FRIDAY! Have a great weekend everyone!

@titus7770 3 года назад

Will you do impulse responses on these?

@maxbeau5062 3 года назад

Ola do you wish it was a full size head? Why’d they make it smaller

@rostamostmann9657 3 года назад

El34 sounds metalierrrrrr.

@Protonaut 3 года назад

I will, because I'll definitely order that yellow AB. Would love to see one in seafoam, the roasted maple + seafoam combo would look killer

@sword7534 3 года назад

have a great weekend ola

@ChannelForty2 3 года назад

I can't get over how aggressive this amp is. I'm really into it. I'm currently on a big Engl kick but Mesa Boogie is just something really special.

@Satchafunkilus 11 месяцев назад

I had the Engl, the Kraken, Laney, Marshall, Peavey. When I tried the Badlander, I was sold! btw I use to own all those amps...but Badlander is currently THE best Rectifier currently, get 1 you won't regret

@ladyjulia4038 3 года назад

Guitars are awesome and keep rocking those shameless plugs. Can't say I could hear a difference in the tubes. That said it might just be a feel thing and how it responds to pick attack and dynamics. I don't know I'm a bass player.

@ilikepotatoes1345 3 года назад

The thumbnail makes the amp head look like it's the size of a minivan.

@JulienMarzanoGuitarist 3 года назад

Or Ola is vert short today

@adrianamorphous 3 года назад

It is

@FEAROWNAGE 3 года назад

Find me a minivan that short.

@mozeby1975 3 года назад

Got my Maxon St9 pro+ a month ago. It really pushed my Mesa Stiletto into new territory. Was using a TS10 which still sounds great and used to have an OD808 which also was good but the ST9 really turns it into a more saturated metal tone. Love it.

@DiscoD777 3 года назад

The amp seems to have plenty of gain without a boost, fine demo sir

@jublaim 3 года назад

Ola, this was a great comparison! The differences you/we hear is to a great deal caused by this: 6L6 got less transconductance or "gain" compared to EL34. It changes how the poweramp, including the Phase Inverter, responds. The PI is hit with the same signal level whether you use 6L6 or EL34, but 6L6 will yield less output power. This also decrease the Negative FeedBack signal that is fed back from the output transformer to the PI, since it's proportional to output power. Less NFB will make for slightly loose bass and not as "tight" sound. The Presence circuit will also change it's behaviour a bit.

@ericv7720 2 года назад

From my experience, 6l6 is tighter, at least when you get the volume up to the point of the power tubes breaking up.

@YOutsider Год назад

the net frequency output of 6L6 is well-know to produce more bass and el34 more midrange; hence tighter sounding bottom end with el34s.

@BBGuitars 3 года назад

Glenn Fricker wants to fight you now!

@pigdick2233 3 года назад

Isn’t he that fat guy who hates everyone and everything?

@tommywd40 3 года назад

@@pigdick2233 pretty much

@impheris 3 года назад

@@pigdick2233 of course not -.- he is a sweet guy, he really loves bassists

@anthonyvabene6697 3 года назад

Fighting Glenn Fricker? LOL, that wouldn't be a fight, it'd be a beating. But why on earth would we want to abuse the mentally handicapped?

@MidnightXII 3 года назад

@@pigdick2233 now he’s the much-less-fat-than-he-used-to-be guy who hates everything

@DodInTheSky 3 года назад

These Solars are absolutely beautiful! I wish I'd waited a little bit longer to buy a guitar...

@flowryan5829 3 года назад

You need to buy another one. Sorry to say that, dude.

@sellsn01 3 года назад

Your the last guy on earth that plans to have 1 guitar lol. Don’t worry the sickness will set in soon enough.

@Rooster7six 3 года назад

You always always need a new guitar! Gotta cover a lot of tunings man!

@nailed2theX 2 года назад

Amazing video as usual! I have to admit, I like how it sounds a lot better with the 6L6 tubes. More bass and low end growl, thicker mids, and I always use a boost with my recto and this amp to my ears(based off various videos) sounds even better than a Recto. It’s almost like a mix between a Recto and a Mark series.

@DavePowell666 3 года назад

I feel like the amp generally sounded better in this video than in the previous video. I wasn't really blown away by the tone in the other video, but now...I'm feeling it bro!

@visualdarkness 3 года назад

Mic placement has a huge effect.

@NZ1one1 Месяц назад

Man alive, that overdrive boosting the amp sounds unbelievable!!! 😮❤😮❤

@mikeus77 3 года назад

I love that EL34 mid frequency "growl". The 6l6 sound flatter.

@rustynales6610 3 года назад

Throatier 🤘

@EdwardKayeplus 3 года назад

The EL34 is clipping earlier, which makes makes it sound more saturated and a little sludgier at those gain levels. They are a little more scooped too. I feel like the 6L6s are tighter, so now I'm confused why they went with EL34.

@guitarocd9984 3 года назад

I'm surprised I liked the 6L6s. El34s sounded s a little harsher. I was surprised I would hear that big of a difference. All around a great sounding amp.

$@Cossfrack$

@Cossfrack 3 года назад

Both sound great. On my travels I found a JCM900 with 6L6s. I tried it out. Imagine a gritty Marshall but with some extra kick to the nuts.

@kalebk0422 3 года назад

Absolutely love this amp! Feel free to keep making videos with it. And as far as plugged straight in(no boost) I liked the el34s the most!

@SpartanLaserCanon 5 месяцев назад

You need very good ears to actually hear the difference L0L, but I prefer the EL34s too.

@sirgerbilmacintosh9101 3 года назад

I've always preferred eL34s for high gain tones and 6L6s more for cleans. This video reinforces that preference.

@Marc-nc3vj 3 года назад

I like the 6l6's for their low end, but I like the el34's for their cuting mids.

@dgarrr2 3 года назад

Interesting! I like the high end and more scooped sound of the 6L6, but much prefer the tighter low end and directness of the EL34. I wonder if it's easier to pull back the mids and boost the highs in an EL34 setup, or easier to just tame the low end on the 6L6? Hmmm

@rockerboy84 3 года назад

Hey Ola, I have a couple questions regarding the Badlander: 1- How do complex chords ring through? Does it has great note separation? 2- How would you compare this one to the Soldano SLO30? I know you mentioned the Soldano sounded like a Rectifier without the need of a boost for chuggah powa, it seems you mentioned the same about the Badlander? Thank you, man. You rock.

@CoolestMcGuy 3 года назад

If you ask me, the SLO doesnt sound like a recto, the spirit is there, but the amps arent identical

@michaelmitchell5909 3 года назад

Get a deziel dmoll brother...unless you can get a mesa for a good used price...play both befor making a choice

@Rooster7six 3 года назад

@@CoolestMcGuy Have you played one or are you going by RU-vid vids?

@rockerboy84 3 года назад

@@CoolestMcGuy I know what you mean. The Recto does not appear to have the richness in harmonic content you hear in a Soldano.

@rockerboy84 3 года назад

@@michaelmitchell5909 not really into my considerations. From Diezel the ones I'm interested in is either the VH4 or the VH2, but not a priority right now. The most oustanding tone (for my tastes of course) I've heard so far is Soldano's. Followed close by the Friedman JJ. In this case I wanted to know how close is this Badlander to the SLO30 in matters of voicing.

@jnbovee 3 года назад

6l6's sounded better to me. More open sounding

@impheris 3 года назад

agree...

@MuffDiver71 3 года назад

Agree

@CarcPazu 3 года назад

Agree

@pressman1788 3 года назад

Agree

@DanishAra 3 года назад

agree

@fjk1138 3 года назад

I hear little to no difference, though I have played with both sets of tubes (6L6's on 3 different Mesas, EL-34s on a Marshall JVM) and to me it was more about the string attack and how the tone "felt" while playing. The 6L6s were more open and clearer, and the EL-34s were more compressed and longer sustaining. Neither was really better than the other, it's just a matter of taste. Though I would believe if you went with 6L6's and used the Tube Screamer (or similar boost) it should arguably make it more compressed like EL-34s. Regardless, I enjoy watching Ola play and explain things. Thank you OIa.

@snapascrew 3 года назад

5:54 6L6 6:17 el34

@matforsbon 3 года назад

How can you not fall in love with these guitars

@LoreAccurateHusky 3 года назад

I really listened closely with my best set of headphones and I could hear a very subtle difference. There wasn't a change in the EQ in any way but there the 6l6's were a bit less compressed than the el34's. Those el34's sounded like they were being pushed slightly harder than the 6l6's, getting more compressed and maybe a little more saturation but don't quote me on that. I kind of liked the subtle flavor of the 6l6's as I prefer a little bit more of that higher-headroom openness going on there but again it's still a very subtle increase in headroom.

@VshnsAudio 3 года назад

I seriously appreciate the variable controls in these.

@kemalardaayar 3 года назад

I fall in love with that flame maple one. Also 6l6 feels more like my kinda tone.

@holdenmcgroin5003 3 года назад

Will it chug: Les paul with P90s Fender esquire Fender acoustasonic Guys i know p90s can chug, i just wanna see what it would sound like and how long would it take Same thing with the fender esquire

@JanXD 3 года назад

P90s will chug and sound good

@JoeBaermann 3 года назад

All of those will chug with the right eq and gain

@StratoBlaster 3 года назад

Toni Iommi's most well known songs were originally played with P90 pickups FYI

@DonnieFreymoyer 3 года назад

Fender acoustasonic amps do not chug its an acoustic amp. If you play an electric through an acoustic amp , no volume. I tried it. If you meant the guitar not amp, it might if you can cover the hole to stop the resonance feedback from the amp to the pickup.

@holdenmcgroin5003 3 года назад

@@DonnieFreymoyer the guitar, not amp

@Talmie 3 года назад

And this is the Solar ACTKSJ 45 HIQHD

@andybungert 3 года назад

I had a kick ass Friday. Got an A1.6 Vinter first run for hella cheap. Guy just wasn't into it. Glad to FINALLY experience a Solar Guitar!!!! 🤘🤘🤘🤘

@MrRyeDaddy 3 года назад

Thanks for the video, would love to see this compared with a Mark V! Have a great weekend yourself!

@raindropcleaners 3 года назад

When you turn on boost that squeel is the beginning of Manson Dope Show.

@killemall1983 3 года назад

Sounded like the sound before "if you'd like to make a call"

@MisterGunsPlano 3 года назад

Ola, I'm not sure if you read these, but I am shopping to buy a guitar in your solar website on my phone. It is pretty difficult to understand which guitar does what in a long list. I love your guitars, I love your channel, but it is a lot of work trying to buy on that site. One businessman to another, and fan offering respectful suggestions, it really needs to be simpler to understand.

@Fitardvark 3 года назад

That AB1.6FRCAR is gonna be mine as soon as its available in Australia!! Its gorgeous

@resington 3 года назад

Glen Fricker was right. Great amp and guitars of course.

@mr.esabsurditiesatrocities1805 3 года назад

Damn. Sounds great without the boost. Mesa did a great job here.

@tman6495 2 года назад

Through Bose headphones... EL34's are missing a frequency that the 6L6's are producing (somewhere in the mid range)...so the 6L6 sound a bit fuller...but, in a live band setting most likely will not be noticed. Now being 100 vs 50 watt.... I do know there maybe a drop in volume from 6L6'S ON THE 50.

@countzero5150 3 года назад

Maybe the sound is more noticeable in person but if I listen with my eyes closed I can't tell when you switched. The deciding factor for me on 6l6 or el34 in my amp is simply what's most readily available, if one's on backorder I'll get the other.

@anthonyvolpe5206 3 года назад

I keep saying this on OLA videos...he gets the BEST CRUNCH sounds I have ever heard...and the SOLAR guitars are just incredible. I wish I could play...😁👍

@seansalo5117 3 года назад

Maybe if you KEEP practising, you will DEVELOP the skills you TALK about.

3 года назад

Hi Ola! can you share your IRs please? your tones are always amazing!

@brianboeckman1666 3 года назад

6L6's sound great in there

@CharlySahona 3 года назад

Badlander vs other versions of the Rectifier would be great ! :-) Great video thanks Ola

@SpectreSoundStudios 3 года назад

No null test? :P

@Gradam88 3 года назад

I was looking for comments with someone referring to the video you recently made. Pretty stoked to find it from the man himself lol

@slowmography1747 3 года назад

Ola is the personified null test. His ears are impeccable and undeceivable. His word is to be trusted. ;)

@OlaEnglund 3 года назад

In Sweden we call it knull test... google it! ❤️

@SpectreSoundStudios 3 года назад

@@OlaEnglund wow, there’s a mental image I didn’t need!

@swanation45 3 года назад

@@OlaEnglund You mean knvll? ;)

@MichaelJordan-yg3nc 3 года назад

Happy Friday Ola! very cool comparison wanted to see the over drive engaged with the El34s happy Friday brother

@chrisleguen2813 3 года назад

I actually think the 6L6's sound smoother and more aggressive imo

@aksh2 3 года назад

Fantastic reviews as always, the Badlander sounds tasty. Really appreciate the multi-faceted approach you take with your videos, different mics, cabs, IRs, etc. Appreciate the effort. Also, I'm amazed just how good the Solar guitar line is becoming day-by-day. Seriously considering ordering one before the holidays. I have question!!! What's with the names though? Why are they names inspired by serial numbers? Apologies if you've answered this before.

@MrMattsac232 3 года назад

The cabinet being “here in the spirit” made me lol. Great video.

@jasoncrump1886 3 года назад

Thanks Ola really diggin that amp man. Like to hear ya on a new song with that thing.

@poundpunch 3 года назад

I just got a Peavey 6505+ and now im addicted to gear tests

@genericuser8348 3 года назад

I don’t really like the boost, it has a weird static-y high end to it and the amp already has enough juice

@hemiram413 3 года назад

OLA I HAVE A LEGIT QUESTION im looking to buy a solar guitar i have not seen a cleaning system yet for maple or raw wood style necks if you read closely they all say do not use on this kind of neck

@elbromas8032 3 года назад

Both sound excellent! Can’t go wrong with the whole amp ;)

@ryanshook8284 3 года назад

I need this exact cab sim!

@cpeplinski 3 года назад

Glad you did this video. Really excited about this amp and think it's time to upgrade from my old Tremoverb. How is the noise floor on Crush and a ton of gain?

@cheesewhisk 3 года назад

The Ferrari of guitars right there. Have a kick ass day too my lovely man

@pointerish 3 года назад

That headstock angle looks wild!

@sebastianlennartsson4158 3 года назад

Vad är det som gör att gainen sjunker ungefär 1 sekund efter du börjat spela?

@albertobettoldi8240 3 года назад

Wow, awesome riff around 3:18.

@sleepisoptional 3 года назад

el34s sound more “marshally”, 6L6 has this “crushed steel wool” sound in the top end i love. cool amp. having the 2 modes is probably great for double tracking. another way to get a slightly different sound for stereo

@digijams 3 года назад

Man that red Solar looks like a Ibanez RG565 and that is a good thing.

@JosephCee 3 года назад

I was pretty dead set on the new Engl Fireball 25 but now I really want this amp, the 50 watt version, I really do NOT need the full 100 watts, 50 watts is already too much power, I know because I had the EVH 50 for a brief time and I returned it because I was scared of how loud it was LOL. So the fact that I can play this amp in 20 watts is PERFECT.

@jordiumethar4963 3 года назад

Ola, question for you. What is your favorite distortion pedal and which one would you buy if you didn't have a lot of money to spend?

@nicholasqquiroz 3 года назад

I like it mo betta when you use microphones rather than an IR. You're still a stud though.

@lydfar2392 3 года назад

It's just a Rectifier with less options... What is new? Any change in the circuit??

@kirkembrey6503 3 года назад

Love that Candy Apple Red does it come left handed :D

@Locoandchooch 3 года назад

Listen to this with studio monitors, you can hear everything. Great amp.

@AngbandMetal 3 года назад

EL34 is a little tighter, really good video

@Guithulhu 3 года назад

Great vid, Ola. Think it sounded better without the pedal. Also, on the Boogie I used for many years, I'd use 6L6 with one EL34 (first tube after the pre section). That way you had the best of both worlds.

@diezelvh4133 2 года назад

So just use 6ca7 tubes then.

@mitchelaramenko5250 3 года назад

El34's with the boost for the win! Sounds like old school Suffocation but with better guitar production ;)

@michaelblaszkiewicz4942 3 года назад

I'm looking to buy a versatile new amp to replace my Orange TH30 and was wondering what your opinion is regarding EVH 5150iii Stealth vs Mesa Badlander vs Orange Rockerverb? Thanks, Mike

@nigel7880 3 года назад

Will it Van Halen? Sylvania 6CA7 in variac mode with bias set to EL-34...

@Vandalis88 3 года назад

Love your vids man thx :D

@M4Y0_ 3 года назад

Please make a video with the normal 808 or Maxon OD-9, that would be awesome. Thanks for the videos! :)

@massttrshrdrharmonicminor2002 3 года назад

Hope your ok Ola, great tones as always

@firmans12 3 года назад

Sounds pretty good with the IR. The videos before sounds nasal ish. I think its the mic Ola use

@colelewis9940 3 года назад

Maybe it's just me, Ola's mic'd sounds have sounded like asshole since like 2018 or so. He tries too hard to make a "room" sound which just sounds like a muffled farting mess. Would sound better with a single SM57. His using dark mics imo gives a god awful sound.

@Miah_ 3 года назад

Was the artist who requested you to use the Maxon, Rob from Cannibal Corpse, by chance?

@davexhayter 3 года назад

That was my guess.

@DanielVanvors 3 года назад

There is a video of him talking about this maxon pedal, but The drive is all the way down, mid and tone are at one or 2 o’clock and the levels all the way up. Plus he brags about the low boost on the pedal so I don’t think it’s him. But if you’re on the fence about buying this pedal? FUCKING DO IT!

@ThyFinalPain 3 года назад

@@DanielVanvors Rob changed his settings in the meantime - see other clip of Ola

@DanielVanvors 3 года назад

@@ThyFinalPain then it’s definitely rob. It’s the exact same setting on Olas cannibal corpse tone video

@ThyFinalPain 3 года назад

@@DanielVanvors Yes, i think so.

@djxxeess 3 года назад

Thanks for doing this Ola! Sounds fkn amazing. I'm sold. Mission accomplished.

@Xyrium 3 года назад

NIce new guitars, I really like the humbucker and single, single coil config.

@samuelnicolay6460 3 года назад

Are the names of the Solar models chosen by randomly typing stuff on the keyboard?

@iLLuzion1st 3 года назад

Acronyms for the finish. CAD = candy apple red

@Chugs4Serotonin 3 года назад

Nah, that's ibanez lol

@jorismak 3 года назад

Is your master volume turned so low (I see it at like one quarter or a bit less in the video).. that way the output-tubes aren't affecting the sound of course.

@chrisplatt7308 3 года назад

I wonder if that was Rob Barrett who requested that pedal 🤔👀

@christopherward4671 3 года назад

Almost guaranteed IMO

@Mizziri 3 года назад

I like the 6l6s more, el34s have a little more high end but it doesn't come out in a good way. Get your distortion from the preamp stage, NOT from the power tubes.

@MichaelDespairs 2 года назад

Thought it sounded better with the 6L6 but was hoping EL34 sounded better - I love the way EL34's saturate at high volume and 6L6's don't sound great cranked to me.

@dodmusic9255 3 года назад

6L6 makes it sound more Recto IMO. Reminds me of a Tremoverb. But the additional Cab Clone is a huge plus.

@jrtme 3 года назад

What 6L6s? Would love to here this amp without a TS. Would love to hear it without high output pickups.

@OlaEnglund 3 года назад

Pickups are medium output alnico pickups. Whole first part is without overdrive. Tube brand is Mesa Boogie

@Kadoogan83 3 года назад

Guitar unveiling, amp review, and tube comparison, all in one short compact video. Ola the multi taskerer.

@thatguitarist9340 3 года назад

For me? 6L6's are the badass play-at-home crank em for some fucking insane bottom end, but EL34's just have this totally fucking badass cut through anything sound. They are tight!

@jeffsoares9667 Год назад

I Fucking love the way it sounded with the Maxon Super Tube ST9 Pro plus engaged! I own 3 of those pedals! Totally understand why Cannibal Corpse use them, so Fucking crushing!! The Badlander does sound good on its own but the pedal enhances it! Great video like always, Ola!

@Mr.Goldbar 25 дней назад

I'm usually way more into amps with EL34s, but on a Rectifier I feel like 6L6 fits better

@mrmadame28 3 года назад

I dont understand, if you are plugged directly in your interface, it mean you took the signal at the effect loop, so it never pass to any power tube...

@mrmadame28 3 года назад

@TeapotMullah i look it up, ive read the user manual, and you can,t go trough the power section with the fx loop or the xlr

@mrmadame28 3 года назад

@TeapotMullah yeah, i miss the reactive load thing, I agree it may is probably passing through the power section after all.

@christopher.k.guitar 3 года назад

I‘m torn between the power tubes... I don‘t know why, but comparing the two videos the EL34 variant sounded more like the classic Recto to me - which is strange. Maybe it’s the youtube compression thing that fools me 🤷🏻‍♂️ Anyways, because of that I‘d go with the stock EL34 tubes.

@michaelmitchell5909 3 года назад

New solar guitars are awesome Ola...

@dissidentt 3 года назад

Hi ola, my peavey 6505+ needs a full tube change NOW! they are almost dead Do you have any suggestion about it?

@Bearjams 3 года назад

Here in Spirit LOL \m/ Hey Ola just got my A1.6 FRFOB and its awesome, I love it. Thank you for making badass guitars!!!!

@andrew-qg8il 3 года назад

Hey, Ola, I need some professional advice! I'm waiting for an Orange Rockerverb 50 MKIII to arrive, but I'm not sure whether to match it with a 212 or 412 cabinet. I'm playing at home and I don't know if having two extra speakers would benefit me at all. The cabs are closed-back Orange cabs. Any thoughts? Thanks

@aarondr594 3 года назад

The orange 212 sound very good and I think you don't need the extra two speakers.

@123lowp 3 года назад

412 for the best sounds. Good luck transporting a 412 cab though.

@SAPlaysMetal 3 года назад

0:58 dude that Gold Solar though 🤘🤘🧡

@CyberneticArgumentCreator 3 года назад

The 6L6 has this slower bass transient response where it woofs on every palm mute, that's the major difference when playing with high gain. I think it has to do with the low end's phase? Not sure, but that's what's happening. I love it because it makes for really dark palm muting sounds but I don't play fast technical metal stuff where tight low end helps articulate the playing.

@van4ope 3 года назад

It's interesting to know which tubes did you use. If both el34's and 6l6's were MESA tubes. Cause recently I discovered that JJ ( everyone uses) are designed for amps that have BIAS ajustment and (according to official info) have 0.9A. Mesa amps usually do't have BIAS ajustment and that's why mesa power tubes have about 2.0A, so they are pushed much more compearing to JJ. specially for mesa ams. Just thought this could be the issue why 6L6's seemed to have less gain.

@blakemansfield2356 3 года назад

Mesa tubes are relabeled JJs

@van4ope 3 года назад

@@blakemansfield2356 I wrote higher the numbers, you can take both tubes yourself and compare. (I'm not talking about listening, I'm talking about measuring) I did. They are very different.

@123lowp 3 года назад

Mesa amps do not allow you to adjust bias. Mesa amps do not adjust their bias to your tubes. Mesa branded tubes are tubes that Mesa has selected because those tubes will match what the power section of their amps are expecting. Therefore, you don't have to pay an amp tech to adjust the bias when replacing tubes. Power tubes do not affect the gain level of the preamp. Mesa tubes were rebranded Electro-Harmonix in the past when I purchased some of their amps 10+ years ago. I don't know if they are rebranding JJs these days. SOURCE = My friend builds and repairs amps and taught me how to bias them properly.