A build similar to EHX LPB-3?

Started by Focalized, September 07, 2024, 08:12:17 PM

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Focalized

There's plenty of boosts and I have layouts for a six band EQ (no boost pot) and the Boss 7 band I might try. Any vero or perf layouts similar to the new LPB-3 that might be worth trying over the two EQs I mentioned?;

Mark Hammer

In the spirit of form-follows-function, what do you need it to do for you?

ElectricDruid

Quote from: Mark Hammer on September 08, 2024, 09:03:17 AMIn the spirit of form-follows-function, what do you need it to do for you?
Good question!

I also noticed the arrival of this boost-on-steroids, and had a go knocking up a workalike schematic. I got it all, pretty much, except for the hi/lo Q switch for the mids. I'm sure they've done that the simplest way possible, but I couldn't work out exactly what that would be. Most of the details you need are in the promo blurb, but what the Q's are is not something they mention.

Here's my version:




Mark Hammer

T'were I, I'd avoid that straight wire link in parallel with R13.  ;)

ElectricDruid

#4
Quote from: Mark Hammer on September 08, 2024, 11:37:33 AMT'were I, I'd avoid that straight wire link in parallel with R13.  ;)

Hey, there's a note on the schematic about that! It's a closed switch...ok, I know it doesn't *look* much like a closed switch, but *electrically* I think you'll find they're pretty similar!! ;)

The bigger ommision is the power supply. The EHX version uses some kind of 18V power supply, so we need either one of those bipolar power modules, or (equivalently) a charge pump chip doing the same job. For the sim I was mostly interested in getting the frequency response and gain right, so there's no mention of the power supply anywhere. These ideal op-amps can put out 10KV if you want them to! (or even if you you don't!!)

Focalized

Didn't notice it being 18v. I'll probably try the GE7 layout as it's a solid EQ. Been hoping to find a great deal on a MXR 10 band on eBay.

Rob Strand

#6
Quote from: Focalized on September 08, 2024, 06:49:50 PMDidn't notice it being 18v. I'll probably try the GE7 layout as it's a solid EQ. Been hoping to find a great deal on a MXR 10 band on eBay.
I think it boosts 9.0V DC on the DC  jack to +/- 15V DC internally.
Send:     . .- .-. - .... / - --- / --. --- .-. -
According to the water analogy of electricity, transistor leakage is caused by holes.

ElectricDruid

Quote from: Rob Strand on September 08, 2024, 10:59:56 PMI think it boosts 9.0V DC on the DC  jack to +/- 15V DC internally.

Checking their website, Rob's right. They say:

"internally extended 30V power rails for enhanced headroom"

which sounds like +/-15V to me!