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VARIABLE DK AND AMS

Sonar

Sr. Member
Apr 8, 2016
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My Madison has a variable output knob where the 1/4" headphone jack is located.
If I'm not careful or not paying attention I'll occasionally move the variable knob changing the dead key while turning on the rig.on as the on/off volume knob is right Right next to the variable. I know that my amp is and was tuned with a 3/4 watt DK but even with a good meter Wich IMO I have, using the variable in order to get it back to the exact 3/4 watt DK in which I tuned the amp for is difficult.
Re tuning these old 6lq6's isn't something I liked doing. Is it okay to use the variable in order and try to get to the original DK or just run the amp with what might not be the exact DK it was originally tuned with? It doesn't happen often but it does indeed happen. When it does what I do now is with the amp on standby switch the meter to the 20 watt scale, and try
my best to get it as close to the 3/4 watt DK. take the amps stand by off and use it as if nothing happened. Re tuning this amp once or twice a week cannot be good but will running the amp at a different DK then it was tuned with not be so good? Will a few milliwatts take the amplifier out of resinance? I guess this post comes down comes down to that last question. Thanks for your input. 73
 

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If the amp is originally tuned for maximum output with a certain input drive level then reducing that drive level will not harm anything at all. In fact a tube amp should ALWAYS be tuned for maximum output and if the operator wants to run less than max output the recommended way to do it is to simply reduce drive level. just make sure you don't overdrive it by bumping the variable power control to maximum.
 
If the amp is originally tuned for maximum output with a certain input drive level then reducing that drive level will not harm anything at all. In fact a tube amp should ALWAYS be tuned for maximum output and if the operator wants to run less than max output the recommended way to do it is to simply reduce drive level. just make sure you don't overdrive it by bumping the variable power control to maximum.
Thanks ckw. Big help. I'd hate to cause these original d&a 6lq6's any unnecessary stress. I assumed that running an amp with a lower output then it was originally tuned at wouldn't be an issue but assuming in this case might've made what is a nice working triple stage a conversation piece. It's always a good idea to get a difinitive answer from one who knows. Thanks again. 73
 
Some think that not fully loading an amp to obtain lower output is fine but it effects IMD performance and lowers efficiency. Tuning for maximum output and then reducing drive is the way to go if less than maximum output is desired.
 
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Maximum MODULATED power output, not carrier power.

If you want to reduce power, select "Low" or reduce the drive level. Just be sure to repeak it AT the power level you're using. The load control will peak at a different spot for full power than it will at half power.

Never peak it for full power and then turn down the drive. Peak the Load control at the drive level you'll be using.

It's an efficiency thing. The tubes work harder at half drive if they were peaked for full drive.

73
 
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he must be in Australia and did not flip it before posting.
I was wondering why some were replying that my op was upside down. It is not showing that that way my smartphone screen. I didn't even know you could actually flip text. Thanks for the heads up. I hope It doesn't happen again and if so I would appreciate it someone would let me know what I need to do in order to stop that from happening. I don't know why but my voice to text it's not working probably on this site. It doesn't happen anywhere else but here. I I will update my voice to text app. That's my stop I'm happy this from happening period I constantly have to go back and basically fix 60%of my postings. thanks 73
 
I was wondering why some were replying that my op was upside down. It is not showing that that way my smartphone screen. I didn't even know you could actually flip text. Thanks for the heads up. I hope It doesn't happen again and if so I would appreciate it someone would let me know what I need to do in order to stop that from happening. I don't know why but my voice to text it's not working probably on this site. It doesn't happen anywhere else but here. I I will update my voice to text app. That's my stop I'm happy this from happening period I constantly have to go back and basically fix 60%of my postings. thanks 73

If on your phone you were probably holding it upside down with auto-rotate on.
 
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