#KT66

[originalcatbeard]

真空管KT66 40W＋40W ステレオ・プッシュプルアンプの製作　自分で作る真空管アンプ

[aitkenaudio]

#marshall #jtm45 #iconic #tone #british #vintage #gec #kt66 lovely example that came back to life after sorting the bias circuit and replacing the gaffa taped in power lead https://www.instagram.com/p/Cj3GxrCM9F0/?igshid=NGJjMDIxMWI=

[axeandyoushallreceive]

We love amps here, that is undeniable. That said, we are super stoked with these particular Silktone amps. They have something for damn near everyone. Super well designed and just killer sounding all around!!!!! Posted @withregram • @silktoneamps Got a full batch of Silktone Amps headed to our friends @axeandyoushallreceive soon! #guitaramps #knowyourtone #toneheaven #electricguitar #silktone #silktoneamps #gearybusey #guitargear #guitar #tonefordays #KT66 #guitaramplifier #handwired #gottone (at Axe and You Shall Receive Inc.) https://www.instagram.com/p/Cddxutcpmpv/?igshid=NGJjMDIxMWI=

[bigzaps]

Talking to a buddy recently inspired me to put together this sampling of my Radio Craftsmen amplifiers. From the left is the RC-2, RC-400, RC-450, RC-500, RC-500A and RC-550, ranging in dates from 1949 for the RC-2 to 1955 for the RC-550. This represents nearly all of the Chicago era Radio Craftsmen amplifiers, missing is a variation of the RC-500 that fits between the 500 and 500A. The company also made tuners, a preamp, chrome plated TV chassis and wall radios. After the mid 50s, a California company bought the name and slapped it on inspired amplifiers. I have been collecting these for over 20 years and have really enjoyed restoring them, notice the extremely rare RC-450 is 100% original. #radiocraftsmen #radiocraftsmenc400 #radiocraftsmen500a #tubeamplifier #tubeamp #kt66 #6v6 https://www.instagram.com/p/CK2NizgDui0/?igshid=18l65uaj7bshj

[rjs-amps]

Monday testing on the RJS 45/100 Hendrix amp for @joegambleguitar @bisonwarofficial #rjsamplification #ampporn #rjsamps #100watts #merrenaudio #kt66 #coolshit #tubeamp #guitarporn #plexi #sozocapacitors #superamplifier #mkIII (at Longmont, Colorado)

[rotor25]

Marantz 8B + préampli Console

[nelly275]

089, Electra, 009

一转眼2017年来了，自己在发烧路上走了差不多十年。周遭早已物是人非，唯在眷念的，是自己当初对音乐那一份火热。走上社会五年多了，也终于用上了自己曾梦寐以求的系统。很多时候身边的人会觉得我很傻，对这些虚幻的事物如此痴迷。这些乐趣的甜蜜与苦，也只有自己知道。Tumblr是个好地方，能分享，能收获。在这个浮躁的社会里，寻一片清潭实属不易……

这个Post是关于静电耳机系统的。2016年里耳机界出现了两个天价怪物，一是森海的HE1系统，一是海菲曼的SHANGRI-LA系统。我要分享的不是这两个高价值怪物，而是远比他们低调的STAX。STAX是典型的工匠厂商，只为制造静电耳机系统而存在。从1960年的SR1开始，到这篇Post的主角SR-009，无一不是长年的成果累积。各种���坛里关于009的介绍并不少，这不是一个耳机系统的开箱贴，因为我的009从迎进家门到现在已经两岁半了。我今天要做的，是聊聊我对这个在我人生低谷时给予温馨陪伴的老朋友的一些理解。如何去驱动？如何去调整？如何去评价？请听我娓娓道来。

我的系统是Burmester 089搭配Eddie Current的ELECTRA来驱动STAX SR-009。ELECTRA是一台罕见的静电全搭桥胆机放大器，国内用家数量应该不少。我使用的放大管是两套两两配对的Mullard CV181(ECC32)，功率管是四支配对的GEC棕座双环KT66。这台放大器最初的设计功率管是EL34/6L6，放大管使用6SN7，可惜EC家原配的天梭EL34和6SN7实在是不尽人意，原厂自带管子的目的也就在于煲机，要想深挖这台机器的潜力，必须得换更好的管子。不建议像我这样用近似管来强行直代，虽然也能用，长久下来肯定会缩短机器尤其是��压器的寿命。朋友有借过我一套配对的飞利浦铁座SY0，可惜有一条管子有接触不良的问题，在不到5分钟的时间内把我机子左一的保护电阻烧了。尽管冒烟了，但在那短短的几分钟内我还是感受到了这套传说中最好声EL34的风韵，声音密度与素质真的无与伦比。我这套KT66和CV181的搭配声音不是走素质的，KT66这种肥厚的管型在灯丝充分加热后散发出来的韵味确实挺让人难以忘怀，所谓胆越老越靓声，浓郁的胆味往往伴随着灵动的乐感，在乐章的每个角落留下芳香，这话身边很多人都验证过了，同样的，也征服了我。     在使用CV181之前我是用的RCA古董40年代NOS管，这些6SN7管子的灵敏度非常高，麦克风效应很明显，换张碟，或者是听快板章不由自主的抖腿产生的震动都能反馈到后端耳机处。这套管子对泛音的表现不尽人意，器乐该有的尾音收得太快，最直观的感受就是有些索然无味。不过这套管子有个好处，声压不需要打开太多也能出很多细节，不像我现在用的CV181，要打到近9点钟位置方可出该有的素质。CV181的优点在于声场和低频，同时它又是一套声底很厚实的管子，对乐器该有音色染上属于它自己的特点。听小提琴协奏曲高潮乐章时的一排排音浪铺面而来，仿若身在其中感受演奏者们忘我的灵感释放……

009这耳机的特点相信很多人都很了解，三频通透、声场自然、没啥低频表现什么的。其实在第三方静电放大器的驱动下，静电耳机的低频并不弱，尤其是低频的下潜非常深，在反复比较同样的曲目下，009在三方驱动器下对于低音提琴、巴松管乃至定音鼓的表现是要好于Audeze的LCD-3的。在我看来低频不应该是以量多为宜，优秀的低频应当是透明得有层次有下潜，越丰富的层次带出来越深的震撼感。2016年12月28日星海音乐厅那场德国广播交响乐团的新年音乐会我听得非常过瘾，不是因为曲目太俗，而是在熟悉的乐章中，那滚滚而来的低频让整个星海音乐厅的地面都在震动，手臂上都开始起鸡皮了。这种反应，应该是人体对低频最自然的表现吧，只可惜这种低频也就在现场演绎中方能感受，再怎么天价的HIFI系统也找不回这种感觉。扯远了，总而言之，就是009的低频在良好的驱动下，下潜很深，量感不算充裕；Audeze LCD-3的低频则是量感非常充裕，但下潜个人感觉明显不足。在我看来009这种低频表现恰到好处，既不会喧宾夺主，又不会影响整体框架的搭建。

009对前端的表现非常敏感，本���是属于高频比较明亮瞬态响应非常���速的耳机，因而在前端的选择上建议选择素质出众三频均衡的音源。身边朋友有用Esoteric上代旗舰分体音源搭配素质型耳放，主听SACD，将009最极致素质的表现挖掘出来的；也有用ARC CD8/EAR ACUTE这种胆合并CD机搭配素质型耳放将009推出音乐表现非常全能的(其实这里我说的素质型耳放就是BHSE)。如果是控制力不够的放大器，往往很多乐器同时演奏时009的高分离度会让整个画面非常混乱；控制力非常强力的放大器则是在构建正确声场的同时让乐器有条不紊地发声，这也是为啥很多静电玩家强烈要求没听过第三方静电放大器的朋友去试试效果。STAX原配的007TII听听咏叹还可以接受，但如果是听康塔塔，人声为主，伴奏为大量乐器的，或者某些编制不算小的作品，感觉肯定很不好。官方原配的两个耳放我认为听独奏、室内乐二重奏三四五重奏、或者奏鸣曲这类型的音乐是完全没问题的，偏交响一类篇章大的，有条件的话还是选择第三方放大器吧。

可能有朋友已经看出来了，我的听感都是基于古典类的作品写出来的。是的，我是一个古典音乐爱好者，现在这个社会太浮躁，能静下心来做事的人太少了。像古典作品这类比较难入门的音乐还就真的心无旁念才能听出一些门道和其独特的���道，当然当今社会有这个时间精力的朋友应该少之又少了吧。我对提琴类作品非常喜爱，这些年中收藏了很多已经绝版的CD碟，首版也有，再版居多，首版/产地/演绎这又是一道很深层次的门槛，有条件的话就各渠道多方位了解外加使劲砸钱投资吧。当下是一个手机扫二维码都能交易个人全套信息的时代，CD这种音乐介质保养起来确实很不方便，对于现今房屋每平方米单价极高的现状，这种存储介质还特别占地方。但我知道每一位玩过CD碟的朋友应该都很喜欢这种音乐文化，说是听音乐的仪式感也毫不为过。很多欧美厂家说了好些年的CD消退浪潮不也没实现么，反倒是黑胶、开盘又开始复兴了。谁知道十年后又会是什么情况呢？

虽然没啥必要，但我承认我常听的碟子有一大半是单声道CD碟。大师们的神演基本上都在单声道时代……我目前最喜欢的小提琴家是梅纽因，他在30年代的录音演绎真的出神入化，黄金十年后因个人信仰动摇导致的技术下滑(风格转变)录的很多作品为人诟病，但不管怎么说，我第一次听勃小协就是他���富特文格勒于1949年灌录的作品，第一次永远是最甜蜜美好的。现在的我觉得最大的财富不是这套听音器材，而是这些伴了我好些年的CD碟，烧器材烧得再高，终点还是会回到音乐本质上来。

全文完，写于不那么冷的广州。

Repost at 2022-3-14 HKT 11:45

[racingtoaredlight]

Marshall Amps

This is Slayer’s backdrop for some recent tour of theirs.

If you’ve followed rock music at all, the “wall of Marshalls” is so iconic, it’s hard to separate the subject of the imagery from the backdrop of Marshall speakers.  Jimmy Page, Slash, Zakk Wylde, Eric Clapton...to name a few...but the man who made Marshalls the “greatest amps of all time” is none other than you know who...

So what is it with Marshalls?  Why did they become the “greatest amps of all time” yet seemingly don’t have a place in today’s guitar world?

***

What defines Marshall amps?

They have “Marshall” written on them.

Kidding aside, you will never hear about Marshall amps being called “versatile.”  “Clean” is something they do out of necessity, not design.  They are stupidly heavy.  They are a pain in the ass to maintain.  They only sound good at volumes that would peel the enamel off your teeth...and that’s just the 50w models, let alone the big boys.

Marshall amps really do one thing well...overdrive.  If you’re in a band that plays loud, plays dirty and plays aggressive, then Marshalls are likely right in your wheelhouse.  Bonus points if someone else is carrying your gear.

Any level of dirt...from bluesy hair on the note to full out metal grind...a Marshall is right at home.  When you overdrive the tubes in a Marshall and they start to produce those beautiful overtones and harmonics, it’s truly a sound of beauty that prickles the hair on the back of your neck.

***

Historical Context Part 1

To define Marshall amps, we need to start with their history.

Remember how when I used to actually write, I’d talk about putting things in historical context?  Lets go back to the early 60′s.  There is ONE amp company doing business on both sides of the Atlantic, Fender.  And, despite being primitive and archaic, those early Tweed Fender amps are still today some of the best sounding amps money can buy, which is even more impressive considering that a 10 year old who can use a soldering iron could build one.

But in America, it’s easy to source parts for an American company’s amp like Fender.  It’s right there in the country, stupid.  But for a company...shit, that’s not even accurate given they weren’t a company yet...for a Brit like Jim Marshall, you had to get creative.

Marshalls, at their very, foundational core, are almost a direct plagiarism of the Fender Bassman amp.  I mean, it’s exactly the same amplifier except for one key difference...the tubes.  The Atlantic Ocean thing mentioned earlier is a big deal...the 6v6 and 6L6 power tubes that Leo Fender used, nothing more than run of the mill military-spec electrical tubes, weren’t available.  Tubes might not be the lifeblood of an amp (the circuit is), but different tubes have a hugely variable presence in practical settings.

Given that most tube amps are powered by tubes that came from either the US, UK or Russian military industrial complexes...and there not being the internet or a secondary market for any of this shit...Marshall used, first, KT66 Russian tubes, and later British EL34 (big bottles) and EL84 (little bottles), depending on use.

As Marshall’s blew up (and it happened quickly), and musicians started playing bigger and bigger halls, Marshall took that Bassman ripoff and housed it in larger cabinets allowing him to add more tubes, and therefore, more power.  It was the perfect storm...

***

Historical Context Part II...the important stuff

So I linked to a bunch of pics above...famous dudes standing in front of walls of Marshalls.  The one I really want to hit on is the Eric Clapton one...

I just mentioned this a couple paragraphs above, but it bears repeating...there was no secondary market for things like tubes, caps, speakers, etc.  That pic of Clapton?  In each of those cabinets housing four speakers, maybe one was fully operational with half of another adding a bunch of fizz.  During Cream’s final show at Royal Albert Hall, he had only one speaker installed in the entire cabinet...the rest were just empty.

Now, that’s not to say there wasn’t any sonic benefit from having cabinets project sound waves with four speakers.  Rather, if one went down, at least you could still play.

Which leads us to the important stuff...

Primitive PA systems were not only garbage to begin with, but they were typically operated by burnouts who didn’t have the first clue of how to properly EQ a room.  This was true as late as the mid 80′s.  As shitty as those PA systems were though, guess what?  That’s still how Cream’s sound got shot through Royal Albert Hall.

Given the choice though, guitarists would rather have a slew of speakers doing the work rather than mic’ing up smaller amps.  Even with this option though, there’s a long history of...behind those walls of Marshall speaker cabs...there being a single half stack with just one speaker being mic’d.

Here’s a dirty little secret...Eddie Van Halen has not just endorsed multiple amps from multiple companies, but been heavily involved in the design of a lot of those as well.  BUT, when you hear him in the studio or live, you’re not hearing any of those amps...you’re hearing this.

Despite all the noise and propaganda regarding Van Halen’s wizardry with guitar and amp parts, the sound he’s most famous for and has relied on his entire career is produced by a relatively stock Marshall 1959SLP, known as the Super Lead.  The “Brown Tone” he’s famous for isn’t due to anything special in the amp itself, rather using something called the Variax to run the 100w amp at 90w, thereby making it warmer and more efficient (Marshall’s imported to the US still made to run at 110 volts despite most American outlets being 120 volts...the Variax reduced the electrical load to the amp, while also being an accidental signal buffer, allowing him to use time-based effects like flangers and delays, where running them into the front of a Marshall would cancel out those signals).

Jesus Christ that was a long aside...there was a point here though.

***

What was that point?

When PA systems and quality mic’s and sound guys became the norm, the necessity for stacks of Marshalls really started to go to shit.  Even before the internet boom, the jokes about wannabes hauling Marshall half stacks to tiny bars with no audience were already essentially canon.

I said this above...unless you are a touring artist in a hard rock band with logistical support and no front of house...Marshalls are completely impractical.  We’re not even going to touch on declines in quality (new Marshalls built on PCB have more in common with your phone than a 1987x, even if you buy a “reissue” of a 1987x), questionable marketing and oversaturating their own market...the fact of the matter is extremely simple.  Big iron is obsolete, no matter who makes it.

Marshall themselves know this, and released the “studio” line...which might as well be called the “shit we better make smaller stuff because our sales are getting FUCKED” line.  If you’ve ever had to pack a car full of gear yourself, it takes one gig before you’re looking for smaller, lighter amps.  Those 100w Marshalls?  They sound AMAZING cranked.

But unless you play them cranked, they sound like shit.  Think about it like driving a Ferrari at 25mph all the time...

For regular working musicians like myself, a great sounding tube combo can be found under 50 lbs.  Or I could ditch all that and go with a modeler, go straight into the PA and never need an amp again (PREDICTION...you will not see amplifiers on stage outside of Nashville and niche acts in 10 years).  That’s for a working musician.

For a touring musician, you can save tens of thousands of dollars per year by not having to hire logistical staff.  You might have scoffed at my prediction above...but these days, the majority of guitar sounds you hear are made digitally by a session guitarist sitting either at home or in the control room of a studio.  That 1987x is a digital patch rather than two trips to the car and ringing ears.

Point being...amps are already obsolete.  And if your amp weighs more than 50 lbs. and has more power than say 40w, it’s remarkably obsolete, no matter how cool it is.

***

Competition

I don’t have to tell you that Marshalls’ legacy was formed in the harder forms of rock.  Take one look at those monsters and you can tell they roar.  “Roar” is an interesting concept though...

Marshalls were made before hard rock really existed.  Guitarists almost ubiquitously came from a “clean” learning point, and even what we consider small amounts of dirt like this (and during the instrumental part of Ramblin’ Man) back then were FULL-THROATED.

Personally, that’s my ideal of the Marshall sound.  That Tweedy breakup that puts a shaggy head of hair on each note.  But to just about 90% of the music-enjoying public, this is the sound that immediately comes to mind when you think of Marshalls.

Definitely more dirty than Duane Allman’s version no doubt, but if you really listen to the guitar, the edge is more due to phrasing and Slash’s ballsy attitude than the guitar tone itself.  It’s still something I’d describe as more crunchy than full on distorted.

Which brings us to the clones.  Now, what better product to copy than a style that’s been obsolete for like two decades now!

We talked about Van Halen’s supposedly modded (but really quite stock) Marshall above...well, here comes one of his amp tech buddies Michael Soldano bringing a hot-rodded Marshall to the masses.  Then Bogner follows right behind.

Slash’s tone might not be that distorted, but plenty of metal guys absolutely were, and Marshall JCM’s were their weapon of choice.  But the time the calendar turned to 1990 though, Mesa Boogie’s rectifiers were already kings of the metal scene.  Almost as much as the Telecaster dominates country music, the Mesa Boogie Rectifiers own metal.

What was the common denominator in the competition?  MORE, sure.  More dirt, more quality, blah blah blah.  The biggest reason was Marshall, the company.  Unlike Fender, Marshall never got bought by bigger companies.  While that might keep them more “genuine” you have to realize that this guy was making amps in a tiny drum shop still when he was making stuff for Hendrix and Pete Townshend.

***

While Fender’s soul got twisted in a series of corporate takeovers, what it also eventually received was outside guidance from people with business AND music knowledge.  Fender was always forward thinking, from the day Leo Fender started the company.  Jim Marshall didn’t have that same type of vision.  The idea of a Fender amp being built on PCB is something Leo Fender would have embraced.  But to Marshall, it’s killing the amp’s soul.  Fenders never were BIG IRON...i.e. huge transformers fed by big bottle tubes...they never got into the size game.

To begin with, Marshalls were a stolen design.  That might sound harsh, but it’s not being unfair either.  They were never known for quality, rather known for quirks and unreliability.  They weren’t even that unique of a sound...you can get a very similar sound from a Fender Tweed cranked...you just cant take a Tweed to a huge hall and project the sound.

We can do that today.  Easily.  Like an $80 mic and a mic cable easy.  And now you have a true, pretty much genuine Marshall roar in a 30 lb. package.

Back in the day you couldn’t demand flawless point-to-point wiring, proper voltage and ohm specs, and wide-sweeping EQ bands.  Soldano and Mesa Boogie offered these as stock parts of their offerings at the same price points.  If you were a lead guy, Soldano was your choice...if you were a metal guy, it was Mesa...and in the two niches of the guitar world Marshall absolutely dominated, they were now second class citizens.

Or maybe even worse...new poor.

***

“Marshall” is a descriptor these days.  It’s describing the sound of a tube amp with a good-sized transformer being fed by British tubes, typically EL34′s.

If you want a “Marshall,” Marshall is probably the fourth or fifth company I’d recommend.  There’s a lot of debate about this, but I do not believe amps built on PCB are worth more than $1k...shit, that’s generous because I would not personally buy an amplifier using PCB.

This is the power amp section for a new Marshall JCM.

For all you IT guys out there, you probably know that PCB ain’t exactly the most receptive thing to changes in temperature.  Hey!  I got a great idea!  Lets put power and preamp tubes, that heat the fuck up, straight on some cheap ass PCB with janky copper wiring and automated solders!

Literally the only people who will tell you PCB is fine are people who build amps for a living.  Now, I don’t know about you, but I don’t give a shit about making your job easier when you’re still charging me full price and plus some.  The only people saying that there’s no reason to do a point-to-point amp are those who are too lazy to, because there’s a big boutique market for this very thing.

Lets do a real apples to apples comparison here...

The top pic is a restored 1972 Marshall 1987x.  You can buy these used for under $2k...but let’s use $2k...plus $200 restoration (just the guts, who cares about how an amp looks).  We’re at $2,200.  And this electric shit is so simple a vacuum repair shop could do it.

The bottom pic is a brand spakin’ new Marshall 1987x reissue, modeled after...you guessed it...the 1972 Marshall 1987x.  That’s some clean wiring on that particle board!  But...wait...why am I paying MORE for a less desirable model, that took exponentially less work on Marshall’s end?  Why would I subsidize their profit margins for an inferior product with less resale value?

Furthermore...the 1987x is a one-channel, stupid simple amp.  Why do you need PCB to begin with?  I get it for a Soldano or Rectifier that’s multi-channel, with huge sweeping EQ sections, reverb, etc...but this is a plug-n-play.

Marshall...the company...has been doing that to their customer base for decades.  Back in the day, you knew what you were getting...a thunderous machine that likely would fail at some point, necessitating multiple amp purchases.  Literally the instant better, higher quality alternatives hit the market, it ripped into Marshall’s market share.

Today, if I were recommending a Marshall, the first place I’d recommend is George Metropoluos.  Second would be Friedman.  I’m currently deeply in love with a Friedman amp that’s a single-channel, point-to-point 40w amp that’s essentially a Tweed Bassman with EL84′s and a switchable gain stage...adorably named the Dirty Shirley.

***

Conclusion

Despite all that, I have a romantic love of Marshalls that overrides anything to do with quality or practicality.  It’s kind of like my love for the Gibson Les Paul grotesquely compounded...

You might think that I have a negative opinion of Marshalls based on everything I’ve just written.  Not true.  All of that stuff, it’s nothing in comparison to just how fucking incredible these things sound in person.  Again, neither of these instruments are in my wheelhouse, but if you asked me what the platonic ideal sound an electric guitar makes, it’d be a Les Paul through a cranked Marshall 1987x.

And even if you’re not into this kinda shit, trust me you’ve heard more than your fair share of Marshalls in the past.  They’re that great.  So great, it doesn’t matter how shitty they may or may not be.

PS...I wrote this in 3 different sessions, didn’t edit or re-read, and just posted away because something is better than nothing.

[mattkassmusic]

Brought this beast outta the studio for the last few @moderninventors shows 🙌🏼 modded by the man himself @paulehammond - tone for days... #marshallamps #bluesbreaker #kt66 (at The Basement East)

[andymcgain]

I veckans EXTRA NÖRDIGA avsnitt testar vi olika typer av förstärkarrör i Dannes Bassmanklon. Vi ger dig ljudexempel av slutstegsrören: 6L6, EL34, 5881, KT66, 6V6 samt Likriktarrör vs Solidstate. Mycket nöje! Tack för all feedback och alla delningar! 🙏🏻 #guitargeekspodcast #guitargear #guitar #guitarsmps #powertubes #guitargear #guitarnerds #podcast #podcasts #podcaster #podcasting #podcasters #podcastshow #6L6 #el34 #EL34 #6V6 #5881 #KT66 (på/i Kultivator Studios)

[aitkenaudio]

#park #50watt with a pair of #gec #kt66 brought back to life as it had had some dodgy work done to it. Sounds #fantastic https://www.instagram.com/p/CFzqWt-ntnr/?igshid=479pt5hkuhx4

[tubeampguru]

Biasing Tube Guitar Amplifiers

A customer, who owns a THD Flexi-50, recently asked me why our recommended bias is so much lower than the "commonly accepted 70% of maximum dissipation."

The following is my rather verbose response:

Let’s start out by stating that I am a proper amplifier designer, not a hobbyist who cuts and pastes from other designs, and gleefully repeats whatever he reads on the internet, as if it were fact. I’ve been at this for 50 years and have consulted for everyone under the sun in terms of sound, reliability, manufacturability, and just about every aspect of analog audio circuit design you can think of. I do amp repairs and restorations for dozens of multi-platinum rock bands, and I’ve often gotten that work because they see that the only amps they have that almost never need repair are their THDs. I’ve also helped Philips, Fluke and Hewlett-Packard design and build better test equipment based on my experience. I don’t even take proper textbooks as gospel, preferring to actually measure and analyze real-world situations, often proving PhD engineers and university department heads wrong in their assumptions.

Whoever started the myth that standard push-pull class AB1 guitar amplifiers (eg. Fender, Marshall, HiWatt, etc...) should be biased to 70% of maximum allowable tube dissipation should have sugar put in their gas tank. This is totally wrong in every way. There is no magic percentage of maximum dissipation to which one should bias, but most class AB1 audio amplifiers are happiest in the 35% to 40% range. (For the record, 70% is what is generally recommended for portable class B2 radio transmitters, and is close to what a class A1 amp wants.) It all depends upon the impedance of the output transformer primary, the load line of the output transformer, the impedance of the screen supply, and a few other, more esoteric factors that aren’t really worth getting into here.

People tend to repeat something that they read somewhere, as if it were truth, and it gets repeated and repeated until 95% of the hits on the internet are recommending something that was wrong to begin with. At times I find it frustrating.

That 70% factor also goes out the window when dealing with current production tubes, which are not designed to proper specs, but rather are made by reverse-engineering well-made old tubes and making countless assumptions as to why things were done the way they were. For instance, few of the Russian power tubes in production will work in a class-A amplifier. They tested their “designs” in Marshall 50-watt heads. If they worked for a few hundred hours, they gave the go-ahead to production to make 100,000 of them. Everyone who really understood how to design power tubes has been dead for 40 years, and their expertise died with them. Most people don’t spend their hard-earned money on NOS tubes because they sound better (some do, some don’t), they usually buy NOS tubes because they will sound good for 10 years of daily use as opposed to 1 year of daily use with current production stuff.

The purpose of biasing a class AB1 push-pull amplifier is to eliminate crossover distortion in the signal, plain and simple. This can be done with a distortion analyzer, but it does not differentiate crossover distortion from other types of distortion, so an oscilloscope is the best way of determining when crossover distortion has gone. When a tube is biased too cold, the signal from one tube (or tubes on one side) stops flowing before the signal from the other tube (or tubes on the other side) starts flowing, and this “gap” is called crossover distortion, as it occurs around the zero-crossing of the signal voltage. You bias a push-pull audio output section by first making it too cold on purpose, applying signal that is well below clipping, usually around 25% to 50% of clipping, and slowly increase the bias current (making the bias voltage less negative) until the gap at zero crossing is gone. When you have reached this point, you have attained the maximum dynamic range possible from the amplifier without the (very ugly-sounding) crossover distortion.

I got curious about where this point fell, as it could be a little bit ambiguous exactly where the crossover distortion “disappeared”, so I started writing down the no-signal (quiescent) dc current in the tubes where I was sure that it was gone. I documented this in roughly 10,000 amplifiers between 1969 and 1999. What I found was that, in high-powered class-AB1 amplifiers with properly designed output stages that ran their tubes near their voltage limits and had relatively linear load lines in the output transformers, the crossover distortion was sometimes gone by the time the bias was set to 21ma quiescent current per tube, often gone by 23ma, and always gone by 25ma quiescent current per tube.

One surprising thing is that it didn’t seem to matter at all what the tube type was. This number held true for 6L6, EL34, 6550, KT66, KT77, KT88, KT90, 7027A, 6CA7, 7591, 7868, USA, German, Dutch, British, French, it just didn’t seem to matter what the tube was, or who made it, as long as it was in this family of tubes that could deliver roughly 50 watts from a pair.

So, in order to make life easier for my techs, and to take some of the “guesswork” out of the biasing process, I determined that with all Marshall and HiWatt 50-watt and 100-watt amps, Fender 40, 50, 80 and 100-watt amps, and similar circuits, that they were to measure cathode current with no signal, and set the bias so that the tubes drew 25ma per tube with no signal. Then they had to do a listening test, to make sure that all was indeed well. On a few occasions the amps sounded bad at that rating, and when that happened, I took over to try to figure out why. Sometimes the two tubes were not matched, sometimes the output transformer was damaged on one side, sometimes the output transformer had been replaced with one that was not correct for the amplifier, sometimes the screen supply had too little or too much impedance. But, when things were as they should be, 25ma always gave a clean signal with no crossover distortion.

So, if your amplifier has maximum dynamic range at 25ma quiescent current per tube, what happens if you run it hotter, like 30ma or 40ma? Good question. First off, the noise floor comes up and, the tubes run physically hotter, which reduces tube life, the power and output transformers run hotter (due to the extra current running through them, even with no signal), increasing resistance in the windings, reducing overall output levels, and shortening the life of the transformers. As you can likely guess, the filter caps don’t last as long, either. I do know a few people who claim to prefer the sound of an amp biased to 40ma per tube, but these people almost always run full out, maximum distortion, 100% of the time, and never ride that expressive slope where clean gives way to “fat”, “fat” gives way to “crunch”, and “crunch” gives way to overdrive.

Another side of this is that the power supply and output stage can only deliver so much power before they just can’t deliver any more, and this is the maximum distorted full output. If you bias the output stage hotter than it needs to be, you are reducing the ratio of clean output to maximum overdrive output, and robbing the amplifier of dynamic range. Think of it like the idle in your car engine. If your engine redlines at 8000 RPM and will idle smoothly at 400 RPM, you have a ratio of 20 to 1 in terms of “dynamic range” when it comes to acceleration and general driving characteristics. You always want your idle as low as you can get it and still have it running smoothly. You can set the idle at 2000 RPM, but you will only have a dynamic range of 4 to 1, and will be shifting gears a LOT more often to get to speed. Also, you’ll be burning a lot more fuel and fixing your car a lot more often.

Biasing your amplifier to 70% of maximum plate dissipation is like setting your car’s idle to 5600 RPM with a redline of 8000 RPM. You’ll be rebuilding your engine (or replacing power tubes, filter caps and transformers) a lot more often.

I have a lot of customers who have amps worked on (under warranty) by other companies (as I only do warranty work on THD amplifiers), and then bring them to me for biasing, as everyone else seems to bias them too hot, and then their tubes don’t last very long, their amps sound overly compressed and “mushy”, and they hum too much.

It is perfectly safe for your Flexi-50 if you want to try running your bias a little bit hotter. I would not recommend going above 40ma per tube, though.

[kalliebolander]

The Mars Vintage 70 seems to like KT66 tubes, and they look good too! The ECC82 phase inverter has low gain and matches perfectly with high output sources like DAC's or CD players. #kt66 #tubeamps #tubeamplifier #diykit #point2point #madeinsouthafrica #marsamps #diytubeamp #diytube #ecc82 https://www.instagram.com/p/Cc-Bo5OKWPQ/?igshid=NGJjMDIxMWI=

[sargenthouse]

Earth Premiere "The Mandrake's Hymn" & Interview / Guitar.com

via guitar.com

Earth’s trajectory is not so much of an orbit as it is a deviation. For the past three decades, the only constant for the band headed by Dylan Carlson has been change – which is ironic for a group whose music relies heavily upon repetition.

Earth started out with ground-shaking seismic drone metal on 1993’s Earth 2, then took a left turn in 2005 into the arid West with the Morricone-inspired Hex; Or Printing In The Infernal Method. Almost a decade later, they ventured into meditative rock with Primitive And Deadly.

Now, the band have purged themselves of any embellishments, stripping instrumentation down to Carlson on guitar and bass and Adrienne Davies on drums and percussion. The upcoming record, Full Upon Her Burning Lips, is a lesson in austerity, and spotlights the duo’s sonic symbiosis.

Ahead of the release, we speak with Carlson about the record, his fascination with Telecaster pickups and his favourite collaborations thus far.

Dylan Carlson (left) and Adrienne Davies of Earth

The new album sees Earth stripped down to the core duo of you and Adrienne Davies. Can you shed more light on this decision?

Well, I’ve been playing with Adrienne for almost 20 years now, and on previous albums, I’ve been fortunate enough to play with a lot of amazing players, but I really wanted this album to focus on the two main members at this point. Just because we really haven’t done that since, probably, Hex; Or Printing In The Infernal Method.

I also felt like live drums have always been a big part of what Earth does, but that has never come across as fully on record. You know, because when you’re recording a bunch of different instruments, you need to leave room for stuff, and I always felt like the drums didn’t show the full potential that Adrienne’s capable of.

And then also, I’ve always sort of been the guy that holds everything down with my guitar and let a lot of other instruments carry the melodic work – whether it’s cello or keys or stuff like that. So I sort of wanted it to just be the two of us showing off the best of our abilities.

The previous records, they’ve all been very lush sounding and I wanted this one to be very present and dry, and upfront. Using the 70s style, you know, where I was running two amps for the basics and hard panning guitars left and right – the kind of stuff that you just don’t really hear any more on record.

Can you tell us a little more about the title Full Upon Her Burning Lips?

I’m always trying to find titles that I feel are numinous and open to multiple interpretations. Many of them, I don’t necessarily see and people tell me about them later. Like someone recently asked if [the title] was about the moon because of the “full upon” bit – which I hadn’t thought of.

I feel like music is a sensual and sensuous experience, so I wanted a title that could evoke that. Originally, the cover idea I had for Primitive And Deadly was going to be much sexier than it turned out. I was sort of on a Scorpions jag at the time [laughs]. I think a lot of music now is missing that element. There’s so much music that’s hyper-male. To me, Metallica is a perfect example – nothing in their music or lyrics reflect the idea that there’s a feminine principle to the universe. So, I guess that’s where it came from.

You mentioned in a statement that you like the “limiting of materials to force oneself to employ even more creatively”. How did that reflect in terms of guitar tone for this album?

For this one I basically used a limited number of effects. I used my live rig, which was like a compressor, an overdrive, a Uni-Vibe and a delay. I mean I used one other overdrive for some cleaner textures and an auto wah on one track, but I pretty much tried to limit it to just the pedals that I use live.

I tried to get the most out of them. For example, I’ve used the Uni-Vibe for a long time, but I’ve always just used the vibrato setting. I never thought the chorus was very useful, and then on this album, I figured out a bunch of really cool sounds with that setting. So that was fun to use in a different way than I normally do.

Image: Sean Stout

A lot of artists tend to compose instrumental music around tension and release. Is that an approach that you take as well?

I guess so, but I don’t know if it’s a conscious one. I feel like all songs should have some kind of arc – I call it a “narrative arc”. Although [with instrumental music] it’s very loose, as there’s obviously not any lyrics telling you what the story is. I sort of – in this very abstract sense – feel like songs and albums should still have a narrative arc. And I hope we convey that in the way that I put stuff together.

Again, it’s a sort of an abstract notion of a narrative, but you know, a song should start somewhere and then go somewhere, in some sort of rudimentary sense. I think that’s why, with instrumental music, the song titles become important. It’s the only way of conveying some kind of narrative with language.

I feel like music is a language in and of itself, and [communicates] in a different way. Music is simultaneously more immediate and more abstract in its meaning. With instrumental music, the audience is also participating in the creation of the meaning or the narrative or the imagery.

It’s not like songs with lyrics where it’s like “Oh my baby left me” or whatever. With instrumental music, it’s more challenging.

This album has a lot of minimalism and repetition. How do you make repetitions sound like progression to the listener?

With repetitive music especially, be it like the riff or the melody or whatever, it should be something that you want to hear again. So I think crafting really memorable riffs is key. They should be something that you want to hear again, and the riffs themselves should have some kind of arc to them as well – so that you’re getting mini arcs that build up to a bigger arc.

That’s one thing I’m constantly trying to do. When I come up with a riff it’s like “Oh, is this something like worth repeating?” There’s that thing that great riffs have where they make you want to hear them again. Whether they’re catchy or whatever, I feel like they should be strong enough – and interesting enough – that they bear repetition.

Image: Holly Carlson

Folklore is a major theme of this album, as it is with much of your work. What draws you to it?

To me, with the music I make, I want it to be timeless and feel like it’s always been there. Folklore has stories and knowledge that have been around forever, transcending cultures. I also feel like, especially with rock music – for lack of a better term – and American music, are all originally from folk sources. You know, blues, jazz, country, rock ’n’ roll – the music is not “high culture”. It’s not like classical music in that it wasn’t created by rich people for other rich people.

It’s popular music from the people, embedded in the salt of the earth, and it’s the same with folklore. It’s interesting and it’s numinous. It’s got a quality of timelessness, like something that’s always been there and that goes along with what I try to do hopefully musically.

Has your gear changed much over the years?

Yeah, I would say so. When I first came back to guitar playing, I hadn’t had a guitar for at least four years. So when I came back to guitar in 2001 or 2002, I was really into gear and was always buying petals. I guess you could call it GAS. But along the way, I realised that it didn’t really matter what I played, it was going to be me like regardless. And so I got a lot less gear-obsessed.

I like gear obviously – I mean, I love guitar – and I’ve found things that allow me to translate what’s in my head better, but I don’t feel like they’re necessary. I’m going to sound like me regardless of what I’m given. I think a lot of people are always looking for that “magic box” or this amp or that amp. At the end of the day, it’s you, you know?

The gear I do get now, I get it because I like how it sounds – which is the most important thing – and then whether it’s functional and helps me with touring. Number one is the sound and number two is functionality and whether it makes my life easier. Those are sort of two of my guiding principles.

Right now I play my live rig which I’m very happy with because I discovered these Trace Elliot Elfs, 200-watt heads that weigh like a pound – I’ve got two of those. And then one has a 1×12 Dietz cab, which I love. The Jesus Lizard guys use them, and Buzz [Osborne] has one. I didn’t know about them before, I was just in Austin and I needed a cab. Yeah, it weighs a shit-tonne, but that’s the only downside to it. It’s got wheels, but it’s a little monster. Then for the other one, I have a 1×12 Mesa cab that’s semi-open.

And then I recorded the album with and did my solo tour with a Burman – it’s a British amp from the early 70s. They were a company out of Newcastle and they basically built these 100-watt power amps called the “Slaves” which ran for either KT66s or EL34s – mine’s got EL34s – and then they did various preamp modules. So they were kind of ahead of the curve, in a certain way.

Image: Sean Stout

You’ve obviously played a lot of guitars over the years. Do you have any favourites?

Yeah, my favourite guitar is the one my wife Holly bought. It has an alder Strat body, and then we had our friend, this artist Jason Borders, carve and stain it. It has no finish. It’s got a Fender neck, the classic player one, with a 12-inch radius pau ferro fretboard, and then I’ve got a brass tremolo. I love brass, I’ve had brass on pretty much all of my guitars that I can. This guitar’s also got a brass bridge and a brass nut.

And then I’ve been running a DiMarzio Fast Track Tele bridge pickup, DiMarzio Cruiser in the middle position, and a DiMarzio Air Classic in the neck. I’m a big DiMarzio fanboy, as you can tell [laughs].

Oh, and this guitar has a little thing called the StratoBlaster which was made by Alembic. It’s a little boost switch – I have mine set for about plus 7- or 8dB, but you can go all the way to 14dB. That’s nice if you want a little bit of oomph.

I have a Tele, it was one of the Roadworn ones which I guess came out in the mid-2000s. That’s got a DiMarzio Tone Zone Tele bridge and a Seymour Duncan Little ‘59 in the neck.

In Europe, I have two guitars that live in a warehouse. I have an Epiphone SG. That one’s got a DiMarzio Tone Zone Tele bridge pickup and a Super Distortion in the neck. I was in a big Jerry Garcia phase then so I got a OBEL (or On-Board Effects Loop) on it, although I very rarely used it [laughs]. And the other’s an Epiphone Explorer that has a DiMarzio Super Distortion Tele bridge pickup. I basically put Tele Bridge pickups in all my guitars.

Some of my guitars have names. Like my favourite one – the Strat or Hollycaster – I call “The Fox”. Tele is “The Cat” and the SG is “The Goddess” because it has a big sticker of Tara Guanyin on it.

Image: Sean Stout

Do you achieve noise through the amps?

I use a lot of gain. Well, maybe not a lot of gain but I push the amps with the compressor and overdrive. With the 200-watt headroom, you’re not going to make it break up, so the tone is really a combination of pickups, overdrive and my hands. It’s not the amp. Same with the Burman – it’s a 100-watt – so the headroom’s massive.

If I’m playing a smaller tube amp, like when I had a 50-watt Plexi for a while, I didn’t use overdrive. I just hit the front end hard with the compressor. That was still like, loud as fuck. Over the years, I’ve come to understand headroom and the fact that no one really needs anything more than 50 watts. Even that is overkill, really, for most venues. Back in Earth 2 days, when I didn’t know any better, and I was young and could lug a shit-tonne of gear, it was like, “Oh yeah, let’s have, all this ridiculous amount of equipment!”. Back then most soundmen didn’t even bother mic-ing us, you know? Now I understand to let the PA do the heavy lifting.

I understand we all grew up on the cool pictures of [Jimi] Hendrix in front of a wall of Marshalls. But there were no PAs and they were playing outdoors half the time. Of course, you need like 25 Marshalls or whatever! It was a different time, with a 100-watt head now you’re never going to get to that sweet spot at a volume that’s not going to kill people.

Let’s talk about collaborations for just a second. What would you say has been your best experience so far?

Well, I love working with Kevin [Martin, aka The Bug]. It’s a whole different world than the one I am used to inhabiting. So it’s very fun for me in that way because I just get to be the guitar player and be creative.

I also love Emma [Ruth Rundle]. I think she’s an amazing musician and a wonderful human being, so that was enjoyable. And with Maddy Prior, that was super because obviously I was really into English folk. Yeah, so getting to meet an OG [laughs] and she was a lovely, lovely woman and really easy to work with. She had written a song and asked me to play guitar on it and I got to just come in and do it.

They’re all incredibly talented and really lovely people, so they’ve all been a real pleasure to work with.

What was recording Concrete Desert like? Would you do something like that again?

Yeah, I’ve been talking to Kevin about it! [Concrete Desert] was our very first collaboration, and he basically sent me the tracks and I played guitar and sent them back. So we actually hadn’t even met in person at that point. I actually just ran into him in on the street in Krakow because we were both playing the same festival.

Then Ninja Tune wanted us to play this anniversary party in LA together, and he had this material and was like, “Hey, why don’t we do this again?” and we were actually in the studio together for a couple days. I mean, he’d already generated much of the material but then after I put my guitar on, he went back and changed it a bunch. He told me he got new ideas from the guitar parts and kinda tweaked it.

But yeah, hopefully the next time we work together we can do it with both of us in the studio, building stuff from the ground up. I don’t know when that’ll happen, but we definitely want to do something together again.

Are there any other guitarists you feel are pushing the instrument to the bleeding edge?

I think Oren Ambarchi is pretty amazing. There’s probably some guys I’m not aware of, but I know Oren and think he’s a pretty good dude. I’m a rock dude and like the fact that he still manages to inject rock into [his music] in some weird way, like with that album he did with the Ace Frehley cover, for example. I think he’s got a lot of swagger to it that others don’t have.

The Rig

Main Guitar: The Fox aka Hollycaster (see above for details)

Amp: Live – 2 x Trace Elliot ‘Elf’ heads (200w solid state) each with 1×12 cab (a Dietz and a Mesa). Recording – Early 70s Burman (100w power amp w/ EL-34s) and a pre-amp module and a DV Mark Micro 50 (50w solid state)

Effects: MXR Custom Comp, MXR Shin-juku Drive, Dunlop Uni-Vibe chorus/vibrato, Dunlop Echoplex Delay, Korg Pitchblack tuner (1st version)

Strings/Accessories: Dunlop Performance Plus Nickel .09-.42, Dunlop Primetone 3mm picks and various other Dunlop picks all around 2mm

Full Upon Her Burning Lips is out 24 May. More information at thronesanddominions.com.

[rjs-amps]

A little more progress while still waiting for transformers to arrive. Boards made and staked today, wired up power supply board. RJS45/100 for Artist @joegambleguitar #joegamble #bisonwarband @bisonwarofficial #custommade #madeinamerica #handmade #handwired #ampporn #guitarporn #rjsamplification #rjs45100 #merrenaudio #merrenaudiotransformers #merrentransformers #kt66 (at City of Longmont)