Any comment? Yeah, I'd like to post some comments.
I can't honestly imagine how anybody could come up with such a crazy idea without testing those resistors first. I've been using TX2575 in some of my projects and contrary to what some people say about sonic virtues of those resistors, I wasn't always happy using them. I much prefer Caddocks TF020 in I/V stage of my DAC and couldn't really stand TXs at the output of my transport.
Paying $365 per set of 8? This is more crazy than paying $250 per single piece of V-Cap.
As a reminder, the PCB layout follow this almost 1:1
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-24.html#post1538826
The 4x missing PRP 1W resistors will also be filled in the new schematics.
You can practically see all components (except for the JFETs underneath the daughter board).
Current limiters are included.
Included is a new option to cascode the input jfets with Vishay (or others) J111/J174.
But this can be bypassed easily.
The MPC74s can be standing, or lying, as shown.
It will supported both floating X or grounded X.
Patrick
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-24.html#post1538826
The 4x missing PRP 1W resistors will also be filled in the new schematics.
You can practically see all components (except for the JFETs underneath the daughter board).
Current limiters are included.
Included is a new option to cascode the input jfets with Vishay (or others) J111/J174.
But this can be bypassed easily.
The MPC74s can be standing, or lying, as shown.
It will supported both floating X or grounded X.
Patrick
This with the daughter removed, showing everything.
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-121.html#post1989095
This particular one connected as grounded X.
Patrick
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-121.html#post1989095
This particular one connected as grounded X.
Patrick
> what is the vishay J111/J174,
N- and P-JFETs with high Idss.
> and why would I want a cascade?
You may not, you may.
There is an excellent article from Nelson on cascode (and not cascade).
A possibly even better one from Erno Borbely.
So I don't need to add to those.
http://www.firstwatt.com/pdf/art_cas_amp.pdf
http://www.borbelyaudio.com/adobe/ae599bor.pdf
> good/bad/ugly?
Much cheaper to find out than Vishay Z-foils.
Patrick
N- and P-JFETs with high Idss.
> and why would I want a cascade?
You may not, you may.
There is an excellent article from Nelson on cascode (and not cascade).
A possibly even better one from Erno Borbely.
So I don't need to add to those.
http://www.firstwatt.com/pdf/art_cas_amp.pdf
http://www.borbelyaudio.com/adobe/ae599bor.pdf
> good/bad/ugly?
Much cheaper to find out than Vishay Z-foils.
Patrick
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On that I must agree.
I only got a quote about them as I Thought some-one else would like to know, I too balked at the price. I only posted it here as someone else wanted to know it. Note: there is a new post about the resistors at:
0.22 ohm Vishay Z-foil 4W resistors
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I have no criticism against anyone in particular who wants to use exotic parts.
I just want to concentrate on the task I set myself, and complete it as soon and as well as I can.
And this thread is possibly not the right thread to discuss those.
(I could not resist pulling your leg in #469. Apologies.)
Patrick
I just want to concentrate on the task I set myself, and complete it as soon and as well as I can.
And this thread is possibly not the right thread to discuss those.
(I could not resist pulling your leg in #469. Apologies.)
Patrick
Patrick
cascode option Is great - Is It build and tested already ?
can we use to higher rails (2 x 18 VAC) and resp power (with better heatsinks) - Is It tested ?
cascode option Is great - Is It build and tested already ?
can we use to higher rails (2 x 18 VAC) and resp power (with better heatsinks) - Is It tested ?
Hi Patrick, whats the purpose of the daughter board?
I have a bunch of MPC70 0.27Ohm, pitty really, I have hundreds but they are only 2 watt. That seems a little low for source or emitter resistors.
I have a bunch of MPC70 0.27Ohm, pitty really, I have hundreds but they are only 2 watt. That seems a little low for source or emitter resistors.
Cascode is not tested, only simulated.
It is not there to enable higher voltage, as there is no need for cascode even with +/-24V.
It is there to (hopefully) reduce Miller effect.
So someone would have to experiment when the boards are ready.
The daughter boards holds the input resistor network and remove them at some distance away from the highish current feedback network.
It also allow optional gate resistors for the JFETs.
MPC70 is too low and also magnetic, but why would you need to save 5 Euros ?
Patrick
It is not there to enable higher voltage, as there is no need for cascode even with +/-24V.
It is there to (hopefully) reduce Miller effect.
So someone would have to experiment when the boards are ready.
The daughter boards holds the input resistor network and remove them at some distance away from the highish current feedback network.
It also allow optional gate resistors for the JFETs.
MPC70 is too low and also magnetic, but why would you need to save 5 Euros ?
Patrick
EUVL said:
Fairy 'nuff Mate... understood
my guess is because he wouldnt mind getting rid of some of the afore-mentioned hundreds of them to a good cause instead of buying anything at all. nice idea on the daughter board to protect low level signals.
Since there are a few people who indicated they want to use regulators, is there someone experienced in PCB layout who want to do this from scratch ?
I only have a schematics with selected components in mind this time. No layouts, no spice, nothing.
Patrick
I only have a schematics with selected components in mind this time. No layouts, no spice, nothing.
Patrick
good to see you here Peter
with risk to go away from topic
Is It the resistor you recommend to use as a I/V resistor - I know you used pcm1704 - I got pcm63
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