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DIY Purifi Amp builds

fraa

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Best looking build I've ever seen. Where did you get the Purifi Stickers or did you have them silkscreened?
Thanks!
To mark where to drill holes on the panels, I used transparent sticker films like this one. That is, I printed lifesize outlines of the holes using an inkjet printer and stuck it on the panel. Making those holes, especially the big one for the vu meter, was the most arduous part of the building the set—the front panel is 8mm thick. The Purifi sticker was an afterthought when there were a few sheets of the films left. I just printed the logo from the Purifi website.
 

mSpot

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The case is BZ3809H it is available from Ali Express and Ebay. I got it from Ali.
It's fairly cheap. I got it for 73USD including shipping.
Very professional looking and amazing for a first build. Especially considering that you started with this:
BZ3809H-Full-Aluminum-Enclosure-AMP-case-power-amplifier-box-chassis-PSU-BOX.jpg_400x400.jpg

What metalworking tools did you use?
 

fraa

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Really awesome build.
Do you plan to share pictures from the inside?

And where are these awesome uv meters from?
Thank you for the praise.
I guess I should have taken some photos while I was building it. I will open it up again and take some. Please hang on. I have to warn you that the inside doesn't look as pretty as the front.

The meters are two of these. I took them apart and connected the back panels (just a plastic boards). I made one big meter panel (? -- where the numbers are printed) printing on a plastic label that looks like a hairlined silver panel. I drove them using a control board called TS-VU001. I bought the meters and the driver from Ali Express.
Very professional looking and amazing for a first build. Especially considering that you started with this:

What metalworking tools did you use?
Thanks!
I am afraid the inside is not that professional looking, though. First build audio amplifier but I used to make some ham-radio rigs some forty years ago (then I turned to software and never did much electronics until now).
I used mostly a handheld power drill. For big, non-round holes I used a jigsaw I bought a few years ago when I built the wooden amp rack you can see in the picture. With these tools, the precision is not that great. So I bored considerably smaller holes and filed away the rest. I spent a long time filing. It was a curiously satisfying experience, filing metal precisely with patience I didn't have as a teenager when I built the radio rigs. I also started with the back panel so that I would get better by the time I tackled the big hole on the front panel.
 

phoenixdogfan

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Thank you for the praise.
I guess I should have taken some photos while I was building it. I will open it up again and take some. Please hang on. I have to warn you that the inside doesn't look as pretty as the front.

The meters are two of these. I took them apart and connected the back panels (just a plastic boards). I made one big meter panel (? -- where the numbers are printed) printing on a plastic label that looks like a hairlined silver panel. I drove them using a control board called TS-VU001. I bought the meters and the driver from Ali Express.

Thanks!
I am afraid the inside is not that professional looking, though. First build audio amplifier but I used to make some ham-radio rigs some forty years ago (then I turned to software and never did much electronics until now).
I used mostly a handheld power drill. For big, non-round holes I used a jigsaw I bought a few years ago when I built the wooden amp rack you can see in the picture. With these tools, the precision is not that great. So I bored considerably smaller holes and filed away the rest. I spent a long time filing. It was a curiously satisfying experience, filing metal precisely with patience I didn't have as a teenager when I built the radio rigs. I also started with the back panel so that I would get better by the time I tackled the big hole on the front panel.
If anyone wants to duplicate fraa's amazing build, I know of a machining shop in Nashville which does custom laser cutting. I used them to custom cut the back of my 300mm case for my Eigentact build which was done before Ghent rolled out his case. I'm not affiliated with them in any way, but they do very good work, and will allow anyone lacking the skills, tools and patience of our friend to get a good result.

 

Madjalapeno

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Another good resource for laser cutting is sendcutsend.com

I've used them on lots of projects, and they've always been great to work with. (Chassis for my 4-channel Neurochrome amp that is powering my LXMini's as I type this. This was when I was working out wiring for the transformer.)

9B053FEF-B789-4A8F-9F71-1314E188227F_1_105_c.jpeg
 
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fraa

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Really nice,
just pull out the IEC filtered socket as per advice by Purifi.
Thanks for the advice. I will replace it with a socket without filter. While I am at it, I also would like to add a fuse. I couldn’t quite understand the discussion about the fuse earlier in this thread though, so I’m not sure exactly how much power consumption indicates malfunction or failure.
 

Count Arthur

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While I am at it, I also would like to add a fuse.
You could probably find an unfiltered switch/power socket combo a similar size to the existing filtered one and use a separate panel mount fuse holder: https://www.mouser.co.uk/ProductDet...GAEpiMZZMvjAcTDbo5QTnY7qUwteo3LwaC8KjJTW%2B8=. Drilling a separate round hole will be quicker than enlarging the exisiting one. :)

The dB meters, logo and labels look great, you've done a really nice job. No doubt laser cutting and milling is quick and really accurate, but you can get good results with a drill press/pillar drill, some engineers files, a steady hand and some patience. :cool:
 

fraa

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You could probably find an unfiltered switch/power socket combo a similar size to the existing filtered one and use a separate panel mount fuse holder: https://www.mouser.co.uk/ProductDetail/Bussmann-Eaton/HPG?qs=sGAEpiMZZMvjAcTDbo5QTnY7qUwteo3LwaC8KjJTW%2B8=. Drilling a separate round hole will be quicker than enlarging the exisiting one. :)

The dB meters, logo and labels look great, you've done a really nice job. No doubt laser cutting and milling is quick and really accurate, but you can get good results with a drill press/pillar drill, some engineers files, a steady hand and some patience. :cool:
Thanks!

About the fuse: would 10A normal blow be ok? (The main voltage is 100V)
 

fraa

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I considered outsourcing the cutting, too. But the cost seemed too high relative to the price of the case. Besides, I already had the necessary tools.
 

Synergy4

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Thanks for the advice. I will replace it with a socket without filter. While I am at it, I also would like to add a fuse. I couldn’t quite understand the discussion about the fuse earlier in this thread though, so I’m not sure exactly how much power consumption indicates malfunction or failure.
The Hypex SMPS1200 12A Slo-Blow fuse is inside the shrink wrap, vertically mounted and soldered near the Hypex PS power connector.

I just put a fast-blow 12A fuse in the IEC holder. So far no issues at any power level I would use.

I used this IEC socket with fuse and switch, it fit after some carefull filing of of the Ghent case, where the original IEC socket went;

FILSHU DE-14-F6 IEC320 C14 inlet with switch & fuse holder (Amazon ), $9.00 shipped.
 

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Rick Sykora

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There are basically 2 reasons to add a case fuse:

1. Avoiding replacement of the power supply fuse.
2. Avoiding shock hazard should AC wiring become loose inside the amp case.

Some have argued that am residential circuit breaker would cover the loose wiring situation. While true for protecting the amp, not as confortable with it as personal shock protection. Anyway, the reason the answer is not simple, is because it depends on the fuse and how fast they blow can vary.

Anyway, for the first case, something that blows faster than power supply fuse seems the be in order. For the second case, just want it to blow as fast as it can AND not need to be replaced due to normal use. Ideally, you should look into how fast, the selected fuse is rated to blow. Practically, from some informal testing, I ran my Hypex NC500 amp with fuses as low as 5A fast blow and did not get any nuisance blows from “normal” use.

I also checked with Hypex as they fuse the case for the NC400. It uses a 5A slow blow fuse as it matched the one in the power supply. Oddly, the power supply was updated to an 8A fuse and it was not matched. So, apparently, no major complaints over nuisance trips. So, given all this. can see why nobody feels very comfortable suggesting a specific answer. I originally went with a 20A fast blow, but lately use something rated a but less than power supply fuse.

So, as a long winded answer for the Purifi EVAL1, a 10A fast blow fuse seems appropriate.
 

Rick Sykora

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Thanks for the advice. I will replace it with a socket without filter. While I am at it, I also would like to add a fuse. I couldn’t quite understand the discussion about the fuse earlier in this thread though, so I’m not sure exactly how much power consumption indicates malfunction or failure.
Btw, if recall correctly, the Purifi recommendation was to avoid Y caps. Most (EDIT) filtered sockets use Y caps. But may be just fine as-is. From personal experience, it may be difficult to find another IEC socket with the same dimensions.

Hope this helps.

Rick
 
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fraa

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The Hypex SMPS1200 12A Slo-Blow fuse is inside the shrink wrap, vertically mounted and soldered near the Hypex PS power connector.

I just put a fast-blow 12A fuse in the IEC holder. So far no issues at any power level I would use.

I used this IEC socket with fuse and switch, it fit after some carefull filing of of the Ghent case, where the original IEC socket went;

FILSHU DE-14-F6 IEC320 C14 inlet with switch & fuse holder (Amazon ), $9.00 shipped.
There are basically 2 reasons to add a case fuse:

1. Avoiding replacement of the power supply fuse.
2. Avoiding shock hazard should AC wiring become loose inside the amp case.

Some have argued that am residential circuit breaker would cover the loose wiring situation. While true for protecting the amp, not as confortable with it as personal shock protection. Anyway, the reason the answer is not simple, is because it depends on the fuse and how fast they blow can vary.

Anyway, for the first case, something that blows faster than power supply fuse seems the be in order. For the second case, just want it to blow as fast as it can AND not need to be replaced due to normal use. Ideally, you should look into how fast, the selected fuse is rated to blow. Practically, from some informal testing, I ran my Hypex NC500 amp with fuses as low as 5A fast blow and did not get any nuisance blows from “normal” use.

I also checked with Hypex as they fuse the case for the NC400. It uses a 5A slow blow fuse as it matched the one in the power supply. Oddly, the power supply was updated to an 8A fuse and it was not matched. So, apparently, no major complaints over nuisance trips. So, given all this. can see why nobody feels very comfortable suggesting a specific answer. I originally went with a 20A fast blow, but lately use something rated a but less than power supply fuse.

So, as a long winded answer for the Purifi EVAL1, a 10A fast blow fuse seems appropriate.
Btw, if recall correctly, the Purifi recommendation was to avoid Y caps. Most (EDIT) filtered sockets use Y caps. But may be just fine as-is. From personal experience, it may be difficult to find another IEC socket with the same dimensions.

Hope this helps.

Rick

Thank you all. So I guess even 5A fuse wouldn't blow too often with normal use. I'll get them.
I do know it uses Y caps. Though it doesn't seem to be a problem as I don't hear any ground noise, I'll replace it anyway as it's cheap and I want to add a fuse.
 

KarVi71

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I run 2.5A slow blow fuses with my setup (230V supply), and they havent blown yet.

And I have run them that way for over 1 year, with the amps in service several hours almost every day.

As you run at 100V, You would need fuses at a little over double (2.3x) my values, but I suspect 5A fuses will work fine.
 
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