F5 power amplifier - Page 1251

doolav · 25th July 2012, 03:11 PM

Quote:

Originally Posted by Zen Mod

Cviller's Blog

- does not look like a lot is going on there. Will be patient, but in a mean time - did not anyone here try to use cviller [old] pcb (from the DIY store) to put together F5 rev.1?

Would it be easier [for a newbie like me] to use P. Daniel's boards for rev.1?

Thanks,
Alex.

AudioSan · 25th July 2012, 03:18 PM

Quote:

Originally Posted by slungu

Ok, I'm not sure if I should open another thread or ask here, but I plan to build two F5 mono blocks and had some questions.
First I would like to keep them small, and was thinking about going with 2x15V 160VA transformers instead of the original 2x18V. Reason would be to need less heat sink area and be able to build them "smaller" so I was hoping to have to loose less power trough the heat sinks. And then : does anybody have a link to a nice calculator for heatsinks ? I once had a link for a very nice calculator that would show the heat on the heat sink depending on positioning and so on - really very nice in order to optimise the placement of the heat sources, but I can not find it anymore.
So, has anybody tried a "undervoltage" F5 ?

Regards, Stefan

hello. that will work.
regarding calculator. use math

max temp rise / dissepation / 1,25 = C/W rating.
placement. 1/3 up from the bottom end. and the sinks can spread the heat in a radius of 10x baseplate thickness

Russellc · 25th July 2012, 09:44 PM

Quote:

Originally Posted by noSmoking

It works ,I guess some folks don't like patches,lol What werks is ok for me,lol!
You know I am amazed with this amp,I have some old RS meters for speaker outputs ,I am putting 5 watts out and it's pretty loud,
I use a pair of kustom 200 watt stage monitors,kinda my test speakers,I don't know the spl,but they drive pretty ez,kinda blows you away,,,,GREAT design Nelson,Thank You!
thanks!
NS

Stage monitors eh? Yes the F-5 likes efficient speaks. I'm using JBL 4507 boxes, 5 cu ft with JBL 2235H tuned similar to 4430 monitor, same LP cross over and zobel mated to "Econowave deluxe" HP with QSC wave guide and B&C DE 250 on top.
F-5 drives the crap out of them, current F-5 build will use 200 or 220 on the feedback resistors, giving more gain. Leaving the limiting circuitry off this one as well.

Russellc

noSmoking · 25th July 2012, 11:50 PM

yes I am at 220 r on them now Those stage monitors where from my old rock and roll days <still have the frontend equipment,sold the speakers no where to keep them, It's been a while ago but had 6 jbl cabinets powered with Qsc and crown amps ,would shake your pants legs,about 75 yards away WE where asked to turn down more than once,lol.Did you see what they did to paul McCarthney and bruce Springsteen ,I laughed 10 pm too,maybe 2 am.....sick,lol.

jackinnj · 26th July 2012, 12:41 AM

Quote:

Originally Posted by noSmoking

from my old rock and roll days <still have the frontend equipment,sold the speakers no where to keep them,

you can probably see a re-run of "History Detectives" on pbs.org which featured Jamerson's Ampeg last night -- he was the bassist who changed the guitar bass in MoTown!

slungu · 26th July 2012, 07:43 AM

I tried to searc a bit and came up with the modifications that Franz has made for his mini F5 that is running on 15Vdc
Now, somehow I find it hard to source the Toshibas, either 2SK1350/2SJ201 or 2SK2013/2SJ313. I can however get the IRFP9240/240 at regular basis, but I understood that they are not recomended for low rail voltage. What would be a good replacement for the Toshibas ?
Regards, Stefan

gaborbela · 26th July 2012, 11:50 AM

Hello

Can someone let me know if I can use these thermistor for my F5 please..
New 10 x 4.7K OHM 472 NTC Thermistor 5mm | eBay
I do not like to purchase parts from Epay since I burned my fingers a couple time but what can I do?
To order from Mouser only these parts shipping is horrible.
I did ask if someone if has some extra unfortunately I didn't got any offer.

Thank you for any help, advise and positive comment!

Greetings Gabor

Zen Mod · 26th July 2012, 01:18 PM

yes

labjr · 26th July 2012, 02:09 PM

I've called Mouser about shipping regular first class mail for small orders. They're usually very accommodating. Friendly girls down there in Texas.

jacco vermeulen · 26th July 2012, 02:58 PM

Quote:

Originally Posted by slungu

replacement

2SK1530 is harder to get, but tried to look for K1529 instead (+J200) ?

26th July 2012, 11:50 AM	#12507
gaborbela diyAudio Member Join Date: Sep 2005	Thermistor helpppppppppppp please Hello Can someone let me know if I can use these thermistor for my F5 please.. New 10 x 4.7K OHM 472 NTC Thermistor 5mm \| eBay I do not like to purchase parts from Epay since I burned my fingers a couple time but what can I do? To order from Mouser only these parts shipping is horrible. I did ask if someone if has some extra unfortunately I didn't got any offer. Thank you for any help, advise and positive comment! Greetings Gabor

26th July 2012, 01:18 PM	#12508
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	yes __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

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25th July 2012, 11:50 PM	#12504
noSmoking diyAudio Member Join Date: May 2010 Location: Texas	yes I am at 220 r on them now Those stage monitors where from my old rock and roll days <still have the frontend equipment,sold the speakers no where to keep them, It's been a while ago but had 6 jbl cabinets powered with Qsc and crown amps ,would shake your pants legs,about 75 yards away WE where asked to turn down more than once,lol.Did you see what they did to paul McCarthney and bruce Springsteen ,I laughed 10 pm too,maybe 2 am.....sick,lol.

26th July 2012, 07:43 AM	#12506
slungu diyAudio Member Join Date: Nov 2010 Location: Germany	I tried to searc a bit and came up with the modifications that Franz has made for his mini F5 that is running on 15Vdc Now, somehow I find it hard to source the Toshibas, either 2SK1350/2SJ201 or 2SK2013/2SJ313. I can however get the IRFP9240/240 at regular basis, but I understood that they are not recomended for low rail voltage. What would be a good replacement for the Toshibas ? Regards, Stefan

26th July 2012, 02:09 PM	#12509
labjr diyAudio Member Join Date: Apr 2003 Location: MA	I've called Mouser about shipping regular first class mail for small orders. They're usually very accommodating. Friendly girls down there in Texas.