Working on Nelson Pass First Watt

[suds]

BOM for F1 , F3 and F5 Kits.
(double the qty for stereo)

 

[keith_correa]

suds:

If you let folks know the brand of the transformer that you have identified - maybe they will be able to source it from the place they are at and so save on the courier costs for the trans.

 

[dub_no_bass]

Sud count me in for 2 f5 kits and maybe a f3, any chance of similar lm3886 kits?
let me know the details on transferring funds etc

 

[grubyhalo]

Hi Suds,
I'd appreciate some input on the transformer details, if you have found a source as well as the brand and type of the other components of the BOM if you have the time. Thanks!

 

[suds]

Nelson Pass PCB Set :
F1 , F3 and F5 PCB Set , 2 X Amp PCB , 1 X PSU PCB

1.6MM Board FR-4 PTH (pb) Lead Plated Pads , 70micron copper Double Side, with Solder mask Silk.

One Stereo Set PCB - 2 X Amp , 1 X PSU PCB
Rs.500 Inclusive of courier with in India only.

Payment : Bank Transfer / Inter Bank Deposit , State Bank of India.
For Account Details : Mail me : [email protected]

At Home Internet was Down from past 15 Days, therefore I was not able to reply to messages, e-mails

 

[anm]

slightly off topic - how to get a linear psu for a low powered computer? Can this be used?

 

[suds]

slightly off topic - how to get a linear psu for a low powered computer? Can this be used?

Very Much Off topic..
What computer you want to power ?
let me know the requirement, PSU voltages required, type of connectors etc..

may be there is good possibility that you can use any old computers SMPS (Switch Mode Power Supply) see if you can get new or used ones with required voltage / current rating.

 

[anm]

will start a new thread.
btw, what would be the cost of complete amp assembled and tested?

 

[suds]

what would be the cost of complete amp assembled and tested?

As this is DIY approach, don't encourage assembled kits.. then it wont be DIY anymore. DIY Means, Do It Your Self (DIY).. so Enjoy Making your own amps, I will help with kits and parts. Happy DIY

 

[anm]

same difference - do it yourself and then give it to me :lol:

 

[suds]

Sorry About so many corrections.

Here is detailed pricing for PCB's (Not Kits)

Nelson Pass PCB Set :
1.6MM Board FR-4 PTH (pb) Lead Plated Pads , 70micron copper Double Side, with Solder mask Silk.

F1 PCB Set: 2 X Amp PCB , 1 X PSU PCB
One Stereo F1 Set PCB - 2 X Amp , 1 X PSU PCB
Rs.500 Inclusive of courier with in India only.

F3 or F5 PCB Set :
One Stereo F3 / F5 Set PCB - 2 X Amp , 1 X PSU PCB
Rs.700 Inclusive of courier with in India only.


The difference in price is due to size difference, and I have some F1 PCB sets, as I had made them in large quantity.
Before transaction, will mail you pic and BOM.


Payment : Bank Transfer / Inter Bank Deposit , State Bank of India.
For Account Details : Mail me : [email protected]

 

[anm]

what about kits?

 

[suds]

what about kits?

F1 kit and F3 kit at Rs.1500 INR all inclusive of courier (with PSU PCB, Parts, Diode Rectifier Block)
F5 Kit - Rs.1250 INR all inclusive of courier. (with PSU PCB, Parts, Diode Rectifier Block)

• Kits Dos Not Include : Transformer, Cabinet, Heatsink, or any other hardware materials.

• Kits Includes : Electronics Parts such as MOSFET, Capacitors, Resistors, PCB's

Downloads : [url=http://www.firstwatt.com/downloads.htm]First Watt Manuals[/url]

 

[vjcritic]

Bump!

I am in the process of building one of these. I am finding quality Toroidal Trafos hard to source.
Just want to know if there are more people out there working on one of these or if there any possibilities of group buys.

 

[GeorgeO]

Toroidals are available on order from Miracle Electronics here in Bangalore-I have bought from them many times and am more than happy.

 

[vjcritic]

Toroidals are available on order from Miracle Electronics here in Bangalore-I have bought from them many times and am more than happy.

I tried the online enquiry form for Miracle. I haven't got a response yet. Do they require a minimum order quantity for custom requests?
Do you have a contact number/person in Miracle I could talk to?

Thanks!

 

[vjcritic]

I am not working with suds' pcbs, but I am building the F5. I got my transformers custom made - they're not toroids, but that doesn't really matter. 18-0-18, 8 amperes continuous, should be enough for an F5. they cost me 750 each - 1500 the pair.

The most expensive things are the heatsinks, I'd like to know what suds/others are using. I got mine locally @2500 each - they weigh around 6kg each and are double-finned.

I have asked my local source in Chennai for a quote on 8 pieces of 6" X 8" X 2.5" heatsinks. They are available and he will give me a quote tom morning. I saw 4"X9"X1.5" (not quite meeting F5 requirement) for Rs 580 each. So I am guessing price should be similar.

 

[grubyhalo]

I tried the online enquiry form for Miracle. I haven't got a response yet. Do they require a minimum order quantity for custom requests?
Do you have a contact number/person in Miracle I could talk to?

Thanks!

Let me know if you don't get through to Miracle, I can give you a Salzer's rep's contact from whom you can order direct...

 

[vjcritic]

Let me know if you don't get through to Miracle, I can give you a Salzer's rep's contact from whom you can order direct...

I talked to Salzer and he requires a Minimum order of 10.

 

[vjcritic]

It's not about the size - it's the thermal rating that's important, which is determined by heatsink design. The fins and the base thickness are important - 6mm base minimum,

2.5" is too small, FWIW. Nelson runs the reference unit in a 3U case with 300mm heatsinks (IOW, 12" x 5" x 4" per side). You'd be surprised at how thermal ratings degrade with the amount of heat input and rise above ambient shoots up out of control. The F5 dissipates roughly 60 watts at idle, so a 0.4 C/W heatsink will be around 60 degrees, which is very, very hot, enough to burn you.

I tried monkeying around with locally available heatsinks for a while, but the only thing that actually helped was looking at the catalogues for Fischer and Hammond, and approximating the size and weight of the required sinks. They turned out to be much, much bigger than I thought they would be.

Would look forward to your pics and results. Am stuck with another project ATM and can only focus on the F5 week after next.

My selection is based on this section from F5 manual.

Heat Sinking
At 1.3 amps per channel, you will see idle heat dissipation of 62 watts. To keep the temperature rise of the heat sink to 20 deg C. above the ambient temperature, you will want a heat sink rated at about .6 deg C./watt for each transistor. An example of this would be a chunk of finned aluminum, with a series of 2 fins attached to an 8 by 6 base.
You will need two per channel. The output devices need to be intimately attached to the heat sink. The mounting surface on the heat sink should be at least inch thick and smooth and shiny. You can use silicone pads for insulation, but Mica and silicone grease are the best.

The sinks I have asked for have a metal wall more than 8mm (greater than 1/4"). The size is 6" X 8" and fins are 2.5 inches long. This is for one FET. So I need four of those for the case. It looks smooth and reasonably shiny and it is made of aluminium. So keeping fingers crossed

People in diyaudio seem to be going for this one over here.
Conrad Heatsinks - Products

Visually at least my sinks look like those in that picture.