{"id":68,"date":"2008-06-09T04:03:20","date_gmt":"2008-06-09T04:03:20","guid":{"rendered":"http:\/\/127.0.0.1\/wordpress63\/?p=68"},"modified":"2008-06-09T04:03:20","modified_gmt":"2008-06-09T04:03:20","slug":"all-tubes-are-equal","status":"publish","type":"post","link":"https:\/\/diyparadise.com\/w\/all-tubes-are-equal\/","title":{"rendered":"All tubes are equal"},"content":{"rendered":"

but some are more equal than others… <\/span><\/span>
\n<\/p>\n

All tubes are equal <\/span><\/h2>\n

but some are more equal than
\nothers<\/span><\/h2>\n

\nAh… tubes… how can you live without them?…<\/span>\n<\/p>\n

\nAlright, there are really thousands of circuits out there,
\neach one purportedly sounding excellent by its diehard advocates. While there is
\nno denying that there are lots of good stuffs out there, there’s also no denying
\nthere’s the extremely "narrow" choice of
\n"audiophile-approved" tubes. Very often, the usual suspects are <\/span>\n<\/p>\n

\nfor driver stage:    12AX7, 12AU7,
\n6SL7, 6SN7, EF86…<\/span>\n<\/p>\n

\nfor PP output stage:    EL84,
\nEL34…<\/span>\n<\/p>\n

\nfor SE output stage:    2A3, 300B,
\n845, 211…<\/span>\n<\/p>\n

\nfor rectifers:    6X4, 5U4G, 5V3,
\n5AR4…<\/span>\n<\/p>\n

\nI have no problem here, but I have a lot of
\nproblems with the prices these NOS tubes command. A piece of NOS Telefunken\/Mullard\/Amperex,
\nsmooth\/black plate, blah blah blah… 12AX7\/12AU7 easily starts at USD50, not
\nexactly the price I’m willing to pay for, no matter how many times audio nuts
\nswear how earth-shattering, how orgasmic these tubes are<\/b>. What the heck? I
\nonce saw a smooth plate NOS Telefunken 12AX7 being traded for USD400!!!!!
\nAlright, granted that these specimens might be the best of the bunch but why the
\nhell do they command such high prices? <\/span>\n<\/p>\n

\nAn Economic student will tell you: <\/span>\n<\/p>\n

\n    "It’s a law of demand
\nand supply."<\/i><\/span>\n<\/p>\n

\nVery true, but even truer when you can get sexy
\nItalian actress Monica Belucci to say,  <\/span>\n<\/p>\n

\n    "Itsa law of demanda
\nand supplya" <\/i><\/span>\n<\/p>\n

\nThat’s right folks. Willing buyer, willing seller.
\n(Willing sucker, willing suckee.) If you think so-and-so specimen is so great after reading so many reviews, and
\nthere is a seller fixing your favourite tube at a price so expensive that
\n"it got to be good", by all means, go for it! That’s why it’s a law of
\ndemander and supplier. <\/span>\n<\/p>\n

\nAlright, all fine here, but what leaves us DIYers? <\/span>\n<\/p>\n

\n \n<\/p>\n

\nStay away from them! Get away from mainstream! <\/span><\/b>\n<\/p>\n

\nWe DIYers always have this advantage over non-DIYers:
\ncontrol. We are in control of our sound. We can change components, tweak
\ncircuits, and of course, change tubes. That’s right! Change tubes! Not just
\nchange from one make to another but a totally different type! DIYers rejoice!
\nIt’s time to be hip! <\/span>\n<\/p>\n

\nThere are lots of great tubes that can not only do
\nthe job, but can even do the job better! The list here isn’t exhaustive but it
\nshould get your grey cells working and stop looking down at tubes you are not so
\nfamiliar with. <\/span>\n<\/p>\n

\n <\/span>\n<\/p>\n

Driver tubes<\/span><\/h4>\n

\n12B4<\/b> is one of those very linear tubes.
\nThis guy can operate really low from 90V up to even 500V! (some guys tried
\nhere!). Mu is only 6 but way low plate resistance of 1kohm makes good preamp
\nduties. Run them at higher current of 30+mA, and you can even use it as a power
\ntube! Yup, a simple 1W tube amp that even got one DIYer complaining, "dang!
\nI can’t get my 300B to convey music as well as this guy!" Guys who have
\nbuilt 12B4-based line-level preamps found it to have a very transparent sound.
\n"It just amplifies, and does nothing else." Better still, 12B4A is
\nelectrically equivalent to 12B4 with the added advantage of a built-in slow
\nheater warm up. Hey! Even expensive Telefunkos don’t have this feature!<\/span>\n<\/p>\n

\nThe 5687<\/a><\/b> maybe isn’t so
\n"non-mainstream" as the rest. Audio Note uses it in their M7 preamp.
\nThe Ongaku has one as cathode follower. Mu is not high at ~18-20 but thanks to
\nits excellent linearity and low plate resistance (~2kohm), it has the making of
\na good preamp tube.<\/span>\n<\/p>\n

\nThe 5842<\/a><\/b> is as similar as can be with the
\nWestern Electric 417A. Hey, buddy, anything with a "Western Electric"
\nname on it isn’t cheap okay? (I bet you if WE did make toilet paper, it’ll cost
\na bomb too.) Capable of high current up to 30+mA, they make a VERY beefy driver.
\nActually, if ran with grid of 2V, 36mA through, you have a one-tube, one-stage
\n~1W tube amp!<\/span>\n<\/p>\n

\nThe 5965<\/a><\/b> is actually similar to 12AV7 but
\ncost a fraction of their 12AX7\/12AU7 siblings. Cheap and good, this is one of my
\nfavourite tubes and I have quite a number of them! Some Joes on Joelist found
\nthat they can be used in place of 12AT7\/12AU7, which really saves you truck loads
\nof $$! But beware, better check with your schematics first. Likewise, if you
\ndon’t need the gain of a 12AX7 (mu=100), they might even work in your amp. For
\nyour info, since this tube is dirt cheap, even a cheapskate like me has compiled
\nNOS samples of RCA, GE, Sylvania and Raytheon. Try this with a 300B!<\/span>\n<\/p>\n

\nThe 6C45Pi<\/a><\/b> seems to be the Russian
\nequivalent of the 5842. Specs are pretty similar but construction wise is night
\nand day! This tube has hefty plates. The plates are so thick that Yankee tubes
\nlook like anorexic waifs beside it.  Look here<\/a>.<\/span>\n<\/p>\n

\nBalanced Audio Technology made a big fuss a couple
\nof years ago saying that the 6H30P<\/b> is the "perfect" preamp
\ntube, saying that it has a plate resistance of only 200 ohms but it was later
\nfound out that BAT achieved an output impedance of 200 ohms only after
\nPARALLELING several stages of 6H30P. What bollocks! Nevertheless, it has a plate
\nresistance of ~1kohm and makes a pretty good driver.<\/span>\n<\/p>\n

\nThe usage of Russian tubes has increased these
\ncouple of years and another good driver is the 6N1P<\/b> but the 6N1P doesn’t
\nbelong to only vodka-drinking Ruskies. Seems that they were made in China as
\nwell and military grades of the 6N1P is said to be "very very good".
\nWith some circuit modifications you can replace the 6922\/6DJ8 with the 6N1P. Word
\nhas it that these 6N1P smoke the hell out of even premium Amperex 6DJ8s…<\/span>\n<\/p>\n

\nThe 8532<\/b> first came to my knowledge as the
\ndriver in the original Darling amp. So far, haven’t heard any negatives being
\nsaid about this tube. With mu ~40s, if your circuit needs a lot of voltage
\nswing, you know which number to dial.<\/span>\n<\/p>\n

\nAlright, the JJ ECC99<\/a><\/b> isn’t NOS as it’s
\nstill in production. Nevertheless, it’s worth considering. Specs pretty similar
\nto 5687 BUT said to be 3 times less noisy. <\/span>\n<\/p>\n

\n \n<\/p>\n

Power tubes<\/span><\/h4>\n

\nI can’t thank Bob "Papa Darling"
\nDanielak enough for discovering the excellent 1626<\/b>. Thanks to its
\navailability and low prices, it’s truly a "poor man’s 300B". The only
\ncomplaint is its low power of only 0.7W. Read them all here at the Darling
\nClub<\/a>. Please visit Papa Darling’s website from a link there. By the way, the
\nDarling Club, at time of writing, has members in the US, Canada, Germany,
\nNetherlands, Philippines and Malaysia!<\/span>\n<\/p>\n

\nOh yeah! If you fancy shortest signal path, you
\ncan’t go wrong with a one-tube, one-stage 1W tube amp! Build the one-tube,
\none-stage 5842<\/b> or 6C45Pi<\/b> amp! You can’t go a shorter signal path
\nthen having this tube INSIDE your CD player. This way, all you need is just a CD
\nplayer with enough space to accomodate 2 tubes (for stereo), a few
\nresistors\/caps, a transformer for providing the appropriate B+\/filament juice
\nand you are done! Yes, use your CDP volume pot! See? No interconnect! Once you
\nbuild this, bring it to a friend’s place and surprise him with your "mini
\ncompo".<\/span>\n<\/p>\n

\nThe 6C33<\/b> is not mainstream yet but slowly
\nbecoming so. Lamm and Graaf has amps built around them. First discovered by the
\nWestern world in a Russian MiG! Yeah! This tube rocks! Built like a tank, it can
\ngive you 15W of SE power, enabling it to drive LOTS of speakers. A DIY friend
\nonce had his coupling cap shorted, so full B+ was on the grid but the tube
\nsurvives! Just goes to show how durable these tubes are. However, there’s 2
\nfactors against them. Extremely current hungry filament (6A!) and terrible input
\ncapacitance. The latter can be solved by using a beefy driver or a cathode
\nfollower but the former requires a chassis with very very good ventilation.
\nOtherwise, fried eggs anyone?<\/span>\n<\/p>\n

\nAnd then there is the rest of the bunch, more
\nobscure ones like 813 etc of which a visit to the excellent Joe’s list is a
\nnecessity for the adventurous DIYer…<\/span>\n<\/p>\n

\n <\/span>\n<\/p>\n

Rectifier tubes<\/span><\/h4>\n

\nI first learned about TV damper diodes after
\nreading Lynn Olson’s work on his Aloha Audio website. (Lots of good stuffs
\nthere!) Lynn Olson is a fan of TV damper diodes and according to him, they (the
\ntubes, not Lynn) give the lowest switching noise of any rectifier ever made, be
\nthey sand rectifiers, or tube rectifiers like 5U4G etc. Ever. Better still, they
\nare relatively cheap and comes with impeccable specs! The 6CK3\/6CL3<\/b> can
\ndo almost 1000VDC and up to plate current of 250mA! Serious stuff! The 6CG3<\/b>
\ncan even go up to 350mA DC! There you 6C33 fans can even use this in your amp.
\nMy main gripe with them is that they need lots of filament juice. The 6CK3\/6CL3
\nneeds 1.2A while the 6CG3 needs 1.8A. Not a big deal but it is when you realize
\nthat you need TWO of them for full wave rectification.<\/span>\n<\/p>\n

\nSurely this isn’t problem for a DIYer right?<\/span>\n<\/p>\n

\nOh yeah, the only TV damper diode still in
\nproduction these days is Svetlana’s 6D22S<\/b>. See? DIYers have CHOICES.<\/span>\n<\/p>\n

\n <\/span>\n<\/p>\n

Another alternative<\/span><\/h2>\n

\nWhat if you JUST have to use 6SL7? Still, there is
\nan alternative. Use 12SL7. 12SL7 is equivalent electrically to 6SL7 EXCEPT that
\nit uses a 12.6V filament while 6SL7 uses 6.3V. So, get the 12SL7 and use a
\ntransformer that has this 12.6V filament rather than 6.3V. Remember you are now
\nunable to use 6SL7 in your amp anymore but this is a small price to pay! Pun
\nmore than heavily intended! However, you can easily implement a switch like what
\nsome DIYers do to go from 6V heating to 12V heating. This way, your amp will be
\nable to cater for both the 6V and 12V versions of your favourite tube.<\/span>\n<\/p>\n

\nAs these are at much lower prices than their more
\npopular "audiophile approved" brethrens, pick them up while you still
\ncan! Remember, one day when all NOS 6SL7 is no longer available, people will
\nturn towards the 12SL7!<\/span>\n<\/p>\n

\nSuffice to say, there are quite a number of tubes
\nthat have electrically equivalent versions but with different filaments. Visit Duncan
\nAmp<\/a> to download the excellent Tube Data Sheet Locator (TDSL) and try to find
\nyour favourite equivalents! You will realize how the hell you lived without this
\ngreat tool all this while.<\/span>\n<\/p>\n

\nFor non-DIYers, you have a choice here as well.
\nGet someone to fit in a separate filament transformer (provided there is enough
\nspace in your amp chassis) that can give you the appropriate filament voltage,
\nrewire a little and you are done.<\/span>\n<\/p>\n

\n That’s all, folks! Just a little ditty to
\nshow you what DIY can bring you. CHOICES. Better stop here, it’s time to go back
\nto my seductive-and-wallet-friendly tubes…<\/span>\n<\/p>\n

\n*In the great George Orwell classic, "Animal
\nFarm", after the farm animals ousted the farmer from their land, they had
\nthe famous decree, "all animals are equal". However, after the pigs,
\nleaders of the farm animals, began to exert their influence, the decree then had
\nan extra line "but some animals are more equal than others". I don’t
\nknow about animals, but one thing for certain, the pigs are right about tubes!<\/i><\/span>\n<\/p>\n

\ndiyparadise.com<\/span><\/a>\n<\/p>\n


\n