Progress Report 13/11/2008

--> pre-amp and driver stage board 60% complete.
--> awaiting enclosure.

Alan Ratcliffe wrote: Good news indeed. So you've gone for solid state rectification. I'm guessing that's for the response to make it more of a metal oriented amp?

No it's because he can't find a NOS GZ34 to do it properly ?

Progress Report 27/11/2008

--> Metal Enclosure drilling and cutting complete.
--> Enclosure Re spray ?ending
--> Ordering of 20 H choke today
--> Plywood housing build: pending
--> Plywood housing vynal cover: pending

Are you building the enclosure yourself, or having one built? If the latter, who is doing the building?

Alan Ratcliffe wrote: Are you building the enclosure yourself, or having one built? If the latter, who is doing the building?

Howzit Alan, yes and no, I am building the wooden enclosure for the metal base part which houses all the tranies and electronic stuff. The metal
enclosure I got from a company called Quaterdeck (Panel manufacturers) which sponsored it to me for free because we(The company I work for)
do buissness with them. As for the paint job, my cuz is really good spray painting so he's gonna do the paint work this weekend. He's using
left over VW Black magic paint.

The wooden box is going to be covered in vynal by a guy that lives near my place.....

Here's a some unsollicited advice: get the metal part(s) powdercoated instead of spraying it. That stuff is thicker, more scratch resistant, shinier and in the long run even cheaper than spray paint.

Gearhead wrote: Here's a some unsollicited advice: get the metal part(s) powdercoated instead of spraying it. That stuff is thicker, more scratch resistant, shinier and in the long run even cheaper than spray paint.

Thanx for the advice GH, but it(metal base part) arrived from the manufactures powder coated black.
I am going to re spray the entire thing which is going to look much better than powder coating.
Powder coating is thick, but not really shiny (depending on what clear overcoat is used) or scratch resistant.
I have many scratches on it already from drilling and filing out of the holes......

I would use powder coating if I plan on manufacturing large scale though...

Progress reports suspended till January 2009 due to holidays..... sorry...

I know don't count your chickens before they hatch, but these chickens have flown their coop...

Here are some preliminary photo's on the stuff that's built and working...... upload test --->

above 2000A /400VAC chiller pannel

The actual photo's.....















end.

I've got some schematics of some amps that I wanted to build or have build for me, as I don't know much about
building amps. Apperently the Soldano SLO clone is one of the easiest amps to built and sounds like a hot rodded marshall.

@Neph: So you also build MCCs ?
Which panelbuilder are you with?

Seeing as you build the power caps on Vero board.. are you not worried that the track width will be too small for the high voltage and that it will 'spark through'?

Gearhead wrote: Seeing as you build the power caps on Vero board.. are you not worried that the track width will be too small for the high voltage and that it will 'spark through'?

you are 100% correct, I only used the board for placement and use wire to join the components underneath , I must admit that vero board is the worst stuff you can use with high voltage....
but I took care in separating the +HT voltage rail from the ground rail by gently cutting large spaces between them. Turret board is the way to go....

Can`t wait to hear what the amp sounds like.....

Thanks for the lovely photos. I think your project is very inspiring. A few questions comes up for me:

Why did you choose to put the EL34's closest to the controls (vol/t/m/b)? You might have to consider putting a shield plate between the controls and the output tubes to eliminate hi frequency oscillation. Those pots are like radio antennae.

6 pre-amp tubes! Are you doing a channel switching amplifier?

Good luck with the project.

Karel Mars wrote: Thanks for the lovely photos. I think your project is very inspiring. A few questions comes up for me:

Why did you choose to put the EL34's closest to the controls (vol/t/m/b)? You might have to consider putting a shield plate between the controls and the output tubes to eliminate hi frequency oscillation. Those pots are like radio antennae.

6 pre-amp tubes! Are you doing a channel switching amplifier?

Thanks for the reply.....

I did not perceive that happening but I am certainly going to consider your info.... I guess that the El34's are less sensitive than the pre - amp tubes which are extremely sensitive to ac noise.....

I think some aluminium foil (covered in plastic)over the controls will do the trick to isolate any high frequency.

There are only 3 gain stages with a toggle switch to eliminate one gain stage before the cathode follower
stage...

The last two 12AX7 tubes are for the driver/phase inverter stage.

I would put a divider plate the full depth of the chassis just behind the pots. Otherwise, when you wire your amp, wire it in such a way that you can insert some screening without having to rip out all your work.

Consider that you are swinging a few hundred volts signal (could even be more than power supply) at the anode of the EL34's. That is just about a radio transmitter. And supersonic frequencies have a habit of perpetuating themselves through the power supply or earth rail (and other devious ways).

What type of driver/phase splitter are you using? Split load PS + differential driver? You have a lot of gain available (2 X 12ax7) - maybe cathode follower drivers?

Progress Report 01/01/2009

--> wiring of power supply, bias supply, preamp, tone stack, valve heaters, power valves , preamp valves,
rectifier, transformer/chokes & protection relays 80% complete...

--> Testing phase: pending...

--> Biasing of valves pending...

--> enclosure build : pending...

Hi All, due to tests and exams my guitar amp project will be on hold for a month from today..... sorry about this.....

I am currently doing my B - Tech degree in electrical power engineering (DUT) as well as trying to keep up
with my schedule at work.

Thanks...

Lee