845 - Progress so far

[Rob11966]

Hi all,

I have been working on my new 845 amp for about 6 months now

This one is taking a lot longer than expected!!

I have posted lots of questions here, some of them not so clever, but I would not have been able to get this far without the help of everyone, so thanks to all who have helped me thus far.

I thought that I would post a couple of progress photos to show where I am at.

The chassis has been completed (finished in aged copper and pewter) and I have basically completed all of the boards - they just need to be put in the chassis and hooked up.

This amp is huge!! there is a 'mini' second story to house all the chokes. This sits on a top plate that covers the plate that you can see in the picture. I did not include a picture of these as I will post when the amp is completed.

The ceramic insulating spacers were cut out of bathroom tiles and the 845 sockets will mount under these.

I think I should have it finished within a couple of months and will post again with a follow up when I have complected the wiring.

Thanks for he help so far.

Cheers,

Rob

[Rob11966]

the underside

[nhuwar]

Nice work.


What's the circuit?


Nick

[Rob11966]

Hi Nick,

It's a modification of Andrea's 845. Using 12au7 drivers instead of the 12ax7 and a different soft start. Otherwise much the same

http://www.audiodesignguide.com/New845/New845v2.html

I hope that it ends up sounding OK - I have spent a lot of time on this one!

Cheers,

Rob

[nhuwar]

Cool, well good luck

[rdf]

What's the story on the chassis? Very slick.

[Rob11966]

Originally posted by rdf
What's the story on the chassis? Very slick.

The chassis was designed for this amp.

In short, I make it as a cardboard 'mock-up' and then I use a local metal shop to have it made up in aluminum. The guy that I use curses every time that he sees me - he claims that he hates making them as the measurements have to be precise but after a lot of whinging and moaning he eventually turns out good work.

I then have it electroplated and lacquered. In this case antique copper and pewter - a combination I initially did not like but it's now growing on me. The power transformers sit on either side of the little box at the top and the covers of these have been electroplated as well.

There is a top plate and a middle plate. The middle plate has all the components attached to it and the top plate holds the power transformers and sits over the middle plate to hide all of the screws etc. There is also a base cover not shown in any of the photos. The main box and top is 3mm aluminum and the rest (including the middle plate) is 2mm.

In this particular amp there is a another box on top as there were too many transformers and chokes to fit in the main box! Also, lots of ventilation holes covered in steel mesh cut from an old metal tray that I had lying around. There are two large holes at the front for the bias meters (old aircraft ammeters I think).

If you search under my name, you can find some other examples I have made using a similar design.

I have included a couple of extra photos.

Thanks for the interest.

Rob

[Rob11966]

And another

[Rob11966]

last one

[nhuwar]

Ya I do agree that is a great looking chassis. I bet it set you back a few bucks LOL.


I was going to have some electro plating done on one of my chassis until I get the price


But man NICE WORK.




Nick