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Old 24th January 2009, 03:50 PM   #741
RCruz is online now RCruz  Switzerland
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Quote:
Originally posted by ikoflexer
Fixed regulator pcb bottom.
Hi ikoflexer

So the initial ExpressPCB is also wrong ?

(I am starting to like this software )

Ricardo
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Old 24th January 2009, 04:15 PM   #742
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and fixed regulator silk screen.
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File Type: pdf sreg10silkscreen.pdf (12.4 KB, 84 views)
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Old 24th January 2009, 04:18 PM   #743
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Quote:
Originally posted by salas
GDS Ikoflexer fix:

Did you etch again, or hacked with a hobby knife and used jumpers to fix the prototype?
I haven't etched again, I was too eager to get it working last night. I just extended the mosfet wires a bit and connected D and G in reverse. It's a pity that this board does not allow to edit older posts. Now I'll have nightmares of people doing to wrong version.
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Old 24th January 2009, 04:24 PM   #744
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Quote:
Originally posted by RCruz


Hi ikoflexer

So the initial ExpressPCB is also wrong ?

(I am starting to like this software )

Ricardo
Hey Ricardo,

Yes, all the pcb related to my initial post about the regulator should have D and G reversed on the mosfets. I'm awfully sorry about that.

I agree, expresspcb is a nice piece of software, and it's free. The nice feature where you can import the netlist of a schematic from ltspice (or other software) is particularly nice, BUT that can also be a source of failure. The pin numbering in ltspice is often different than the pin numbering in expresspcb. That's how D and G were reversed on the first pcb.

I'm inclined to just post links to my website from now on, that way I can keep in one place the latest version of everything, with fixes and all that. I'd feel awful if someone got and implemented the broken version.
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Old 24th January 2009, 04:31 PM   #745
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Cruz you know that the Salas Works are better then meridian ??

use toroid if you can get easily
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Old 24th January 2009, 05:01 PM   #746
RCruz is online now RCruz  Switzerland
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Quote:
Originally posted by nicoch46
Cruz you know that the Salas Works are better then meridian ??

use toroid if you can get easily
Salas Riaa is much more simple than the Meridian. Also uses jfet (tube like)... It must sound faster and more open sounstage ... I will see for myself.
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Old 24th January 2009, 05:04 PM   #747
RCruz is online now RCruz  Switzerland
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Quote:
Originally posted by ikoflexer


I'd feel awful if someone got and implemented the broken version.
Hi ikoflexer

Do not worry... I am used to these changes... would you post the corrected expresspcb file ? or send it to my e-mail

Great Work !!!

Ricardo
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Old 24th January 2009, 05:24 PM   #748
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Here it is.
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File Type: zip salasshunt10.zip (8.9 KB, 84 views)
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Old 24th January 2009, 07:37 PM   #749
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Pfft, man, what a frustrating thing. ExpressPCB uses on most components square pads for positive pins, and round pads for negative pins... except for LEDs. I just realized that now, and made the minor change once again. I'm over and done with the regulator pcb for now, I tested the LED version as well and it works as per this attachment. Tested with both bf245a and sk170 jfets; my scope does not show a difference between the two. Perhaps there is sound wise, but I don't have phono circuit done yet. Nice to see the filtered input trace swing up when some power device in the house turns on and off in the house, but the regulated does not move. Neato!

Contents of sreg10.zip
sreg10bottom.pdf
sreg10silkscreen.pdf
salasshunt10.pcb
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File Type: zip sreg10.zip (27.5 KB, 72 views)
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Old 24th January 2009, 07:42 PM   #750
Salas is online now Salas  Greece
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Quote:
Originally posted by ikoflexer
Here it is.
We must clarify the alternatives for the CCS Voltage reference and their configuration here:

In Ikoflexer's board you can either use 3X 1.7V LEDS or a resistor (R10) voltage drop governed by the JFET on its tail.

a) If using the LEDS, at least a 6mA IDSS JFET (J22) must be used so to keep them in their low noise region. With 6R8 R1 the CCS will run at about 200mA. A recommended value.

b) If using a 1600R R10, you better use a 3mA IDSS JFET (J1). That will give again about 200mA with a 6R8 R1, or 140mA with a 10R R1 as per original Ikoflexer's value. More IDSS will magnify the resistor voltage drop, and its positive difference from VGS (about 3.4V). That difference, divided by R1 sets the running current. A 6 mA IDSS will skyrocket the CCS to 0.9A for 6R8 R1 or 0.62A for 10R. So be careful! You can downsize R10 if you are left with some 2SK170BL between 6.5-11mA IDSS after matching for the phono, and you want to use them in the shunt, which is the most probable scenario.
In this case, say you have a 7mA 2SK170, use 680R for R10, and your CCS will run at 200mA with 6R8 R1.
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