Building an F5 Turbo v2 (in-Progress)

[buzzforb]

Save smoke later.

[PKI]

The question is: can I stack transformers on a top of each other? It will help me to put them far from the boards and save me some space for nicer wiring. However, I do not want them to be coupled though the "leaking" magnetic field... and I have no idea how it is important.
I can make some estimations, but being a theorist I know how far can it be from reality ;-). Thats why I'd like to rely on engineering experience :-)

Buzz, I did the same thing on my aleph's trims half a year ago, I used a different color, but patent is pending ;-)

[Zen Mod]

yes , you can

put ring of softer and thicker rubber between them

I'm using it all the time , on both sides of toroid , glued with neoprene based glue

[6L6]

Originally Posted by danielutzu

6L6: how did you configure the first PSU board with the filter resistors so that all 8 caps are connected BEFORE the resistors (and not 2 caps before the resistors and 2 caps after them per rail)?

Sorry I didn't see this sooner...


I didn't.

On the first board there are 4 caps after the bridge, then the resistors, then the next 4. The next board is connected in series via some wire, where there are 8 caps. The resistor postions need to be jumpered on the 2nd board. Also on the second board is where the bleeder and LEDs are mounted.

There wasn't an easy and clean-looking way to evenly divide the 2 cap banks. That said, this could be considered a CRCRCRC filter, as the wire and jumpers have some resistance.

[bugzbunny]

Two questions, if I may:
a. What varies if one is building monoblocks?
b. How much is different from a V3 build, up to this point?

[6L6]

a) V2 or V3 monoblocks? In either case you would only need one Front-End board.

b) The V3 would need the cascode transistors in the Front-End, and their associated parts, and the pictured output boards and power supply would be for one channel. I.E., what you see so far (and the other heatsinks, which you haven't seen yet,) would be for one monoblock channel.

The rule of thumb is that a stereo V2 or a mono V3 will be in a 5U 400mm 'Big Amp Chassis'

[bugzbunny]

V3 monoblocks (but since the answer is the same, I guess it does not matter?).
Darn, so I will have to buy 2 5U 'Big Amp chassis'? Time to buy some chocolates and a bunch of flowers for the spouse.

Originally Posted by 6L6

a) V2 or V3 monoblocks? In either case you would only need one Front-End board.

b) The V3 would need the cascode transistors in the Front-End, and their associated parts, and the pictured output boards and power supply would be for one channel. I.E., what you see so far (and the other heatsinks, which you haven't seen yet,) would be for one monoblock channel.

The rule of thumb is that a stereo V2 or a mono V3 will be in a 5U 400mm 'Big Amp Chassis'

[6L6]

Lol, yes, you will need basically 2 of everything you are seeing in this guide.

The (stereo) V2 PSU will be good for one V3 monoblock, the 5U 400mm chassis will hold either a stereo v2 or mono v3 etc...

I just though of something -- I bet that with just a little creativity you could make a BA-3 front-end (which is a great preamp gainstage) on the F5T Front-end boards... The circuit isn't all that different, and there are lots of places to mount things on this particular PCB. And if you are building monoblocks, you will have a pair of FE boards extra...

[6L6]

THIS IS EXACTLY WHY YOU NEED A LIGHT BULB MAINS LEAD --

Look at this photo:



It looks good, yes? It's not. The wire color from the rectifier is logical - Black is V-, white is GND, and red is V+. Looking at the polarity of the caps, it seems that the leads are going to the proper place... but the board isn't setup that way, and the polarity of the caps looks backwards to how it's wired.

The PCB is marked correctly. I didn't double check the markings, and got it backwards.

I tested the amp PSU with a bench-top power supply, and this this the first time it has been powered on it's own.

The only thing that saved me from letting the smoke out was the current-limiting of the light bulb mains tester.

I have been smart and lucky enough to always turn on everything during building and testing with the light bulb mains lead first to save me from my own mistakes.

[bugzbunny]

I think I have seen this somewhere before on diyaudio (mains light bulb tester.), but would it be possible for you to upload a photo of where the light bulb is connected in your circuit? 100W bulb?