I am considering building an 9vac and 12vac power supply to power several units. I was wondering if there is a need to filter AC power like you do when building a DC power supply. If so, could someone please provide me with a schematic or layout for the filtering.
could they be powered by this power supply (the outputs marked 'analog', there is enough current)? could they be powered by +6vdc alone, or would the bipolar supply help somehow?
the schematic:
would this work:
(that's connecting all of the grounds of the schematic to -v, and all of the vref stuff (V/2) to ground?)
So I'm having a lot of trouble wrapping my brain around the concept of positive ground. I built myself a beavis-boardesque prototyping setup. In an enclosure i have a true bypass switch, battery, volt starve etc with leads going to breadboards. I've managed all that and have built several fuzz circuits of the modern (?) npn variety with much success.
Today I built RnFR's toecutter, using PNP Ge trannys, and I worked out what parts of the circuit go to + ground and which parts go to -9v. The...
I have a pedal that is running on 12vdc and it works just fine, but I need to power another circuit along with it and tap power off of the one that's working fine. The problem that I'm running into is that there is a hum on the secondary circuit that is power related.
I tried a 78L05 (that's all I had on hand) and the secondary unit powers up and works without hum, but 5 volts isn't enough.
If I get a 78L09 or a LM7809, that tells me that it'll all be good - right?
Is there anything else I can...
Can someone introduce me to power filtering basics with regard to stompbox design? I've seen designs with one 100Ohm resistor in front of a 100uF capacitor and other designs with 100Ohm resistors surrounding a 220uF capacitor. I've seen designs with one cap, and designs with two caps. Can someone explain the reasoning behind these designs and what are the benefits of designing something a certain way over the other. Or can you refer me to some online literature that I can read to better...
I bought a rackmount compressor in america last week, and in my excitement, plugged it in over here straight away, and blew the fuse. silly me. Anyway, I found out that the fuse in it is a 100 - 120 V ~: T 250 mA H, and for UK, it needs a 200 - 240 V ~: T 125 mA H. So i headded off to my local DIY, and the closest they had was a 1A fuse that size, which is considerably larger. Could i use a 1A fuse??
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Ok, here's what a good friend can do with a chinese wall wart (those 9v to 12v w/ polarity selector)
It's a TS808 I built for him as birthday gift and now is working again, but I can not forget that I lost a nice sounding 4558 for failing to put a simple diode, so I need to learn more.
I saw the 1N400x's are the most common diodes for polarity protection in so many stompboxes , so I assume to be the most appropriate, but what about the configuration: is better to connect the diode...
Can somebody help me determine the proper values for some decoupling resistors and capacitors.
What I want to do is decouple the preamp and modulation stages from the 9vdc supply.
I would like to lose less than 1 volt because I need at least 7v for this build.
My book says
RC time constant should represent a frequency 10 times lower than the lowest frequency you wish to amplify.
Not sure what values to choose for RC , so I don't lose too much voltage or alter my frequency response.
Any...
Sorry if this is the wrong place for this question, but here goes:
Recently, I tried running my '86 Rat clone at 18V. The components inside are all rated higher than 18V, AFAIK, and the voltage going to pin 3 of the LM308 in this scenario would be a bit less than 9V, if my limited knowledge of electronics serves me correctly. I really liked the sound - really tight, Marshally dirt a la Alice Cooper or Aerosmith - and nothing exploded or smelt bad. The power supply is essentially this, courtesy...
I read comments and articles all of the time that say something to the effect of, positive and negative grounded pedals can't be daisy chained.
So, to all of the closet geniuses out there ... is there a way to work these misfits into a pedal chain without complications?
Surely someone must have come up with a gadget by now ... right?
I'm using a 12V (5A) adaptor that's OEM of a laptop, I use it only for overdives and distortions such as DS-1, SD-1, TS9 because I know I won't burn anything... I've made a simple project that I've found on Beavis audio research, a simple pot that sags the 12V all the way to 0V...
Can you tell me what to build to make the 12V voltage always 9V?
Is there a verified project because I don't want to vurn my modulation pedals... TNX!
Is this just mojo? Or do carbon batteries actually have different electrical properties that alter their sound - and if so, what's responsible for it? The first thing that comes to mind is voltage output, but I've also heard mention of resistance and capacitance and whatnot. And could these traits be modelled in an effect's power circuitry?
Just picked-up a new DMM, and for the freaking life of me, I can't figure out how to test current draw. I have an old crappy needle meter and it's getting readings, so I know I have everything hooked-up properly, but no matter where I connect the leads or where I set the dial, I get nothing but -.02 on the display. The user manual is worthless, BTW.
The black lead goes to the common, and for mA, I would assume I should have the red hooked up to the mA jack. I get -.02. So I slap the red lead...
Hi friends,
I am in the midst of attempting to build my own power supply unit :applause:
I am planning to use this circuit by RG which can be found at his site:
RG Spyder.png
I have this transformer and bridge rectifier:
IMG_3473.JPG
I need some help to understand a few things:
1. What would be the transformer Amp output? It says 12VA. I did a search on the net but couldn't understand the conversion from VA to A :(
2. I couldn't get any DB01s, but I have RB154 which has similar tech...
Are there any reasons not to use a switching-mode power supply as opposed to a conventional magnetic transformer to power my pedalboard and stompboxes? :scratch:
Just learn from data sheet that 78LM09 only capable to deliver 100mA.
If i put 2 pcs of 78LM09 in parallel, would it able to supply 200mA?
My transformer is capable to supply 250mA.
I'm fairly new to the pedal building scene... build a mxr dist+ clone that worked for about a week!! lol...
I Have some metal DC jacks and was wanting to check if i needed to ground them or anything?
and i'm not 100% sure how to wire them up.. I used a black plastic one before but that meant everything needed to be wired into the case where as the metal one means i can build the whole circuit and then sort the case out after... that one was pos to tip and ground to pin... will it be...
As described here I have two old transformers from an old radio. My aim is to build a Deacy-amp workalike.
One is a push-pull driver, the other is the output one. You can find the schematic in the above link (last page).
First of all, I'd like to say that I roughly understand the purpose of the transformers, but can't figure out what ratios should be used to achieve what they are designed for, so any help is gently welcomed... :scratch:
I'm just trying to figure out what I need and in what order to make an adapter box that takes my pedal power's 9Vac 1000mA output and converts it to 12vdc 500mA. I'm trying to power a particular delay that keeps giving me trouble.
I assume at the basic level I need a rectifier and a smoothing cap.
I'm about to order a transformer to build my own power supply. It is 30VA with 2x12v secondary. I know how to calculate the output (in mA) for single secondary. But in this case is the 30 VA shared between the two secondary or each secondary has 30 VA output (which I expect)?
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