How to build the F5

[6L6]

Double post. Moderator please delete.

Thanks!!

 

[Russellc]

Remote hosting the pics saves the bandwidth costs to the DIYaudio server.

I could also go and resize them in photobucket... I guess I haven't noticed, as my pages load quickly and auto-resize to a smaller photo that you can click into.

But as a photo is worth 1000 words, some members might want the detail...

You can see the main problem with remote hosting if you peruse old posts...The pics are missing b/c original poster no longer has the account. up load them here and they stay...just saying, nice build, really enjoying it!

Russellc

 

[Russellc]

here is a cropped example.
still same detail, jpeg and only 48k

and its here forever...

Russellc

 

[Russellc]

My solution to avoid rectangular cutting.
Neutrik - powerCON 20 Amp

Pretty much the same openings as XLR. The only problem is that they should not be "hot" plugged or unplugged.

Nice! I've been looking for something like this. What is meant by "hot plugged"?

thanks,

Russellc

 

[labjr]

Nice! I've been looking for something like this. What is meant by "hot plugged"?

thanks,

Russellc

Connected or disconnected while running.

 

[Russellc]

Gotcha. Thanks for that.

Russellc

 

[CanAm Man]

Re: Locktite

Yep--I've used Locktite Blue to help retain semiconductors to heatsinks. If used sparingly, it serves a purpose--as long as you don't overdo it!

Re: Thermal grease effectively being an "anti-seize compound" in composition. I never thought of it (thermal grease) in that sense (anti-seize compound) but now that you brought it up, 6L6, that's a valid point. From a guy who's built up a lot of aluminum racing engines with Grade 8 steel fasteners, that's an interested way to look at the amp-building situation. I guess that's why I've always tried to keep Arctic Silver off my heatsink threads, when I'm building electronics stuff.....

 

[tinitus]

anyone tried to use the very thin japan paper, with thermal grease, or even silicone glue, maybe ?

but only for the fearless I guess

but think about it
once tightened up and dried, you have created your own isolation pad, and a very thin one, and stable too

 

[crazycody1993]

So what voltage secondaries do you order when you buy a transformer?? i may have screwed up and ordered the wrong one..

 

[Woody1911a1]

for a standard f5 , 18v . although some using the antecs are using 20v .

 

[Woody1911a1]

Nelson recommends "I recommend rail voltages from 23 to 25
volts."

most USA builders are buying from antec and finding the rail volts for the 18v trannies at 22-23v and the 20v ers @25 ish .

i just started soldering my boards tonite and haven't ordered my transformers yet , but thinking of getting one of each .

 

[crazycody1993]

oh.. thats problematic! is there a way to reduce my voltage, either into or after my power supply? i ordered a 24v transformer!

 

[Woody1911a1]

yes but , like you i'm still learning . where'd you order it from ? might just be easier to pay the $10 each way to get the right one .

 

[flg]

Higher voltage might be an excuse to cascode? It's actually pretty easy to take off a few windings and reduce the voltage. I've beeen using Avel's fm Parts Express and I've been getting 23.5VDC. It really depends on the cRc. The bigger Rs will loose a little more but give less ripple
Me, for the F5, I'm using 2 pair of Toshiba's at higher current and I'm going with the Antek 400VA 2X15/ch hopping to get 19VDC. Haven't done any testing yet though.

 

[6L6]

I agree with Woody, it's probably best to eat the shipping and get an 18v+18v transformer.

 

[6L6]

Re: Thermal grease effectively being an "anti-seize compound" in composition. I never thought of it (thermal grease) in that sense (anti-seize compound) but now that you brought it up, 6L6, that's a valid point.

Actually, it's not so much the white thermal grease I was thinking about, but the very fine (powered, actually) aluminum shavings and oil remaining from tapping the threads in the holes.

I have cleaned them out with Q-tips and alcohol, but I am still getting some residue on the bolt threads that looks exactly like the anti-seize I use on my shotgun's choketubes...

 

[crazycody1993]

Higher voltage might be an excuse to cascode? It's actually pretty easy to take off a few windings and reduce the voltage. I've beeen using Avel's fm Parts Express and I've been getting 23.5VDC. It really depends on the cRc. The bigger Rs will loose a little more but give less ripple
Me, for the F5, I'm using 2 pair of Toshiba's at higher current and I'm going with the Antek 400VA 2X15/ch hopping to get 19VDC. Haven't done any testing yet though.

yes but , like you i'm still learning . where'd you order it from ? might just be easier to pay the $10 each way to get the right one .

i wouldn't be opposed to taking off windings. depending on what it takes, i dont want to end this little party with a 'bang'. So if taking off windings isnt too hard, and i can be confident in doing so, i will. And what do you mean by bigger Rs losing more? as in losing more voltage?

I ended up ordering mine from Antek

 

[flg]

Yes. The R of your CRC filter sees the Idle current continuously. Say you are driving 1.3A to the amp the R has 1.3A*R of voltage dropped across it. A .38 ohm resistor would be dropping 1/2V.

 

[crazycody1993]

So even if you use bigger resistors, you wont lose amperage, but it will lower your voltage? My power supply will be able to be a CRC PS, so if I add enough resistors, I can lower my voltage where it needs to be?

 

[santa]

Thanks for this thread.
I have been considering an F5 build but dealing with the big thread seems more daunting than actually building the amp.