EL34, KT66, KT88, 6550....??

Dans mon JCM800 2203. Dans le moment. J'ai des "C" qui ont 2 ans environs. Je commence a penser a les changer. Quel serais les avantages, est-ce possible, difference, et cout de modif seraient impliquer.??

Bonne question...tu recherche quoi comme tonalité?..je présume que tu run des EL34 présentement?..de quelle marques?.

des 6550 necessite une modification du circuit de bias ( c pas juste un ajustement du bias) elle sont supposer avoir plus de headroom et être plus tight dans les basse

EL34POWER, je sais pas si t'as déjà lu ça mais il y a un post sur le forum de MetroAmp qui décrit les différentes caractéristiques sonores des tubes de power amp:

Citation :

Basically I can distinguish 8 types of end tubes that will fit in a Marshall plexi no problem, each with their own characteristics in sound, feel and response: EL34, 6CA7, 6L6, 7581A, 5881, KT66, KT88, 6550.

EL34: Current-production EL34's are designed to give you that midrange crunch rock music is known for. I never had the pleasure of hearing a new old stock or used old stock EL34 (Mullard) but from the descriptions George has given on this forum they sound warmer and more versatile than the newer EL34's. They are also cleaner with more headroom, which means that when they break up or are pushed by pedals the sound still doesn't get overly compressed or saturated. I find most current-production EL34's to be good only at producing that middy grind. They break up early and most of them tend to get shrill in the high end. The general consensus seems to be that the Svetlana EL34 and the JJ EL34L are the best new EL34's. I personally find the EL34's to be too much of a one-trick-pony for my taste but if you're looking for the classic 70's and 80's rock sound then EL34's are definitely the way to go.

6CA7: The term 6CA7 is often used synonymously with EL34. This is not correct as a true 6CA7 is an American big-bottle version of the British EL34 design. I don't know how it works exactly but from what I understand the 6CA7 is the basic EL34 design but with an added element of the American 6L6 design. The only decent new-production 6CA7 IMO is the GT-6CA7GE (remake of the General Electrics 6CA7 - yes, the one EVH used!). I own some original GE 6CA7's and I would describe them as a cleaner version of an EL34 which is slightly more American-sounding (i.e. more midscooped, less midrange grind, cleaner with more headroom, later breakup). The main feature of the big-bottle 6CA7 is its HUGE dark and tight low end response while still retaining its brightness. This tube is often used by bass players but you guitar players looking for a tube with lots of warm, clean output without sounding sterile might like it too. A very musical tube which is great for use in combination with pedals or heavy preamp gain because of their tight sound and clean headroom.

6L6: The tube you associate with Fender amps. The classic American tube sound: lots of lows and highs, midrange is not so well pronounced. The slightly midscooped quality of a 6L6 gives it its sweet and round 'glassy' character. The 6L6 is less 'forward-sounding' than a British tube like the EL34, yet in return you get a very sparkly tube with bell-like highs. The lows can get muddy when pushed so if you're gonna go for 6L6's in your Marshall I suggest you choose the 6L6GC which has a slightly higher output than a regular 6L6 and will sound tighter due to its increased headroom, especially in the low-end department. Best current-production 6L6's IMO are the JJ's and Svetlana's. I hear the GT-6L6GE (Groove Tubes replica of the GE 6L6) is very good too.

7581A: This is the military version of the 6L6GC, in other words a 'harder' tube (even cleaner and tighter). Expect HUGE low end and sweet, glassy, bell-like highs. This tube has all the qualities of a 6L6, only enhanced due to its bigger headroom. This tube is also favored by bass players but guitarists looking for the American midscooped 6L6 sound with later breakup will love it too. Great for use with pedals or heavy preamp gain to keep your sound nice and tight without it getting muddy when pushed. Unfortunately there's no current-production version of the 7581A on the market today so you'll have to look for NOS ones made by American companies like GE and RCA. They show up regularly on eBay and if you bid smart you can get them for decent $. The 7581A is often called the American KT66 because it's similar in design to that British tube. The 7581A does sound distinctly American (less pronounced mids), tho, whereas the KT66 sounds British (more pronounced mids).

5881: Also called the 6L6WGB and NOT the 6L6GC as they are often referred to. You guessed it, the 5881 is another version of a 6L6. This time, tho, it actually has a LOWER output with LESS headroom. Great for guitarists seeking the classic midscooped American sound with early breakup. Has a tendency to get muddy in the lows and shouldn't be pushed too hard. Not my favorite 6L6-type tube.

KT66: The British equivalent of the 6L6 design. The difference being they eliminated the mid 'kink', that slightly midscooped quality that gives the 6L6 its sweet and round character. KT stands for Kinkless Triode. What the KT66 gives you in return is a more pronounced and wider midrange and more clean headroom. The KT66 is capable of producing a midrange crunch which is similar to an EL34, yet it's considered a more versatile and musical tube. It's the perfect tube if you're looking for a hybrid British/American sound, i.e. the middy grind associated with British amps (Marshall, Vox, Hiwatt, Orange, etc.) coupled with the clean glassiness of American amps (Fender, early Mesa Boogies, etc.). The best KT66 ever is the GEC (Genelex). These go for hundreds of dollars on eBay. Best current-production, according to many, is the GT-KT66HP (Russian-made KT66 designed exclusively for Groove Tubes). Sounds great with pedals.

KT88: The British version of the American 6550 design. Again the mid 'kink' is eliminated, giving you a broader, more dynamic midrange. This tube has HUGE headroom and sounds darker than the KT66 because it enhances the lower frequencies especially. This is why the KT88 is liked by bassists. Guitarists looking for that extra bit of OOMPH! in their sound use either KT88's or 6550's depending on how much midrange they want their preferred sound to have. Again the GEC KT88 is considered the ultimate KT88 which explains their high $ value. Best current-production KT88 is without a doubt the JJ KT88.

6550: If you like the American 6L6 type of sound but you need even more clean headroom than a 7581A then a 6550 is what you want. These tubes sound very stiff and will take any kind of abuse gladly and not even blink an eye, which is great if you're looking for maximum clean headroom in a tube. On the other hand, the 6550 is less musical than its British counterpart the KT88 because of its less pronounced midrange. This causes the 6550 to always respond in a very stiff manner no matter how hard you dig in on your guitar. Bass players love this tube. Most guitarists will prefer the KT88 over the 6550. Yet it's a great tube for guitar if you're into HUGE clean output, especially in combination with heavy preamp gain (Zakk Wylde, Slash). Best current-production 6550 IMHO is the Svetlana 6550-C.

Source: http://forum.metroamp.com/viewtopic.php?f=13&t=1749

Cool merci PM.
Maintenant. est-ce que les KT66, ou 88. sont installable directment avec ajustement du bias, sans modif?

De mon expérience personnel dans mon 2204, j'ai essayer desEl34 neuve..tres bien, des KT88, et j'ai finalement remis les EL34 original...oui oui, apres les avoir fait tester que que la moyenne testais encore à 75%...wow, je les ai remis disons. des lampes original..sa sonne vraiment pas pareil, pourtant j'avais acheter de TRES bonne lampe neuve. Je joue du metal des année 80...Van Halen, maiden, judas, ozzy...ce style la finalement..et c'est génial comme tone pour ca..

BigAl a écrit:

De mon expérience personnel dans mon 2204, j'ai essayer desEl34 neuve..tres bien, des KT88, et j'ai finalement remis les EL34 original...oui oui, apres les avoir fait tester que que la moyenne testais encore à 75%...wow, je les ai remis disons. des lampes original..sa sonne vraiment pas pareil, pourtant j'avais acheter de TRES bonne lampe neuve. Je joue du metal des année 80...Van Halen, maiden, judas, ozzy...ce style la finalement..et c'est génial comme tone pour ca..

Tu aimes Van Halen toi ???













....

JohStro...ben oui!...les mec de ma génération qui étais headbanger et surtous musicien, on pas mal toute tripper Van Halen..

oui oui je me doute bien !!!
C'est juste qu'avec tes 14 Frankie, on aurait trouvé ca bizarre que tu l'aimes pas !

JohStro a écrit:

oui oui je me doute bien !!!
C'est juste qu'avec tes 14 Frankie, on aurait trouvé ca bizarre que tu l'aimes pas !

Ahaha...une franky à vrai dire...

BigAl a écrit:

JohStro a écrit:

oui oui je me doute bien !!!
C'est juste qu'avec tes 14 Frankie, on aurait trouvé ca bizarre que tu l'aimes pas !

Ahaha...une franky à vrai dire...

Frankie !!! J'aime pensez que mes guitares possèdent une certaine féminité !!

J'aurai bien aimer qu'il parle des kt77,car j'ai lu quelque part qu'ils pouvaient remplacé des el34.
Vrai ou faux?

J'esperais que JFL reponde la dessus

Il semble que ça les remplace, les EL34
Voici ce que j'ai trouvé sur Tubes Store.com un magasin ou j'achète beaucoup de tubes.

Alors vas-y si le descriptif t'intéresse

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The JJ KT77 is an alternative to the common EL34 tube.

From our review: "Overall a nice balance of tone in bass, midrange and treble. The breakup is earlier than a 6L6 with more compression but not as compressed as the EL34. If you have a Marshall amp and find EL34’s too compressed and 6550’s too crunchy the JJ KT77 may be just the ticket."

The now rare KT77 tube was introduced by MO-Valve in the late 1950's and has recently been brought back by JJ. They use the same base and biasing as any EL34 tube so they are a great option for substitution in any EL34 amp.

View JJ KT77 tube data sheet.

Other JJ tubes EL34 Types

EL34POWER a écrit:

J'esperais que JFL reponde la dessus

Oui les kt77 peuvrnt être une très bonne alternative aux el34, même que les vieux kt77 (GEC, etc.) sont de perles rares, très rare mais qui vaut vraiment la peine d'avoir, il vous durerons toute votre vie si 100% NOS.. mais ils sont le double du prix des vieux mullard el34 xf2 par exemple et aussi casi extinct/on en trouve plus ou presque plus ....

Le kt77 est l'ancêtre du el34.... pas les même specs mais a la base ils ont casi le même "plate to load factor", et il sonnent mieu x a mon avis, plus BIG, comme ds le post de stratele.......

Merci les boys. Semble qu'il n'y en pas beaucoup de disponible, des KT77....

EL34POWER a écrit:

Merci les boys. Semble qu'il n'y en pas beaucoup de disponible, des KT77....

Oui chez tubestore
http://thetubestore.com/el346ca7types.html

Oui je sais. J'ai deja acheter la. Mais il n'y a que les Gold lions, et JJ. La descriptions des Lions ne me fait pas tripper. et les JJ, ben. peut-etre

En effet les critiques sont + ou - bonnes.

Je ne sais pas si c'est le cas avec les KT77 de JJ mais je me rappelle d'avoir lu qu'il y a beaucoup de KT66 de production actuelle qui sont en fait plus des 6L6 dans un enveloppe de verre 'fancy' (donc pas de vraies KT66). De ce que je me rappelle, seulement les KT66 de Chine et de Saratov en Russie (discontunée) sont de vrai KT66 en terme de design. Les vraies KT66 n'ont pas de base en métal.

Les techs sur le forum doivent en savoir plus que moi à ce sujet...

sa te fait bien la brabe rasée EtLa

J'imagine que le port des boules y est pour quelque chose aussi...

Balou a écrit:

J'imagine que le port des boules y est pour quelque chose aussi...

pour en avoir une meilleur idée il faut voir l'exellent film Factotum.