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nbabmf wrote:A simpler solution would be to add a DC jack right where the transformer output is and use a Dunlop 18V adapter. The voltage regulator wont't have to work nearly as hard to step it down to the 13-15V those BBDs want to see and you won't get any weird noise from a LT1054 voltage doubling board.
Mind going more into that a bit? You mean removed the transformer, and connect the dc jack to the board (where I have circled in the above pic)? Seems too simple, lol. Why would I only need an 18v adapter (aren't they 24v)?
The actual effect circuit runs off 15V. The transformer steps 110-120VAC down to 24VDC, then a voltage regulator (NE5554) steps 24V down to 15V. You can feed the NE5554 less than 24V and it will still put out 15V.
I love the smell of solder in the morning.
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nbabmf wrote:The actual effect circuit runs off 15V. The transformer steps 110-120VAC down to 24VDC, then a voltage regulator (NE5554) steps 24V down to 15V. You can feed the NE5554 less than 24V and it will still put out 15V.
Ok see that's what was throwing me off. So then I need to wire the dc jack to the board and just leave the volt reg be? I literally only need a power jack for this? (i have a 24v ehx supply for 'my' other memory man already).
nbabmf wrote:The actual effect circuit runs off 15V. The transformer steps 110-120VAC down to 24VDC, then a voltage regulator (NE5554) steps 24V down to 15V. You can feed the NE5554 less than 24V and it will still put out 15V.
There's no on board regulator, it's performed by the diodes instead which wont be so forgiving in just giving out 15V, a regulator would need adding, yes a viable option, but the LT1054 (which might add heterodyning but shouldn't with proper precautions) would allow the effect to run off a 9V daisy chain which is the benefit to it.
And don't forget you still need to provide Bi-Polar power, not just straight.
Since there's no regulator, I don't think there's going to be a bipolar supply. That's what the NE5554 was for, right? I presume it was to provide a clean headroom to the op amps responsible for buffering and blending, since those delay chips don't need it.
I love the smell of solder in the morning.
Successful dealings with: blooghost, starcastic, bronzetalon, theavondon, absent, jero, sevenSHARPnine, magiclawnchair, oldangelmidnight, and others that I can't remember lol
nbabmf wrote:Since there's no regulator, I don't think there's going to be a bipolar supply. That's what the NE5554 was for, right? I presume it was to provide a clean headroom to the op amps responsible for buffering and blending, since those delay chips don't need it.
Hmm i'm not so sure, Notice the 3 wires to the board from the transformer, not just two, I will admit that this isn't my strong point with all the shrouded information about this unit about and multiple versions but this is EHX we're talking about, them re-designing something without having to is pretty unlikely in which case the Op-Amps still need Bi-Polar because that's how they've been designed to run. The regulator just took it down to 15V and nothing more because that was the limitation of the chips but also the optimal voltage to run them at, hence the strange supply voltage.
The delay chips don't 'need' the higher voltage but they certainly run better on it and get more headroom, alot of vintage effects using the 300X series run at higher voltages for this reason, the 320X came along and ran happier at lower voltages so was more suited to stompboxes but that's why people say the 300X sound better because they're getting more voltage usually.
