Search found 522 matches

by MikeDB
Wed Feb 24, 2021 7:31 pm
Forum: Music Tech DIY
Topic: What's the best way to learn how to troubleshoot circuits?
Replies: 17
Views: 293

Re: What's the best way to learn how to troubleshoot circuits?

Troubleshooting Analog Circuits by Bob Pease (RIP). Learn from a master who knew how to talk to a wide range from neophyte to expert. Skip Horowitz and Hill. Bob P's books, or the collection of EE Design articles are well worth it. My argument for Horowitz and Hill is that anyone interested in audi...
by MikeDB
Wed Feb 24, 2021 11:27 am
Forum: Music Tech DIY
Topic: What's the best way to learn how to troubleshoot circuits?
Replies: 17
Views: 293

Re: What's the best way to learn how to troubleshoot circuits?

I agree on the Self book. Also Horowitz and Hill "Art of Electronics" (terrible title) has lots on audio within its pages, including best discussion on transistor noise.
by MikeDB
Wed Feb 24, 2021 11:25 am
Forum: Music Tech DIY
Topic: Mixer volume goes down after 30 mins + distortion [SOLVED]
Replies: 11
Views: 136

Re: Mixer volume goes down after 30 mins + distortion. Help needed.

My guess would be pot 6 is playing up. Put a 220k resistor in parallel with it (op amp pins 2 to 1) and see if the gain returns.
by MikeDB
Tue Feb 23, 2021 9:40 pm
Forum: Music Tech DIY
Topic: What's the best way to learn how to troubleshoot circuits?
Replies: 17
Views: 293

Re: What's the best way to learn how to troubleshoot circuits?

I don't mean to sound sarcastic but the best way may be to build more circuits. When I was young most circuits failed to work first time because components were so bad, so you quickly learn troubleshooting. But nowadays most parts are in specification, and those specs are good, so it's a little hard...
by MikeDB
Tue Feb 23, 2021 1:17 pm
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

:agree: and was going to make the exact same quote -and near same comment- but was working on reply to MDB first. -------------------------------------------------------------------------------------------------------- @MikeDB How about pointing us to a couple good SMPS 'replacements' for the typic...
by MikeDB
Tue Feb 23, 2021 10:28 am
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

A good SMPS should cost you about the same as a decent linear one. The power supply is the basis of any electronic device, you dont start with the cheapest shittiest thing you can find, you start with the best possible power and work backwards from there to find the "good enough" point. Having a be...
by MikeDB
Tue Feb 23, 2021 7:55 am
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

Low noise is only one of the classic reasons to employ linear over SMPS. Transient load response is another. 'Classic reasons' are usually based on hearsay or fantasy, nothing more. As I've said repeatedly, a good linear PSU is always noisier than a good SMPS. Likewise the transient load response i...
by MikeDB
Mon Feb 22, 2021 8:04 pm
Forum: Music Tech DIY
Topic: Faulty Magneto Question
Replies: 2
Views: 64

Re: Faulty Magneto Question

No need to replace the jack. Just plug in a cable and use a multimeter to probe from one end of the cable to the PCB to see if each wire is making contact.
by MikeDB
Mon Feb 22, 2021 12:57 pm
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

Also worth noting, the complexity of small SMPS devices is like that for a reason, the $5 aliexpress devices will probably get you the voltages they advertise but this will come with 100+ mV noise on the outputs. I have a drawer full of them and none have even come close to something usable noise w...
by MikeDB
Sun Feb 21, 2021 2:57 pm
Forum: Music Tech DIY
Topic: Audio programming for hardware
Replies: 21
Views: 380

Re: Audio programming for hardware

There loads of audio languages if you google for them. Some people like them, I've never bothered. But when you get onto heavyweight stuff or coding vsts you'll still need C/C++. One of the easiest ways to get going is to get a Teensy or Daisy Seed and program those first, before producing custom d...
by MikeDB
Sat Feb 20, 2021 9:23 pm
Forum: Music Tech DIY
Topic: Audio programming for hardware
Replies: 21
Views: 380

Re: Audio programming for hardware

There loads of audio languages if you google for them. Some people like them, I've never bothered. But when you get onto heavyweight stuff or coding vsts you'll still need C/C++. One of the easiest ways to get going is to get a Teensy or Daisy Seed and program those first, before producing custom de...
by MikeDB
Sat Feb 20, 2021 8:50 am
Forum: Music Tech DIY
Topic: digital modules and a/symmetric power draw
Replies: 3
Views: 136

Re: digital modules and a/symmetric power draw

Yes a SEPIC convertor can be referenced to almost any point you choose. As well as a symmetric load the HUGE advantage of doing it this way is that any noise going back into the source goes nowhere near the ground wires. Opamps are very good at rejecting power supply noise, but as we've all experien...
by MikeDB
Fri Feb 19, 2021 8:47 pm
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

As you can see are pretty strict limits for efficiency in the directive, and although it states a no-load input power of 0.3W on the page, which is legal, the actual spec sheet says 35mA which is almost 9 Watts, so one of these numbers is wrong ! If the latter is correct it doesn't meet Annex I whic...
by MikeDB
Fri Feb 19, 2021 3:47 pm
Forum: Music Tech DIY
Topic: What connectors
Replies: 2
Views: 154

Re: What connectors

I'd suggest buying these pre-assembled cables to solder to the pots, and the matching connectors from the same place. As you can see they are a few pence each and if you're plug and forget they won't wear out.

https://www.aliexpress.com/item/4000029 ... 4c4dnYJKM6
by MikeDB
Fri Feb 19, 2021 2:52 pm
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

plushterry wrote:
Fri Feb 19, 2021 2:33 pm
Nice one Mike, you're a legend for dishing out all this info.
Hehe, been there, f***ed that up ! :-)
by MikeDB
Fri Feb 19, 2021 1:09 pm
Forum: Music Tech DIY
Topic: bat85 replacement for coolaudio V2164
Replies: 17
Views: 530

Re: bat85 replacement for coolaudio V2164

One is enough if they are all the ICs are wired to the same supply lines
by MikeDB
Fri Feb 19, 2021 12:21 pm
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

rich_de wrote:
Fri Feb 19, 2021 11:53 am
One significant downside is that 12V AC wall plugs are rather hard to get these days (a proper big and heavy transformer means expensive),
... and the sale of them is banned in some EU countries, with the rest supposedly getting round to implementing REGULATION (EC) No 278/2009 sometime.
by MikeDB
Fri Feb 19, 2021 9:57 am
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

Do you have the reverse protection diodes from input to output of the two regulators ? If the regulator sees a voltage less than it's ground pin already on the output, some decide that's a short circuit and so don't switch on. Mindlessly tacked a diode (1N4148) across the 7812 O-to-I, still refused...
by MikeDB
Fri Feb 19, 2021 12:25 am
Forum: Music Tech DIY
Topic: 1V/oct scale circuit
Replies: 2
Views: 179

Re: 1V/oct scale circuit

You can try the trimpot first. I don't know what the output impedance of the external source is so can't advise a value.
by MikeDB
Fri Feb 19, 2021 12:22 am
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

plushterry wrote:
Thu Feb 18, 2021 6:42 pm

the board has come out a bit longer, 70×40mm now, which means the regs have a little more room to breathe at least.
You seem to have vias in the pads of C1-3 and under the regulator tabs. Some PCB fabs won't like that or charge more for them. Best to move them slightly
by MikeDB
Fri Feb 19, 2021 12:19 am
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

Do you have the reverse protection diodes from input to output of the two regulators ? If the regulator sees a voltage less than it's ground pin already on the output, some decide that's a short circuit and so don't switch on. Even with the diodes, I suspect this might still be the problem, it all d...
by MikeDB
Thu Feb 18, 2021 2:14 pm
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

You've been on SynthDIY ;-). If you add a zener across the capacitor it both regulates and smoothes ripple reasonably well Haha, no it was an eevblog video that YouTube has been nagging me to watch for ages. It's almost as if they know what I want. How strange :hmm: This is the one referred to on S...
by MikeDB
Thu Feb 18, 2021 10:06 am
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

I wondered last night if it would be a good idea to get a second PCB fabbed that's the same dimensions as my PSU board with just copper fill on it. I could mount it on standoffs above the PSU, and attach via a thick wire to the ground on the PSU board to act as a shield. It's going to affect the am...
by MikeDB
Thu Feb 18, 2021 10:05 am
Forum: Music Tech DIY
Topic: What's the 'best' way to get bipolar power from a wall-wart?
Replies: 88
Views: 1453

Re: What's the 'best' way to get bipolar power from a wall-wart?

Nice one Mike After doing some more research it seems like a capacitance multiplier circuit would probably be more effective than the regulators at removing switching ripple. You've been on SynthDIY ;-). If you add a zener across the capacitor it both regulates and smoothes ripple reasonably well
by MikeDB
Thu Feb 18, 2021 6:38 am
Forum: Music Tech DIY
Topic: Stock of microcontrollers Mouser (Mutable Builds)
Replies: 5
Views: 192

Re: Stock of microcontrollers Mouser (Mutable Builds)

Stock available here: STM32F405RGT6 https://lcsc.com/product-detail/ST-Microelectronics_STMicroelectronics-STM32F405RGT6_C15742.html STM32F103CBT6 https://lcsc.com/product-detail/ST-Microelectronics_STMicroelectronics-STM32F103CBT6_C8304.html Thanks! Get in quick. I went to place and order for STM3...

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