Toshiba MOSFETs with a twist

[abraxalito]

it would seem a perfect DAC for headphone use?

Nice features - but how does it sound compared to a tricked out 1387 followed by a headbuff?

[jkeny]

it would seem a perfect DAC for headphone use?

Nice features - but how does it sound compared to a tricked out 1387 followed by a headbuff?

Yea, that will be the next build for comparison - hopefully can get some help from you on that build?

[abraxalito]

Yea, that will be the next build for comparison - hopefully can get some help from you on that build?

That's the build I'm focussing on at the moment. I played around with filters and tried to source some ready-made high value inductors (10mH and up) for the AIF. The best shielded 10mH miniature inductor is a Coilcraft (LPS6235) but they're hard to get here and relatively expensive so I have moved the filter to a low impedance circuit for this prototype. Low impedance loading means smaller valued inductors (I have 22uH right now, there are a few choices) but the fly in the ointment is larger valued caps. I'm trying out X5Rs...

[nige2000]

Richard

im trying to learn ltspice, it seems not overly difficult so far was just wondering how you get around the lack of models for these Toshiba fets?

k35s arrived, sure wouldn't like them to be any smaller :)

any chance of the schematic for the loudspeaker amp and gain stage ?
pretty much ready to start that

[abraxalito]

I found there's a Siliconix FET in LTspice which works close enough for me. I've sent you the LTS file so you'll be able to run the sim on it. Only the input FET is the K35, the others are J327 (P) or K339 (N).

The loudspeaker amp schematic I've not drawn up completely but I've already shared half of it - just needs two of those channels paralleling via their output caps.

[nige2000]

I found there's a Siliconix FET in LTspice which works close enough for me. I've sent you the LTS file so you'll be able to run the sim on it. Only the input FET is the K35, the others are J327 (P) or K339 (N).

ok i think i can work from that. there is no j327 in it ?
only one k35 and two k339's and a bunch of bc847b/857b?

The loudspeaker amp schematic I've not drawn up completely but I've already shared half of it - just needs two of those channels paralleling via their output caps.

right ok

thanks

[abraxalito]

ok i think i can work from that. there is no j327 in it ?
only one k35 and two k339's and a bunch of bc847b/857b?

Yep you got it, this one hasn't a P channel FET. I might try putting one in when the J36s arrive.

[nige2000]

RS has j36's too at similar cost, so will be able to play along

are u soldering these tiny fets directly on prototype board or are u using adapter boards?
ive mislaid my stash of adapter boards :(
its shameful the amount of electronic stuff ive gathered up over time.........

[abraxalito]

Yeah directly to 0.1" double sided prototyping board. How I did it was use a 0ohm 0603 as a bridge between one of the 'triangle' of pads and the source connection. I soldered the gate and drain down directly to pads.

[nige2000]

this might work