[tomphillips]

I'm getting a little bit fed up with the cost of batteries with my little amps I have (been trying) to make, and I've noticed on Tangent's web site that he has the plans for making two power supplies, the 'Tangent Easy Power Supply' and the TREAD.

I've noticed a lot of info about ripple current? I'm assuming this is pretty much self explanatory - that it is the current rippling from when it has been smoothed from AC to DC. Is that correct?

I guess that you want the lowest ripple current possible, but how much is enough to affect the op amp enough?

So... to the main question. I want to be able to, take a mains voltage (230V, 50Hz, United Kingdom) and step it down and smooth so I can use it with a Cmoy or equivilent to replace a battery. Basically I'll be taking its DC output straight into the potential divider or a TLE2426 rail splitter.

What would you recommend? TREAD or STEPS. Anyone had any good or bad experiences?

Also..... I'm choosing an external psu because I can use it with various headphone amps, just plug it into a different amp. If you see what im saying!


Thanks

 

[Fresno Bob]

you can always build a recharging circut and use rechargable batts.

 

[tomphillips]

Quote:

Originally Posted by Fresno Bob you can always build a recharging circut and use rechargable batts.

I guess that would eliminate the problem of noise and ripple. Just exploring different possible methods - charging batteries takes time ...

Any other suggestions?

 

[BrokenEnglish]

eliminating noise is one of the main purposes of an audio psu, there you're right. ripple current increases with the current your amp draws. related noise can be suppressed by capacitance: the more capacitance, the lower the ripple, your amp sees. there are different approaches to lower other aspects of noise: capacitor-resistor or inductor-capacitor networks or both for example.
basically STEPS and TREAD both are able to suppress ripple current equally well. TREAD is much smaller and allows you to pair it with transformers of your choice, but you'll be restricted with parts-selection, esp. the size of your smoothing caps (no problem at all with a cmoy). STEPS on the other hand offers an one-pcb solution with the transformer onboard. oh... and there's also a basic netfilter on the board, another noise-suppressor.

 

[rickcr42]

http://www.welbornelabs.com/ps1.htm

download the pdf file

 

[drewd]

Quote:

Originally Posted by rickcr42 http://www.welbornelabs.com/ps1.htm download the pdf file

Ack, the link to the PDF is broken. I sent Ron an email.

-Drew

 

[rickcr42]

easy enough to figure out from using the schematic,the regulator chip data sheets and the newsletter archives in combination.you would maybe be surprised at some of what is found there..........

 

[dsavitsk]

Quote:

Originally Posted by drewd Ack, the link to the PDF is broken. I sent Ron an email. -Drew

Ron sent it to me a few weeks ago. Send me a PM with your email address and I'll send it to you ("you" generally, not just Drew).

-d

 

[mono]

Quote:

Originally Posted by tomphillips I'm getting a little bit fed up with the cost of batteries with my little amps I have (been trying) to make, and I've noticed on Tangent's web site that he has the plans for making two power supplies, the 'Tangent Easy Power Supply' and the TREAD. I've noticed a lot of info about ripple current? I'm assuming this is pretty much self explanatory - that it is the current rippling from when it has been smoothed from AC to DC. Is that correct?

Yes that's right for the most part, but in general no, ripple is ripple, it matters not if it were the AC-DC conversion or another cause, it is an absolute reading of ripple regardless of the cause, whether it be the AC-DC conversion or noisey AC input power, or noise picked up along the way.

Quote:

I guess that you want the lowest ripple current possible, but how much is enough to affect the op amp enough?

It's is the "ideal" vs "reality", vs budget, vs size, vs ...

Generally speaking I wouldn't put fine leather seats in a CHevy Cavalier and I wouldn't build a high-end power supply for a CMOY. Pick your target voltage, odds are a standard/reference LM78nn circuit would do fine for a CMOY. For example, 12V operation would use LM7812. However, Tangent's Tread is an improvement and using a nice professional PCB is also a plus. It's worthwhile rather than building something from scratch, using protoboard or having to etch a single board for this.

Quote:

So... to the main question. I want to be able to, take a mains voltage (230V, 50Hz, United Kingdom) and step it down and smooth so I can use it with a Cmoy or equivilent to replace a battery. Basically I'll be taking its DC output straight into the potential divider or a TLE2426 rail splitter. What would you recommend? TREAD or STEPS. Anyone had any good or bad experiences?

As mentioned above, Tread is plenty, maybe more than a CMOY warrants but thanks to Tangent's work it is easy too, a win-win situation. Remaining issue is finding the transformer (or wall-wart) you want to use with it.

Quote:

Also..... I'm choosing an external psu because I can use it with various headphone amps, just plug it into a different amp. If you see what im saying!

The additional benefit of the Steps is the AC filtering. The downsize is the higher construction cost and size. Determine the project goals, whether you need small and low-cost. IMO, either will be fine for the average use, though if you feel your AC power is particularly noisey, go with the Steps. You can always populate only what you feel you need with the Steps, making it essentially a Tread with an onboard transformer. That means one less part to mount elsewhere, but again slight construction cost increase if you already had a suitable transformer.

Determine the maximum amperage you expect to EVER use from the supply. Personally I don't like trying to get max output from a sealed transformer as used on the Steps- it may blow the thermal fuse. Obviously that means choosing a suitable capacity transformer, but it's also more of a limit for higher voltage use, with a Tread you can fit a 5A regulator on it and a larger (separately mounted) transformer than would be reasonable on the Steps. That's power-amp range though, dozens of watts or more, not what is needed for most headphone amps.


Thanks

[/QUOTE]

 

[Jazper]

I'm intending to build an M3 in the near future (as funds allow) but have decided to stray away from the steps/tread because I want an amp that is more unique and because I decided I could put something similar together for less cost that would be just as good if not better.

Anyhow, I've built a design based on the one here:
http://www.diyaudio.com/forums/showt...threadid=56106

I've basically halved the design as I only need one rail, changed the voltage (so I get the voltage I require) through the resistors and used an LM317 regulator instead of a 338. I've also done a few other minor mods (like running a small LED/metal film resistor in parallel to the output so I know when it's on) but it works a treat

I'm also using an EMI filtered IEC socket on the input so I don't have to have a filter in the circuit.

The design itself should be able to handle up to about 10A/60v(600W

) across both rails if you go with suggested components however I figure I'll never be using more than 600-700mA(~20W) so it should be right.

All up (without transformer but using low esr/high quality caps) cost me about $20AUD(aussie dollars) which I doubt you could put a steps together for. Effectively double the cost if you ask for dual rail.

You could modify the circuit so that you had the resistors on a 4-5 position switch so you could have different voltages as you needed it also.

 

[skyskraper]

using a filtered iec filter you get a lot of the steps advantages at a lower cost, with less parts to solder

tread + filtered iec = cool

i like the low cost of the parts myself hehehe and that theyre the sort of parts that are quite common in people's parts bins

 

[tomphillips]

hmm... more to think about now

I think mono's point that there isn't much point putting a high end power supply in a cmoy - since the amp isn't high end anyway.

Thanks for all the info everyone has posted - very helpful

I think I'll continue to read up on this before I start using mains electricty!

 

[skyskraper]

you could probably get away with an unregulated power supply with most of the headphone amps we build on here

 

[Tomo]

Hi,

I am a heretic and I think some people will call me audioelectronic-blasphemer. But I gotta say SWITCHING PSUs are quite a nice alternative.

SWITCHING PSUs are light, compact, run cool, more efficient/powerful, and CHEAP. These little monsters are really powerful. I found one that supplies 24V at 1A with a size of a slighted bigger wall plug. You can run a Class-A from these.

As for sound, I am not HEARING any difference. It may show up in your oscilloscopes, but you won't hear any difference.

Another alternative is what Skyscraper recommended. Unregulated PSU/Wallwart. These are quite small as well and pack a good punch. OPAMPs have quite high supply regulation and it is probably not necessary to regulated as much as we do. Most of us build PSU with better than -100dB rejection, but that is overkill to begin with. ...

Tomo

 

[skyskraper]

i was quite surprised to recently find out in my research on amps that power supplies are usually bridge -> caps -> amp, in a lot of them.

u could also use a wall wart (switcher or unregulated) quite easily with a tread, for a cheap and simpleish solution.