An illustrated guide to building an F5

[flg]

Originally Posted by CanAm Man

6L6.... Jim.... Clear, concise, succinct of your F5 build. Great pics, too. Hopefully, no one will hijack your thread! (Can you get it "locked up"?)



Ooohhhh, Merlin--congrats on being the first and quickest to hijack this fine thread. Perhaps you ought to consider posting your own thread, on your build and problems. And yeah....the 2.2k ohm resistor is a BLEEDER resistor (there for your safety). In any case, where did you find a requirement for .47kohm (470 ohm) resistors in the power supply? They are not part of the design.... (If you want to answer, best to do in a new thread, or one of your existing ones).

And everyones, superb, congrats, Phenomenal, great spirit and positive enthusiasm, Clear, concise, succinct etc. etc. etc. is not hijacking? Not screwing up the topic? Not OT? And of coarse, As sic as it sounds "Perhaps you ought to consider posting your own thread, on your build and problems".
So we can be "HiJack free". Hey, we need another thread with 1 page of info for every 2 pages of what's in the last paragraph. Especially another F5 thread? If many members complained about all the chit chat in the original, and they can't read that thread what do you think they will say about the dozen odd, or more, F5 threads
Sorry, call it like I see it

[6L6]

flg, CanAmMan, russellc -

Stop arguing about off-topic and threadjacking right now. Stop. Desist. Quit. It's not helping anyone. I have corresponded with all 3 of you at one time or another and am very surprised that you are acting like this.

Please guys, we are all friends here.

/rant

As I said before, because all the photos and captions are in the top posts, those pictures, descriptions, et. all., cannot get buried and stuck under a million random posts as my first thread did. All anybody needs to do, to see all the goodies in one place, it click the 'first' button. That's why I made this thread. To help people in making this phenomenal amp. If someone can glean some bit of insight in the assembly by seeing what I did (which in no way is the 'right' or 'only' way of doing it, merely a way) then my intentions have been fulfilled. I have been corresponding with a number of people in various stages of their build, from completely done to 'thinking about it' and everything in between. That has been a very rewarding experience for me, and I quite enjoy it. One of those people, whom got completely jumped on, is

merlin2069er - Yes, it seems that you installed the resistors in the wrong spot! The 2.2k are the bleeders, they should be installed across the input caps.(C1 and C3 on the pass schematic, not sure how the cviller board is labeled) The four .47ohm (not .47k) are between C4 and C7, C2 and C5. Your voltages do, however, seem a bit low.

russellc - My understanding is that the toshiba FETs need a slightly lower value, like you said, the common value is 1.5k . I too, invite people to share their observations and experiences with this. My case is most likely because the input FETs where all the way towards one side of their range, and the outputs on the other side of their range, and because of that combination of wonkyness, needed quite a bit more R to get the bias flowing. Anyway, it was a easy fix.

[Woody1911a1]

Originally Posted by merlin2069er

Ok, I've figured out what is happening. I must have been looking at the f5 service guide when I put together the PSU board. CViller's power supply boards labels are not in sync with that schematic.

So the correct value should be 2.2k ohm across the input of (T1 & T2) & (T3 + T4) and not .47kohms.

That's what has been popping my fuse. Silly me. I'll have to swap them around.

I've measured about ~15v dc & ~ 19v dc from the outputs of the bridges. Does that sound about right?

on cvillars board the 2.2k's are R1 &rR4 and yes the labeling does not agree with the pass diagram . your voltages besides from being very uneven are low if you're using an 18v tranny .

cheers Woody

[h_a]

By the way,

This time I really do not want to solder the board again (and risk lifting a trace)

no need to worry, it's close to impossible to lift a trace with modern fiberglass boards; not like in the old times with the paper boards where it was a piece of cake

Hannes

[merlin2069er]

ok, I've wired up the ac inlet and switch to the psu (with the 2x cl-60's and capacitor)... (they were held in place by patch cables before).

Now I'm seeing about 19v+ @ V-in+, but my v-in- rail doesn't seem to give me anything.

I did swap the 2.2k and .47 ohm resistors around - I'm thinking I have a bad connection in the psu ( on that side) or possibly I smoked something.

I did see a puff of smoke before I blew my fuses...lol.

I've got to stock up on 2.5amp slow blow fuses - luckily I didn't use any 'audiophile' grade $40 fuse...

[Marra]

Originally Posted by merlin2069er

ok, I've wired up the ac inlet and switch to the psu (with the 2x cl-60's and capacitor)... (they were held in place by patch cables before).

Now I'm seeing about 19v+ @ V-in+, but my v-in- rail doesn't seem to give me anything.

I did swap the 2.2k and .47 ohm resistors around - I'm thinking I have a bad connection in the psu ( on that side) or possibly I smoked something.

I did see a puff of smoke before I blew my fuses...lol.

I've got to stock up on 2.5amp slow blow fuses - luckily I didn't use any 'audiophile' grade $40 fuse...

Build a light bulb tester it will save a fortune in blown fuses and smoking components. See page one of this thread.

[merlin2069er]

Oh, I've got one of those. You mean the light bulb in series with LN?

[6L6]

Some photos would be of great help. Can you post some?

Also, are you sure you have the transformer primaries and secondaries connected properly?

[merlin2069er]

Ok, I'll post some.

I connected one pair of primaries at a time to find out which pair of secondary windings to use.

I could double check, what method should I use to pair them up?

I don't know why they just don't use different color wiring to save a few headaches.

[merlin2069er]

I asked Antek about determining how to pair up the windings.

They said...

"Actually it doesn't matter. The two primary windings are parallel, not one after another."