Calling all Amplifier Design Experts

[WA6DJM]

I own a Ameritron AL-811 3 Tube Amp and I realize the difference in wattage and DB Gain isn't really noticible but I was looking at the amp and the schematic and realized that a 4th tube and socket and all could be added to the mix. The ckt board for the cap hat is already setup for it, and I was wanting to know any concerns or design changes that would have to take place. Regardless of which tube I choose I think that it would be an improvement over the AL-811H with all the extra Circuitry. I would like my responses forwarded to my e-mail account also if you would be so kind.

Thanks;
WA6DJM
Always Learning, Always Improving, Always Striving for a ounce of Perfection
K3DJM1@gmail.com

[WB2WIK]

I don't really get the question.

[K1ZJH]

I don't really get the question.

He wants to make his AL-811 into an AL-811H by sticking another socket and 811 tube in his amp...
without regard for the HV supply limitations, or if the filament transformer can handle it.

Pete

[WA7PRC]

Why would anyone WANT to do that? An 811A is worth about 200W. The improvement (assuming the PS can handle it) is 10LOG (800/600) = 1.25 dB. Putting it in perspective, assuming everyone's S-meter is accurate, the improvement will be about ¼ S-unit. Most folk have a hard time telling a 3 dB difference, and 1¼ dB change is barely preceptible. If you're determined to step up in power, it'd be better to just sell the AL-811 and build/buy something that'll do the legal limit. That would net you 10LOG (1500/600) = 4dB.

[WA6DJM]

I was looking for information on what when where and why the PS issues is enough to start with I am just trying to learn not change my system I also didn't know if it would allow me to decrease the tube duty cycle by using the extra tube and sharing the load, I wasn't really interested in the power gain.

Thanks;
WA6DJM
Always Learning, Always Improving, Always Striving for a ounce of Perfection
K3DJM1@gmail.com

[AH6RR]

They use the same transformer in both amps so the PS should be no problem.

[AH6RR]

They just add a Neutralizing transformer for 4 tubes look at the parts list for both amps.

[WA7PRC]

While the xfmr is the same, a bunch more needs to be changed to turn the AL-811 into the AL-811H. And again, if the tubes were pushed to their ratings, the OP would realize a paltry 1.25 dB increase in RF output. And, if not pushed, useful tube life would not be noticeably increased. For tubes that are inexpensive to start with (about $20 each), there's virtually nothing to gain from that.

[W1QJ]

While the xfmr is the same, a bunch more needs to be changed to turn the AL-811 into the AL-811H. And again, if the tubes were pushed to their ratings, the OP would realize a paltry 1.25 dB increase in RF output. And, if not pushed, useful tube life would not be noticeably increased. For tubes that are inexpensive to start with (about $20 each), there's virtually nothing to gain from that.

That is not the issue here. The true answer to his question is this, add the missing parts and you have the same amp. Power supply is same one.

[K1ZJH]

I wonder why Ameritron produce two models if there is no savings in the cost of the iron? One extra tube and a few
supporting parts isn't that much cost?

Pete