F5 with 2SK2013/2SJ313

[permaneder]

what is different from the Pass BA-3 frontend ?
looking at schematics I see only minor difernces
I really can't figure out why this is a poweramp, and the BA-3 only a gain/driver stage

btw, some time ago I worked hard to find good TO-220 devices for the F5
maybe some of them could be good ?
or is it all down to these special Toshiba devices ?

And where do you discover the similarity? Same transistor types?

 

[juma]

what is different from the Pass BA-3 frontend ? ...

Everything... Much smaller gain of the input stage, highly degenerated output stage which is also very low biased, absence of feedback loop which makes the circuit a transconductance amp...

 

[permaneder]

Just for fun, here is a little pcb for your amp. Each five MOSFETs allow either lower bias and higher supply voltage rails for more power@8Ohms or more power@4Ohms with 400mA bias (total 2A per rail) and +-20V supplies.

 

[Telstar]

Just for fun, here is a little pcb for your amp.

sweet!

 

[nik_d]

Just for fun, here is a little pcb for your amp.

me likes to!

 

[Rush]

Just for fun, here is a little pcb for your amp. Each five MOSFETs allow either lower bias and higher supply voltage rails for more power@8Ohms or more power@4Ohms with 400mA bias (total 2A per rail) and +-20V supplies.

Nice looking board. What are the dimensions? Output device spacing?
Have you tested the board, any errors?

Rush

 

[permaneder]

290mm*46mm. Not tested, but absolutely free of errors. It is just a finger exercise.

 

[The Space Egg Corp]

Cool !

Si.

 

[permaneder]

I would order boards of Juma's F5, if there is sufficient interest. The price per set depends on the number of ordered boards. From ten or more sets on we we can expect reasonable costs.

 

[zoe]

I would order at lest one set!

 

[Luke]

me too...

 

[secanbj]

+1

 

[nik_d]

+1

 

[jameshillj]

I would like a pair of boards also, Per - can easily trim them down to 3 o/p Fets if required -

Could you add 2 small electro/solid poly caps across the rails to a separate 0Volt point near the jfet input, maybe 47uF+ ...

 

[tinitus]

From ten or more sets on we we can expect reasonable costs.

+1

 

[permaneder]

I would like a pair of boards also, Per - can easily trim them down to 3 o/p Fets if required -

Could you add 2 small electro/solid poly caps across the rails to a separate 0Volt point near the jfet input, maybe 47uF+ ...

What about those: Panasonic FP V low ESR SMD electrolytics EEEFP1V470AP (~ EUR .30 each here in Germany)? Send PM with your email address and I'll mail the datasheet.

 

[permaneder]

...or even better NIPPON CHEMI-CON Series PXA (~ EUR 1 each)

 

[pchw]

+1 for a stereo set, too.

 

[ixix]

+1 set


...or two types of pads (SMD and pasthrough) to choose the type of capacitor. I like the sound of Silmics and others audio capacitors (these values ​​are cheap).

 

[Rush]

Boards

I will take 2 stereo pairs (4 boards).
Will you do a regulated supply board too? I'd take 8 or more of those.

Rush