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JackLondon

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3 minutes ago, Wilson_51_ said:

Yeah pins 1 and 8 are connected, I’m unsure if it fully is the charge pump but it’s a siren type sound almost like a flanger noise. 
 

Thanks for this! The mouser ones have a £12 postage on them which feels massively steep. 

If it sounds like a flanger then the frequency is shifting which suggests it's probably not the charge pump, and the boost should take the charge pump noise well out of audible range. Probably worth looking at other culrprits.

 

All mouser stock is held in the US - they do a good job on intl. Shipping but it is still expensive.

 

I edited my response above, farnell have the LTC1144. Delivery is free but there's a £10 handling charge under £24, and a £6 handling charge between £24 and £48. Over £48 is free, so if you wanted to stock up it could be worthwhile.

 

Full disclosure I do work for farnell, please buy components so I can continue to spend my wages on components.

 

 

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I've come across this issue with 7660's when trying to do some repairs. The J Rocket Archer uses a 7660S, and I've swapped out a failed one and introduced a HF whistle. The issue I had was caused by accidentally using a 7660 which has nothing connected to pin 1 (so no boost mode, just runs at 10KHz) as opposed to a 7660S with the boost on pin 1. 

 

I've had better luck with the LT1054 compared to the 7660S and the 1044. I've replaced a lot of MAX1044's in bogner la granges. 

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8 minutes ago, bobbass4k said:

If it sounds like a flanger then the frequency is shifting which suggests it's probably not the charge pump, and the boost should take the charge pump noise well out of audible range. Probably worth looking at other culrprits.

 

Thanks for this, I’ll look for what else could be causing this. Apart from this odd noise the rest of the circuit seems to be working. 

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42 minutes ago, bobbass4k said:

Are you using the 7660s in boost mode (pins 1 and 8 connected)?

 

Also the LTC1144 is available at farnell (search 4029296) - they are expensive though.

 

I searched CPC Farnell for LTC1144 and couldn't find it, then I tried searching with that part number and also couldn't find it. Are you going via the website or the internal stock system?

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22 minutes ago, tauzero said:

 

I searched CPC Farnell for LTC1144 and couldn't find it, then I tried searching with that part number and also couldn't find it. Are you going via the website or the internal stock system?

That was on the website on my phone. As neko says, CPC are for all intents and purposes a different company - especially on components they don't stock nearly the range we do, as it's not big business for them.

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38 minutes ago, bobbass4k said:

That was on the website on my phone. As neko says, CPC are for all intents and purposes a different company - especially on components they don't stock nearly the range we do, as it's not big business for them.

I must say it confuses me - CPC seem more aimed at b2c and the Farnell are more b2b? 

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20 minutes ago, LukeFRC said:

I must say it confuses me - CPC seem more aimed at b2c and the Farnell are more b2b? 

Basically yeah - farnell is aimed at design engineers, small volume manufacturing, repair/servicing etc. and the main focus is on board level components. CPC is aimed at anyone with money and is focussed much more on businesses, trade and normal consumers. Basically they sell plant pots, and we do not.

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1 hour ago, LukeFRC said:

My low tide mini works. I’m very excited. 

Be mindful that it needs to be calibrated very carefully. I say that because PedalPCBs documentation for his $30 PCB doesn't mention it at all..... He makes good boards and I get that his focus is on tracing and pumping out new boards, but the lack of information makes them risky investments. He claims it's just a manpower/time issue, but it is interesting how many of the boards without schematics published are the unique and exciting ones that he's traced himself, like the low tide...

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7 hours ago, bobbass4k said:

Be mindful that it needs to be calibrated very carefully. I say that because PedalPCBs documentation for his $30 PCB doesn't mention it at all..... He makes good boards and I get that his focus is on tracing and pumping out new boards, but the lack of information makes them risky investments. He claims it's just a manpower/time issue, but it is interesting how many of the boards without schematics published are the unique and exciting ones that he's traced himself, like the low tide...

I wasn’t expecting it to work and then stayed up far too late sorting the calibration.
 

The daft thing is about PedalPCB that the forum seems to have most the info on it, including schematic - https://docs.pedalpcb.com/project/LowTide-Schematic-PedalPCB.pdf

but you have to root around to find things - one post on one thread - LDSS needs for the barbershop, another post is someone telling you how to bias it… another is… 

it’s not beginner friendly 

 

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On 06/01/2023 at 18:19, LukeFRC said:

Random question- what are the 2m resistors doing here? One I think is to stop a pop on switch on? Other set input impedance?

should if work without them? 

E2FD7719-1A0A-4102-A8D8-2EFC5F51615E.jpeg

 

Yes, R1 allows C1 to discharge to 0V to minimise pops on plugging in.

R3 biases the Gate of Q1 to 0Vdc.

The input Z is essentially 2M inn parallel with 2.033M. In round numbers = 1M

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On 06/01/2023 at 15:15, Smanth said:

I feel you!  The "Big Boys Race Our ..." mnemonic is etched in my head since my early exploits with breadboards, a cheap and nasty soldering iron and a stack of Babani books ... but these days (as you) I just bung a multimeter on them ... it has the secondary advantage of allowing me to pick one from the strip that is closest to the nominal value.

 

S'manth x

 

Confession - I'm an electronics design engineer and never read resistor codes - just measure them.

And of course SMT resistors have the value marked on them in some form.

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4 hours ago, LukeFRC said:

I wasn’t expecting it to work and then stayed up far too late sorting the calibration.
 

The daft thing is about PedalPCB that the forum seems to have most the info on it, including schematic - https://docs.pedalpcb.com/project/LowTide-Schematic-PedalPCB.pdf

but you have to root around to find things - one post on one thread - LDSS needs for the barbershop, another post is someone telling you how to bias it… another is… 

it’s not beginner friendly 

 

Yeah, I basically had to beg for that low tide schematic - claims it's not included in the build doc because it's visually very large, but... Split it over 2 pages? Include it as is and let people zoom? Include a link to it hosted somewhere? I guess he makes no claim to being beginner friendly, and if you know what you're doing his boards are very usable, and the forum's do a great job of plugging the gap, but I do wish he'd just be honest about why the schematics are so scarce.

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On 06/01/2023 at 12:42, Woodinblack said:

I must admit in all my years of working both as hobby electronics and later as an electronic engineer (which I guess counts for about 20+), I have been liucky enough to never has found a resistor with the wrong values on it. Some are harder to see than others, but never wrong.

Capacitors on the other hand...

 

It's well worth getting a cheap component tester kit off t'interweb. LCR and transistors (FET and bipolar). So useful!

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1 hour ago, Stub Mandrel said:

 

It's well worth getting a cheap component tester kit off t'interweb. LCR and transistors (FET and bipolar). So useful!

 

It is - I have a few. I was just saying if there is something to not trust the value is printed wrong, it is a capacitor, mostly because everyone labels them their own way, unlike resistors

 

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3 hours ago, bobbass4k said:

Yeah, I basically had to beg for that low tide schematic - claims it's not included in the build doc because it's visually very large, but... Split it over 2 pages? Include it as is and let people zoom? Include a link to it hosted somewhere? I guess he makes no claim to being beginner friendly, and if you know what you're doing his boards are very usable, and the forum's do a great job of plugging the gap, but I do wish he'd just be honest about why the schematics are so scarce.

it's kinda a slight detour away from the freestompboxes open source tracing of things 
 

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