I am planning to use ZTX450 and ZTX550 respectively, unless the PCB I end up buying requires something else.
what kind of measurement that i can perform? I only have dmm. it seems that not possible to return this item, taobao only cover 7days guarantee.
I have tested several jfet for Idss, but no idea to test vfet
@ JPS1964
You can learn better amplifiers pcb's design from this one
http://www.diyaudio.com/forums/pass-labs/276711-sony-vfet-amplifier-part-2-a-35.html#post4401429
or http://www.diyaudio.com/forums/pass-labs/276711-sony-vfet-amplifier-part-2-a-35.html#post4401259
Have a nice day
@soundhappy
Definitively, I don´t think so!
How can you claim this? Analog circuit board design is very difficult, no rules at all. You need a lot of experience.
The first I learn is to keep trace as short as possible. And I´m sure symmetrie and a sexy routing have direct impact of the final results, but this is my own opinion, nothing provable.
Tea-Bag is only a copy of Nelson Pass design. To your charge, the VFET are rareties, so never change a winning design!
Definitively, I don´t think so!
How can you claim this? Analog circuit board design is very difficult, no rules at all. You need a lot of experience.
The first I learn is to keep trace as short as possible. And I´m sure symmetrie and a sexy routing have direct impact of the final results, but this is my own opinion, nothing provable.
Tea-Bag is only a copy of Nelson Pass design. To your charge, the VFET are rareties, so never change a winning design!
Attachments
Just remember if you want to use the TO-247 parts you will need to take precautions to ensure that the TO-3 pads don't short against the heat sink. You might want to find someone to prototype this configuration.
Look at Tea-Bag's layout and you will see what I mean.
I don't think a "milled channel" as you propose is the right solution either, seems like a lot of mechanical stress on the board - mounting torque for the devices is critical.
@ JPS1964
Yes lot of experience but not only with software if you have build ready by your self just one pure class A amplifier at home you can understand needs for big heat sinks and T fat aluminium profile to attach power transistors all with some distance between heat sinks and components on pcb's all in big chassais who garantie lot of air flow inside and some distance from psu transformer as well.Personally i am not in logic to fix pcb's directly on heat sinks because heat toast slowly all components , capacitors first & so more cook thermal distortion. Short path is ok but safety and long time service first.
Audio signal is best with quality cooper wire soldered directly to pcb track, aluminium parts are to avoid if we can.
Take my opinions like constructive critics i feel JP you like it design.
Courage have fun
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@soundhappy
I know about power dissipation with class A amplifier. Proud and experienced after building Hiraga´s Monster. Big heatsinks and mainly mechanical construction difficulties. I finished the construction of a new jumbo tube socket... yes I know about temperature.
If there is no air flow inside the case the temperature will rise inside and you will toast the electronic components (electrolytics will suffer a lot --> WIMA offers a 220µF MKT, but whats about the big power supplies electrolyticsß the problem remains). You have to create some artificial chimeys to allow better air flow.
Thermal distorsion problems? Then you have to move to vacuum tube amplifier
I don´t like wirings and try to reduce this to a minimum: AUDIO-IN (shielded, good quality, available = no problem), AUDIO-OUT (I like twisted flat cable but nobody use this kind of connexion) and the power supplies wiring. I´m not a fan of direct soldering cable into PCB, they can broken and the soldering is not the best electrical connexion on PCB, right, better is a press-fit connexion but no specific developped solution exists for diy audio (Würth propose a nice solderless connexion solution)! And like the NOS transistors and mosfets no market today for this kind of components, they want to deliver the big consumer market, low cost and shortest lifetime.
Good software and experienced usage will give you 70% of the good end results; think about the possibilities 20 years ago!
My purpose was to propose an other approach then only stupidely copying an existing and demonstrated functional PCB.
Too bad, I don´t have the SONY NOS mosfets and I will never buid this amplifier
@luvdunhill
... sorry I don´t see for the TO247!?
Tea-Bag puts the voltage stage onto separate board. I don´t see anything about variants for the mosfets.
I know about power dissipation with class A amplifier. Proud and experienced after building Hiraga´s Monster. Big heatsinks and mainly mechanical construction difficulties. I finished the construction of a new jumbo tube socket... yes I know about temperature.
If there is no air flow inside the case the temperature will rise inside and you will toast the electronic components (electrolytics will suffer a lot --> WIMA offers a 220µF MKT, but whats about the big power supplies electrolyticsß the problem remains). You have to create some artificial chimeys to allow better air flow.
Thermal distorsion problems? Then you have to move to vacuum tube amplifier
I don´t like wirings and try to reduce this to a minimum: AUDIO-IN (shielded, good quality, available = no problem), AUDIO-OUT (I like twisted flat cable but nobody use this kind of connexion) and the power supplies wiring. I´m not a fan of direct soldering cable into PCB, they can broken and the soldering is not the best electrical connexion on PCB, right, better is a press-fit connexion but no specific developped solution exists for diy audio (Würth propose a nice solderless connexion solution)! And like the NOS transistors and mosfets no market today for this kind of components, they want to deliver the big consumer market, low cost and shortest lifetime.
Good software and experienced usage will give you 70% of the good end results; think about the possibilities 20 years ago!
My purpose was to propose an other approach then only stupidely copying an existing and demonstrated functional PCB.
Too bad, I don´t have the SONY NOS mosfets and I will never buid this amplifier
@luvdunhill
... sorry I don´t see for the TO247!?
Tea-Bag puts the voltage stage onto separate board. I don´t see anything about variants for the mosfets.
Good news JPS you can build very interesting amplifier with Sony Vfets
http://www.diyaudio.com/forums/pass-labs/276711-sony-vfet-amplifier-part-2-a-57.html#post4434577
... and they don´t like SMD components!
where is a rope? ... my last contribution to this thread
People don't like surface mount components cause if repairs need to be made the average diy guy can't repair it. Which means you have to throw it in the bin.
Don't take people's suggestions personally. If you want your pcb to be of interest to others then you need to fairly consider their concerns or ideas.
The way you have it I don't see a lot of room for a 500VA transformer (that's what I have).
Need to make it flexible like Zen Mod.
Have a look at Zen Mod's Bablefish J pcbs. He's covered everything to make it very versatile.
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In what cases would a CSX1 with paralleled output devices be interesting? I suppose there are two answers: system dependent and sound. If you ran each at half the output, i assume it would sound pretty similar to the original. I would add some 220 ohm resistors like in the newest amp, but any other changes? I have a 400VA 2x22 VA transformer, so that would be my current limitation. I am guessing some parts needs to change on the regulators to give me a wider adjustment range?
I am also thinking of one regulator per channel per rail, which would distribute a bit more heat across the two sides.
Does anyone have a reliable source for the single die / smaller cousin VFETs?
I am also thinking of one regulator per channel per rail, which would distribute a bit more heat across the two sides.
Does anyone have a reliable source for the single die / smaller cousin VFETs?