[Nisbeth]

Quote:

Originally Posted by bidoux /img/forum/go_quote.gif Sorry to up this, does anyone have a clue ? For the ultra-reg power supply, is a center taped transformer 48VAC as good as 2*24 VAC ?

In short, yes. However, if I can choose between 2x24V and 48VCT I'll always choose the 2x24V because of the extra flexibility of a true dual secondary. It's not important in this application but still...

/U.

 

[bidoux]

Quote:

Originally Posted by Nisbeth /img/forum/go_quote.gif In short, yes. However, if I can choose between 2x24V and 48VCT I'll always choose the 2x24V because of the extra flexibility of a true dual secondary. It's not important in this application but still... /U.

Thanks a lot for your answer ! Now I have another question:

What is the VA ? there is to informations for the transformer, the output voltage and the VA. What is the VA and how much will I need for the Dynalo ?
Is this kind better than this one ? The first one is often used.

 

[FallenAngel]

First one is toroidal and is better for this purpose. 15VA is good for a Dynalo (well, 2x 15V, 500mA), if going with 24V transformers (which I really don't know why unless you're making something like a Sigma22), go with 25VA.

 

[bidoux]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif First one is toroidal and is better for this purpose. 15VA is good for a Dynalo (well, 2x 15V, 500mA), if going with 24V transformers (which I really don't know why unless you're making something like a Sigma22), go with 25VA.

In the original article, the PSU is 36 V (Kevin Gilmore he

), I thought I could low it to 24V but if 2*15V works too (we are talking about the one with op-amp, right ?)

Edit: about the op-amp used in the power-supply, would these two work ? TDA2040V and TDA2005. For reference, here are two datasheet of op-amp that work: OPA541 and OPA548. I only want to know if they will burn or not when used...

Thanks everyone.

 

[kvant]

Quote:

Originally Posted by bidoux /img/forum/go_quote.gif I have some heat issues with the regulators. Does anyone knows how to calculate the size of Headtsinks I need on these regulators ?

I have noticed in the "pictures" thread that you run your regulators naked. They are quite rugged, but using them entirely without heatsinks is hardly optimal. How many volts do you drop across the regulators? Bolt to them at least small heatsinks, for instance something along the lines of what tangent shows on his TREAD.

As for the power supply from the article on Headwize, I think it is not the best route you can go. Do some reading around, I believe I saw some complaints about stability somewhere.

 

[bidoux]

If there is actually too much heat, they are supposed to stop working without being damaged. But you are very right, I was thinking of getting them some heatsink.

 

[FallenAngel]

The "original" was 36V - that's 2x 18V.

 

[Pars]

Actually, the original was a Triad F-378P, which was shown on the headwize schematic as being dual 36VAC secondaries, but the datasheet shows dual 28VAC.

A 2x18Vac transformer is a good choice, and is what headamp used on the Gilmore V2s, etc. which used the std. Gilmore Dynamic OPA548 PSU.

 

[steinchen]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Has anybody been able to get a hold of Dan from djgardner lately? I've sent him 3 emails since July 25th with no reply. Or does somebody have some Dynalo boards around? Thanks

I got a populated spare board, pm me if you are interested

 

[Pars]

Quote:

Originally Posted by steinchen /img/forum/go_quote.gif I got a populated spare board, pm me if you are interested

I had sent him an email a week or so ago and got a reply. He was in the middle of a move, but is settled in now and should reply. He does have all the stuff listed on his site still available.

 

[bidoux]

Are two PSU needed for a balanced dynalo ? I often see two power supply on Béta22 build but once, there was a balanced Beta22 with only one power supply so...

 

[FallenAngel]

Quote:

Originally Posted by steinchen /img/forum/go_quote.gif I got a populated spare board, pm me if you are interested

Thanks for the offer, but I just finally got a reply from him a couple of days ago.

Quote:

Originally Posted by Pars /img/forum/go_quote.gif I had sent him an email a week or so ago and got a reply. He was in the middle of a move, but is settled in now and should reply. He does have all the stuff listed on his site still available.

Yep, he was moving, said he's now settling in and selling boards/parts again.

Quote:

Originally Posted by bidoux /img/forum/go_quote.gif Are two PSU needed for a balanced dynalo ? I often see two power supply on Béta22 build but once, there was a balanced Beta22 with only one power supply so...

The Dynalo does not draw nearly enough current to warrant separate power supplies, but if you want dual-mono balanced, why not.

 

[bidoux]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif The Dynalo does not draw nearly enough current to warrant separate power supplies, but if you want dual-mono balanced, why not.

price, as usual

Now, is a LM317 and LM337 better than an ultra-reg with kind of cheap op-amp instead of the OP548 ones (which are gonna cost 20€ each...)?

 

[Pars]

For the n-th time, just build a sigma22 and be done with it. Cheaper to build than the Gilmore supply and just as good. Glass Jar audio will ship you a kit.

 

[bidoux]

Quote:

Originally Posted by Pars /img/forum/go_quote.gif For the n-th time, just build a sigma22 and be done with it. Cheaper to build than the Gilmore supply and just as good. Glass Jar audio will ship you a kit.

Ok

, I think I'll stop annoying everybody with this !