Another question F5 thread

[kafkaesque]

Hello,

I have looked at hundreds of posts on the F5. However, there are still many questions I have.

I am planning on a F5 build. I will use boards from diyaudio store.

The power supply recommended is the antek an-4218 (400VA unshielded). Is there a good improvement is using dual power supply? And is the shielded power supply better?

I terms of case, I was thinking on using a server rackmount case Newegg.ca - Rosewill RSV-L4000 Black Metal / Steel, 1.0 mm thickness, 4U Rackmount Server Chassis 8 Internal Bays, 7 Included Cooling Fans
These case seems to be a nice size, ventilated hole and a nice design to match. They even have some fans if electricity is wired to them.

The heatsink recommended is from heatsinkusa, about the lenght of the case and as wide as possible.

For component, tech-diy seems to have all the necessary transistor and other component except for power supply. Is the upgrade worthwhile to have the caddock resistors?

Is there any kit for the power supply regulation? Or should it simply be P2P for ease of creation + lower costs?

I am also planning on a lightstep attenuator for volume control and a gamma 1 dac for optical in. I wonder if all this could be integrated into 1 box. Potentially adding futher PSU and regulation for other items.

For RCA connectors and wire what is your suggested item for best performance by $.

Also, any suggestion on good value upgrade?

Cheers

[6L6]

Originally Posted by kafkaesque

The power supply recommended is the antek an-4218 (400VA unshielded). Is there a good improvement is using dual power supply?

Some think so, others don't. It can't hurt. It does add cost.

And is the shielded power supply better?

Again, it can't hurt.

I terms of case, I was thinking on using a server rackmount case Newegg.ca - Rosewill RSV-L4000 Black Metal / Steel, 1.0 mm thickness, 4U Rackmount Server Chassis 8 Internal Bays, 7 Included Cooling Fans

It's huge! With that much forced cooling you could build an Aleph 1.2!!! And if it were me, using that much case, I would. But that's me.

These case seems to be a nice size, ventilated hole and a nice design to match. They even have some fans if electricity is wired to them.

If you have the heatsinks internal to the case, you will need the fans. Look to starving them a bit so they run slower and more quietly. Server fans are usually loud enough to wake the dead.

The heatsink recommended is from heatsinkusa, about the lenght of the case and as wide as possible.

If you run the fins front to back, the fans will again be necessary. Slower is still ok, you don't need to move much air to make a big difference.

For component, tech-diy seems to have all the necessary transistor and other component except for power supply.

I used Tech-DIY for my build and their kits are a great deal. I have no complaints.

Is the upgrade worthwhile to have the caddock resistors?

That's a religious question. I abstain from answering.

Is there any kit for the power supply regulation? Or should it simply be P2P for ease of creation + lower costs?

The standard PSU is not regulated. There are a few PCB commonly available for the PSU that can be used. Peter Daniel's (Audiosector.com) board, or the Alpeh PSU PCB available from Chipamp.com

I am also planning on a lightstep attenuator for volume control and a gamma 1 dac for optical in. I wonder if all this could be integrated into 1 box. Potentially adding futher PSU and regulation for other items.

Sure! Sounds like a good idea, I love integrated.

For RCA connectors and wire what is your suggested item for best performance by $.

Again, that's a religious question, some people think you are a moron if you don't shell out a bazillion dollars for the expensive stuff, and others think you are an idiot if you do anything other than using the inexpensive ones.

Also, any suggestion on good value upgrade?

Ummmm... For what, specifically?

[BeachAssault]

I'm in the process of building an F5 as well, very slowly however. I selected the single shielded transformer only because the shield option wasn't really expensive compared to the transformer itself. A double rated single transformer would not be as good as 2, at least theoretically, but I can't see it making that big a difference unless you woefully under-spec your single transformer.
The CRC power supply filter came from ebay. It wasn't expensive and is adequate quality. You have to assemble it, but it like it is still available. Search "PASS F5 power".
I got the case from vt4c.com and it is adequate as well. It's not a perfect fit and it has other text on it, but it will do. It comes withe the power circuitry, input and output connectors & I have to admit they were a surprise. They're fine. But the case will end up being the single biggest expence unless you go cheap or totally DIY it.
I use Newark.com for parts mostly, but some of the stuff has come from other sources like ebay & DIY store. There circuit card are pretty good.
Good luck.

[bear]

I would not recommend running a regulated supply... one could try it of course. But since it is a class A amp, the draw is reasonably constant from the supply. Focus on getting the supply ripple low by non-regulating means, imo.

I would not use fans, unless you are in a noisy environment.
I hear hum in my LR if it is there. Fan noise is clearly heard as well.
Convection cooling is the way to go for this amp.

Again, imo.

People have reported hearing diffs in bias level, output devices and the larger power resistors, and of course the power supply. In short, ALMOST everything!!

I'd add layout and wiring has an audible effect on this amp as well.

Reconsider the chassis requirements and sources I would suggest.
Unless you need or want the standard "look" rack mount amp, think "out of the box".
The heatsink is the determining part.
Build to it?



_-_-bear

PS. a cap multiplier might be ok, but you have to think about the heat that the pass devices will add - it already is a candidate for a small room heater. That's a big reason that I would not want to use a regulated supply, you have to drop a lot of voltage to get real regulation under peak loads, which equals heat. But even so it is still something to consider for a full out "no-holds-barred" implementation. (but I'd test it sonically in a prototype before spending the time and $ to make a final and slick amp) Of course some folks will tell you that regulators impart their own "sound"...

[CanAm Man]

Perhaps the best "chassis alternative" is DIY. The large heatsinks easily form the sides of the chassis, and with some drilling and tapping (which you'll have to do anyway (to mount the amp PCBs and the MOSFETs), you can build a nifty chassis of your own design. You can use "Front Panel Express" to create your remaining front and rear chassis panels, and for the top--get creative. I built my F5 using 3/16" aluminum plate, and it is largely indestructable. I also used the large Conrad heatsinks. You can also run cooling fans--I did.....running 120vac fans at about 65vac (for reduced speed and noise).

My build, FYI: Another F5 build--beautiful music, different drummer

[bear]

CanAm,

How did the heat without fans work out?

And, did you ever get together with those other DIY'ers?

<limited thread hijack alert!>

_-_-bear

[oneplustwo]

For what it's worth, I'm going to get heat sinks from Antek. I saw their ebay enclosure and asked if I could get their heatsinks alone for which they quoted me $25 each. I also ordered the transformer from them (as well as my B1 transformer) which helped cut down on shipping costs collectively. Of course, you can get the full enclosure if you don't want to fuss with DIY-ing that part of it.

The stuff is in the mail so I'll post pics when I get them in the build thread I just started.

[CanAm Man]

Originally Posted by bear

CanAm,

How did the heat without fans work out?

And, did you ever get together with those other DIY'ers?

<limited thread hijack alert!>

_-_-bear

[CanAm Man]

bear,

the Conrad heatsinks with fan cooling was serious overkill, but it gave me the opportunity to try higher bias (which I experiemented with). Having said that, my chassis (with low-noise fans) is now a great candidate for the F5 turbo....

Yep....... 6L6 is in Denver, and bbm3 is just "up the road" from me in Colorado Springs. We got together at my house to poke and prod the F5, and to talk "car talk". Right now, I'm getting ready to move to Florida, and that will probably throw the monkey wrench into further sessions.......

[skunark]

I'm considering using a HiFi 2000 Pesante Dissipante chassis. If I understand the temperature coefficient right the 5U/500mm chassis should be good for about ~200 watts/per sink (0.23 C°/W @50C°). With four sinks that's about ~800 watts total. The 4U/400mm chassis is about half that. Am I on the right track here?

The price and shipping (to US) are both high, but not sure if there is anything as complete.

Also, I would like to build BA3, Aleph X-J and the F5/F5 turbo during the next year or two, and was considering using a separate power supply chassis and each amp having it's own chassis. Goal of one killer power supply vs three power supplies... Would it be best to size the transformer to the largest amp with extra care to lower the voltage on the others, or size to the smallest amp sacrificing power on the others? My thought here is to purchase two large plitron transfers vs several various transformers (say plitron or antek). Any thoughts here?

Jim