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Messages - Rockhorst

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Whine changes with delay pot, goes supersonic when turning delay time down.

4558 closest to the jacks
Pin 1: 5.5 V
Pin 2: 5.5 V
Pin 3: 5.5 V
Pin 4: 0V

Pin 5: 0 V
Pin 6: 10.6 V
Pin 7: 11 V
Pin 8: 11.6 V

4558 middle of the board
Pin 1: 4.2 V
Pin 2: 4.2 V
Pin 3: 4.2 V
Pin 4: 0V

Pin 5: 5.8 V
Pin 6: 4.8 V
Pin 7: 11 V
Pin 8: 11.6 V

So that looks like both the b-sides of the chips are not doing what they should be doing.

Only had time for a quick power test. When powering the effect you clearly hear a high pitched whine that starts up almost immediately and persists. This is usually followed a few seconds later with static noise (from a delay line?). No audio probing yet, that's going to be the weekend.

[one thing I noticed is that approaching the -24V probe to the center tap produces a little spark between circuit board and probe. The outer tap does not]

Open Discussion / Re: Going for broke (healthy eating thread)
« on: February 11, 2019, 05:19:13 PM »
A steady weight loss of no more than 1 kg a week is 'healthy'. I can't diet for shit. I need to do sports with it, but I find less and less time (and motivation) to get into it. I have a racing bike and I should start somewhere this month for cycling to work in the spring (30 km one way). Hoping to drop 10 kg again this summer.

Anyway, that plateau is nothing to worry about. You went down fast, maybe too fast, initially. Your changing your lifestyle, takes time. Think about how it makes you feel better, that's the important part for now.

Thanks for chiming in Scruffie :)
The reason I mentioned mods is that I saw some components that aren't on the circuit board but rather fly over it. I just assumed they where added later.

Which terminals should I attach the 24V supply to? Referring to picture 03 in my original post, I would say that the top wire is for the ground terminal (outer sleeve of adapter)? Center tap is for the LED, so -24V on the bottom connection in the picture? Power is then very crudely rectified by those 2 diodes, right?

Open Discussion / Looking for help with an actual vintage EHX Memory Man
« on: February 10, 2019, 05:52:11 PM »
note: pictures of the unit attached.

Someone sent me an early EHX Memory Man hoping I can repair it. I'm a bit apprehensive to start working on it, so I hope someone with experience with these units can help me out a bit. It looks like there have been some modifications over the years, the transformer is dead and there's a loose wire coming from the boost switch. No clue if the delay chips are still good. Still looking for a verified schematic for this particular unit.

On the EHX forum I found that a replacement transformer for the DMM is the F-115X which Mouser carries. I'm going to compare some specs, but I expect it will work with the MM as well. I have a EHX 24V center positive wall wart, was wondering if I can use this to test the unit before buying the transformer.

Any other suggestions for testing the unit are very welcome.

Open Discussion / Re: Ibanez Super Metal SM-9
« on: January 28, 2019, 03:53:09 PM »
Tiny update: I've bought a second hand Maxon 4-knobber for some real life testing. Will keep you posted :)

Open Discussion / Re: NPN Rangemaster Transistor by mistake. Now what?
« on: January 16, 2019, 09:19:23 AM »
NPN or PNP doesn't really influence the sound and both can make excellent rangemasters. They just need a different circuit (or some tweaks) like Timbo suggested.

Open Discussion / Re: Ibanez Super Metal SM-9
« on: January 14, 2019, 04:00:12 PM »
Well mostly I've been swamped with work for the day job and will be so until mid February. Any spare time goes into staying sane, taking care of my kiddo and (hopefully) finalizing some new Nucleon projects that where supposed to come out past November. But this is still on my radar :) I'm actually more curious about that 4 knob Maxon. From the demos I've heard it seems a bit more my cup of tea. Might buy one to attempt a trace.

Open Discussion / Re: 2013 Harbinger One
« on: January 06, 2019, 04:31:20 PM »
I've built both and they work equally well. So don't let that 2013 board go to waste, I'd say.

Open Discussion / Re: Ibanez Super Metal SM-9
« on: December 28, 2018, 11:11:15 AM »
The tone control is interesting for sure. And it's nice to see Ibanez/Maxon used a buffered output on the pedal. It definitely has a few things going for it looking at the schematic. I also saw Maxon has a 4-knob metal distortion that seems a derivative of this thing (called the SM-9 Pro +).

I might whip up a PCB in the coming week if there's any interest in it, how about that :) Let me know below

Open Discussion / Re: Ibanez Super Metal SM-9
« on: December 27, 2018, 05:54:05 PM »
I think that this...
Everybody loves the Boss HM-2 and it seems to be fairly similar circuit. a controversial statement at best ;)

I DO love the records that the thing was/is used on, but that's not in the pedal that's in the songs.

Tech Help - Projects Page / Re: Harbinger One - Rate LED not flashing
« on: December 23, 2018, 04:35:22 PM »
Don't know what was wrong, but I replaced the 1uF electrolytic with a similar one and now it works fine.

Tech Help - Projects Page / Harbinger One - Rate LED not flashing
« on: December 22, 2018, 10:21:20 AM »
Two questions:

1) what's the benefit of the buffered rate LED circuit in the 2015 Harbinger compared to the old version? Is it to prevent ticking?

2) I subbed a BC560C for the 2N5087 in the rate LED circuit and the LED doesn't flash now. It does sometimes, but usually is just permanently on. Maybe I see a very faint flickering. Could this be due to the substitution? I looks to me like the 1uF cap may be charging up to quickly and the potential not going down anymore. Maybe subbing a smaller cap will fix it, but maybe there's other ideas?

Other than this, the build is working fine by the way :)

General Questions / Re: 50kC to 25kC Pot Mod?
« on: December 18, 2018, 03:24:10 AM »
Some info on the particular circuit would be helpful.

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