Spring Reverb Driver Power Supply Question

[patrick398]

I plan on building a spring reverb unit using this driver from Tape Op magazine




I drew up a layout for vero but i'm a bit stumped as to how to get +-18v. Would i be able to use a 18VDC power supply into a couple of 18v regulators, one wired normally the other backwards...like this?



But surely the driver far exceeds that current rating?

My other thought was to use a 7660S but i think it's maximum voltage rating is like 13v or something

[Mark Hammer]

An LM1875?  That's pretty hefty for feeding a reverb pan with maybe only 1W or less.

Does the article provide a rationale for using such a power-amp chip?  I'm not disputing it, but presumably there was some sort of justification for not using a low-power headphone amp chip, so I'm curious.  And what sort of pan is it going to be driving?

[patrick398]

I'll have to re-read the article...however annoyingly it seems to not be free anymore, requires a subscription to the websites archive section. Luckily i printed it out.
I seem to recall it saying something about the importance of driving the tank as hard as possible...this is new ground for me so i don't understand why but fairly sure i read that.
It also talked about this circuit being designed with the intention of being able to use a wide variety of tanks. I'm yet to take the plunge but looking for a big accutronics tanks on the bay

*edit: This is the one i was looking at the other day. https://www.ebay.co.uk/itm/Accutronics-Reverb-Tank-4BB3C1D/162121940999?hash=item25bf388007:g:a6sAAOSwGWNUXKlx

[PRR]

"as hard as possible", so why not a 100 Watt Marshall?

Anything close to 30V total ought to be ample enough to rock. (More drive than Mr Dale has.) Regulation is pointless; indeed the Hampton plan anti-regulates with resistors in the rails. The chips have ample PSRR.

K.I.S.S.


The 1N4001 would work, but you should not be buying them. The 1N4007 is same-price and good for many more things.

[patrick398]

That's great, thank you. I am a little confused however, how is there 18v (maybe 16v) on the output when there's only 12v on the input?

[noisette]

It´s 12ADC but +/-18VDC.
Since it is AC, the positive side of the waveform can be rectified to positive DC, and the negative side of AC wave to negative DC. When rectified the DC voltage rises to X1.414 of the AC input.

[patrick398]

Amazing, thanks. I've been reading about rectification recently, must go back over that

[noisette]

It´s 12ADC but +/-18VDC.
Since it is AC, the positive side of the waveform can be rectified to positive DC, and the negative side of AC wave to negative DC. When rectified the DC voltage rises to X1.414 of the AC input.

It´s 12VAC at the input, had a typo there...