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Group Build: Dynafet


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Just quote the following list and add your info:

name - # channels willing/able to build - # channels wanted to have and hold

luvdunhill - 8 - 4

Not sure how to read this, I'd be in for a 6-channel balanced version, so would that be:

Asr - 0 - 6?

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Did some work on mocking up the chassis and getting into a more listenable state. I will need to get aluminum top/bottom and rear panels for this (not using the steel ones that it came with). I'm also

Got both boards up and running with mods 1 and 2 above. Ran RMAA on it at 150mA, 100mA and 75mA bias. I think 150mA is probably the best. See what any of you think of the plots attached. Als

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luvdunhill,

I've lost track of the board configuration for the DynaFet, can you post a pic and some dimensions? What about PSU?

I would be willing to get in on a 4-ch for myself and build a couple of 4-ch for others. By build, are we talking just the pcb's or entire amps??

What would be the heatsinking configuration for the output drivers?

Holes placement identical to the Dynahi boards would be nice, or onboard heatsinks ala beta22 is handy.

Cheers

Pete

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luvdunhill,

I've lost track of the board configuration for the DynaFet, can you post a pic and some dimensions? What about PSU?

I would be willing to get in on a 4-ch for myself and build a couple of 4-ch for others. By build, are we talking just the pcb's or entire amps??

What would be the heatsinking configuration for the output drivers?

Holes placement identical to the Dynahi boards would be nice, or onboard heatsinks ala beta22 is handy.

Cheers

Pete

I'll post silk pics tonite.

I'd recommend 1 sigma22 per pair of boards. I was thinking "by build" to mean just stuffing the PCBs, as well as some other task, like matching devices and/or helping with procurement of various aspects of the build. We need to consider casing as well, but I'd recommend a one size fits all casing option. I already have some ideas for this. Mounting holes would indeed be the same as Dynahi boards, but I'm only entertaining the off board heat sink layout (see post #1).

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I'll post silk pics tonite.

I'd recommend 1 sigma22 per pair of boards. I was thinking "by build" to mean just stuffing the PCBs, as well as some other task, like matching devices and/or helping with procurement of various aspects of the build. We need to consider casing as well, but I'd recommend a one size fits all casing option. I already have some ideas for this. Mounting holes would indeed be the same as Dynahi boards, but I'm only entertaining the off board heat sink layout (see post #1).

So these little heat sinks would be attached to the output devices,

and then what... to some larger heatsink on the side of the case.

What about a 2 chassis option: one for the psu's and one for the amp boards.

The case I just got from Par Metals was very nice, .18" brushed aluminum face plate, with black painted body, countersunk stainless screws.

digipete-albums-pass-pearl-phono-picture318-parmetal-01.jpg

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I'm interested in 4 boards, but can't do the building... yet. I might be able to tap my dad/brother or dad's employees though.

I'd be interested in another 4 boards if there are any left over for hoarding purposes as an eventual project for when I do skill up to be able to build them :)

I plan on picking up DIY gear as soon as the balancing act resolves and building some of the more basic things to start.

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All this is totally up for discussion.

My preference would be heat sinks that are totally external to the case. The heat sinks I got from Conrad are absolutely beautiful and the rabbited edge and pre-tapped holes make things very easy to assemble. There is the possibility that more of these would be made available, in which case this would be my recommendation. We could also interface directly with Conrad or R-Theta, both of which I've used in the past for things. Total cost to my door (as part of a large GB) was ~$100 a pair for the largest profile from Conrad. I'll post pics (some are in the n_maher beta24 thread)

I suppose we need to run some numbers on the output device heat dissipation.

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All this is totally up for discussion.

I suppose we need to run some numbers on the output device heat dissipation.

I thought it was about half of the Dynahi. If so, I have internal heatsinks in the 12"x12"x3" Par-metal case for my Dynamite and they work just fine.

Of course those heatsinks were labor intensive to build and mount to the dynahi boards.

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I thought it was about half of the Dynahi. If so, I have internal heatsinks in the 12"x12"x3" Par-metal case for my Dynamite and they work just fine.

looks like this can scale up via adjustable bias and the psu... in this case, you can never can have too much aluminum :)

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If you have to ask, this probably isn't the project for you :) I have no desire to calculate the rough cost honestly. Obviously things will be done in mass in order to keep the cost down, but the idea is to get things done in parallel and when possible just build them all identical with maybe one or two options. That's my vision at least.

I can understand you don't want to do an estimate, but just to give an idea, would this fit in the 1k$-2k$, 2k$-3k$, 3k$+ ?

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looks like this can scale up via adjustable bias and the psu... in this case, you can never can have too much aluminum :)

Here is what my Dynamite heatsinks look like. Drilling all the holes to the precision required to mount the fabricated heatsink was not easy.

digipete-albums-dynamite-picture256-dynahi-002.jpg

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What's the parts count per board?

And it's one thing to populate a few boards, it's another thing entirely to build an amp soup to nuts. Even with a fully machined chassis it's no small feat with an amp of this complexity.

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What should I expect soundwise from a Dynafet? A more tube like sound than the B22, but with the same power capabilities and transparency?

I have no DIY capabilities, more for the lack of a place where leaving a project as long as needed to finish it than anything else, but also lacking the equipment for the adjustments and measurements, which is important. However I might participate if someone else builds the thing for me. Perhaps a friend of mine is interested, I can ask him, but I'd be thankful if someone having used a Dynafet before posted his impressions.

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  • luvdunhill - 8 - 4
  • Asr - 0 - 4
  • Stretch - 0 - 4
  • looser101 - 4 -2
  • PFKMan23 - 0 - 4
  • Naamanf -? - 4

As for the cases I think the Hi-Fi 2000 Pesante Dissipante is a good option. And it seems if you order 4 or more they don't charge shipping. Could also be an error in their software.

Edited by naamanf
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