Balanced F5 question - Page 29

neb001 · 25th October 2010, 05:35 PM

I'm surprised that you've become such a proponent of the Hifi2000 cases now, Patrick

EUVL · 25th October 2010, 05:51 PM

Only because of impatient people here who cannot wait until December, and already want to order things now.

Of course they may, but then I also don't want to be blamed that the case won't fit their GB components.

So a large case measuring so 500x500x200mm will fit anything.

Patrick

EUVL · 25th October 2010, 05:52 PM

I need one more volunteer to cross check my ACAD drawings vs those from bksabath.

Please send me a PM if you have a dwg and Gerber viewer.

Thx,
Patrick

johnwmclean · 25th October 2010, 06:50 PM

Patrick, you have a pm.

EUVL · 25th October 2010, 09:56 PM

You too.

Patrick

luvdunhill · 26th October 2010, 02:08 AM

Quote:

Originally Posted by thanh1973

Just an update on resistors.
I managed to find some Futaba MPC71 5W 0.22 Ohm resistors in my parts box (basically the same as mpc74).
I tested them at both 1A and 2A and the performance is as good as two cpf3 3W resistors in parrallel.

just for fun I tried to matched some .47 ohm resistors. It looks like measuring current or voltage is perhaps the better way to group the devices, even with a high precision ohmmeter.

I think when it all comes down to it, either you don't bother as Patrick mentioned or you trim the resulting amp, as Zen Mod mentioned

luvdunhill · 26th October 2010, 02:10 AM

one more question with regard to the heat sink calculations. Are you leaving the option for attaching a regulated PSU to the heat sink, or are these calcs just for the amplifier boards?

Melon Head · 26th October 2010, 02:21 AM

If you are intending on using a regulated supply, It will have to be in its own separate case with heatsinks.

EUVL · 04:37 AM

Correct.

Making a larger case with large heatsinks to accomdate more dissipation will make is too expensive to make and to ship.
Then it is better to buy commercial ones.

You may consider putting the regulator device on its own free standing heatsink within the case.
There is not a lot of spcae, but you might manage.
If you allow 4V drop & 4A bias, total dissipation is 16W, so the free-standing sink has to be 2W/°C.

Something like

V 5512G Profilkühlkörper - reichelt elektronik - Der Techniksortimenter - OnlineShop für Elektronik, Netbooks, PC-Komponenten, Kabel, Bauteile, Software & Bücher - ISO 9001:2000 Zertifiziert

(75x50x25mm, not small)

Patrick

EUVL · 26th October 2010, 04:35 AM

> It looks like measuring current or voltage is perhaps the better way to group the devices, even with a high precision ohmmeter.

> either you don't bother as Patrick mentioned

I do bother.

> you trim the resulting amp, as Zen Mod mentioned

That depends what you trim. You suggest trimming THD.
My approach is to trim second (and maybe third) harmonics without getting higher 4th, 5th, ....., before soldering.

If THD is the goal, then opamp and high feedback amp (like the Goldmund ?) rules.
No point going to Class A.

Patrick

26th October 2010, 04:30 AM	#289
EUVL diyAudio Member Join Date: Oct 2003	Correct. Making a larger case with large heatsinks to accomdate more dissipation will make is too expensive to make and to ship. Then it is better to buy commercial ones. You may consider putting the regulator device on its own free standing heatsink within the case. There is not a lot of spcae, but you might manage. If you allow 4V drop & 4A bias, total dissipation is 16W, so the free-standing sink has to be 2W/°C. Something like V 5512G Profilkühlkörper - reichelt elektronik - Der Techniksortimenter - OnlineShop für Elektronik, Netbooks, PC-Komponenten, Kabel, Bauteile, Software & Bücher - ISO 9001:2000 Zertifiziert (75x50x25mm, not small) Patrick Last edited by EUVL; 26th October 2010 at 04:37 AM.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
F5 bias question	richD	Pass Labs	12	4th March 2013 12:57 PM
F5 - Antek 4218 Wiring Question	vdi_nenna	Pass Labs	17	7th May 2011 12:05 AM
F2 and F5 heat question	trusound	Pass Labs	14	1st July 2010 02:28 PM
F5 Output Connection Question	rtate	Pass Labs	1	5th January 2010 11:58 PM
question re: sony ps-f5 portable turntable	voicegyrl	The Lounge	0	31st July 2008 09:36 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

25th October 2010, 05:35 PM	#281
neb001 diyAudio Member Join Date: Mar 2007	I'm surprised that you've become such a proponent of the Hifi2000 cases now, Patrick

25th October 2010, 05:51 PM	#282
EUVL diyAudio Member Join Date: Oct 2003	Only because of impatient people here who cannot wait until December, and already want to order things now. Of course they may, but then I also don't want to be blamed that the case won't fit their GB components. So a large case measuring so 500x500x200mm will fit anything. Patrick

25th October 2010, 05:52 PM	#283
EUVL diyAudio Member Join Date: Oct 2003	I need one more volunteer to cross check my ACAD drawings vs those from bksabath. Please send me a PM if you have a dwg and Gerber viewer. Thx, Patrick

25th October 2010, 06:50 PM	#284
johnwmclean diyAudio Member Join Date: Oct 2009	Patrick, you have a pm.

25th October 2010, 09:56 PM	#285
EUVL diyAudio Member Join Date: Oct 2003	You too. Patrick

26th October 2010, 02:10 AM	#287
luvdunhill diyAudio Member Join Date: Jul 2006	one more question with regard to the heat sink calculations. Are you leaving the option for attaching a regulated PSU to the heat sink, or are these calcs just for the amplifier boards?

26th October 2010, 02:21 AM	#288
Melon Head Banned Join Date: Nov 2006	If you are intending on using a regulated supply, It will have to be in its own separate case with heatsinks.

26th October 2010, 04:35 AM	#290
EUVL diyAudio Member Join Date: Oct 2003	> It looks like measuring current or voltage is perhaps the better way to group the devices, even with a high precision ohmmeter. > either you don't bother as Patrick mentioned I do bother. > you trim the resulting amp, as Zen Mod mentioned That depends what you trim. You suggest trimming THD. My approach is to trim second (and maybe third) harmonics without getting higher 4th, 5th, ....., before soldering. If THD is the goal, then opamp and high feedback amp (like the Goldmund ?) rules. No point going to Class A. Patrick