Well, after I found the complementary floating JFET input stage topology I'm never going back to BJT's for input stages and output stages. For VAS, drivers and other stuff I would still use them.
Yeah, I haven't been able to get it to work yet in my simulation software, Tina. I don't have models for the JFETs you specify. I used others but it didn't look too good.
I use these :
.model 2SK246 NJF (Beta=1.07m Rs=56.76 Rd=56.76 Betatce=-.5 Lambda=2.8m Vto=-2.638 Vtotc=-2.5m Cgd=10.38p M=.4373 Pb=.3905 Fc=.5 Cgs=6.043p Isr=112.8p Nr=2 Is=11.28p N=1 Xti=3 Alpha=10u Vk=100 Kf=1E-18 Af=1)
and
.model 2SJ103 PJF (Beta=2.197m Rs=76.76 Rd=76.76 Betatce=-.5 Lambda=735.3u Vto=-2.037 Vtotc=-2.5m Cgd=18.95p M=.5045 Pb=.3905 Fc=.5 Cgs=17.02p Isr=38.48f Nr=2 Is=3.848f N=1 Xti=3 Alpha=10u Vk=100 Kf=1E-18 Af=1)
Below info is for those who are interested in a pair of PCB's :
First of all, there will be no BOM with a complete list of components from Mouser, Digikey, Farnell or similar. What I supply is the schematic as attached and a component list generated from Eagle which I have attached as well. So you do have to go out and spend some time and effort sourcing all the components yourself. However, if there is any question about component choice I will ofcourse be answering those.
There will be no handhelding, so a minimum of experience with electronics is required, including soldering(there is a small SMD OPAMP and a few 0603 resistors and caps). Also, you will need a DMM to do the matching of the input JFET's and setting the correct output stage bias.
Payment will be by Paypal.
Price will be $20 USD for a pair of boards + $10 USD packaging, handling,shipping.
If you are still interested send me a PM with :
Diyaudio.com Screen name
Real Name
Shipping adress
3 pairs of boards should be spoken for already so 2 pairs left.
First of all, there will be no BOM with a complete list of components from Mouser, Digikey, Farnell or similar. What I supply is the schematic as attached and a component list generated from Eagle which I have attached as well. So you do have to go out and spend some time and effort sourcing all the components yourself. However, if there is any question about component choice I will ofcourse be answering those.
There will be no handhelding, so a minimum of experience with electronics is required, including soldering(there is a small SMD OPAMP and a few 0603 resistors and caps). Also, you will need a DMM to do the matching of the input JFET's and setting the correct output stage bias.
Payment will be by Paypal.
Price will be $20 USD for a pair of boards + $10 USD packaging, handling,shipping.
If you are still interested send me a PM with :
Diyaudio.com Screen name
Real Name
Shipping adress
3 pairs of boards should be spoken for already so 2 pairs left.
Attachments
so is there any pics of the boards? smd is good, in fact i would have loved it if all of the small signal and 100nf decoupling was smd. i'll probably get a set i reckon, as i have most parts, but i would love to see pics.
edit: found the pics, for some reason didnt see them yesterday. hmm yeah stuff it I think i'll grab a set. i'm going to have to add an instrumentation amp in front if them though, for bal-se. I could get 2 sets and patch them together but that seems silly.i have to sort out my finances as i have other purchases i have to make today, but i'll get back to you in a few hours
edit: found the pics, for some reason didnt see them yesterday. hmm yeah stuff it I think i'll grab a set. i'm going to have to add an instrumentation amp in front if them though, for bal-se. I could get 2 sets and patch them together but that seems silly.i have to sort out my finances as i have other purchases i have to make today, but i'll get back to you in a few hours
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I'm working on a revision to the layout in a possible Thor MKII PCB.
Made more room for the compensation caps, moved some components around, most noticable is the heatsinks and output Laterals FET's. Overall the layout is cleaner and more streamlined than the first.
Price would be $25USD for a pair of boards. All depends on how it goes with my remaining boards.
Attached is the layout.
Regarding building the Thor amp with the current amp boards, the 100nF cap across bias resistor R5 should be omitted, it is not needed, was a TBD component that managed to stay in the design all through the design phase, layout phase and manufacturing of boards.
Made more room for the compensation caps, moved some components around, most noticable is the heatsinks and output Laterals FET's. Overall the layout is cleaner and more streamlined than the first.
Price would be $25USD for a pair of boards. All depends on how it goes with my remaining boards.
Attached is the layout.
Regarding building the Thor amp with the current amp boards, the 100nF cap across bias resistor R5 should be omitted, it is not needed, was a TBD component that managed to stay in the design all through the design phase, layout phase and manufacturing of boards.
Attachments
Well, havent really though about that. Besides, they are totally symmetric so you can mount stuff on either side.
And thanks.
Did you post this to hoved-fi.dk (weel, I guess you didn't, but you should
/U.
No I haven't. I might consider it, but then I would have to keep up to date with 2 different threads about the same thing.
Lets see what happens.
Received payment for 1 pair of boards, have 1 payment pending. That leaves 3 pairs of the first boards left.
When they are sold and if there is still interest some interest in boards, MKII will be finalized, ordered, built and tested.
Same performance, better layout. Slighty larger board, on the order of less than 1mm in width and length as well as the mounting holes moved slightly. This is due to the first board being in imperial, while I used metric for MKII.
Old boards are 99 x 99mm while MKII are 100 x 100mm.
Everything, including Amp boards, Supply board and No-Thump board is made to fit in a 1NGXA283 case from Modushop.biz
When they are sold and if there is still interest some interest in boards, MKII will be finalized, ordered, built and tested.
Same performance, better layout. Slighty larger board, on the order of less than 1mm in width and length as well as the mounting holes moved slightly. This is due to the first board being in imperial, while I used metric for MKII.
Old boards are 99 x 99mm while MKII are 100 x 100mm.
Everything, including Amp boards, Supply board and No-Thump board is made to fit in a 1NGXA283 case from Modushop.biz
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