finished my PPA (with pics now)

[Voodoochile]

Pics further down thread now.

Well, it's more than 90% finished as of last night.

Sorry- no pics yet, but maybe tonight.

I started it about a year ago, and it has been living on a piece of plywood with it's power supply for the last ten months. I finally started casing it recently, and actually screwed the cover down last night.

It's not quite finished because it will have an outboard PSU chassis, which is not done. This was not part of the original plan actually- it is more due to odd lack of space. The amp has the huge ladder attenuator I made installed, and this limits the clearance in a big way. It will be more evident with pics. I had hoped to have the PSU and amp in one, and the case is certainly large enough otherwise to do it, though it would be cramped. I did make my own PSU board for this, but still too tight. I should have made it modular, with seperate bridge and filter board and regulation/postreg board, but that is hindsight, and I'm not going to do it over now, adding another six months to this! I just want to have it cased up finally. The amp has been sounding excellent on the plywood all along, but looks like ass.

The power comes in via an umbilical made with XLR connections, and there is a rear switch above the power inlet. One set of inputs on the rear, and the face has a volume knob and output jack, that's it. The chassis is a (IHO) cool external SCSI drive case that I have been eyeing since I bought the drive many years ago. I've been waiting for the drive to expire so I could repurpose the case! It was a 36 gig LaCie (IBM), and was a pile of cash once upon a time. The drive itself was full-height! Funny stuff in today's light.

Anyway, I will bump this up with some pics soon.

 

[Voodoochile]

Here is an early pic of it, but the amp, volume control, and PSU have all been changed. So have the input and output jacks. But the plywood remained the same, so it's grandfathered under local ordinance as being the same amp, just a remodelling job.

 

[Madcat05]

I remember seeing that pic in the post your DIY amp thread last year.

Nice work.

 

[Voodoochile]

Pretty sad that it's taken so long, eh?

 

[Jahn]

Coolest looking slab of wood evar.

 

[Voodoochile]

Quote:

Originally Posted by Jahn Coolest looking slab of wood evar.

Very carefully selected from a mile-high stack of Fir plywood. And it has that special varnish you get on a $500 volume knob.

 

[tangent]

Quote:

The drive itself was full-height!

I have one of those, only 4GB in my case. Sounds like a jet airplane starting up.

Quote:

it has that special varnish you get on a $500 volume knob.

That would be the non-vibrating kind, right?

 

[Earwax]

I've heard that ignition coils really improve the bass response, is that true?

 

[Nisbeth]

Quote:

Originally Posted by Earwax I've heard that ignition coils really improve the bass response, is that true?

No, they provide extra headroom by increasing the voltage

/U.

 

[Voodoochile]

I have since replaced that coil with three CoOA modules (Coil on Op-Amp), sort of like an ignition cassette. Less cross-firing that way!

Tangent: Isn't it the truth? This case had a 60mm x 20mm deep cooling fan in the back. One of the earliest 10k drives, before anyone knew about fluid bearings or any other acoustic treatments. You could literally hear it spin up from across the room ( a room with five PCs, eight Macs, two 40" inkjets and a 40" filmsetter running in it). Just about a week before it bit the dust, the heads started clicking severely, and I knew it would soon be mine.

That poor case is so grateful to be silently housing my amp at last.

I just found a 'before' pic online:

Looks like that same size chassis today comes with a cool terabyte. Probably for less than the 36 gigger cost back in the day.

 

[Voodoochile]

Outside pics tonight. I have more inside work to do still.
The paint is Gunmetal Gray Hammerite, I've attached a swatch because you can't really see the finish in these pics. Mine is not quite as hammered as this swatch though:

overall view:

with earmuffs for scale:

detail of hammerite over original textured finish:

temporary rear panel, I'm making a new one out of some aluminum bar stock:

I should have the outboard PSU done this weekend if I get some spare moments... tomorrows plans have been changed due to rain. I was listening to this last night, and thinking 'it's just not as good as it was on the plywood, what happened to the detail???'

Forgot it was connected to my (albeit decent) utility PSU, not the tweakish one I built for the ppa- DOH!

Plans for the front include placing some frosted acetate behind the panel, and having a dim diffused amber LED in the rear of the chassis facing forward to illuminate the back of the acetate. Going for that oiled paper or tortoise-shell type of effect in subtle illumination. Instead of the ever-present blue led.

 

[thrice]

Wow, that's a great looking amp. Where did you get that knob? Very nice work Voodoochile

 

[Madcat05]

That case looks really nice. My next amp will be a PPA in a full size Par Metal case.

 

[yhmzzz]

Wow..
I look forward to seeing inside..

 

[Megaptera]

Wow, looking good there. There should be a "Found Amp Art" gallery somewhere.