Search found 38 matches

by donturner
Tue Apr 28, 2020 11:25 am
Forum: Music Tech DIY
Topic: How does this ADSR circuit work?
Replies: 10
Views: 357

Re: How does this ADSR circuit work?

Big thanks to everyone who responded. Despite almost certainly switching to the suggested circuit from BartBral the guidance is extremely useful...now I can read up on "integrator circuits" and "exponential converters", maybe I'll come back to this circuit once I have a bit more knowledge.
by donturner
Tue Apr 28, 2020 11:19 am
Forum: Music Tech DIY
Topic: How does this ADSR circuit work?
Replies: 10
Views: 357

Re: How does this ADSR circuit work?

There already are Attack-Release envelope generator circuits, that are voltage controllable. for example: https://kassu2000.blogspot.com/2016/04/slope-generator.html?m=1 Why not start there and then add extra stuff when you understand how that works, instead of first trying to understand the whole ...
by donturner
Tue Apr 28, 2020 6:39 am
Forum: Music Tech DIY
Topic: How does this ADSR circuit work?
Replies: 10
Views: 357

How does this ADSR circuit work?

I'm attempting to design and build an Attack-Release envelope generator which has CV control for both Attack and Release timings. My goal is not only to design this as a Eurorack module, but also improve my understanding of electronics, particularly op amps and transistors. I've found this circuit: ...
by donturner
Thu Aug 15, 2019 7:40 am
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

I ended up using a Doepfer PSU3 and so far I'm very happy with it, as in I have not electrocuted myself, started any fires, blown up any modules and have actually be able to get back to making music :) Full thread here (skip past the bit where I try to use a Bel Power linear PSU): https://www.muffwi...
by donturner
Thu Aug 08, 2019 7:47 am
Forum: Music Tech DIY
Topic: DIY power supply (take 2) - Bel Power - Will this kill me?
Replies: 35
Views: 1815

Update. I have done the following: - Replaced the Bel Power PSU with a Doepfer PSU3 - Fitted a flanged IEC inlet with matching insulating shroud - Created a custom perspex cover which insulates all the mains wiring Photos: https://www.muffwiggler.com/forum/userpix2/44719_modularback_1.jpg https://ww...
by donturner
Thu Jul 18, 2019 8:36 am
Forum: Music Tech DIY
Topic: DIY power supply (take 2) - Bel Power - Will this kill me?
Replies: 35
Views: 1815

You have spent over £5000 on modules which means that you should budget about £500 for the foundation that supports them: PSU AND Power distribution. They're all DIY builds apart from the Bastl GrandPA so I reckon I've spent about £1k on components. Also built the case from old kitchen units. I'm i...
by donturner
Thu Jul 18, 2019 4:51 am
Forum: Music Tech DIY
Topic: DIY power supply (take 2) - Bel Power - Will this kill me?
Replies: 35
Views: 1815

Thanks again for all the advice. Rest assured, I am heeding the warnings about working with mains and will get my work checked by a qualified electrician (a friend of mine) when I'm done. My house is fitted with RCDs and wherever possible I work with the power supply off and disconnected from mains....
by donturner
Wed Jul 17, 2019 7:27 am
Forum: Music Tech DIY
Topic: DIY power supply (take 2) - Bel Power - Will this kill me?
Replies: 35
Views: 1815

But there is a group of loud users on this site who argue anything other than linear mains earthed supplies are to be avoided for noise/safety/performance/cost matters, when the truth is other options are all about the same if you select appropriate options. Out of interest what power supply would ...
by donturner
Thu Jul 11, 2019 1:13 am
Forum: Music Tech DIY
Topic: DIY power supply (take 2) - Bel Power - Will this kill me?
Replies: 35
Views: 1815

I take your point about insulation - I'll replace the inlet for a more suitable one, get one of those insulation boots and box in the mains wires. There are plenty of discussions on these forums about the fact that the SIGNAL 0V (the one on your busboard and modules) should NOT be connected to EARTH...
by donturner
Wed Jul 10, 2019 4:09 pm
Forum: Music Tech DIY
Topic: DIY power supply (take 2) - Bel Power - Will this kill me?
Replies: 35
Views: 1815

How would moving the psu outside fix the hum?
by donturner
Wed Jul 10, 2019 1:05 pm
Forum: Music Tech DIY
Topic: DIY power supply (take 2) - Bel Power - Will this kill me?
Replies: 35
Views: 1815

I would have pushed the power unit as close to the mains input Yes, I tried that, but then I couldn't get my hand/glue gun in easily. Also, the transformer is *heavy*, it made more sense to me in the end to have it more centrally located because it makes the overall case more stable. woudl you feel...
by donturner
Wed Jul 10, 2019 7:53 am
Forum: Music Tech DIY
Topic: DIY power supply (take 2) - Bel Power - Will this kill me?
Replies: 35
Views: 1815

DIY power supply (take 2) - Bel Power - Will this kill me?

After spending many hours attempting to build a power supply out of a Meanwell RT65b ( https://www.muffwiggler.com/forum/viewtopic.php?p=3079816 ) I ditched it and bought a linear PSU. It's a Bel Power HCC15-3-AG with 2 outputs: 12V @ 3.4A and -12V @ 3.4A. It seems very similar to the Condor and Pow...
by donturner
Wed Jul 03, 2019 5:08 pm
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

Thanks. I've narrowed it down to the Bel Power Solutions HCC15-3-AG. Why? - It has 3.4A output on both +12 and -12V outputs, plenty for a 9U or even 12U rack - It doesn't have a +5V rail, none of my modules (or any that I intend to build need +5V - maybe this will bite me but 3 output linear supplie...
by donturner
Wed Jul 03, 2019 12:53 pm
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

I've tried swapping out the 10Ω 10W resistor for a much larger 10Ω 50W resistor. It takes longer to heat up but still becomes too hot to touch after about 5 mins. I'm not happy with that inside my (wooden) case. I'm also not happy about running less than the minimum 0.5A load on the +5V output. I'm ...
by donturner
Thu Jun 27, 2019 4:43 pm
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

Graham, I'm getting the feeling you're not a fan of this PSU ;-) The ripple is clearly over 60mVp-p, but your scope measurements say 22.4mV. Minor technicality, it was actually showing 40.8mV which is still not accurate. I was able to get a more accurate reading over a longer time division: https://...
by donturner
Wed Jun 26, 2019 12:05 pm
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

Just a quick thing on the insulation boots. I did a bit more research (thanks for the link) and did eventually find one boot which could fit an inlet which has both a fuse and a switch. I won't use it now I've done the hot glue but just in case anyone else needs one, here it is: https://uk.rs-online...
by donturner
Wed Jun 26, 2019 11:31 am
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

With some testing I found that the power supply only whines when it's got zero load across all the outputs, so instead of having a 10Ω power resistor on the 5V output all I needed to do was plug in a module (I'm using a Braids which draws +12V: 100mA -12V: 15mA) and the whining went away. I tested a...
by donturner
Mon Jun 24, 2019 5:33 pm
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

Once again thanks so much for answering my questions and sharing knowledge, really interesting and useful info. I've now built version 2 of the power supply. It's still a work in progress but here it is: https://www.muffwiggler.com/forum/userpix2/44719_img_20190624_223602_1.jpg What's changed? - Wir...
by donturner
Mon Jun 24, 2019 10:48 am
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

Thanks Graham. I'm going to break this down to make sure I have it correct. The wire between the PSU COM and the busboard 0V is carrying current, potentially quite large if the rails aren't even, so there will be a voltage drop along it and it will vary dynamically with module usage. The PSU is esse...
by donturner
Mon Jun 24, 2019 4:52 am
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

Oh one other thing on the wiring... The 0V of the distribution should be connected directly to mains Earth, not via a DC power supply cable. The picture starting this thread is not quite correct because it connects half way along the supply cable. Sorry, I'm not sure entirely clear, are you saying t...
by donturner
Mon Jun 24, 2019 4:43 am
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

You need a 2A or 3A slow blow fuse that can stand a higher current for a short time, i.e. it will warm up, but not melt. I'm looking at the characteristics of slow burn (speed T) fuses and there are 2 types: glass and ceramic. The main differences seems to be the rupture capacity with typical value...
by donturner
Fri Jun 21, 2019 4:29 am
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

Learning a lot here, thank you. Here's the modifications I'm going to make: - Use the correct coloured wiring - Fit a 2mm aluminium mounting plate - Buy a flanged inlet with bolt holes and matching insulation boot - Fit a 3A slow burn fuse Thanks for the info on wiring resistance: The smallest gauge...
by donturner
Thu Jun 20, 2019 4:24 am
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

Interesting. Delving into the datasheet a bit more there's this: Current range: 5V: 0.5 ~ 8A 12V: 0.2 ~ 3.5A -12V: 0 ~ 1A and in a footnote it says "Each output can work within current range. But total output power can't exceed rated output power" The rated output power is 64.6W which means if you u...
by donturner
Wed Jun 19, 2019 5:17 pm
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

This is gold - thanks Graham. That strip on the back of the inlet is exposed live mains. It goes between the Live pin and the fuse and it is the mains side of the switch so it is always on. There are purpose made rubber boots to cover the backs of all standard inlet sizes. It's this C14 power inlet ...
by donturner
Wed Jun 19, 2019 12:54 pm
Forum: Music Tech DIY
Topic: DIY power supply - Meanwell RT-65b - will this kill me?
Replies: 39
Views: 3086

DIY power supply - Meanwell RT-65b - will this kill me?

I've built a power supply using a Meanwell RT-65b and an Error Instruments PRO busboard. It's intended to be a simpler version of the one in this thread . Here it is: https://www.muffwiggler.com/forum/userpix2/44719_power_supply_1_1.jpg I powered it on and it didn't immediately explode and the volta...

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