if ever comes a time i have issues i will post them here...
the local on line store put up the JJ KT88's pairs and quads
for sale and one week later they were all gobbled up....
JJ pricing seem to be very competitive....
the local on line store put up the JJ KT88's pairs and quads
for sale and one week later they were all gobbled up....
JJ pricing seem to be very competitive....
JJ 6V6 can handle those Voltages with ease...they just don't sound that much like a real 6v6 more like a 5881 or something....don't worry they can dissipate waay more.
Ran/Seen Sylvania GTAs pretty high before.
Ran/Seen Sylvania GTAs pretty high before.
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Waaaay more than what? Post #9 gives a link to the data sheet for 6V6S and gives 14 watts as max. Any tube can dissipate more than given in the data sheet. It's just a question of how long you want your tubes to last.
14 watts Max my *** haha....and no... not any tube is real happy like that... asking for some meltdowns real quick with some...
If you wanna Red-Plate your **** with some of them go right ahead haha.....I have smoked the **** out a lot 6v6's believe me I know...haha
Think I'm gonna see if these 6F6s will Meltdown next haha
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I would not put much faith in these modern day tube data sheets.....
Most of the time they just copy and paste the data from old RCA handbooks...
Thats not to say these tubes are bad....just not the same...in many cases these tubes can exceed original voltage specs...
If you are truly interested in the tubes capabilities , send it to me... I will put it on my modified 570 ...I also use a infrared camera to monitor bulb temperatures for checking thermal dissipation...
Most of the time they just copy and paste the data from old RCA handbooks...
Thats not to say these tubes are bad....just not the same...in many cases these tubes can exceed original voltage specs...
If you are truly interested in the tubes capabilities , send it to me... I will put it on my modified 570 ...I also use a infrared camera to monitor bulb temperatures for checking thermal dissipation...
The specs for this one is surely different: Not sure if I would trust those voltages though. 500v plate and 450v screen for 6V6? Another good option is to buy one of those IR temp guns. I have one and it woks really slick. Not very expensive either. https://www.tubesandmore.com/sites/default/files/associated_files/t-6v6-s-jj_specificationsheet.pdf
http://www.ebay.com/itm/NON-CONTACT...ITAL-THERMOMETER-SIGHT-HANDHELD-/130979214461
http://www.ebay.com/itm/NON-CONTACT...ITAL-THERMOMETER-SIGHT-HANDHELD-/130979214461
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Here is some food for thought.. This is from some of the professors I had in college many moons ago,.... Some of them designed tubes for RCA and Tunsol....
The real working voltage of a tube is usually more than TWICE the recommended max voltage listed in the tube data sheets... ie, this is usually specified as the CLASS A MAX plate voltage... in Single Ended operation..
Class A assumes the idle voltage to be the DC level..and the AC voltage to swing up to TWICE the DC level....then there is a margin before arc over...
SO it boils down to sum of DC + AC voltage ...
In Push-Pall Class AB operation... The voltage swing does not need to go beyond the DC operating point, maybe slightly... The AC swings DOWN from the DC voltage point not up...
The average plate dissipation integrated over the cycle is reduced roughly 50% .... so the load line can go over the plate dissipation curve if need be...
It's not the plate voltage that creates the destruction ... It's the SCREEN voltage that typically causes the problems...
The real working voltage of a tube is usually more than TWICE the recommended max voltage listed in the tube data sheets... ie, this is usually specified as the CLASS A MAX plate voltage... in Single Ended operation..
Class A assumes the idle voltage to be the DC level..and the AC voltage to swing up to TWICE the DC level....then there is a margin before arc over...
SO it boils down to sum of DC + AC voltage ...
In Push-Pall Class AB operation... The voltage swing does not need to go beyond the DC operating point, maybe slightly... The AC swings DOWN from the DC voltage point not up...
The average plate dissipation integrated over the cycle is reduced roughly 50% .... so the load line can go over the plate dissipation curve if need be...
It's not the plate voltage that creates the destruction ... It's the SCREEN voltage that typically causes the problems...
add to that is the possible arc over, i had a 6ca7 arc over to pin 2, fortunately only happened once and the amp survived it....i slipped a heatshrink tubing over pin 3...
Hi Guys
Jim Kelly used a quad of 6V6s to get 60W. Where a pair of Vs can sound creamy or muddy, a quad opens up and is a much more balanced tone. Va and vs at 490V with proper screen-stop values. See TUT5.
At 450V with a 4kaa OT you should get 50W. There is almost no audible difference between 50W and 60W through a dynamically linear speaker.
I wouldn't waste much effort on simulclass. This is a mix of class-A and class-B operation promoted in a 1950s electronics magazine. It is a more useful concept in an SE amp than in push-pull. As TUT6 details, mesa distorted the truth of the simulclass wiring in their hand-drawn schematics. The OT is nothing more than one with UL taps and the class-A pair tied to them. The power contribution of the inner tube pair is thus only 16% of the total output.
Be sure to give each output tube its own bias control. It would also be wise to have enough heater current available to use larger tubes, then you can mix them.
Have fun
Jim Kelly used a quad of 6V6s to get 60W. Where a pair of Vs can sound creamy or muddy, a quad opens up and is a much more balanced tone. Va and vs at 490V with proper screen-stop values. See TUT5.
At 450V with a 4kaa OT you should get 50W. There is almost no audible difference between 50W and 60W through a dynamically linear speaker.
I wouldn't waste much effort on simulclass. This is a mix of class-A and class-B operation promoted in a 1950s electronics magazine. It is a more useful concept in an SE amp than in push-pull. As TUT6 details, mesa distorted the truth of the simulclass wiring in their hand-drawn schematics. The OT is nothing more than one with UL taps and the class-A pair tied to them. The power contribution of the inner tube pair is thus only 16% of the total output.
Be sure to give each output tube its own bias control. It would also be wise to have enough heater current available to use larger tubes, then you can mix them.
Have fun
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