As you can see (this is my 801 preamp in building state, but other DHT preamp is similar) there are in the upper left to right Ale's gyrator -with yellow capacitor-, then Rod Coleman regulator and 50W bias resistor. Both of them are installed on heat sink.
Tube sockets (required resistors and output capacitor too) are in the suspended (3mm alu) subschassis.
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Plenty of heatsinking! You might need it for the 801. That's a useful chassis - solid state amp type. Should sound great.
Just ask Ale. He's very human! He'll also give you equivalents commonly available to you. He doesn't do kits as such - he's a very busy guy with a demanding job and this is just a hobby. I don't know how he even has time for all the hifi research he does, except that he's very bright and very quick. You would have to work out how to build it from the schematic, which is what we all have to do here at DIY more or less. Ale's 01A design is fairly new so the user base should build up. Rod Coleman's regs have been going for many years now, and he has had time to refine his kits and build instructions.
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Not quite right.
The box (a little chinese Aluminum Cabinet Heatsink Chassis DIY Case Amplifier Enclosure Box 212 70 257mm | eBay ) is very compact (212*70*257mm) and the heatsinks on his side not too large. After one hour the heatsink temperature is about 48-50 C.
I have larger (311*70*260mm) boxes, but I'm saving its for monoblock amp project.
470R Kiwame 2W.
It's good up to 35-50mA (depending of the "lower" JFET type and saturation current).
I use J310 -39mA saturation current- at 30mA.
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Give him time. He travels with his work. May not be at home. He tends to catch up in binges of activity.
Hi Bela,I also use in my 801 preamp J310 (and 1kV depletion MOSFET) in Ale's gyrator.
I prefer higher (25-30mA) anode current.
The tone -IMHO- "smoothens" about 25mA (I mainly use graphite anode 801s with moderate -7..8W- dissipation). The "steel" plate tubes (10, 10Y, 801 a etc.) "requires" higher anode current (in my 841-10Y-801a PSE amplifier I use this tubes at 30mA).
In this region -if the tube is in good working condition- the 3th distortion spectrum line is decreasing a little (according to my measurements), second is dominated (at line levels), so overall tone is become cleaner.
It's my experience, in my system, appropriate for my taste, so strongly subjective.
Did your gyrator worked properly from the start? I am trying Ale's gyrator with DN2540 and J310 and I can't adjust the plate voltage. The LND150 CCS works fine and I can adjust the reference. I use a bench HV supply, and as I increase the b+ the plate voltage increases with B+.
I can use a little help.
Thank you,
Radu
Hi Radu,
Now I use in my 801 preamp - quasi - fix B+ (simple CLCLC) and gyrators with J310 without any problem.
I tested this gyrator scheme with both (J310 and DN2540) FETs (and 01N100D a "upper" FET) in my test apparatus, but only with regulated B+ (Tomchr's MaidaII regulator).
Soon (at evening -European time- ) I will test it with variable power supply and will inform you.
p.s. I use higher reference voltage -aka greater resistor: 300k), than Ale.
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