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Old 16th September 2008, 04:13 PM   #11
cfcubed is offline cfcubed  United States
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Quote:
Originally posted by Nelson Pass
Another triumph for DIY.
Thanks! And it is looking like it will be a triumph... for me anyway

Only had one errant trace that needed cutting on my F2 boards (prevented P1 from balancing V+ (1/2 V+ at C3+)).

BTW, I was waffling between an F1 & F2 from the beginning after reading about them w/my horns & went initially for F1 because of PCB availability.

So, doing this because; of reading F1/F2 comps, cannot leave well enough alone, have the room in the case & adding F2 option would not be too expensive.

It's coming along nicely.. Here is the left channel F1/F2 bank installed & operational (note piggybacked aluminum Ls for each bank w/HS compound):

Click the image to open in full size.

The left side F1/F2 package is working & sounding great even on my awful bench speakers. Expect both to sound great but different (e.g. like blonds vs brunettes, might want F1 bank in some situations & F2 in others). Although can be actively switched (mini DPDT switch on back swinging each PS rail ground to the relays), will be more of a day by day or week by week switcheroo I think.

F2 15kUF Caps - Yes, someday I'll pay attention to the SIZE column in my parts searches but maybe bigger is better.

$7 5A 4PDT single blank switch relay w/rail->12v reg:

Click the image to open in full size.

Setup so that 12v REG (w/anti-noise caps) is connected to rail + & just waiting for PS ground/negative to come along.
No need for balanced input at this time, so switching V+, Out+, Out- & In+ (rest is shared).

Fun!
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Old 19th September 2008, 02:20 PM   #12
cfcubed is offline cfcubed  United States
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Default Whew, its done & working great.

It's a wrap... NOW I think it'll stay closed for a while so I can listen to it Had to play with angle/location of those giant caps for open/close clearance...

Click the image to open in full size.

And although I may do the ε24 thing for F1/F2 bank switching someday (+ matching front panel switch), think the mini DPDT is fine:


Click the image to open in full size.

back:

Click the image to open in full size.

Think that's it for me for amps for a while - This thing is really the ticket for my setup...

Thanks again Nelson for releasing the designs into the wild.

P.S. I have experienced a couple ε24 dropouts in the couple weeks this has existed... Raised the ε24 470uf cap -> 1000uf but it could be that cheap 12v transformer OR 120v line transients.
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Old 19th January 2009, 02:15 AM   #13
Tea-Bag is offline Tea-Bag  United States
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Default Neat



I like the switch piece,
do you just have the power ground tied to the switch between the two different amps PS inputs?

I assume the inputs and speakers outs are just all ganged together....

Can you get to full bias with heatsink the that. That's 200W of dissapation isn't it?
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Old 19th January 2009, 11:43 PM   #14
cfcubed is offline cfcubed  United States
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> do you just have the power ground tied to the switch between...

As I recall, I've got the power grounds tied & the input grounds tied (no balanced input)... So I'm switching input +, PS +, and both output leads (+ & -)... That's 4 poles per side.

It's running full bias, don't remember what F1s & F2s are dissipation wise, but again, only running one pair of channels at a time. And it works very well with that HS... It does not get hotter than about 50C AFAIR.
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Old 20th January 2009, 02:43 PM   #15
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Congratulations on completing your build.

I have a couple general questions about the heat sinking ( I will be tackling an F5 in the near future).

How effective are the heat sinks with fins that are that shallow?

What is the compromise when attaching the output devices to angled aluminum and then having that attached to the heat sink. Is there a compromise or does the heat transfer still work adequately?

Good Luck.
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Old 20th January 2009, 03:25 PM   #16
cfcubed is offline cfcubed  United States
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Quote:
Originally posted by WithTarragon

How effective are the heat sinks with fins that are that shallow?

What is the compromise when attaching the output devices to angled aluminum and then having that attached to the heat sink. Is there a compromise or does the heat transfer still work adequately?
Shallow fins - When building this & my miniA was scoping ebay for salvaged heatsinks. Think this one was 20"x14"x1.5" & I cut off 5 or 6" for the miniA. But top placement of the HS is best thermally I think... E.g. no fin surfaces are heating other fin surfaces, so can get by w/more shallow fins. I've no science to back this up tho.

L brackets - Finger testing seems to indicate the FETs are not that much hotter than L bracket & immediate HS area. Lapped the L bracket & mating HS section and used heatsink compound on surfaces.

Again, I believe I'm running "full bias", whatever that is, and things are working quite well.

Quote:
Originally posted by WithTarragon
Good Luck.
Thanks... I'll use the good luck wish for my current collaborative effort - nice little tube hybrid headamp since I'm good on speaker amps for a while

Re: 4PDT relays - I did recall correctly, from my post about them "Setup so that 12v REG (w/anti-noise caps) is connected to rail + & just waiting for PS ground/negative to come along. No need for balanced input at this time, so switching V+, Out+, Out- & In+ (rest is shared)."
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Old 22nd January 2009, 12:08 PM   #17
cfcubed is offline cfcubed  United States
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Few more things about this build:

* Raised the ε24 470uf "tank" cap -> 4700 uF way back & get no dropouts from it now... The A/C circuit this amp is plugged into is heavily loaded, lights on it actually dim when sump pump or dehumidifier on the circuit kick in. So, not ε24's fault I had to raise this & I *should* move some things around A/C circuit-wise in the house.

* Heatsink - When I said I've no science to backup that top placement is thermally best, I should say other than the fact that heat rises

The heat spreads nicely across HS too, perhaps due to base thickness and the actual alum grade (hardness - did break 3/4 taps in it - far more than my other HS materials). Large, long L brackets help here too.

Thermally isolating HS from case should pay off too... Measured within-case temp and it peaks about 120degF (sides get warm - not hot). So its a nice comfy place for all the non-FET comps. Removing 1 screw allows me to raise HS & show it off too, using gloves on HS of course

Got some Elegant Anodized Alum feet that raise it up enough so bottom holes/case side slots feed air...
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Old 29th April 2009, 12:51 PM   #18
cfcubed is offline cfcubed  United States
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Default Wrong about "horizontal up" HS mounting attitude

Quote:
Originally posted by cfcubed After a quick look around, I didn't find any other top-mount HS DIYs... But I think it may be the best thermally & there's no way I was putting any other components on top anyway.
Heh, talking to myself here again but need to clarify that, although this amp is working fine, it seems I was quite wrong about HS efficiency WRT top-mounting:

4.6. Thermal performance .v. mounting attitude

BTW upon rennovating the living room it appears this beast is not allowed to live there anymore. Marriage. Heh.
Anyway I'll be pulling the F1 boards & fitting them & a new PS in a smaller, remote-on-triggerable case to hide somewhere.
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Old 23rd May 2009, 04:14 PM   #19
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Default PCB's

Hey cfcubed, I'm looking to build an F1 clone similar to yours but don't know where to go for the pcbs. Unfortunately I think a recent group buy fell through. It looks like at the moment the only option is to buy them in individual batches. If you (or anyone here) knows of a group buy or somewhere that will print them individually at a decent price, please help. Thank you.
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Old 23rd May 2009, 10:57 PM   #20
max426 is offline max426  United States
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Default Re: PCB's

Quote:
Originally posted by milezone
Hey cfcubed, I'm looking to build an F1 clone similar to yours but don't know where to go for the pcbs. Unfortunately I think a recent group buy fell through. It looks like at the moment the only option is to buy them in individual batches. If you (or anyone here) knows of a group buy or somewhere that will print them individually at a decent price, please help. Thank you.



here are some pcb's

also here


jim
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