Ebay AL-811H, What Have I done?

[drgrant]

That does bring up a question I have had for a while. It looks like the ts440 you mentioned doesn't have variable power. Everything I read says it is not good to use the Mic gain to control power. If this is true, wouldn't it be better to adjust the power through the alc jack on the radio and not use the alc with the amp?

Well, on a TS440 you have to use the mic gain to adjust SSB power. ALC jacks are pretty much for amplifiers only, its like a feedback circuit between the radio and the amp to "leash" the radio's output depending on what the amp thinks it is getting for input
power. Also, at some point or another with the amp ALC pot etc, you as the operator basically get to define the boundaries of that leashing system, if you really want to.

 

[Dmans]

How-To TS-440 SSB adjustable output power control

If you clip or remove diode D49 on the IF board (the first board you see after removing the top cover), you will be able to control your output power on SSB with the carrier control. I can dial my TS440 down to 1 watt (or less) or up to 100+ watts using the carrier control. AM, FM and CW is still adjustable with the carrier control after this "Mod".

Be forewarned, there is a lot of power output adjustment in a small turn of the carrier control potentiometer (I.E. Minimum at 0-Maximum at 4). It is a bit touchy, but once set it doesn't move or drift.

73's
David

 

[338_MtRushmore]

Well, on a TS440 you have to use the mic gain to adjust SSB power. ALC jacks are pretty much for amplifiers only, its like a feedback circuit between the radio and the amp to "leash" the radio's output depending on what the amp thinks it is getting for input
power. Also, at some point or another with the amp ALC pot etc, you as the operator basically get to define the boundaries of that leashing system, if you really want to.

There is a very simple circuit that can be plugged into an ALC jack to control output, but I forget exactly what it is off hand. Ameritron makes a box that intercepts the alc signal with separate pots for tuning power and normal operation.

As far as defining the boundaries, the boundary of the ALC is defined by the designer of the amplifier. On this 811H the boundary is 80 watts by actual output and currents, and the manual.

 

[BlowinSmoke]

The TS-440s does have a variable RF power control. But does not work on SSB.

 

[338_MtRushmore]

The TS-440s does have a variable RF power control.

I don't own one, I just saw there wasn't one on the face.

 

[drgrant]

There is a very simple circuit that can be plugged into an ALC jack to control output, but I forget exactly what it is off hand. Ameritron makes a box that intercepts the alc signal with separate pots for tuning power and normal operation.

This is good to know!

As far as defining the boundaries, the boundary of the ALC is defined by the designer of the amplifier. On this 811H the boundary is 80 watts by actual output and currents, and the manual.

I meant that in a literal sense, the operator is doing this when setting up the adjustment..., Obviously, the designer is going to say "set it to drive only with X maximum!" etc.

 

[338_MtRushmore]

This is good to know!



I meant that in a literal sense, the operator is doing this when setting up the adjustment..., Obviously, the designer is going to say "set it to drive only with X maximum!" etc.

I was understanding you to mean that the alc could be adjusted for any power the operator decides. I think we are on the same page, but just in case... The alc on this type of amp has exactly 1 setting. No more, and no less. Correct?

 

[drgrant]

I was understanding you to mean that the alc could be adjusted for any power the operator decides. I think we are on the same page, but just in case... The alc on this type of amp has exactly 1 setting. No more, and no less. Correct?

I wasn't aware of that, most tube amps I've seen with ALC jacks have some kind of a pot on the back of the amp and then there's often one on the radio side, as well.

 

[338_MtRushmore]

There is a pot on the back to adjust the alc. I don't know about amps with 2 pots for the alc, I've never researched those.

If I adjust the alc to more than 80 watts then I can easily over drive it, and the alc won't prevent it from being over driven.

If I adjust it for less than 80 watts I won't be able to drive it with the 80 watts necessary to properly tune the amplifier.

This is my understanding of it at this moment

 

[BlowinSmoke]

If you only had a 50 watt radio then you would load the amp with 50 watts, you would have to because you don't have any more power. Now, just because you loaded it with 50 watts does NOT mean it is not loaded properly because you did not load it with 80 watts. The amp is properly loaded for your radio for a maximum output of 50 watts. Does that clear it up?

 

[338_MtRushmore]

That could be true, but I haven't found any evidence to support that. Do you know where I could find that info?

 

[BlowinSmoke]

That could be true, but I haven't found any evidence to support that. Do you know where I could find that info?

A simple understanding of a linear amplifier is all the proof you need. If the amplifier is operated anywhere along it's linear curve, (the linear portion is basically a straight line) the amp will be linear. A linear amp becomes non linear when it is operated out of the linear region So, if an amplifier will remain linear up to 80 watts of drive, and you only drive it with 50 watts it is surely in the linear region. Obviously you can't over drive it. They key is that when you load the amp you load it at the 50 watt maximum you will be driving it with. If you drive it with more power now the loading is no longer optimum, the amp will be too lightly loaded.

 

[338_MtRushmore]

So the recommendation to tune it it at full output is just for safety? Everything I have seen specifically says not to tune at a reduced drive level.

 

[BlowinSmoke]

So the recommendation to tune it it at full output is just for safety? Everything I have seen specifically says not to tune at a reduced drive level.

Your last sentence should be "Everything I have seen specifically says not to tune at reduced power AND THEN DRIVE THE AMP WITH ADDITIONAL POWER.

That is was you have seen.

 

[338_MtRushmore]

Ok, I see now what you mean. I reread some stuff, and it is a little more clear. It should be tuned to maximum exciter power or 80 watts, whichever comes first. Then reduce drive to desired output. Am I correct yet?