F5 with 2SK2013/2SJ313

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#105
EUVL said:
What I said :

http://www.diyaudio.com/forums/pass...ing-impressions-discussion-9.html#post2151601

And what NP said :

http://www.diyaudio.com/forums/pass...ing-impressions-discussion-9.html#post2151655


Patrick
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Which for me means that it's only worthwhile if done very well. Possibly using two regulated supplies - a simple one for output and something really nice for the input. There might also be an issue of an output switch-on/off transient if the supplies have different time constants.
 
#107
analog_sa said:
Which for me means that it's only worthwhile if done very well. Possibly using two regulated supplies - a simple one for output and something really nice for the input. There might also be an issue of an output switch-on/off transient if the supplies have different time constants.
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nope nope nope

ppoint is - for upper part of circ - positive rail is base for biasing and modulating the output mosfet

same for lower part of circ - negative rail is base for bias and modulating the output mosfet

include any series element between mosfet and adjacent modulating source ( adjacent jfet) , you'll induce who knows what

there is simply no benefit but only harm , trying to separate supply paths between jfet and mosfet

if you want anything regulated - try with entire PSU , either real reg , or "just" cap multiplier

wanna proof ?

mount additional steering wheel in your car , right in front of passenger seat ;

connect it with real steering wheel with soft rubber band ; then say to your passenger to lay hands on it and do exactly in time whatever you do with steering wheel ; observe .

then replace soft rubber band with firm chain and repeat operation ; observe

:rofl:

:cheers:
 
#111
umut1001 said:
I did not see your message and write it 🙂 i deleted a min ago 🙂
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naah - you didn't must ........

fun in learning is even greater when we are able to laugh together ;

I'm still able to embarrass my self in public - every day ...... and I have fun in that

that's real brain-storming - say whatever you need to say ........ when day is good , that will lead in most wakoo ways ......... :cheers:
 
#113
Poor Padanian Man's Xed Balanced Amp F5 Pass/Juma/Euvl-based with 2SK2013/2SJ313

While waiting for the little Toshibas to come from Zhoufang (10 weeks lead time :sad:), I’ve been attracted (and who has not?) from this http://www.diyaudio.com/forums/pass-labs/172770-balanced-f5-question.html thread, so I thought to a 313/2013-based version. The attached schematic comes directly from that thread, and the values of R1/R101 and R2/R102 (widely commented) so as R7/R8 and R9/R10 are copied from EUVL’s schematic (see attached), so consider them as tentative values.
Is this beast feasible? Are there alternative values of supply voltage / idle current that could be considered in order to achieve the “sweet spot” or even lower the overall dissipation (at the price of a lower max power output)?
I’m aware of dissipation issues, so we (in fact, I’m representing a bunch of ardent DIYers) are already thinking to a very ambitious (for us) case, but this is another story (another case, in fact 😉).

Juma (or any other), could you comment please?

Guido (poor Padanian Man)
 

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#117
Juma,
Thank you for your reply.
However, my target is to reduce dissipation, not to increase it.
What about 3 pairs @ 0,5A? (keeping in mind cost-benefit ratio, following ZenMod's PSM policy 😀)

And furthermore, what is your opinion about FB resistors' value? Difference between the lower and upper half or standard 50 Ohm for both as in F5?

Guido
 
#118
That way you'll have lower bias, meaning less A class power. Having an 16 Ohms speaker would be nice with lower Id.

No reason to use asymmetrical FB resistors. Amount of feedback is yours to choose - listening tests will tell you do you prefer less feedback/more distortion or vice versa.
 
#120
Guido -

This is very much like what I was thinking of doing. I like Juma's idea about 4 pairs of outputs on each side.

I've also been trying to chase down the IRFP balanced XF5. How do you optimize the resistors around the outputs for any device? It seems like this knowledge would be useful in trying a number of outputs.

GuidoR said:
While waiting for the little Toshibas to come from Zhoufang (10 weeks lead time :sad:), I’ve been attracted (and who has not?) from this http://www.diyaudio.com/forums/pass-labs/172770-balanced-f5-question.html thread, so I thought to a 313/2013-based version. The attached schematic comes directly from that thread, and the values of R1/R101 and R2/R102 (widely commented) so as R7/R8 and R9/R10 are copied from EUVL’s schematic (see attached), so consider them as tentative values.
Is this beast feasible? Are there alternative values of supply voltage / idle current that could be considered in order to achieve the “sweet spot” or even lower the overall dissipation (at the price of a lower max power output)?
I’m aware of dissipation issues, so we (in fact, I’m representing a bunch of ardent DIYers) are already thinking to a very ambitious (for us) case, but this is another story (another case, in fact 😉).

Juma (or any other), could you comment please?

Guido (poor Padanian Man)
Click to expand...
 
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