Gb: F5 Pcb - Page 72

cviller · 18th April 2009, 08:35 AM

Quote:

Originally posted by smyslow
Hi Christian,

just sent you an order about some F5 and PSU boards.

Thanks for your effort.

smyslow

And I got the payment and confirm mail - this gb site seems to be working smoothly.

bobodioulasso · 18th April 2009, 11:55 AM

Quote:

I will check again but I don't think so (+/- 24 V).

Did you try to disconnect one channel at a time from psu?

cowboy99 · 18th April 2009, 12:00 PM

Hi Christian,
From your Jan. GB: I've been distracted lately with putting together/equipping a varily decent build/test bench: Just current with thread. Curious; the new PCB-3/13/09, Is only change to Q5 silk?

Also, new Rect.B PCB---2 diode bridges, etc. vs PCB. Is improvement because of 'better' ultra fast recovery of To-247 devices like MUR3020W? Or is mainly just to simplify/organize PS input? On brd heatsink option a +plus if needed; yes but I'm using big Conrads with plenty of surplus 'sink' for To-247 RBs . If no real advantage, RectB PCB seems more costly? Just curious, cause cuz last GB you only had 1/2 of PSU brds I needed so I got a couple of Peter's PSBs with snap off RB chips. Just considering my PS options.
Thanks

Charles

cviller · 18th April 2009, 01:48 PM

Quote:

Originally posted by cowboy99
Hi Christian,
1. From your Jan. GB: I've been distracted lately with putting together/equipping a varily decent build/test bench: Just current with thread. Curious; the new PCB-3/13/09, Is only change to Q5 silk?

2. Also, new Rect.B PCB---2 diode bridges, etc. vs PCB. Is improvement because of 'better' ultra fast recovery of To-247 devices like MUR3020W? Or is mainly just to simplify/organize PS input? On brd heatsink option a +plus if needed; yes but I'm using big Conrads with plenty of surplus 'sink' for To-247 RBs . If no real advantage, RectB PCB seems more costly? Just curious, cause cuz last GB you only had 1/2 of PSU brds I needed so I got a couple of Peter's PSBs with snap off RB chips. Just considering my PS options.

1. And I have added a pin header footprint for the LED - but you're right - nothing serious.

2. Well lots of people have asked for these, and they make it easy to use ultra fast recovery diodes and supply more current for bigger amps. In fact I consider them of general purpose nature - and not directly related to the F5, although it seems like an upgrade well worth it.

Tea-Bag · 18th April 2009, 01:56 PM

I think the rectifier boards look wicked slick. Or will with black pcb and heatsinks!

1MOR · 18th April 2009, 05:48 PM

Order just sent for set of F5 PS boards.

labjr · 18th April 2009, 06:13 PM

Do high speed rectifiers make this amp sound better? Doesn't Nelson use ordinary bridge rectifiers?

korben69 · 19th April 2009, 11:45 AM

Some informations from Nelson PASS about Power Supplies :
http://passlabs.com/articles.htm
Download the PDF and read the section about Recifiers.

"Yeah, sure, rectifiers are important, after all, the AC has to get converted to DC, but I don't like the fast recovery types that some audiophiles have raved about. Fast recovery means that they withstand many amps and volts in a tenth of a few nano-seconds, something we don't see very often on the old 60 Hz AC line. They are essential element in switching power supplies, but for regular "linear" power supplies, I much prefer SLOW diodes, and we create them by placing small capacitor circuits across the diodes, which greatly reduces radiated noise."

Just wondering about the caps type and values...

cviller · 19th April 2009, 12:16 PM

Quote:

Originally posted by korben69
Some informations from Nelson PASS about Power Supplies :
http://passlabs.com/articles.htm
Download the PDF and read the section about Recifiers.

"Yeah, sure, rectifiers are important, after all, the AC has to get converted to DC, but I don't like the fast recovery types that some audiophiles have raved about. Fast recovery means that they withstand many amps and volts in a tenth of a few nano-seconds, something we don't see very often on the old 60 Hz AC line. They are essential element in switching power supplies, but for regular "linear" power supplies, I much prefer SLOW diodes, and we create them by placing small capacitor circuits across the diodes, which greatly reduces radiated noise."

Just wondering about the caps type and values...

Papa has changed his mind since that article, I have read it several times in the pass labs forum, but my search only gave this reference:
http://www.diyaudio.com/forums/showt...830#post321830

This may also be an inspiration:
http://www.diyaudio.com/forums/showt...ght=#post17199

vdi_nenna · 19th April 2009, 01:01 PM

But aren't Fast recovery different fron Ultra fast recovery?

18th April 2009, 12:00 PM	#713
cowboy99 diyAudio Member Join Date: Dec 2008 Location: Texas Hill Country, SSW of Austin	Back at Pass Hi Christian, From your Jan. GB: I've been distracted lately with putting together/equipping a varily decent build/test bench: Just current with thread. Curious; the new PCB-3/13/09, Is only change to Q5 silk? Also, new Rect.B PCB---2 diode bridges, etc. vs PCB. Is improvement because of 'better' ultra fast recovery of To-247 devices like MUR3020W? Or is mainly just to simplify/organize PS input? On brd heatsink option a +plus if needed; yes but I'm using big Conrads with plenty of surplus 'sink' for To-247 RBs . If no real advantage, RectB PCB seems more costly? Just curious, cause cuz last GB you only had 1/2 of PSU brds I needed so I got a couple of Peter's PSBs with snap off RB chips. Just considering my PS options. Thanks Charles __________________ I'm kinda curious about that myself........

19th April 2009, 01:01 PM	#720
vdi_nenna diyAudio Member Join Date: Oct 2000 Location: PA, USA Blog Entries: 1	But aren't Fast recovery different fron Ultra fast recovery? __________________ I build, therefore I am.

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18th April 2009, 01:56 PM	#715
Tea-Bag not politcally affiliated diyAudio Member Join Date: Feb 2006 Location: Kennebunk Blog Entries: 7	I think the rectifier boards look wicked slick. Or will with black pcb and heatsinks!

18th April 2009, 05:48 PM	#716
1MOR diyAudio Member Join Date: Jul 2008	Order just sent for set of F5 PS boards.

18th April 2009, 06:13 PM	#717
labjr diyAudio Member Join Date: Apr 2003 Location: MA	Do high speed rectifiers make this amp sound better? Doesn't Nelson use ordinary bridge rectifiers?

19th April 2009, 11:45 AM	#718
korben69 diyAudio Member Join Date: Nov 2006 Location: Near Lyon	Some informations from Nelson PASS about Power Supplies : http://passlabs.com/articles.htm Download the PDF and read the section about Recifiers. "Yeah, sure, rectifiers are important, after all, the AC has to get converted to DC, but I don't like the fast recovery types that some audiophiles have raved about. Fast recovery means that they withstand many amps and volts in a tenth of a few nano-seconds, something we don't see very often on the old 60 Hz AC line. They are essential element in switching power supplies, but for regular "linear" power supplies, I much prefer SLOW diodes, and we create them by placing small capacitor circuits across the diodes, which greatly reduces radiated noise." Just wondering about the caps type and values...