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Gentlemen, I want to thank you all for your input and help and especially to Lou for giving me some critical information. I gave the amp a road test today with a friend on 6 meters and he said it

OK, thanks for clarifying that, Lou, as it wasn't clear before. 73, Steve K0XP

NO NO NO. Not grid driven. ?Cathode driven! Neither?Carl or myself did grid driven! ?It was cathode driven. ?Yes I know 20?watts drive sounds crazy but handling the bit of positive feedback with

Yup; he was never real open about how he did some of the "successful" schtuff he was able to accomplish. So, Lou: are you saying that you believe Carl converted this "SB-206" to full grid-driven

Yup! Leave well enough alone. Sent from the all new AOL app for iOS

Yeah...I suffer from mess-with-it-itis sometimes but not in this case.? :) If it ain't broke, don't fix it. Warren

There should be about 70-90 ma. ?of idle current. I’d leave it alone. Sent from the all new AOL app for iOS

Thanks for that, Lou. And I re-read the meter explanation in the Heathkit manual and saw what you said. The end of the white range is 100 mA. This may or may not be an issue but I do not show any

Skip, he is reading the grid current wrong!!!!!! ?THE SB200 amp does not have a graduated scale for grid current!!!!!! It only has a white area as a safe zone. ?The last mm of the white zone is 100

Warren, at 50 mhz the neutralization on 572b tubes?is way out in outer space. ?It’s bad enough on 10 meters let alone on 50mhz. ?That said, you can’t expect a dip in the plate at maximum

Chuck, The grid question is a good one and there is NO schematic of the conversion. It is written on the "manual" page in big script that there is no schematic. That is part of the reason I am

This is interesting…was this amp modified for grid drive instead of grounded grid? Another possibility is that there could be a bit of positive feedback, not enough to cause self oscillation but

Steve, With no REL PWR function, I have just been peaking everything up using a watt meter. Like you, I am a little bit curious as to why it only takes 18 watts of drive to get 600 out. I just wrote

Lou, I am tuning it to keep the grid current at 500 mA or less. The white area tops at 500 mA so that is what I have been referencing. This is a very touchy tank circuit! The amp came with some pencil

Something doesn't sound right... you shouldn't be able to get 500 mils grid current and still have working tubes, ESPECIALLY with only 18 watts drive... That's a RIDICULOUSLY-LOW amount of drive; most

The grid current?isn’t 500, it’s has?nothing to do with the scale reading. ?As long as it’s in the white area it’s ok. ?With the 572b tube it’s the temperature of the plates that is the

If his license expired that long ago , his e-mail is not valid any longer, and his phone is disconned... that doesn't bode well. If I still lived in Mashachewzits, I'd take a drive up there to see

OK. Thanks for the replies, guys. I am getting 600 watts out at 18 watts of drive with the load backed off CCW ~25 watts from peak (per the instructions). The grid current is at 500 mA. The plate

Carl hadn’t been in on the various groups since before Covid. ?Reports say he’s ok but probably got tired of fighting on the groups and is pounding sand somewhere else. Sent from the all new

Can anybody with a two tube 2500 Commander ( those with grid trip protection) tell me at what grid current their amp trips out at? ?I have an older model in for work and it doesn’t have a grid