First build: 50W reverb head....an update...

[Guitarman18]

That is a great looking build markusw. Congratulations . The face plates look really good also.

Cheers, Paul.

PS. Where did you get your chassis?

[markusw]

Thanks

The chassis is from Ceriatone.

[Aurora]

Markus - is there direct reference here to the reverb circuit you used?
( It is not always easy to find details around here.. )

[markusw]

Markus - is there direct reference here to the reverb circuit you used?
( It is not always easy to find details around here.. )

https://tubeamparchive.com/viewtopic.ph ... b&start=15

It's in this thread.

[Aurora]

Vielen Dank

[markusw]

Vielen Dank

Gern geschehen

[Structo]

That really looks good!

And the face plate turned out great!

Can you describe the steps to make the face plate?

[markusw]

Can you describe the steps to make the face plate?

I had the layout positive printed on clear polyester foil at a local printing shop. Since the print wasn't that dense - to be on the safe side - I did an overlay of two print outs I glued together with some pieces of tape.
Exposure is done like for PCBs. It just takes about twice as long because the black anodized layer absorbes light in contrast to the shiny PCB surface.
For exposure I used 400nm diodes I soldered to some strip boards. I ended up with 15 min exposure.
Development of the boards (i.e. removing exposed photo laquer and etching away the black anodized layer below) is done in 1% sodium hydroxide or Bungard's developer (which I assume IS sodium hydroxide). It takes about 5 min, maybe a bit longer.
Finally, I added a thin coat of Zapon laquer. Looks nicer IMHO.

Hope this helps.....

[Aurora]

Alucorex is, as noted, a trademark of the german co. Bungard.
3M had a similar product which I used some 15-20 years ago, but for the best of me I cannot remember the name ! ( Not a very good sign, I'm afraid )
3M has/had a heavy plastic foil in the same line, called Scotchcal.
I think that's still available...... A 3M sales rep should be able to help...?

[markusw]

The polyester foli I had it printed on is used to print out plans for architecture firms. It's pretty stable. So it doesn't shrink.
For PCBs I simply use inkjet transparecies. Works great.
The faceplates were too large for them. Since I didn't want to twiddle with glueing two parts together I went for the printing shop. Wasn't that expensive either....

[Aurora]

Marcus....
In my experience inkjet/laser transparencies often gives insufficient contrast, particularly over larger black areas, as ground planes and heavy conductors. ( We do make both RF and high speed digital at work)
I use a product called "laserstar" for PCB films, which gives excellent results, a somewhat matte looking polyester foil. This does however look and feel astonishingly like the polyester drawing foil we used with the Rotring ink pens in the 70s.........?????

[Structo]

Anybody in the USA know if there is anything like this available here?

I tried googling it and didn't come up with much.

[markusw]

Marcus....
In my experience inkjet/laser transparencies often gives insufficient contrast, particularly over larger black areas, as ground planes and heavy conductors. ( We do make both RF and high speed digital at work)
I use a product called "laserstar" for PCB films, which gives excellent results, a somewhat matte looking polyester foil. This does however look and feel astonishingly like the polyester drawing foil we used with the Rotring ink pens in the 70s.........?????

Thanks for the tip with "laserstar". Will google....
I had the same problem with large areas. With an overlay of two copies it worked fine so far (but I didn't do any ultra-thin traces though).
I still have some of those Rotring pens.
Had to use them in the 80s at school...the thin ones always got dry

[Aurora]

Hi guys!
Ended up with some "dead" time at work today.
The 3M alu foil was called Dynamark!

Some googling tells me it has been replaced by another product called
Quickmark - slightly different method.
Another stuff is called ID-mark - essentially same procedure as the Alucorex....