F5 power amplifier

[AlanElsdon]

Thank you all for the replies - since I have a bunch of CL6's I will initially try two of them in series on the Neutral feed.

Would it be better (in general terms) to go for twin primaries with the suggested series CL6's between the windings rather a single primary with the sereis CL6's on the neutral line?

I ask as I am about to order some more transformers for the F2.

Alan

[AndrewT]

no,
use a single primary where you only have access to a single supply voltage.
Twin primaries increases the cost and possibly the field leakage.

Keep in mind that most transformers are available as 230:Vsecondary, but your supply varies between 216Vac and 254Vac.

You have typed CL6 again.
What is a CL6?

[AlanElsdon]

Originally posted by AndrewT
no,
use a single primary where you only have access to a single supply voltage.
Twin primaries increases the cost and possibly the field leakage.

Keep in mind that most transformers are available as 230:Vsecondary, but your supply varies between 216Vac and 254Vac.

You have typed CL6 again.
What is a CL6?

Silly me - should be CL60.

On the mains side I wish people in this country would make the transformers for 240v - at least it would keep the transformer outputs closer to the required values. I usually find that the mains is higher than 240v - cannot say that I have seen very low readings. Either that or have lower secondaries and hope the mains voltage is high.

Thanks for the primary info.

Alan

[vdi_nenna]

Is using a bridge rectifier with 50v PIV and 25 amps too small for the F5? The recommended F4 PS schem says 35A 200V.

If we are looking at 18v off the transfo taps, is 50V a safe enough margin?

Thanks,

Vince

[Babowana]

Originally posted by vdi_nenna

Is using a bridge rectifier with 50v PIV and 25 amps too small for the F5? The recommended F4 PS schem says 35A 200V.

If we are looking at 18v off the transfo taps, is 50V a safe enough margin?

Since the peak inverse voltage is rated at 50V, maximum RMS bridge input voltage is to be no more than 35V(rms). So, I think the bridge questioned is considered acceptable with the 18V(rms) input.

[AndrewT]

18+18Vac will develop <=60Vdc across the rectifier in worst case conditions.
Using a 50V rectifier is risky, just as using 25V capacitors is risky.

[h_a]

If the bridge blows, caps may see reverse voltage and may explode in the worst case. Wether your speakers will be happy with the fed funny signal is also hard to say.

If only half the bridge blows (and goes open), you get most likely nice DC at the output.

Believe me, you don't want a blown bridge.

Go for a larger voltage rating.

Have fun, Hannes

EDIT: only blown Schottky bridges are more fun, they usually short.

[vdi_nenna]

Just a shot in the dark, but I calculated 18+18=36 * 1.414= 50.904v peak.

or 24*=48 * 1.414 = 67.87v peak?

[AndrewT]

allow for regulation and allow for maximum mains supply voltage.

[Babowana]

Originally posted by vdi_nenna

a shot in the dark . . .

Your doggie is cute . . .