F5 Turbo Circuit Boards

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Variac

Variac

diyAudio Editor
Joined 2001
BurningAmp.org
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No, the spreadsheet is to gauge interest in different options. However it was started with the intent of it becoming an order form I think. Now, we'll decide on the options (the new design is more versatile IMHO so there will be less need for so many options.) and post the "winning" board options in the store where you can order them. All boards will come from the store. There was interest in hundreds of boards. Seems that it might be best to do a first run of about 100 or so to make sure the board is perfect. People willing to risk it will be able to sign up and pre-order at the store, and the boards will be sent out as soon as they arrive. The more cautious can then order from the second batch. That's the plan for now.
 
SRMcGee

SRMcGee

Member
Joined 2004
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Folks:

I'm not well educated in the heat abatement requirements of Class A amps but am planning on building a couple of F5 Turbo V3 amps -- one will likely be a stereo amp (in the HiFi2000 5U/400mm chassis) and the other a set of monoblocks (probably in two of the same enclosure). Given my lack of experience, I'm disinclined to stretch the outside of the envelope any more than necessary. As a result, I've reconsidered my opposition to forced air cooling in the stereo F5 Turbo amp and am thinking about using a single 80mm super quiet fan operating at low speed. The top and bottom panels on the chassis are expected to either have HiFi2000's standard venting (4 rows) or, if it is readily available, the 6 vented row option.

My question: is it reasonable to assume that such a fan, mounted squarely in the center of the rear panel, would facilitate even cooling throughout the interior of the chassis or is it likely that there will be "hot spots" where the air circulates and cools less. If the latter, would you expect any unevenness in the cooling to adversely affect the MOSFETs' operation?

Your feedback is appreciated.

Regards,
Scott
 
a.wayne

a.wayne

Member
Joined 2008
Variac said:
Yes, We're working with UKToecutter. So far his boards fit the Universal Mounting Standard. Now he's debugging them. Since the general concept has been/is being tested
he is quite confident they'll be right. We'll Shortly update Toecutter's spreadsheet and announce it here when you should go review the spreadsheet and confirm your interest.
Mark
Click to expand...

Variac said:
No, the spreadsheet is to gauge interest in different options. However it was started with the intent of it becoming an order form I think. Now, we'll decide on the options (the new design is more versatile IMHO so there will be less need for so many options.) and post the "winning" board options in the store where you can order them. All boards will come from the store. There was interest in hundreds of boards. Seems that it might be best to do a first run of about 100 or so to make sure the board is perfect. People willing to risk it will be able to sign up and pre-order at the store, and the boards will be sent out as soon as they arrive. The more cautious can then order from the second batch. That's the plan for now.
Click to expand...

Great Mark , Toe cutter, Timeline .....?
 
buzzforb

buzzforb

Member
Joined 2010
SRMcGee said:
Folks:

I'm not well educated in the heat abatement requirements of Class A amps but am planning on building a couple of F5 Turbo V3 amps -- one will likely be a stereo amp (in the HiFi2000 5U/400mm chassis) and the other a set of monoblocks (probably in two of the same enclosure). Given my lack of experience, I'm disinclined to stretch the outside of the envelope any more than necessary. As a result, I've reconsidered my opposition to forced air cooling in the stereo F5 Turbo amp and am thinking about using a single 80mm super quiet fan operating at low speed. The top and bottom panels on the chassis are expected to either have HiFi2000's standard venting (4 rows) or, if it is readily available, the 6 vented row option.

My question: is it reasonable to assume that such a fan, mounted squarely in the center of the rear panel, would facilitate even cooling throughout the interior of the chassis or is it likely that there will be "hot spots" where the air circulates and cools less. If the latter, would you expect any unevenness in the cooling to adversely affect the MOSFETs' operation?

Your feedback is appreciated.

Regards,
Scott
Click to expand...

any fan based air movement inside the case or across the heat-sink will work wonders for your temperature level.
 
Variac

Variac

diyAudio Editor
Joined 2001
BurningAmp.org
Paid Member
I've never tried this, but I've always been tempted to drill holes between each fin of the heatsinks through the base plate into the interior of the amp. Then have a fan mounted in the top inside of the cover with no other opening, oriented to pressurize the internal space creating a plenum. The air would exit between the fins "scrubbing" off the hot air next to the fin surface. If the fan fails, or has a thermal switch cutting in and out as needed, the fan hole would vent internal air.

I cleverly have a friend with a milling machine, which would make it a lot easier than drilling like 150 holes so will probably give it a try.
Easiest way would be to mill grooves through the backplate side to side from the inside. Opposite the direction of the fins. But they would have to be staggered or something because a long side to side slot would stop heat from spreading through the heatsink base
 
Last edited:
buzzforb

buzzforb

Member
Joined 2010
Any sort of entry hole or slot will allow for air movement through the case. Trying to direct that air movement is possible, but difficult. Too many holes, and the fan may have trouble pressurizing the case and there will not be as much air flow as a result. Velocity may be the more appropriate word instead of flow on the last bit.
 
noSmoking

noSmoking

Member
Joined 2010
fuse sizes

hi,
I keep seeing folks post about what fuse to use ,Here's my 2cents form 40 years of building,
The ac side of the transformer is one circuit be it 120 or 220 volts ac,it needs a fuse in this circuit.
The DC side if it's a single voltage it needs ONE fuse to cover the whole load.
If the DC side is using 2 DC outputs you need 2 fuses one for the positive side and one for the negative, each one half the whole load,
Now here comes the figuring each fuse must at least cover it's load ,ohm's law will give you a idea of load current, and then the amount over what is required is your insurance I have seen 25% or more and a slo-blow is x2 it's normal requirement,but in the dc side a fast fuse is best and rated about 10% above what is required,
I have had many amps that oscillate blow the fuse, not the outputs so I use them,For my personal F5 I use the cl60 thermistor and the fuses recommended by Mr.Pass,,,,,,anyone wants to pinch in on there recommended values Please do!!!!!!:)
 
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