audio-talk

cressy · Posted: Sun Nov 16, 2008 8:26 pm Post subject: first timer and 45s

well ive got started on the amp today, started with the casework. im going to build it into one chassis rather than monoblocking it, simply to reduce the costs abit by using one power supply. andrew has sorted me out with alot of the bits, still needed in terms of ironware are the interstages (nick put me onto those so should be able to get them fairly shortly) and the choke. speaking to andrew he reckons rather than a 10h 100ma id be better with a 10h 200ma if having a single psu. i shall be sourcing one fairly soon.
to start off, i got a 6 foot window sill out of a skip (cos im a cheapskate when it comes to buying wood) and ripped it down on the table saw. i put a 45 degree bevel on the bottom edge and mitred the corner joints to make the main case, then used the offcuts from the bevel to create the 'upper deck' so to speak. im going to make it the same way i did the case for the rocky amp by skimming it with body filler again so i can get a good paint finish. the bottom deck will have the 45s, drivers and controls on it, the top will have the rectifier and mains tx on it. depending how big the optx's are they may also go on the top. choke and interstages will go inside. the deck plates will be either carbon fibre or aluminium depending what colour i go with for the wood, should give an idea of the looks. more to follow as it starts to take shape

Graeme · Old Hand Joined: 28 Oct 2008 Posts: 1040

Looking nice.

Ive got these amps filed under 'future project' so am keeping an eye on your progress Smile

cressy · Posted: Sat Nov 22, 2008 7:47 pm Post subject:

abit more info on the 45, sourced most of the psu bits now, got a big hunts 100 mf 450v cap and an unbranded 33 mf 450v cap, big 2a3 mains tx and gz34 from andrew along with the 45s and optx's. rather than a 10h 100ma choke ive got 2 6h 150 ma chokes to connect in series. should get 12h and 150 ma so abit better suited to the 45s on the current front. i found a bulgin socket and plug in my box of bits (god knows where that came from) and an in line fuse and holder. can i expect any problems or benefits from using 2 chokes?
casework is almost done, i went with 3mm ally plate for the deck plates instead of the carbon fibre, just because the local engineering firm had an 18"x14" sheet for a fiver. so it'll be gloss black woodwork and i might lacquer the ally if i can be bothered though paint doesnt take well on it so im not sure. i'll post some pics of the casework when i can find the damned cable for the camera (again)

Graeme · Old Hand Joined: 28 Oct 2008 Posts: 1040

If you want to paint the ally, get a can of etch primer.

Dont bother with the 'special metals primer' etc from hammerite, go to a proper car paint shop, or even halfords sell ti, and get a spray can of etch.

Not cheap, about £10 a can, but you only need a light coat, then normal primer, then paint.

Look after the can and it will last for ages.

cressy · Posted: Sun Nov 23, 2008 10:04 pm Post subject:

found the cable for the camera so a couple of pics of the rough case

al newall · Old Hand Joined: 06 Aug 2007 Posts: 910 Location: Chester

So thats where our snooker triangle went.

cressy · Posted: Mon Nov 24, 2008 10:27 am Post subject:

I V mey geddit Very Happy

andrew Ivimey · Posted: Mon Nov 24, 2008 10:32 am Post subject:

Crikey!

I'm flattered. It'd better work. Wink

Nick · Posted: Mon Nov 24, 2008 11:33 am Post subject:

I am thinking more, it had better all fit Smile

SteveTheShadow · Posted: Mon Nov 24, 2008 11:37 am Post subject:

cressy · Posted: Mon Nov 24, 2008 12:45 pm Post subject:

psu is going in a separate box when i get some more time to make it, shouldnt take 2 minutes.............when i get 2 minutes! one thing though, can someone recommend a material to make a guard for the gz34? where the psu will have to go is where the kids could get at it. i dont really want to use mesh. i was thinking a large perspex box, about 4" square with loads of holes in the top but im not sure what temps that can stand without starting to melt

Nick · Posted: Mon Nov 24, 2008 1:13 pm Post subject:

Why not have PSU fully enclosed, gz34 will be happy on its side.

andrew Ivimey · Posted: Mon Nov 24, 2008 1:19 pm Post subject:

I like the idea of spreading out a bit!

Also if you are going to move up to individual power supplies for each channel then you have the luxury of space.

onwards!

cressy · Posted: Mon Nov 24, 2008 3:05 pm Post subject:

nice idea for the rectifier, if its inside i could cut holes in the top for cooling and have mesh inside them, that way the kids cant cut themselves on the edges of the mesh. ive also got 2 iec inlets so i was going to put those on the back of the amp for separate psu's at some point and put the bulgin one on as the inlet for this psu. im hoping to get the psu box done later today

cressy · Posted: Mon Nov 24, 2008 7:05 pm Post subject:

well i made the psu case, nothing fancy and abit too big, not really interesting tbh! (better mitres though!)