F5 power amplifier

[chchyong89]

oh, it's my 240 dead, by the way, my P2 pot, no matter how i tune it, it still remain at 1.0XXk ohm... any ideas?

[chchyong89]

figure out again, is ztx450 dead.. =__=

[LucasAdamson]

Using Peter Daniels boards, First Watt Schematic & CViller's One Channel Only BOM, I have some issues:

1. Schematic says that R21 & R22 are 10K. CViller's BOM says they're 22K. I bought 22K now. Anybody know why the change?

2. These boards are small. No problem. What is a bit scary, however, is the traces come to within a hair of each other at some solder points. Has anybody had any short circuits as a result of this?

3. What's R35 from the BOM? It's 33K, but not on the board or schematic?

Many thanks
Lucas

[labjr]

Originally Posted by LucasAdamson

Using Peter Daniels boards, First Watt Schematic & CViller's One Channel Only BOM, I have some issues:

1. Schematic says that R21 & R22 are 10K. CViller's BOM says they're 22K. I bought 22K now. Anybody know why the change?

2. These boards are small. No problem. What is a bit scary, however, is the traces come to within a hair of each other at some solder points. Has anybody had any short circuits as a result of this?

3. What's R35 from the BOM? It's 33K, but not on the board or schematic?

Many thanks
Lucas

1. I think somewhere in this thread, Nelson commented that the 22K sounded marginally better.

2 Peter's boards do seem pretty dense. I have Cvillers boards so I haven't tried them. I guess they work.

3. R35 goes in series with the LED.

[LucasAdamson]

Originally Posted by labjr

1. I think somewhere in this thread, Nelson commented that the 22K sounded marginally better.

2 Peter's boards do seem pretty dense. I have Cvillers boards so I haven't tried them. I guess they work.

3. R35 goes in series with the LED.

You're a diamond. Thanks

[Tripmaster]

I appreciate these questions are a little tedious, but please bare with me.

I've been re-checking all of my connections and I cant see where the hum problem may be. I know this isn't safe, but I decided to quickly remove the safety earth lead from the IEC mains inlet (now reconnected) to see if it made any difference, and it didn't. Can you still have a hum loop with the safety earth removed?

[Tea-Bag]

Originally Posted by Tripmaster

I appreciate these questions are a little tedious, but please bare with me.

I've been re-checking all of my connections and I cant see where the hum problem may be. I know this isn't safe, but I decided to quickly remove the safety earth lead from the IEC mains inlet (now reconnected) to see if it made any difference, and it didn't. Can you still have a hum loop with the safety earth removed?

Have you tried moving the tranny further away from the outputs?
I've had a Silchar tranny in an F5 that was noisy no matter where I put it.
The little Plitron's work well here.

[Russellc]

Originally Posted by Tripmaster

I appreciate these questions are a little tedious, but please bare with me.

I've been re-checking all of my connections and I cant see where the hum problem may be. I know this isn't safe, but I decided to quickly remove the safety earth lead from the IEC mains inlet (now reconnected) to see if it made any difference, and it didn't. Can you still have a hum loop with the safety earth removed?

Mine isnt hooked up yet, (grounds) power cords just temporarly clipped on. Silent as can be, it is virtually impossible tell if it is on.

Russellc

[EUVL]

This article explains why you might want to degenerate the 2SJ74 to make it truly complementary with the 2SK170.


Patrick

PS You can open and read the pdf, but not extract and not print.
... I make my living on memory chips, so I don't support paper copies.


.

[Russellc]

Originally Posted by LucasAdamson

Using Peter Daniels boards, First Watt Schematic & CViller's One Channel Only BOM, I have some issues:

1. Schematic says that R21 & R22 are 10K. CViller's BOM says they're 22K. I bought 22K now. Anybody know why the change?

2. These boards are small. No problem. What is a bit scary, however, is the traces come to within a hair of each other at some solder points. Has anybody had any short circuits as a result of this?

3. What's R35 from the BOM? It's 33K, but not on the board or schematic?

Many thanks
Lucas

As far as the Daniels boards, Ive built 2 sets of them, shorts not a problem.

Russellc