DirtyErnie Posted January 7, 2021 Share Posted January 7, 2021 EL84 400v plates, 300v screens, 20 watts. Pick up an old Scott and fix it, or just the transformers. Or just the schematic for the power amp and build. They're simple and sound great. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 7, 2021 Share Posted January 7, 2021 Some EL84/6BQ5 may not hold up too long with a 400 volt anode voltage...7189 and EL84M are a bit more rated for the application I'm guessing. Quote Link to comment Share on other sites More sharing options...
DirtyErnie Posted January 8, 2021 Share Posted January 8, 2021 Maybe. If my brain's not broken tonight, I though high screen voltage was harder on tube life than high plate voltage. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 8, 2021 Share Posted January 8, 2021 TDSL Tube data [EL84] (duncanamps.com) Quote Link to comment Share on other sites More sharing options...
Last Lemming Posted January 10, 2021 Author Share Posted January 10, 2021 So, I did find Audio Note as kits. They seem like fine kits, but many threads of builds I’ve found (when I say many I mean 3) that pieces were missing or failed soon after installation. I decided to start with something a bit less ambitious, maybe a tube phono pre. I did just pick up a vintage Audio Research V35. It 30 watts per channel Triode, so power should be ok. On the discussion of power I do have a question of curiosity. I was trying to determine how much power my current amp was putting out. I went to an online calculator and i plugged in 95 db/watt efficiency for the speakers - since this is what I hear the forte iii’s actually come closer to when tested - I set my distance to 8’ sitting distance from speakers and tried to figure if I wanted 87 dB I would only need about 1/2 watt. does this seem about right? I think 30 watts should be ok , since I typically don’t listen above 85 db (sitting position) Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted January 10, 2021 Share Posted January 10, 2021 38 minutes ago, Last Lemming said: So, I did find Audio Note as kits. They seem like fine kits, but many threads of builds I’ve found (when I say many I mean 3) that pieces were missing or failed soon after installation. I decided to start with something a bit less ambitious, maybe a tube phono pre. I did just pick up a vintage Audio Research V35. It 30 watts per channel Triode, so power should be ok. On the discussion of power I do have a question of curiosity. I was trying to determine how much power my current amp was putting out. I went to an online calculator and i plugged in 95 db/watt efficiency for the speakers - since this is what I hear the forte iii’s actually come closer to when tested - I set my distance to 8’ sitting distance from speakers and tried to figure if I wanted 87 dB I would only need about 1/2 watt. does this seem about right? I think 30 watts should be ok , since I typically don’t listen above 85 db (sitting position) The best way to know how much power is needed is to take an actual measurement: https://community.klipsch.com/index.php?/topic/170414-who-wants-to-measure-how-much-power-voltage-is-really-needed/ A more rudimentary measurement can be taken with a simple multimeter alone if you are interested. Maynard Quote Link to comment Share on other sites More sharing options...
Last Lemming Posted January 12, 2021 Author Share Posted January 12, 2021 So I bought a temperature controlled soldering kit with hot air, some .032” 60/40 solder, and two practice solder kits from eBay. I also ordered the Bottlehead Phono preamp kit. I’ve soldered basic things before like speaker connections and such, but never circuit boards, so I’ll practice up a bit first. I looked over and read the BH instructions for the phono preamp and it seems straight forward enough. Just got to get my soldering skills updated. 1 Quote Link to comment Share on other sites More sharing options...
BadChile Posted January 13, 2021 Share Posted January 13, 2021 Nice. Having built a reduction, post here if you have issues. Heads up that the voltage check on terminals 44 and 45 is wonky: measuring DC you should read 0 Volts, but there is AC on those terminals so your meter might spit out a reading (mine reads 75V). One other thing is that a high resistance, say over 1 MOhm is as good as open. Good luck. Other than the case I really enjoyed my build and it worked great right off the bat. 1 Quote Link to comment Share on other sites More sharing options...
henry4841 Posted January 13, 2021 Share Posted January 13, 2021 Plenty of youtube videos on how to solder. The main thing with any type of soldering or welding for that matter is the the pieces you want joined together must get hot enough to melt the solder. You do not melt the solder with the iron. The pieces being joined together have to melt the solder for a good joint. Be sure you see the solder flow. Too many are afraid of overheating the components. More chance of bad joint then overheating them. The are made to weld together. Modern tiny SMT, SMD, etc components are placed on a board then put into an oven that is hot enough to melt the solder under them. Quote Link to comment Share on other sites More sharing options...
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