Лампи

[Black Bird]

Напоследък се образовам за лампите и попаднах на яки постове в един форум.

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Tube Basics

 

The operative parts of a tube are, from inside out, a cathode, control grid(s), and a collector plate. The cathode is always spewing electrons; magnetism on the control grid keeps them in or lets them through.. the plate, charged with a lotta volts, jumps like a spooked cat with each electron that hits. So, when you hook signal up to the control grid, and your output to the plate, you have amplification.

 

A triode has one control grid, a pentode has three. Each of the three grids does something different, not sure exactly what. All the main power tubes are pentodes, and 12A?7 are twin triodes, two triodes in one glass envelope.

 

Tubes that have the same pinout -- the same heater pins, plate voltage pin, etc, can generally be swapped out. That makes all the twin triodes - the 12 series (so named because they need a 12v filament voltage when run in series, as they use two 6.3v filaments). AX, AY, AT, AU, they're all swappable with differing gains and whatnot. 12AX7 = max gain, that's why they're so popular for amps.

 

Here's a run down of what tube alpha-numeric designations "mean", for example a 12AX7

12: filament voltage

AX: model number

7: #of internal elements, including filament

 

Any extra letters either designate voltage ranges, in which case you want to talk to the distributor is your swapping to find out what exactly you're looking at, or they are design revisions.

 

Tube amps come in two common flavors, Class A and Class AB.

 

Class A: The output devices/ stages remain turned on all the time. This reduces thermal variation and eliminates crossover distortion, but is inefficient as you're running full bore across the board all the time, even when you're not pumping your signal through it. Class A amps can be gain monsters or amazing clean machines and are very easy to change tonal characteristics on via tube changes. Massive attack, gobs and gobs of headroom are the territory of Class A amps, not to mention volume beyond what you normally associate with a wattage rating.

 

Class A/B: The output devices/ stages remain on for only 1/2 of the power cycle (when you have the amp on) and thus more efficiently delivers power as you're only firing on all cylinders when you're playing. The downfall, in my opinion, is that this tends to mello out an amp making it more docile, and the "sweet spot" that is present in Class A/B amps is due to the ramp up of the power cycle as you're playing.

 

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Common Power Tube Types and Swapping Tubes

 

 

EL34, 6550, KT88, KT66, 6L6GC and 6V6 are all the same pinout (called "octal base"). They're swappable to some extent, they have WILDLY differing performance characteristics and major internal adjustment (rebiasing) is needed. In some cases they're fully incompatible. All these tubes use the same socket.

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12AX7, 12AU7, 12AT7 etc, what's the differences?

 

These tubes are all interchangeable but have varying gain. The 12AX7s are the highest gain and the most popular vacuum tube on the planet. You can swap all tube types out safely, though it might sound like crap.

 

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How about that EF86 preamp tube?

 

EF 86 preamp tubes are described (in several old tube manuals I have read) as being 'hi fidelity', and they were quite a common choice in hi-end audio amplifiers. They were re-introduced to modern guitar amps in the Matchless C-30. Lately I have noticed that the Dr. Z Route 66 uses an EF 86 in it's preamp for the same reason, to supply a very accurate representation of the source sound through to the power amp. I have plugged my guitar into an old tube hi-fi amp (with no less than 7 EF 86's in it's preamp), through to a 2 X 12" speaker cabinet. The tone was the most transparent, lush clean sound I've ever heard, bar none- very little background noise or hiss. When I turned it up, the overdrive was smooth as silk!

 

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What about Rectifier tubes?

 

The rectifier converts AC to DC. Some amps do this with a tube -- a 5AR4, 5U4, 5V4, or something like that. Others use a solid state rectifier. Fender and Marshall, notably, use solid state rectification. Mesa and Matchless use tubes. While the prevailing attitude is that tube is essential in the power stage, it is not so clear with the rectifier.

 

It appears that the actual circuit design decides whether a tube rectifier would make a difference in the tone. Generally this is where "voltage sag" comes from -- once you start actually drawing from your 450v supply, the supply voltage drops. (I find it convenient to think of electricity as water; volts = pressure, amps = flow, watts = units per minute, which is pressure x flow). The 5AR4 will hit a minimum supply of 417v. A 5V4 has a minimum supply of 350 or so volts. Your volume will sag a little bit when this occurs, and naturally "brown out" the sound some. The higher gain your amp is, the crunchier the sound, the more the sag seems to matter.

 

WeberVST makes "copper cap" replacements for your tube rectifier. Does anyone have any experience with them? They are supposed to sag just like tubes.

 

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What are these other designations like '7025' and 'ECC83'?

 

They're different names for tubes that are very similar. For example, ECC83 is the European designation for a 12AX7. This chart should point you towards some common ones:

 

12AX7 > 7025, ECC83

12AU7 > 5814, 5963, ECC82

12AT7 > ECC81

12AV7 > 5965

EF86 > 6267, CV4004

 

EL34 > 6CA7

EL84 > 6BQ5

6L6 > 5881

======================

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How should I turn on / turn off my tube amplifier?

 

Short form: For powering up, turn it 'on', wait one minute, and then take it off 'standby'. For powering it down, turn it 'off', wait at least one minute, and then turn 'standby' on so you don't forget it next time you use the amp.

 

The standby switch controls the plate voltage. With the switch off, no voltage. If the plates are cold when you hit them with that voltage it seriously affects the metal in ways that greatly shorten the life of the tube. So if you have a standby switch, you should always have it on standby, ie. not "on", when you turn the power on.

 

However, when turning power off, it's my opinion and practice that you should leave the amp off standby, ie. "on". This has no effect on tube life, but it empties the powerful filter capacitors which store a charge strong enough to KILL YOU if you become its conduit. Leaving standby off for the minute after powering off the amp fully discharges the caps and leaves your amp save to fiddle with.

 

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Who currently manufactures tubes for guitar amps?

 

There are five manufacturers: Sovtek and Svetlana in Russia, Shuguang (Sino) in China, EI in Yugoslavia, and JJ/Tesla in the Slovak Republic. JJ/Tesla is so named because this was the Tesla factory, using Tesla tools and based on Tesla and Telefunken designs, but the new company is called JJ Electronic.

 

Other tube companies, such as Ruby, ARS, Groove Tubes and Electro Harmonix don't manufacture tubes. They buy them in bulk, test them and reject any that don't meet their specs.

 

One note about Groove Tubes: I believe they have started new manufacture of 6L6GC tubes, but I don't know anything more specific about it than that.

 

The question was put out to the geeks: What do you think of various tube manufacturers? Here are the responses, by manufacturer:

 

Sovtek

"Sovteks are usually reliable, sound good and are reasonabley priced."

"I hate Sovteks. They sound like cardboard."

"I will never waste any more money on Sovteks again."

"I've never had an application where the Sovtek tubes improved an amp's tone, in fact I find them to be almost claustrophobic sounding compared to EH or JJ tubes."

"these are my favorites. Smooth transitional breakup, responsive, and what, in my opinion, an EL84 should sound like"

"I wouldn't recommended it for effects users as it has fairly high microphonics, but it does have tone. Easy to break up and crunchy. If you want Sovtek I'd recommend their KT66... a phenomenal all around 6L6 tube."

 

Svetlana

"Almost all of Svetlana's production goes direct to Marshall. If you get a new Marshall head, it'll have Svetlanas in it."

"Svetlanas are really good, but pricey."

"Svetlana seems to be the best all-around power tube maker, whereas the preamp tubes seem to vary more by preference."

 

Shuguang

For preamp tubes I use 9th generation Shuguang 12AX7's. They are a a bright sounding preamp tube and go well with the darker JJ's."

 

EI

"Clean, clean, clean, Very smooth, cheap, but haven't lasted in hotter amps like a Vox."

 

JJ/Tesla (Note: www.eurotubes.com seems to be a VERY popular JJ supplier with the geeks)

"JJ's are very popular with the members of this forum. I haven't had any experience with them."

"I love JJ/Teslas and NOS tubes."

"I replaced all the original "Mesa" tubes in my Mesa Maverick with JJs (12AX7s and EL84s) and the tone is much much better. It now sounds warmer/darker to me. I hear JJs last longer too, but I don't know that yet...."

"I use JJ 6L6's and can't reccomend them enough. They have a lot of body and warmth to them."

"I use the JJ EL84's in my Koch in combination with 3 JJ ECC83(S) pre-amp tubes for gain and a Sovtek 12ax7wb in the clean channel. (still wondering to switch it out for a ECC83(S) as well, but I wanted as little break up as possible and for that it's a pretty good solution). At shows I often get compliments on how good this amp sounds (no joke) a guy with a Bogner Metropolis asked if I possibly wanted to sell the amp. (thought about it... for about a nanosecond) I'm certainly going to retube my Rivera with JJ's (EL34 or 6L6 or both, haven't decided yet) when I have the money."

"Teslas would also be suitable as they are comparable on gain level and almost as good of a tube but they sound a little darker (than EHX.)"

"I have JJ tubes in my amp and they are badass."

"Low noise, excellent for effects users as it is very balanced, and harmonic characteristics. Very durable."

"Quality, tone, high end tube that in my opinion is worth every penny. Every amp I've used it in has really responded well."

 

Electro-Harmonix

"I had Electro Harmonix EL34's in the power amp, but one of 'em F***ed out on me."

"I really like the sound of EL34's and the Electro Harmonix tubes sounded good."

"I've have had varying success with EHX."

"I use EHX, but would love to try some NOS tubes."

"For preamp tubes, I like the warm sound of the Electro Harmonix tubes the best..."

"Also may I recommend Electro Harmonix 12AX7s in the preamp... quite warm sounding tubes and I have been ever so happy since I put a EH 12ax7 in the gain stage in my Major. With my Ibanez Jem, it should sound something like Iron Maiden."

"I do believe EH 12AX7s also put out less noise than most 12ax7s on the market at the time being!"

"Electro Harmonix is the only way to go for me. Full, balanced, no noise, their tubes in my opinion allow for my guitar's tone to come through. Beware of re-labeled Sovteks though... unless you prefer the Sovtek sound."

"Dynamic, great smooth power, a good middle of the road priced tube."

 

Other Resellers

"At the moment in one setup I've got Ruby EL84's in my power amp and Ruby 12AX7's in my Preamp. Sounds good and no complaints."

"My experience with Ruby has been good. I've wanted to try Groove tubes, but they're too pricey for me."

"The Groove Tube 6L6GT (aka GT6L6 GE) are supposed to be amazing...but pricey at like $55'ish each."

 

NOS

"So far the absolute best sounds for me have come out of NOS tubes."

"Nothing touches an old Telefunken."

"There's a reason that Mullards were the tube of choice for the guitar gods of the '60s and '70s."

==================

Common Amplifiers and their Tube Complement

 

Fender Twin Reverb takes one 12AX7, three 7025s (modern equiv: 12AX7) and two 12AT7s.

BassBreaker takes 3 x 12AX7, 2 x 6L6, and a 5AR4 or 5U4GB

Vibrolux Reverb has 4 12AX7, 2 12AT7, and two KT66.

 

Marshall Studio 15 has 2 12AX7s, 2 6V6

1969 Major has 2 ECC83, 1 ECC82, 4 KT88 (I am running GE 6550s from the early 80s or late 70s sometime as of now... currently no 6550s will handle the voltage for the amp, and few current kt88s will)

 

Matchless C-30 chassis takes three 12AX7s, a single EF86, and four EL84s. There is also a 5AR4 or 2 5V4 rectifier(s) as well.

 

Mesa Strategy 500 has 4 6550's, 8 6l6's, and 3 12ax7a's.

Orange AD30TC takes 4 x ECC83, 4 x EL84

 

Peavey Classic 30 has three 12AX7's in the pre-amp and 4 EL84's in the power amp.

 

THD's amplifiers (Univalve, Bivalve and Flexi-50) take all sorts of different tubes.

 

Soldano Astroverb takes 5 12AX7's and 2 EL84s

 

Vox AC30TBX takes 5 x ECC83, 1 x ECC82, 4 x EL84, and a GZ34 (5AR4) rectifier.

AC30TBR (reverb) 6 ECC83, 1 ECC82, 1 GZ34, and 4 EL84

 

Ampeg V4/VT22: Four 7027as, 3-12ax7s, a 6k11, a 6gc7, a 12at7 and a 12dw7.

 

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Biasing a Twin Reverb

 

(This text was given to me by Bob Pletka @ www.eurotubes.com)

 

The Twin Reverb is adjustable bias and does not need a resistor change, just a bias adjustment. You can pay someone to do this, or you can do it yourself. Here's how. It's fall down easy to do yourself. All you need is a bias probe. A bias probe looks just like the base of a 6L6 tube, and it fits between your tube socket and your tube goes. Then you turn on the amp, wait 30 seconds, and switch off the standby switch. The probe will read the amount of plate current that the tube is drawing. You only need a single probe because the trim pot controls all the tubes and since your tubes are matched you only need to measure one tube. You can adjust the bias by turning the trim pot which is located on the inside of the amp. To calculate your bias, you should measure the DC plate voltage from pin #3 of any power tube to ground using a multimeter. For most amps it will be between 400 to 500 volts.

 

The formula for biasing is the plate dissipation of the tube ( 25 watts for a 6L6 or an EL34 ) divided by the plate voltage ( lets use 480 for this example ) times 0.7 will just get you out of crossover distortion and you can go as high as 0.9 (90% of max dissipation).

 

25 divided by 480 = .0520 or 52 milliamps X .7 = .036 or 36 milliamps

 

25 divided by 480 = .0520 or 52 milliamps X .9 = .046 or 46 milliamps

 

25 divided by 500 = .050 or 50 milliamps X .7 = .035 or 35 milliamps so you can see that a variation of 20 volts only equate to 1mA.

 

A bias probe can be purchased from WeberVST for 90.00 or from Alessandro ( 215-355-6424 ) for 99.99.

Редактирано Март 26, 2008 от Black Bird

[Black Bird]

И нещо близо до темата търся 5 броя Shuguang 12AX7 9th gen. Лампи. Дали се намират в БГ ? Аз сега съм с Electro-Harmonix

Редактирано Март 26, 2008 от Black Bird

[bir4o]

И нещо близо до темата търся 5 броя Shuguang 12AX7 9th gen. Лампи. Дали се намират в БГ ? Аз сега съм с Electro-Harmonix

 

Няма в България -виж в този форум правят комбинирани заявки от чужбина -

http://www.bgaudioclub.org/forum/viewtopic.php?t=4230

 

може би трябва да се регистрираш за да влезеш в него

[Overdrive]

и още малко допълнение за по-достъпните в бг руски

6V6GT=6п6с, с тази разлика че руската се тормози от анодни над 400в като във старите фендери и изгаря (аз съм горил една), но звучат много добре

EL84=6п14п

6l6=6п3с, като руската е копие на американска 6l6 от 30те и звучи отвратително

6l6gc=6п3с-е - много много добър звук

5881=6п3с-ев (хеви дюти милитари )

 

предусилвателните руски не мисля че са добриа заместители на западните, а и не са 100 % еднакви пиновете

 

и още нещо лампите мисля на совтек (но може и на друг производител) 6v6gt са руско производство 6п6с премаркирани

по същия начин съм чувал че се срещат премаркирани 6п3с-е

Редактирано Март 26, 2008 от Overdrive

[Nikifena]

и JJ тюбс са руски премаркирани

[Jordan_J]

и JJ тюбс са руски премаркирани

 

JJ tubes са чехски премаркирани

[Jordan_J]

предусилвателните руски не мисля че са добриа заместители на западните, а и не са 100 % еднакви пиновете

 

Всичките МЕСА и МУЛАРД лампи са премаркирани руски, че и Маршалските и кой знае още кои ...

[bir4o]

предусилвателните руски не мисля че са добриа заместители на западните, а и не са 100 % еднакви пиновете

 

Всичките МЕСА и МУЛАРД лампи са премаркирани руски, че и Маршалските и кой знае още кои ...

 

Да но има разлика в звука от тия премаркирани и ЕлектроХармоник (за които се знае че са руски) - в предимство на премаркираните

[Jordan_J]

Ми то реално има разлика и между две лампи от един и същи тип, произведени от една и съща фирма и с поредни серийни номера. Естествено е да има разлика.

[DILETANT]

и JJ тюбс са руски премаркирани

 

JJ tubes са чехски премаркирани

 

 

JJ са Made In Slovakia производство на JJ Electronics.

[Baby Thomas]

Най-точно казано! Аз съм с такива и кефят повече от останалите, които пробвах - Меса, Груув, Совтек и нек'ви загадъчни. ЕН също кефят!

[bratmito]

предусилвателните руски не мисля че са добриа заместители на западните, а и не са 100 % еднакви пиновете

 

Всичките МЕСА и МУЛАРД лампи са премаркирани руски, че и Маршалските и кой знае още кои ...

Мисля че ставаше въпрос за 6н2п,6н1п,6н3п.....6н2п има почти същите характеристики като ЕЦЦ83/12АХ7 ,но с различи пинове на отоплението.

[Overdrive]

именно - и звукяа е много различен - аз говорих за соц производството които се намират на достъпни цени

a да меса и муллард премаркират евтините Совтек, които се правят в същите заводи където са се правили 6н2п

 

а за преамп аз ползвам RFT NOS ECC83 и много ме кефят

Редактирано Март 27, 2008 от Overdrive

[bir4o]

а за преамп аз ползвам RFT NOS ECC83 и много ме кефят

 

Имам 2 броя RFT ЕЛ34 на много години служба и по звук сдухват чисто новите ЕЛ 34 ЕлектроХармоник който купих наскоро .

[benedict]

a да меса и муллард премаркират евтините Совтек, които се правят в същите заводи където са се правили 6н2п

 

 

Има една малка подробност,че Меса отделя години да подбира точните предусилвателни лампи.От 1000 броя могат да излязат 4-5 ,примерно.

 

Иначе и аз съм фен на JJs,но никак не смятам,че тона става "warmer/darker",особено спрямо лампите в блусарски амп като Maverick,а точно обратното - осреднен,студен рокаджийски саунд и хавата е мощен хай-гейн.Това се дължи на скъсените решетки.Като първа лампа в hi-gain preamp звучи върха.Чистите звуци са много тънки и лесно криви,дори на малко гейн.Имам Меса лампи и спрямо JJs са по-балансирани честотно,но са подобни.

Редактирано Април 2, 2008 от benedict