pedal power supply question about RG's article

[mikepukmel]

Reading up to build a pedal power supply with 4 or 6 9v ports.

http://geofex.com/article_folders/ol.../oldspyder.htm

RG's article is a few years old, and the 41PG006 transformers are not mfg'd any longer.

What I don't understand yet is the current requirement for pedals. I read someplace that a 9v battery can supply about 400 ma/H for an hour ,before its toast. So I had bought 2 brand new 9v batteries, and they lasted a few hours running Klon Centaur clone pedals, which have a voltage doubler that Im told are battery killers.

Don't I need at least 400ma transformers to power pedals like the klon, then? Or am I interpreting the numbers wrong (ac vs dc, something like that).

Maybe something like this:

https://www.mouser.com/ProductDetail...fUB3BvSXVfc%3d

that is just 1.37" tall, so it would fit in one of the boxes I was looking at.


Thanks,
MP

[Chuck H]

The way I would approach it would be simpler.

1) What is the mA requirement of the highest current pedals on the market.
2) Multiply that figure by the number of outputs you plan to use.
3) Find a 12V transformer capable of 20% more current. (regulation will eat some current)
4) Regulate it to 8.6V/9V (8.6V seems to be what most 9V batteries actually put out)

Easy peazy lemon squeezey.

[mozz]

Been building fuzz pedals lately and the cheap heavy duty 9v are putting out 9.8 and alkaline energizers are at least 9.2.

One spot is 9.4v which i don't like(on a scope anyway, noise from switching supply), it should be 9.0. Radio shack old 9/7.5/6/4.5/3/1.5 supply hums bad, 60mv ripple, i had to put 4700uf on it to quiet it down.

If i was going to build a supply, which is on my list of things to do one day, i would have at least 1amp, non switch mode, separate diodes on each output to isolate them from each other, big filter caps, small filter decoupling caps, regulated to 9vdc.

[olddawg]

Honestly... I use and have used a One Spot daisy chained with several pedals both in clubs and in studio. I have noticed that a couple of digital pedals didn’t like it. I assumed the switching hash riding on the rail beat on the chip clock frequency. But for analog.. I can’t
hear a difference between a battery and the One Spot. But that’s me.

[frus]

My BBD analog delay had problems with One spot, other stuff worked perfectly

[Dave H]

I read someplace that a 9v battery can supply about 400 ma/H for an hour ,before its toast. So I had bought 2 brand new 9v batteries, and they lasted a few hours running Klon Centaur clone pedals, which have a voltage doubler that Im told are battery killers.

Don't I need at least 400ma transformers to power pedals like the klon, then?

You don't need a 400mA transformer. 400 mAH means the battery can (optimistically) supply 400mA for 1 hour before it's toast or 40mA for 10 hours or 4 mA for 100 hours etc. If you are using separate transformers each output only has to supply the current required by your highest current pedal.

[doctor]

The transformer’s power supply is the day before yesterday design.
Modern SMPS has low noises. In addition, most modern pedals have built-in DC-DC converters that are insensitive to power supply noise and use its own SMPS.
Therefore, it is necessary to take 1 or 2 SMPS 9V/3A (depending on the total current consumption) and connect them to DC jacks.
This multichannel power supply will be 10 times cheaper and it will take 10 times less time to do it.

[nosaj]

The transformer’s power supply is the day before yesterday design.
Modern SMPS have low noises. In addition, most modern pedals have built-in DC-DC converters that are insensitive to power supply noise and use its own SMPS.
Therefore, it is necessary to take 1 or 2 SMPS 9V/3A (depending on the total current consumption) and connect them to DC jacks.
This multichannel power supply will be 10 times cheaper and it will take 10 times less time to do it.

10x cheaper and 10x less time to do it does not equal longevity. I do not find SMPS to last nearly as long as a transformer power supply.
nosaj

[Chuck H]

The transformer’s power supply is the day before yesterday design.
Modern SMPS have low noises. In addition, most modern pedals have built-in DC-DC converters that are insensitive to power supply noise and use its own SMPS.
Therefore, it is necessary to take 1 or 2 SMPS 9V/3A (depending on the total current consumption) and connect them to DC jacks.
This multichannel power supply will be 10 times cheaper and it will take 10 times less time to do it.

Point taken. But there may still (in the present day AFTER yesterday ) be some pedals that interact with the power supply switching as noticed by olddawg. And, of course, there's the longevity aspect mentioned by nosaj. Certainly there's no doubt of the reliability of transformers. Not that a lighter and less expensive alternative isn't valid. I just don't think it has invalidated transformers yet.

[doctor]

How long does the pedal work until the repair? 5 years, at best 10 years. And then it must be repaired. SPMS will work no less. MTBF for the SPMS usually is not less than 20,000 hours (2 years of continuous work without shutdown). No pedal will work so long.

For any pedal (as for any audio equipment) MTBF isn’t controlled parameter at all. And reliability is determined by luck (although the quality of development, components and manufacturing also affects).

In addition, all modern pedals (like other audio equipment) use SMPS.

[TomCarlos]

I built a Jameco Dual Output Power Supply Kit. If you look on YouTube, you will see videos of the kit being built. Just get yourself a project box, drill some holes to mount you outputs and you're done. I am only using one side of the kit and it supplies ample power to my pedal board (7 pedals).

[nosaj]

How long does the pedal work until the repair? 5 years, at best 10 years. And then it must be repaired. SPMS will work no less. MTBF for the SPMS usually is not less than 20,000 hours (2 years of continuous work without shutdown). No pedal will work so long.

For any pedal (as for any audio equipment) MTBF isn’t controlled parameter at all. And reliability is determined by luck (although the quality of development, components and manufacturing also affects).

In addition, all modern pedals (like other audio equipment) use SMPS.

By that argument nobody should be using tubes either? So we can be modern...

nosaj

[Chuck H]

How long does the pedal work until the repair? 5 years, at best 10 years. And then it must be repaired. SPMS will work no less. MTBF for the SPMS usually is not less than 20,000 hours (2 years of continuous work without shutdown). No pedal will work so long.

Disagree. For one thing I don't think the pedal board power supply's life span should be limited to pedal life. I, for one, would prefer not to replace my pedal board power supply EVER. I'd like to count on it as hardware rather than software. For another, you're probably not going to turn a power supply on and leave it alone for two years. There are the stresses on jack connections, powering up and down repeatedly and being jostled to and from gigs/practices.

In addition, all modern pedals (like other audio equipment) use SMPS.

Well that's just too much of a blanket statement and not true at all. But I don't see it as a consideration in the matter. If switch mode is better then it's better. But maybe it's not. It's just different. There are pros and cons to either power supply choice for this application.

[mozz]

If someone, here, is going to build a power supply, i doubt very much they are going to build a smps. The one spot also degrades over time, i know people who said "it use to work fine but now it's noisy". You throw it away, you don't repair it. I can give you a screen shot or video of a one spot that was given to me because it's noisy. The noise is random, large spikes that come and go and the regular smps noise. I tried to repair it, switched a few caps, then gave up. It works with some pedals fine, it doesn't effect them.

If you want to build the Jameco, they have other cheaper models that should work fine. I have some of these if you want 1, i bought a case of 36 for about $2 each.
https://www.mouser.com/ProductDetail...5JEytUCg%3D%3D

Feel sorry for those who live in CA, no more regular power supplies, they have to be SMPS.

[Leo_Gnardo]

If someone, here, is going to build a power supply, i doubt very much they are going to build a smps.

True, who would bother building a complex SMPS when you can buy one ready made for $20 or so. And when that a power supply costs $20 more or less, buy a spare! Those who build their own PSU's would be wise to stick to the cheap & reliable, low parts count, ol' fashioned standard supply.

Feel sorry for those who live in CA, no more regular power supplies, they have to be SMPS.

I hope that's a joke, but - California - yikes!