Anybody run an 811A tube amp?

[Captain Kilowatt]

Well I now have all the parts to build a four tube 811A 160-10m amp except for the tubes themselves and I will be ordering them from RF Parts soon.I was just wondering if anyone out there is or has run 811A's.I know the Ameritron AL-811H has four tubes and so did the old Heathkit Warrior HA-10 amp.Just wondering how you like them especially if the amp was home brew.This project will be a labor of love I assure you.Most of the parts are heavy commercial or broadcast duty.The plate transformers will be able to supply 1500 volts DC at 750mA and just idle.They are Hammond units scrounged from some air force surpluss.The tank coil is edge wound silver plated bar 8mm wide and 1.5mm thick.The tune and load capacitors are Jennings vacuum variables.Both are 1000pf and one is rated at 7500 volts and the other for 10,000 volts.Filament and plate voltages will be adjustable using a Stabiline AC voltage regulator built in.The entire unit will be built into a standard 19 inch Hammond rack cabinet 40 inches high.Over kill you say? You may be right but I have the parts and they cost me next to nothing,most were obtained from scrapping old broadcast transmitters.This will take me a loooooong time to complete as I want it to be something that I can truly be proud of.It will even have a clear glass window so you can see the tubes operating.<img src=http://www.ezboard.com/intl/aenglish/images/emoticons/nerd.gif ALT="8o"> <img src=http://www.ezboard.com/intl/aenglish/images/emoticons/eek.gif ALT=":eek"> <img src=http://www.ezboard.com/intl/aenglish/images/emoticons/happy.gif ALT="">

Garth 9VE01 PE993 CDX993 Learn from others mistakes.You can not live long enough to make them all yourself.</p>

 

[AudioShockwav]

These tubes have been around forever! I have a NOS 811(not even an 811-A) that is still in the old style "RCA Radiotron, better performance throughout the world box", the little 8 page booklet that came with the tube is still in with the packing and says copyright 1939.

It includes schematics to build a 2 tube-plate modulated RF Amplifier, and a single tube CW Amp.



73

Jeff


CDX 339 Radioactive

</p>

 

[AudioShockwav]

Ditto on what Doc has said, and I love his statment" one of those things that you 'cuss' for ever. It has had problems, but always seems to work" <img src=http://www.ezboard.com/intl/aenglish/images/emoticons/happy.gif ALT=""> , I sometimes badmouth the amp....but I would never get rid of it because it has yet to fail(less by my own abuse of the tubes, and they are cheap enough that you just buy some more and go on) I also have the 3 tube Amp, I Have found that the GE or Early RCA style tubes hold up better than the tubes(china?) that came with the unit. This would be the equal to the 811A Marshall that RF parts sells, but even at those , if you over drive them you can melt/burn holes in the plates. The GE/Marshall seem to hold up the best( I have 3 GE`s in it now,) when the plates are starting to glow dull red <img src=http://www.ezboard.com/intl/aenglish/images/emoticons/eek.gif ALT=":eek"> and I did put a faster (read LOUD) fan on the thing. They are good tubes within there limits, and the cost is such that if you toast one (or more) you don`t go broke buying a few .......

Have fun!



73

Jeff


CDX 339 Radioactive

</p>Edited by: <A HREF=http://pub86.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=audioshockwav>AudioShockwav</A> 

at: 11/18/03 4:40 pm