6L6's vs KT66's
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STRATDELUXER97
Stratoblaster Tone Meister
Stratman
Guitaris Maximus
Re: 6L6's vs KT66's
Not interchangable!
GEC KT-66 (The real ones) take 1.3 amps for the heater circuit and are kinkless design!
6L6 tubes only draw 0.9 amps for the heater circuit.
If your transformer can handle that heater amp load, then go ahead and install the KT-66 tubes and re-bias.
If not, DON'T risk blowing up your transformer and amp....
Not interchangable!
GEC KT-66 (The real ones) take 1.3 amps for the heater circuit and are kinkless design!
6L6 tubes only draw 0.9 amps for the heater circuit.
If your transformer can handle that heater amp load, then go ahead and install the KT-66 tubes and re-bias.
If not, DON'T risk blowing up your transformer and amp....
Stratman
Guitaris Maximus
Lake Placid Blues
New member
Re: 6L6's vs KT66's
The KT66 is just huge sounding in all frequency ranges with lot's of harmonic detail, but not necessarilly that upper mid swirl of an American 6L6. When I use KT66's in Marshalls, I notice a distinct overdrive tone best heard on the early Cream albums. Listen to a lot of 60's EC, that's what they sound like. In shared cathode Marshalls the KT66 has way more bass than a regular 6L6, but it's not really a tight bass. I mean its almost over powering, but thick bass. For deep, tight, punchy, bass, the 6CA7 is the one for that.
Some KT66s pull 1.5 amps heater current, so don't use these in most non-Marshalls.
The KT66 is just huge sounding in all frequency ranges with lot's of harmonic detail, but not necessarilly that upper mid swirl of an American 6L6. When I use KT66's in Marshalls, I notice a distinct overdrive tone best heard on the early Cream albums. Listen to a lot of 60's EC, that's what they sound like. In shared cathode Marshalls the KT66 has way more bass than a regular 6L6, but it's not really a tight bass. I mean its almost over powering, but thick bass. For deep, tight, punchy, bass, the 6CA7 is the one for that.
Some KT66s pull 1.5 amps heater current, so don't use these in most non-Marshalls.
the guy who invented fire
Fuzzy. Guitars
the guy who invented fire
Fuzzy. Guitars
Re: 6L6's vs KT66's
It's funny...everybody seems to equate the tone of a JTM-45 with KT-66's...I've heard and used JTM-45 clones with KT66's, EL34's, 6L6's...even 6V6's and they all have that signature JTM-45 thickness as well as the chime on top!
It's funny...everybody seems to equate the tone of a JTM-45 with KT-66's...I've heard and used JTM-45 clones with KT66's, EL34's, 6L6's...even 6V6's and they all have that signature JTM-45 thickness as well as the chime on top!
Gr8Scott
Wookieologist
Re: 6L6's vs KT66's
The other tubes are close to my ears, but the super thick and unyeilding ultra low end bass is lacking in anything that isn't a real KT-66 tube IMHO. I can tell a difference between the Tung Sol KT-66 and my Groove Tube KT-66 tubes. The Tung Sol KT-66 is pretty much a standard 6L6 in a big bottle. Nothing comes close to the Groove Tube KT-66's that came standard in the Edana. I have yet to successfully try the Shuguang KT-66 tubes (I bought a set that lost vacuum the second I fired them up). I have heard those Chinese KT-66's have some serious bass response as well though.
The other tubes are close to my ears, but the super thick and unyeilding ultra low end bass is lacking in anything that isn't a real KT-66 tube IMHO. I can tell a difference between the Tung Sol KT-66 and my Groove Tube KT-66 tubes. The Tung Sol KT-66 is pretty much a standard 6L6 in a big bottle. Nothing comes close to the Groove Tube KT-66's that came standard in the Edana. I have yet to successfully try the Shuguang KT-66 tubes (I bought a set that lost vacuum the second I fired them up). I have heard those Chinese KT-66's have some serious bass response as well though.
eschoendorff
New member
Re: 6L6's vs KT66's
Who would need more bass than what's available in a 6L6???
Who would need more bass than what's available in a 6L6???
Terpdudematt
New member
Re: 6L6's vs KT66's
I swapped the 6L6's in my Peavey Vypyr with Tung-Sol KT66's. It was a direct swap. Didn't have to re-bias or anything. I noticed a better bass response, but all around they just sound better to me. I can't describe it. It's a more full sound. However, the bottles for the KT66's are bigger, so depending on your amp it may be hard to fit them in if your tube sockets are close together. Also, if you have "bearclaw" retainers, you will have to remove them because the KT66's have a metal base. Hope that helps.
I swapped the 6L6's in my Peavey Vypyr with Tung-Sol KT66's. It was a direct swap. Didn't have to re-bias or anything. I noticed a better bass response, but all around they just sound better to me. I can't describe it. It's a more full sound. However, the bottles for the KT66's are bigger, so depending on your amp it may be hard to fit them in if your tube sockets are close together. Also, if you have "bearclaw" retainers, you will have to remove them because the KT66's have a metal base. Hope that helps.
BenPerkins
New member
Re: 6L6's vs KT66's
Is there a list of small bottle KT-66's?
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Is there a list of small bottle KT-66's?
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BenPerkins
New member
Re: 6L6's vs KT66's
There's a seller on eBay that has KT-66's that are 3 inches - so I might give that a shot
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There's a seller on eBay that has KT-66's that are 3 inches - so I might give that a shot
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Lake Placid Blues
New member
Re: 6L6's vs KT66's
The JJs and the Tung Sol are supposed to be 6550 /KT88 sized, which is smaller than the Gold Lions or the Chinese version. The Tung Sol KT-66 has the same current draw as a 6L6 (0.9 amps).
The JJs and the Tung Sol are supposed to be 6550 /KT88 sized, which is smaller than the Gold Lions or the Chinese version. The Tung Sol KT-66 has the same current draw as a 6L6 (0.9 amps).
Re: 6L6's vs KT66's
what brand? as i alluded to before it might not be an actual kt66, could be a 5881 or 6l6gc they are calling a kt66 since no one keeps track of these things anymore. a 5751 used to be a 5751, now people sell soft 12ax7's labeled as 5751 but they are just soft 12ax7s.
what brand? as i alluded to before it might not be an actual kt66, could be a 5881 or 6l6gc they are calling a kt66 since no one keeps track of these things anymore. a 5751 used to be a 5751, now people sell soft 12ax7's labeled as 5751 but they are just soft 12ax7s.
Chickenwings
Alnico 6/8
Re: 6L6's vs KT66's
fwiw my jtm runs on el34s. It works good on 6l6s too.
Thick and bassy as heck.
I think it is more about the amp design than the tube choice.
fwiw my jtm runs on el34s. It works good on 6l6s too.
Thick and bassy as heck.
I think it is more about the amp design than the tube choice.
Lake Placid Blues
New member
Re: 6L6's vs KT66's
^^ I also often run my JTM45 with EL34s. There's a pretty dramatic difference as to where the bias pot needs to be adjusted to, but both tube types can be adjusted for within the pot's range. The amp is brighter and cleaner with KT-66s (gold lions) than with EL34s, which are darker and more easily over driven. To get the impedance matched better, you can run the amp into an 8 ohm cab with it set for 16 ohms when using EL34s, depending on which output transformer the amp has. A big factor for the tone of a JTM45 is actually the rectifier tube. One would not think it would effect the tone, but it does. You can completely change the tone and feel of a JTM45 by changing the rectifier tube.
As to running KT-66s in a cathode biased amp: I have been trying several big bottle octal tube types in the new mini Jubilee. (one of the amp's designers posted on the marshall forum that this is perfectly okay with this amp.)
KT66s: classic rock and heavy blues heaven. More clean head room than with EL34s and brighter. Glassier cleans, and more broken crunch when over driven. Probably not for metal at all.
6L6GCs: Very open and clear across the board. More clean headroom but rather boring distortions and over drives, in my opinion. Might be good for pedals.
6CA7s: Close to EL34 tone but everything thing is bigger and bolder, especially the bass. Less snarl in the upper mids compared to regular EL34s. Crystal clear highs even on high gain.
^^ I also often run my JTM45 with EL34s. There's a pretty dramatic difference as to where the bias pot needs to be adjusted to, but both tube types can be adjusted for within the pot's range. The amp is brighter and cleaner with KT-66s (gold lions) than with EL34s, which are darker and more easily over driven. To get the impedance matched better, you can run the amp into an 8 ohm cab with it set for 16 ohms when using EL34s, depending on which output transformer the amp has. A big factor for the tone of a JTM45 is actually the rectifier tube. One would not think it would effect the tone, but it does. You can completely change the tone and feel of a JTM45 by changing the rectifier tube.
As to running KT-66s in a cathode biased amp: I have been trying several big bottle octal tube types in the new mini Jubilee. (one of the amp's designers posted on the marshall forum that this is perfectly okay with this amp.)
KT66s: classic rock and heavy blues heaven. More clean head room than with EL34s and brighter. Glassier cleans, and more broken crunch when over driven. Probably not for metal at all.
6L6GCs: Very open and clear across the board. More clean headroom but rather boring distortions and over drives, in my opinion. Might be good for pedals.
6CA7s: Close to EL34 tone but everything thing is bigger and bolder, especially the bass. Less snarl in the upper mids compared to regular EL34s. Crystal clear highs even on high gain.
