My Pass F5 Amplifier Build

[Audiodoc]

With the winds of Nelson Pass blowing through the Hifivision community I thought that I should present my build which has been waiting for months for a good anodized aluminum case with the obligatory heat sinks for this Class A design. All components are soldered except few wire bridges and output transistors.

The bridge rectifiers as well speaker protection circuits are also ready.

This is the classical F5 which produces 25W per channel into an 8 ohm load. Power consumption is around 180W. Have ordered a slim profile toroid to make a relatively slim Amplifier. Vertical mounting could also be tried.

Hope the coming group buy will help me. Although their are some companies making heat sinks for LG and Samsung in Chandigarh they take orders in bulk.

Want an enclosure / sinks like this

http://hifi4sale.fullboards.com/t2455-diy-pass-f5-amp

More details of the first watt F5 review are here:

http://www.6moons.com/audioreviews/firstwatt7/f5_2.html

 

[sachu888]

Thats look cool Doc.Could you tell us from where did you buy the kit and approx cost.

Regards,
Sachin

 

[Audiodoc]

I bought it from a forum member in December last year after he PMed me. Although he is not active now, don't even remember his name cost me around 3500 without the toroid.

 

[captrajesh]

I bought it from a forum member in December last year after he PMed me. Although he is not active now, don't even remember his name cost me around 3500 without the toroid.

You must be referring to Suds. I was dabbling of making a F5 but later changed my mind.

A couple of our FMs dissuaded me from buying from the gent.

 

[spirovious]

That looks cool,what about sound?

 

[2chFreak]

The SQ of that F5 will be dictated totally by those 8 large reservoir caps. And any bypass that you may want to create.

 

[doors666]

Here you go
Low Cost Large 100W Al Class-A Enclosure - diyAudio

 

[Audiodoc]

The power supply is an important part of any amplifier let alone this design.
@ captain. You are right it was Suds and he took almost 3 months to send my kit after payment however the kit looks good.
The worst part of class A design is the massive heat sinks. At least this may act like a room heater for my home in Srinagar.

I know about Siliconray and has great enclosures on his site however the class A enclosures are very costly plus the shipping and Dollar conversion right know will run northwards of 20000 bucks.

 

[anilva]

Audiodoc,

You will find many heat sinks which suit this at your nearest aluminum extrusion dealer. He will have 6' or 4' length monster heats sinks. You will need to pick what suits you and get it cut. I have done my previous 4 Pass Amps in this manner. Don't go to a electronic shop for heatsinks.

Regards

 

[anilva]

Also our FM Magma can help you source the heatsinks as well.

 

[captrajesh]

How about using heat sinks with fans from the computer world like 'Coolermaster' etc. Some even have liquid cooling option.

 

[Audiodoc]

That will be effective but costly. There are some pass builds that I have seen mounted on 4 processor heat sinks with copper bases and heat pipe design.

 

[omishra]

That will be effective but costly. There are some pass builds that I have seen mounted on 4 processor heat sinks with copper bases and heat pipe design.

I was thinking exactly same, also as Manvendra suggested bigger fans with slower speed wil be noise free operation. I have seen his HTPC with huge fans.

 

[captrajesh]

That will be effective but costly.

Huge aluminum heatsinks are not cheap either, besides being unwieldy. They would also require a heavy rack, which would also add to the expenditure.

 

[Audiodoc]

The top and bottom plates can be made of perforated mesh plates which will make the mounting of a 120 mm slow speed or temperature controlled exhaust fan on the top easier and aesthetically pleasing.

 

[mbhangui]

The top and bottom plates can be made of perforated mesh plates which will make the mounting of a 120 mm slow speed or temperature controlled exhaust fan on the top easier and aesthetically pleasing.

This looks lovely. Instead of soldering the power transistor/chip directly on the board, we can connect them to the PCB using wires. and those 4 red PCBs can get freedom and be placed elsewhere. It will also allow you to place the 4 heatsinks more conveniently somewhere else as per the design of the casing.

 

[omishra]

This looks lovely. Instead of soldering the power transistor/chip directly on the board, we can connect them to the PCB using wires. and those 4 red PCBs can get freedom and be placed elsewhere. It will also allow you to place the 4 heatsinks more conveniently somewhere else as per the design of the casing.

No no no.. This will add oscillations and could self destroy the amp. I have tried in small amp. This huge will be no different.

Whatever AudioDoc has done looks fine unless fan noise is inaudible.

 

[Audiodoc]

This is not what I have done as yet. This is a solution I found online and suggested by captain. I am just waiting for the perfect solution.

Mishraji is right in soldering the transistors direstly to the board to prevent oscillations however small length of wire may be used in case direct mounting is not possible.

Here is another cooling solution I found. Just the fans need to to temperature controlled ones to decrease the noise.

 

[mbhangui]

No no no.. This will add oscillations and could self destroy the amp. I have tried in small amp. This huge will be no different.

Whatever AudioDoc has done looks fine unless fan noise is inaudible.

Thanks for pointing this out. Learned something today

 

[omishra]

Thanks for pointing this out. Learned something today

Welcome Sir!

There are two ways of cooling -
active - means small size, more electricity and higher price
passive - large size, no electricity and lower price.
But for F5 it seems no less than 10-12K for heatsink.

BTW I am seriously looking at these wrt price and noise factors.
Cooler CPU Cooler in India | Buy CPU Cooler Online at cheap Price