F5 power amplifier

[tms0425]

Can someone point us to an example of how two channels are put together as a balanced amp? What are the disadvantages when used in a non balanced way? Can one then still have the double power? Thanks!

Use search on this thread or take a look at post #1907

 

[Peter Daniel]

Can someone point us to an example of how two channels are put together as a balanced amp?

Check page 7 of F4 Owner Manual: http://www.firstwatt.com/products.htm

 

[labjr]

According to the spreadsheet the smaller enclosure will not work for the f5 as it comes out to 0.811 deg C / Watt higher than the recommended .6 deg c /Watt.

The larger one should work with 0.4227 deg C / Watt but it's too large of an enclosure for that project.

 

[Tea-Bag]

Heatsinks

LabJr. email me directly. I cant email you.
Your close by - I work in Andover. Live in ME

I have some surplus heatsinks that you can see if they work for you. You would need to develop metal working stills to build a case. (hacksaw, drill, taps) but they might be enough for an F5. Wont know till I get some boards...

 

[labjr]

Re: Heatsinks

LabJr. email me directly. I cant email you.
Your close by - I work in Andover. Live in ME

I have some surplus heatsinks that you can see if they work for you. You would need to develop metal working stills to build a case. (hacksaw, drill, taps) but they might be enough for an F5. Wont know till I get some boards...

Thanks for the offer.

I'm curious about what your heatsinks actually look like although I probably will try to find some kind of enclosure with heatsinks already attached. I would have to be bothersome to a friend with a metal shop to make an enclosure.

Before you build the boards you can probably calculate the appoximate dissipation of the heatsinks by inputting the various parameters in the spreadsheet.

 

[labjr]

I was reading through the F5 PDF file and notice that Nelson recommmends a 6"x 8" heatsink with 2" fins for each output device.

On that spreadsheet it calculates to approx= 0.3935 deg C / Watt when plugging 17 as the number of fins. That's about 33% better than the .6 deg C/ Watt he recommends if the calculations the correct. I guess more is better? But are calculations correct?

 

[jacco vermeulen]

According to the spreadsheet the smaller enclosure comes out to 0.811 deg C/Watt

Did you check the Drawings page on the Heatsink Excel file for the right parameter input ?

 

[labjr]

The spreadsheet says "width is optional" . What is considered the width. I thought the fin height was the width?

 

[Zen Mod]

even if I hate to admit that

enough

Jaccovitty is right , as usual ;

just don't tell to Dutchy Whale that I said that .

 

[woodturner-fran]

Would anyone have a few CL60 thermistors that they would be willing to part with? Mouser are out of stock until the new year......

Fran

 

[labjr]

Would anyone have a few CL60 thermistors that they would be willing to part with? Mouser are out of stock until the new year......

Fran

I haven't bought any parts yet. Digikey has them in stock. Probably won't help you if you want to order everything from one source.

 

[rhysh]

Hi Everyone,

Do you think i would be able to get away with a pair of MF35-151's from conrad as shown here http://www.conradheatsinks.com/products/flat100_350.html#MF35 .

I would use one per channel.

Thanks!

 

[labjr]

Hi Everyone,

Do you think i would be able to get away with a pair of MF35-151's from conrad as shown here http://www.conradheatsinks.com/products/flat100_350.html#MF35 .

I would use one per channel.

Thanks!

I think that's about the same as what is recommended in the F5 article.

 

[rhysh]

I think that's about the same as what is recommended in the F5 article.

Cheers pal, i must have missed that.

 

[rhysh]

Having looked over my casing options again, would a 3u case from hifi2000 in italy with heatsinks be enough?

An externally hosted image should be here but it was not working when we last tested it.

I would have no problem in adding a couple fans on the back panel if needed.

Cheers

 

[cviller]

I'm currently using the 40cm 3u version for my f5 and it does not get too hot at all. In fact I think the 30cm would be sufficient.

 

[massimo]

Having looked over my casing options again, would a 3u case from hifi2000 in italy with heatsinks be enough?

It could be useful to check this document from hifi2000

 

[rhysh]

Well, How much heat am i looking to get rid of? I would like to get the 2u version if possible, as it costs quite a bit less, and i only loose 15w of dissipation.

Thanks for the datasheet.

Edit: Nevermind, i then have the height issue.

 

[rhysh]

Can anyone tell me the real power output of this amplifier, per channel into 8ohms using standard rails?

Thanks

 

[massimo]

Can anyone tell me the real power output of this amplifier, per channel into 8ohms using standard rails?

Thanks

Check the F5 article/manual that can be downloaded here: http://www.firstwatt.com/products.htm