Is the voltage of the power tubes lowered in low wattage mode of 6505MH?

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NakajimaYusuke
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Is the voltage of the power tubes lowered in low wattage mode of 6505MH?

Post by NakajimaYusuke » Sun Jun 25, 2017 12:33 pm

Hi, I am tube amp beginner and using 6505MH as my first tube amp. :D

I have a question about switching output wattage. :?:
6505 mh can choose the output wattage from 20w, 5w, 1w.

Is it literally a function to reduce the operating voltage of power tubes?

I am not sure of this mechanism yet.
I think that it is a different function from attenuator.
And this is also different function from the POST-GAIN knobs.


And another question.
If I used 1w mode or 5w mode,
Does damage to the power tubes increase? Or decrease? Or does not it change? :?:

I have only used 20w mode until now.
But, I noticed that lower wattagew mode are useful depending on several purpose.
I felt the effect of PRESENCE knob and RESONANCE knob changes in lower wattage mode.

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Enzo
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Re: Is the voltage of the power tubes lowered in low wattage mode of 6505MH?

Post by Enzo » Sun Jun 25, 2017 5:26 pm

I cannot answer those questions without a schematic.

But as to wearing the power tubes, let me ask you this: Do you play blues? Do you bend notes? If so, do you try to not bend any more than you have to because it shortens string life? or do you play like you play? In other words, if the 5w mode sounds better for you or is more useful, then that is how you should use it, and tube life will be whatever it is. There will not be some huge night and day difference anyway.

wheelman
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Re: Is the voltage of the power tubes lowered in low wattage mode of 6505MH?

Post by wheelman » Mon Jun 26, 2017 10:51 am

Changing the output wattage does not change the voltage at the power tubes, it routes the additional current to a set of load resistors that shunt it to ground and convert part of it to heat.

Wheelman

NakajimaYusuke
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Re: Is the voltage of the power tubes lowered in low wattage mode of 6505MH?

Post by NakajimaYusuke » Mon Jun 26, 2017 2:40 pm

Enzo wrote:I cannot answer those questions without a schematic.

But as to wearing the power tubes, let me ask you this: Do you play blues? Do you bend notes? If so, do you try to not bend any more than you have to because it shortens string life? or do you play like you play? In other words, if the 5w mode sounds better for you or is more useful, then that is how you should use it, and tube life will be whatever it is. There will not be some huge night and day difference anyway.
Thank you. I was relieved. I will try to utilize low watt mode as well. :D
I am a cautious man.
If "damage to strings due to bend" is unknown, I might hesitate to bend.
Similarly, because "damage to tubes due to low watt mode" was unknown for me, I was hesitant to use it.

From now on I will use it with confidence.

wheelman wrote:Changing the output wattage does not change the voltage at the power tubes, it routes the additional current to a set of load resistors that shunt it to ground and convert part of it to heat.

Wheelman
Thank you. That is, when I used the low watt mode, 6505 MH become a bit hotter than usual. :oops: :oops: :oops:
But if that is only a little, I do not mind.

Of course, I will be careful "not to produce loud volume in low watt mode".

Evil Z06
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Re: Is the voltage of the power tubes lowered in low wattage mode of 6505MH?

Post by Evil Z06 » Tue Jun 27, 2017 6:52 am

Don't be too concerned about saving the power tubes crank that puppy up and enjoy the amp.As soon I got mine the first thing I did was re bias the power tubes.It came from the factory at 23 mA I bumped it up to 26.5 mA and it sounds vicious. I also removed the front black wood panel and put back on the black metal grill so the ventilation of heat is much better and looks very cool .... Plus I added some white LEDs inside.

NakajimaYusuke
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Re: Is the voltage of the power tubes lowered in low wattage mode of 6505MH?

Post by NakajimaYusuke » Wed Jun 28, 2017 3:34 am

Thanks. I also removed the front black wood panel now. :D
With this, I quit worrying about overheating too.
I will simply enjoy this amp. :lol:

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