Hi,
Well that helps a bit but still I have no idea where the extra black wire went or should go.
Schematic should tell you.

I'd leave it off as (I assume) the amp will work without that cap connected.

As to the power transistors swapping
If you put them in the wrong side the amp will surely blow fuses.

one will be a "npn" device and the other a "pnp" They are polar devices and only work one way.
Make damn sure you get them the right way around.
Phil.

Quote from: Enzo on December 19, 2010, 12:57:02 AM
All TO3 bipolar transistors have the same pinout.   

All bipolar TO220, TO218, and TO247 transistors have the same pinout - ECB across the front.

I knew the TO3's where all the same but was not sure about the other tab types.
Arrh darn You Enzo you got me again  :grr,,, I must owe you a point then :tu:
Cheers Phil.

I'd fly over and have a better look at it for you,,, but my private Jet has a flat tyre. :lmao:
Phil.

Thanks for that correction Enzo.

Whoops My thermals are getting mixed with my mistors.

In light of your timely correction then the mustard disc next to fuse is likely a *Thermistor* which are wired in *series with the mains, unless I'm way off again.
(I'm just going on the PCB pic on the first post where the tracks seem to follow that series path)

Either way without better pics or schemo of amp not a lot can be done by anyone.

As to chassis,, My concern is that there is none.
Phil.

Did you check the pin out of the new output devices? :trouble

Like Valves,, just because it fits in the same holes does not mean they are identical.
Phil.

A suggestion.

Open the pdf.
Magnify the area of confusion.
Print screen button (top of keyboard)
Open paint.
Hit Control V.
Save as Jpeg.

Post.

well that's how I do it?
Phil.

Thanks Joecool point taken,, but I just cringe when I see bad design (i.e. the mains fuse on the edge of a pcb only mm from the audio circuitry)

Then someone with little knowledge trying to modify same can easy leed to premature death. 8|


OK lets get on with it best we can.
Clampup,
I can't see the wiring clearly enough but Bry Melvin may see more than myself.

That Capacitor looking device could be a *Varistor* which would be in series with the mains and not to ground.
If it's a Capacitor then it would be across the mains wires and not to ground.

Here is a pic of what would be close to the wiring you have there.

The secondaries are obviously 2 reds and a black but the primary side you will have to track that yourself, so use my pic as guide only.

If this Amp was in my shed that Mains fuse would be *Permanantly removed* from the Audio PCB and put in a sealed jiffy box away from harm.

But the Main switch is still (I assume) on the front panel which (I assume) is Metal?
If so then the *EARTH* wire needs to be connected to that panel to be safe.

BTW that board looks like it is hanging it's weight from the pots?
If so it won't last long.
Best of luck, Phil.

You say you know Nothing about Amps?

Yet you are playing around with the mains :duh

I sense another Darwin Award coming soon 0:)

Take a breath and check you are still alive,,, if so take some better pictures of the wiring then We all have a better chance of helping.

THE GREEN Wire is connected to the case for Safety reasons,,, it's not just their to confuse the ignorant. :trouble

That fuse and White/Black/Black Are mains wires and if you mess up you can kill yourself.
Phil.

Hi Rowdy R,
Just remember your sand has to be DRY and I mean Really DRY.
Any mosture and boom it will explode in the cast and destroy itself.

Remember this is molten metal you are playing with,,,
YES I've Worked in both a Steel foundry and also a small Bronze Art foundry.

Lost Wax (done correctly) will yeild extremly accuate results,,, far better than sand.

If you just can't help yourself ( and it sounds like that might be the case LOL )
Then consider taking on pedal cases!
These can be made from *Monks metal* which melts at fairly low temp.
(about 400 deg C from memory,,, been a long time)
A soft "Zinc based Alloy" used to make door handles and automotive parts,,,and Yes the Boss pedals also.

You would then have something Totally Original and likely worth selling :tu:
just look at the Mayer Octavia pedal as example,,, very unique and oh so cool. 8|
Cheers Phil.

Does it have a EFX send return setup?
Or preamp out poweramp input sockets?

If so,,, take a lead from either of these outputs and run into another *Working Amplifier* and if all sounds fine then the power amp section is the problem.

Phil.

If it helps I fixed a Laney Amp in the land downunder (240Vac Aust)
LC 30's kept blowing mains 630mA fuse.
Replaced with 750mA and the unit has not returned well over a year now.

It's actually the reason I asked about the fuse because I've since read that there are apparently some issues with OS gear imported into Australia.

Now do I get a browny point for being so clever?  0:)
Just kidding.

Not sure of the maths but in general the fuse is doubled for 110 ac mains.

But then 110 ac Mains is 60 Hertz and 240 ac Mains is 50 /Hertz.
(headscratch)

Also a point to ponder is the use of donut Xformers they have a bigger inrush at turn on which over time may weaken the fuse element. Again a head scratch,, too deep for my abbacus.
Cheers, Phil.

Sand Casting,, jeezz mate long gone :lmao:

If you ever see how fast Ally comes out of an extrusion machine you will instanly see the folly of the idea.

Casting Only used now for specialised applications.

Trust JMF to try it,,,   Somehow that does not suprise me as he has been known to try the impossible.  :lmao:

Re Fans,
= Cheap crap in my opinion,,, If one cares to look at almost any industry a proper heat sink is not cheap and in this day Fans are proly 10 times cheaper that a heat sink.

A fan might look trick but WILL ONE DAY STOP!!! Whereas a correctly designed heat sink will NEVER FAIL.
Phil.

Can you read the labels next to the fuse ,, or next to power cord input?
Reply with what is written there before you worry.
(better still a pic of panel)

Example, 1 Amp @ 240VAC

Cheers, Phil.

Hi folks,
I found this led voltages listed down the page. :tu:

http://www.kpsec.freeuk.com/components/led.htm

I used little Green Leds for testing Joes circuit but I doubt it makes a lot of difference.

I tend to find the debate about the pros and cons of small details like this is hardly ever going to be noticed in live situation.

Quite frankly a lot of these opamp type OD tricks are much the same,,, in the end whether you limit the swing with a pair (or more) of diodes or let the signal slam into the supply rails it often sounds much the same.

It's more circuit design and other tone shaping tricks that tend to make the difference.

I even tried some very high voltage diodes once but I think the fv drop was likely much bigger that the 9 Volt battery the circuit ran from.  :duh
But it was all good fun to experiment, even though I was a clueless noob at the time. :lmao:
Phil.

Quote from: J M Fahey on December 06, 2010, 08:10:51 PM

PS: it even admits the excellent Phatt's tone control instead of the original one.

Awwh shucks,, thanks chum but I think you are pulling my leg.

Re the Red Fet Circuit,,, a quick sim but got cut short (wife wanted to go shopping :loco Grr)
BIg Massive bass loss thru that by the looks of it.

I actually built my PhAbbtone both ways, Opamps and Fets.
I really wanted the Fets to work so I bootstraped the input,,, tried mu fets for bigger swing,,, you name it,,,,but alas after much testing,,,, the opamp won.
Phil.