ALC Use

[fogdog]

I've got a 811h I use with my very rare icom 7300 . I've been told by my old buddy not use the ALC cord. . I'm just wondering if this is sound advise. So far everything is working fine, and I keep the power under 600 watts usually. Not knowing anybody else to ask near me, hear I am. What's the general thoughts out there?

 

[groundwire]

The alc on amps were originally for old radios that had no drive control. For newer radios that do, its not really necessary. But some radios like icoms ( some of them) will have a power spike when you first modulate. This could overdrive or damage the amp. So its really up to you. I use it just as a fail safe, cant hurt.

 

[fogdog]

Thank you for the info, that's pretty much what I thought. I know my 7300 will spike. I've seen it, but then again I usually only run the 7300 at 40% power. Maybe I should run it as a precaution like you have said groundwire.
I'd like to hear from some owners of the 7300/al811h combination. I know there out there. I've heard them on the radio, but didn't get a chance to talk with them about it. Again, thank you for the information. I feel it's the smart move to use the ALC. I guess it's just 1 more step in the tuning procedure.
73

 

[BlowinSmoke]

If the ALC is not adjusted correctly that is worse than not using it at all. If your radio has an adjustable output then you don't need ALC. The 811H is not a solid state amp and a leading edge spike does not bother it. If the radio's ALC does not catch the leading edge spike on its own it's too late by the time it gets to the amp.

 

[Ranch55]

I run an Ameritron AL-1500 behind my I-7300 ......
I have not ever been able to get the ALC connection from the amp back to the transceiver to ever do any controlling of the radio output.
SO, I just turn the output power down on the 7300 to about 18% - 20% when I run the AL-1500 also.
Been running it like that for about 3 years ......

 

[443]

When I got my AL-811H the grid resistors had fallen off from overheating, had tubes blown, all kinds of mess. I replaced those resistors with direct wire to ground, if I remember right about 68 watts of drive power into the amp gets pretty much full output. No need for ALC to amp connection since your radio has adjustable output power. Run the AL-811H with 811 tubes, (not 572 tube version) at about 500W-600W output on SSB and you probably won't have to replace the tubes for a long time.

 

[Road Squawker]

...edit.... Run the AL-811H with 811 tubes, (not 572 tube version) at about 500W-600W output on SSB and you probably won't have to replace the tubes for a long time.

...

 

[fogdog]

I've been tuning with 70 watts in, then I operate between 40-60 watts in, with 400-650 watts out, and no ALC connection. Been working great. I just keep an eye on my alc meter. I also worked with KC9VKV to get the best audio one can expect with my IC 7300, and the reports I get are very good.

 

[fogdog]

...

Oh no, the dreaded popcorn emoji.

 

[443]

I don't get the popcorn emoji. The tubes in my amp been in there for 5+ years, maybe more like 7-8 years and haven't ever had a problem. If someone is slamming the grid current too hard because they don't know how to load an amp, that's the problem...

 

[fourstringburn]

my very rare icom 7300

I didn't know there are rare Icom 7300 models in existence…

What's rare about it?

 

[fogdog]

I didn't know there are rare Icom 7300 models in existence…

What's rare about it?

It's a joke Brother. Because there are so many of them out there. Not rare, quite the opposite. Savvy?

 

[fogdog]

I don't get the popcorn emoji. The tubes in my amp been in there for 5+ years, maybe more like 7-8 years and haven't ever had a problem. If someone is slamming the grid current too hard because they don't know how to load an amp, that's the problem...

This is also what I've been told. I'm diggin my 811H. Unbelievable how it gets through a pile up, and I'm really not using it to its full potential. 400-500 watts makes a huge difference. I haven't tried it on CW yet. Sure glad I bought this amp. Happy, happy, happy.