Spencerleehorton

24v/48v PSU Halfwave rectified vs Fullwave
« on: May 21, 2020, 09:21:58 AM »
Hi All,

Just wondered whether a halfwave rectified PSU (double the caps values from the fullwave version) is the same as a fullwave version, or there is some difference in the ripple (hum) produced?

Im rebuilding a Neve PSU which has a mod version of the SSL 9k PSU and the 48v side has failed, Im using a single turn secondary rather than 2 secondaries, didnt know if i was wasting my time in the long run to upgrade to fullwave?
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!


Spencerleehorton

Re: 24v/48v PSU Halfwave rectified vs Fullwave
« Reply #1 on: May 21, 2020, 09:22:58 AM »
halfwave version, did i do that right?
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Re: 24v/48v PSU Halfwave rectified vs Fullwave
« Reply #2 on: May 21, 2020, 12:10:04 PM »
Both power supply circuits that you posted are full wave rectified. If you only use one diode then it would be half wave, and in that case you definitely have more ripple.

Spencerleehorton

Re: 24v/48v PSU Halfwave rectified vs Fullwave
« Reply #3 on: May 21, 2020, 10:23:38 PM »
ah ok, whats the avantage or disadvantage of using single secondary winding to feed diodes as opposed to two AC feeds and a 0v?
I thought a single secondary winding was halfwave? as in a 24v and a 0v AC.
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

scott2000

Re: 24v/48v PSU Halfwave rectified vs Fullwave
« Reply #4 on: May 21, 2020, 10:37:56 PM »
ah ok, whats the avantage or disadvantage of using single secondary winding to feed diodes as opposed to two AC feeds and a 0v?
I thought a single secondary winding was halfwave? as in a 24v and a 0v AC.

Decent info here...

https://www.hammfg.com/electronics/transformers/rectifier

PRR

Re: 24v/48v PSU Halfwave rectified vs Fullwave
« Reply #5 on: May 22, 2020, 02:48:23 AM »
> Decent info here...

Hammond persists in posting that rubbish.

Fer example: how can a CAPacitor have precisely different peak and average? 0.71 and 0.45? Yes they are different but by the ripple action which is not remotely covered in that image.

Spencerleehorton

Re: 24v/48v PSU Halfwave rectified vs Fullwave
« Reply #6 on: May 22, 2020, 05:01:31 AM »
Doesn't really answer my question which is better and why?
I'm interest in what's the best way to build a psu to have as little ripple as possible.
I have some single winding 24v txf and double winding 12v  txf.
Using a diode bridge seems to be the best way.
And using a 0.1uf then a 1000uf, then 78xx or lm317/783 then 1000uf, 0 1uf.
Then the appropriate resistors and caps on the adjust leg.

By just changing the power txf what would the advantages disadvantages be?
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

scott2000

Re: 24v/48v PSU Halfwave rectified vs Fullwave
« Reply #7 on: May 22, 2020, 07:55:28 AM »
Doesn't really answer my question which is better and why?


Sorry...Was trying to point out the full wave/half wave differences...

I have some single winding 24v txf and double winding 12v  txf.
Using a diode bridge seems to be the best way.

Confusing a bit what you are trying. The first drawing uses a 40vct transformer ? Do those caps raise the power?


> Decent info here...

Hammond persists in posting that rubbish.

Fer example: how can a CAPacitor have precisely different peak and average? 0.71 and 0.45? Yes they are different but by the ripple action which is not remotely covered in that image.

I'm too inexperienced to fact check.... Maybe I should've posted in the Brewery first.... ???
« Last Edit: May 22, 2020, 09:50:43 AM by scott2000 »

Re: 24v/48v PSU Halfwave rectified vs Fullwave
« Reply #8 on: May 22, 2020, 02:36:45 PM »
Doesn't really answer my question which is better and why?
I'm interest in what's the best way to build a psu to have as little ripple as possible.
I have some single winding 24v txf and double winding 12v  txf.
Using a diode bridge seems to be the best way.
And using a 0.1uf then a 1000uf, then 78xx or lm317/783 then 1000uf, 0 1uf.
Then the appropriate resistors and caps on the adjust leg.

By just changing the power txf what would the advantages disadvantages be?

Full wave is better since you need a smaller capacitor than using half wave to obtain the same ammount of ripple. Full wave with a bridge makes better use of the transformer voltage, since full wave with only 2 diodes will output the half the voltage of the transformer secondary , both have the same ripple characteristics thou. So yeah, the best way to go is usually with a bridge rectifier.

Spencerleehorton

Re: 24v/48v PSU Halfwave rectified vs Fullwave
« Reply #9 on: May 22, 2020, 05:27:54 PM »
Is the second schematic correct?

Does it feed the upper 48v correctly?
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!


 

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