Search found 78 matches

by welhamc
Sun Jun 07, 2020 12:36 pm
Forum: Music Tech DIY
Topic: ring modulator troubleshooting
Replies: 31
Views: 1098

Re: ring modulator troubleshooting

Could be because you're using a TRS cable - try TS
by welhamc
Fri Jun 05, 2020 7:03 pm
Forum: Music Tech DIY
Topic: Toroidal EMI
Replies: 13
Views: 432

Re: Toroidal EMI

Thanks for all the advice - I'm going to use nylon screws to fix the 3 regulators to prevent any chance of shorting the toroid
by welhamc
Fri Jun 05, 2020 1:53 pm
Forum: Music Tech DIY
Topic: Toroidal EMI
Replies: 13
Views: 432

Re: Toroidal EMI

Thanks Neil - theres no possibility of the mounting bolt coming into contact with the top or bottom of the case - I could insulate the top and bottom case panels around the transformer but this may be overkill Theres a good 30-40 mil of clearance between the toroid and the voltage regulators. I thin...
by welhamc
Fri Jun 05, 2020 1:34 pm
Forum: Music Tech DIY
Topic: Toroidal EMI
Replies: 13
Views: 432

Re: Toroidal EMI

How would you go about measuring this practically - would an oscilloscope probe (maybe with ground lead attached to the signal probe) held in area near to the toroid measure this? My feeling is that I would probably get away with location of the voltage regulators, but if the stray inductance was si...
by welhamc
Fri Jun 05, 2020 1:23 pm
Forum: Music Tech DIY
Topic: Toroidal EMI
Replies: 13
Views: 432

Re: Toroidal EMI

Thanks for the reply - would copper tape be sufficient to shield the circuit from electric field interference?

Would you bother wrapping the whole transformer or just the circumference? I'm tempted to go with your suggestion - much cheaper than mu metal or similar
by welhamc
Fri Jun 05, 2020 12:55 pm
Forum: Music Tech DIY
Topic: ring modulator troubleshooting
Replies: 31
Views: 1098

Re: ring modulator troubleshooting

I'm interested as to why the cathodes (negative side of diode) are marked positive in the schematic. Unless this is meant to denote electron current using conventional + to - (this seems unusual)

Perhaps your diodes are reverse biased - its difficult to tell without seeing the circuit
by welhamc
Fri Jun 05, 2020 11:43 am
Forum: Music Tech DIY
Topic: Toroidal EMI
Replies: 13
Views: 432

Toroidal EMI

Hi muffs, I'm arranging the layout for my 9090, and as my enclosure is relatively small, I am in a bit of a predicament with the PSU transformer. I'm using a 30VA toroidal transformer to step down the mains voltage for the PSU of the 9090. With how the boards are laid out currently, I have spotted a...
by welhamc
Fri Jun 05, 2020 3:00 am
Forum: Music Tech DIY
Topic: Steda Electronics SR-909 Full kit for $909 last 3 days!
Replies: 85
Views: 9240

Re: 909 Drum Machine REPLICA build thread

Following - also very pleased for standalone sequencer option!
by welhamc
Mon Mar 02, 2020 5:16 pm
Forum: Oakley Sound Systems
Topic: Euro PSU
Replies: 5
Views: 576

Re: Euro PSU

All working now! The problem was D13... it must've been fried when the LM337 was shorted but replacing it has given me -12v on the negative rail at last
by welhamc
Mon Mar 02, 2020 5:08 pm
Forum: Oakley Sound Systems
Topic: Euro PSU
Replies: 5
Views: 576

Re: Euro PSU

The voltage on pin 1 of u3 is around -24v whereas on pin 1 of the LM317 its is +11v - it seems that the problem is further upstream than the lm337 but cannot find anything obvious on the board..
by welhamc
Mon Mar 02, 2020 4:27 pm
Forum: Oakley Sound Systems
Topic: Euro PSU
Replies: 5
Views: 576

Re: Euro PSU

No luck swapping out for a new LM337. I also swapped out D11, the NEG trimmer and R7 and R9 and checked all the diodes - still getting around -23v on the -12v rail

I have an LM337BT instead of an LM337T - is this an issue?
by welhamc
Sun Mar 01, 2020 12:57 pm
Forum: Music Tech DIY
Topic: Is this fixable? First build, turing machine, overheated elements
Replies: 15
Views: 660

Re: Is this fixable? First build, turing machine, overheated elements

This is the solder I use, its a British seller on eBay but sends to EU https://www.ebay.de/itm/EXPO-77598-REEL-OF-HIGH-QUALITY-110-GRAM-LOCTITE-MULTICORE-LEADED-SOLDER/222265194619?epid=1354628864&hash=item33c009b87b:g:3ugAAOSwqu9U5ODs Soldering at higher temperatures runs the risk of pulling pads o...
by welhamc
Sun Mar 01, 2020 9:21 am
Forum: Music Tech DIY
Topic: Is this fixable? First build, turing machine, overheated elements
Replies: 15
Views: 660

Re: Is this fixable? First build, turing machine, overheated elements

Also make sure to clean off all the flux residue after you have finished soldering - it can become potentially corrosive over time

I use some 99% isopropyl alcohol and a stiff brush
by welhamc
Sun Mar 01, 2020 9:15 am
Forum: Music Tech DIY
Topic: Is this fixable? First build, turing machine, overheated elements
Replies: 15
Views: 660

Re: Is this fixable? First build, turing machine, overheated elements

Also as another point, I would always recommend leaded solder - thats just my preference but it flows a lot better in general
by welhamc
Sun Mar 01, 2020 9:12 am
Forum: Music Tech DIY
Topic: Is this fixable? First build, turing machine, overheated elements
Replies: 15
Views: 660

Re: Is this fixable? First build, turing machine, overheated elements

You may have had troubles due to the ground plane (the expansive area of copper on the board). Copper is obviously electrically conductive, but is also a good conductor of heat. If you are heating up a component lug that is coupled to the ground plane you are essentially heating up the entire large ...
by welhamc
Sat Feb 29, 2020 7:37 pm
Forum: Music Tech DIY
Topic: Is this fixable? First build, turing machine, overheated elements
Replies: 15
Views: 660

Re: Is this fixable? First build, turing machine, overheated elements

It looks salvageable - you could solder the left hand side to the component lug above it (follow the trace), the right hand side can be soldered to anywhere around the hole as it looks like a ground plane - you could just scrape back and solder If you're a beginner it may be better to just order ano...
by welhamc
Fri Feb 28, 2020 4:29 pm
Forum: Oakley Sound Systems
Topic: Euro PSU
Replies: 5
Views: 576

Euro PSU

I'm having an issue with a build of a eurorack PSU. The +12v and +5v rails are all working as expected, but the -12v rail is reading as -24v. I have checked that all the components are correct (including R7 and R9) and there are no dry solder joints. When I first powered the module there was a short...
by welhamc
Tue Feb 18, 2020 12:19 pm
Forum: Production Techniques
Topic: Phaedra synthesis
Replies: 15
Views: 1393

Re: Phaedra synthesis

Are you talking about this? http://randomsource.net/haible/krautrock

I'm tempted to build one in 5u...
by welhamc
Tue Feb 18, 2020 11:43 am
Forum: Production Techniques
Topic: Phaedra synthesis
Replies: 15
Views: 1393

Re: Phaedra synthesis

Ah thanks for that - I'm guessing it would be best to get some strings samples into my Akai sampler then and go from there. I probably could not afford a mellotron...

In terms of trying to recreate some of these mellotron sounds with synthesis, where would be a good place to start?
by welhamc
Mon Feb 17, 2020 7:12 pm
Forum: Music Tech DIY
Topic: DIY builders for hire
Replies: 293
Views: 61408

Re: DIY builders for hire

I'm located in Bristol, UK. I am happy to offer a range of DIY services including module building (5U/MOTM/Eurorack/4u), power supply building and some repair services. If you have anything to ask please PM me!
by welhamc
Mon Feb 17, 2020 8:29 am
Forum: Production Techniques
Topic: Phaedra synthesis
Replies: 15
Views: 1393

Phaedra synthesis

I have recently discovered TD (I know) and have been thoroughly rinsing through their discography over the last few weeks One of the sounds that keeps coming back to me is the early lead in Phaedra (https://www.youtube.com/watch?v=URssLwPXkVk, around 3:40 in) and was thinking about the process in th...
by welhamc
Sat Feb 08, 2020 10:49 am
Forum: Music Tech DIY
Topic: Akai ME30pii input dead
Replies: 0
Views: 351

Akai ME30pii input dead

Hi muff, wondering if anyone can help me One of the inputs on my Akai ME30pii midi patchbay doesn't seem to be working recently Its not a connector issue as I have opened up the unit and continuity tested the inputs. There does seem to be quite a suspect burnt-out electronics smell though. I have in...
by welhamc
Thu Feb 06, 2020 10:06 am
Forum: Modular Synth General Discussion
Topic: Starter Setup ?
Replies: 51
Views: 2827

Re: Starter Setup ?

If you ever need someone to build you a DIY module feel free to PM me :)
by welhamc
Sat Feb 01, 2020 7:38 am
Forum: Oakley Sound Systems
Topic: PSU Resistor
Replies: 1
Views: 351

PSU Resistor

Hi everyone

I am currently building am Oakley PSU2

However, I have just noticed I do not have any 240r resistors for R2 and R3... I have 220r though, will these be a sufficient sub?

Chris
by welhamc
Sat Feb 01, 2020 7:16 am
Forum: Music Tech DIY
Topic: PSU Grounding
Replies: 1
Views: 313

PSU Grounding

Hi muff I have a question about grounding for a PSU I'm building. As my access to metal working tools is pretty limited, I decided to use a 1u panel with a punched out IEC slot as my input which then connects to a 4u panel containing the PSU, transformer etc. The IEC panel is coupled to the main pan...

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