Hello Tim, circuit I used is the same you, but this circuit I thought was for demonstration, not real, so I used drivers parts of next circuit of evolve page. It works very well (10Wrms 8ohm with 0.08% thd). I am collecting materials for doing second channel. Using resistive divider, 2K and 100 ohm feedback is around 26dB, as you calculate too. For open loop gain real, I need build the second channel and then I will measure because I have dismount connections (space, space....). And I need use a lot better heatsink because dissipate 60w between ccs and vfet.
LuminAria Test Channel
Received the components from Digikey, so I put together a pilot channel for testing ... and it works.
No optimization yet, I set the operating condition arbitrarily to:
B+ - 120V, Rd - 600R, Vbias = -19.7V
This gives:
Id - 60mA, Vds - 84V, Gain - 17.5dB
The 2SK82 runs quite hot (case temp 56 degC), it's currently mounted on a small aluminum block but the actual onboard heatsink is not any bigger, but the leakage current stays quite stable at around 3.8uA
Next step is to find the sweet spot, but with 3 parameters (B+, Rd and Vbias) that can change, this is going to be challenging
. Another challenge will be to find two 2SK82 that gives similar gain.
Received the components from Digikey, so I put together a pilot channel for testing ... and it works.
No optimization yet, I set the operating condition arbitrarily to:
B+ - 120V, Rd - 600R, Vbias = -19.7V
This gives:
Id - 60mA, Vds - 84V, Gain - 17.5dB
The 2SK82 runs quite hot (case temp 56 degC), it's currently mounted on a small aluminum block but the actual onboard heatsink is not any bigger, but the leakage current stays quite stable at around 3.8uA
Next step is to find the sweet spot, but with 3 parameters (B+, Rd and Vbias) that can change, this is going to be challenging
. Another challenge will be to find two 2SK82 that gives similar gain.Attachments
Not Quite Sea Ranch
The long holiday weekend afforded me time to finish a couple of room related projects. Some record storage, a drawer for my main rack, and a new rack for the bi-amp/tri-amp review project: it holds three amps and B4 crossovers. all in glorious baltic birch. My listening room doubles as my office so, there's my "instant office in a closet"
The long holiday weekend afforded me time to finish a couple of room related projects. Some record storage, a drawer for my main rack, and a new rack for the bi-amp/tri-amp review project: it holds three amps and B4 crossovers. all in glorious baltic birch. My listening room doubles as my office so, there's my "instant office in a closet"
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Incredible Michael play Moog Theremin
https://www.youtube.com/watch?v=8bakI0ITCqQ
Beaty work nice room congratulations
Greetings
Christophe
https://www.youtube.com/watch?v=8bakI0ITCqQ
Beaty work nice room congratulations
Greetings
Christophe
Nice work there, Tim
Not quite actually, when I put it under the QA400 last night, I noticed a 50Hz hum which is -50dB, and then it's harmonics also. I will re-arrange the messy cabling and twist them properly (was lazy to do that, thought it was only a test) to see if it solves the problem, I just hope it's not the board,
Your office and listening room is very very nice.
Burning Amp Festival:2015 Michael you are pioneer who bring to DiyAudio first & real
constructions projects , topologys with Sony sits in L'Amp articles.
Live Lab Hangout´s is about next pioneer work with Tokins
imho please keep that way to BAF 2015.
Balanced single-ended à la Son of Zen, Zen V6 ?
Greetings
Christophe
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Thanks for the ideas guys. I've got a few unconventional ideas for P-channel parts, but you should save them for what Nelson's working on.
Christophe, you make a fair point. A few nice members sent me some 2SK182ES and I think I should honor them with an amp at the show. I'll see if I can find someone to ship them to. Well, I should probably design and build them first.
Sorry Christophe, I don't have enough parts for anything balanced...but there are other parts.
Christophe, you make a fair point. A few nice members sent me some 2SK182ES and I think I should honor them with an amp at the show.
I'll see if I can find someone to ship them to. Well, I should probably design and build them first.Sorry Christophe, I don't have enough parts for anything balanced...but there are other parts.
A few nice members sent me some 2SK182ES and I think I should honor them with an amp at the show.
More the reason for me to try attend BA2015, since I don't imagine I'll
get another change to see those honking Tokins in action.
Dennis
Real time YouTube video live and Doctor Who amp with Dalek sit's
All Good News thanks for Diyers who send Tokins to Michael
All Good News thanks for Diyers who send Tokins to Michael
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