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Messages - reddesert

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Open Discussion / Re: Disappointed by the modern flangers
« on: February 09, 2019, 03:44:44 AM »
If you have a couple of SAD1024's like I do can I just swap out the MN3007 or do some other tweaks have to be made? How about the MN3006 as well? Can I just swap it out for one without additional tweaks?

Definitely don't do this. They have different pinouts and numbers of pins, but more importantly they have opposite polarities and you could fry the chip. The MN3007 uses P-MOS devices and requires a negative supply voltage, while the MN3207 and SAD1024 are N-MOS and use a positive supply (but the voltage requirements are different too: the MN3207 wants max +10V and the SAD1024 is supposed to operate off +15V). Someone more expert than me with analog delays, flangers etc will have to tell you more about the differences in clocks, signal filtering, etc, between circuits using the different devices.

Open Discussion / Re: Big Island recommendations?
« on: January 31, 2019, 01:27:21 AM »
The landscape on the Big Island changes wildly from one part to another, so make sure to spend time in different areas. Anywhere you go, stop to enjoy the vegetation, birds, etc. Find little beaches at the end of roads and hang out.

The Kohala coast in the northern tip is relatively little visited (compared to the rest of the island anyway) and really scenic.

The Waipi'o valley overlook in the northeast is famous for good reason.  Maybe a bit too famous, but worth the trip. If you're up for a short but fairly strenuous hike, you can walk down the road (super steep but not super long) and then out a muddy road/path to a black sand beach in an incredible setting. I do not recommend trying to drive the road or the path. If you aren't up for walking it, just enjoy the view.

Volcanoes NP has many different cool things. You used to be able to walk close to a big crater in the Kilauea caldera, but I think that is closed due to eruptions. I did not have a chance to do the walk through the (extinct!) lava tube, bet that is cool. Depending on the state of the lava flow, you may be able to drive to the end of the Chain of Craters road where it has been cut by lava flow. If the lava is flowing slowly and not into the ocean (steam explosions!), as of a few years ago you could walk inland to where the lava is flowing and practically up to it. I would describe fresh, slow flowing lava as "so hot even teenage boys don't do stupid things around it." The NPS put little markers on the old cooled lava to show you where to walk. The walk can be very hot during the day. We bought cheapo flashlights, took water bottles, and walked it in late afternoon so we saw glowing lava at dusk, then walked back in the dark. Incredible.

Before you go I recommend reading a little bit about the history of Hawaii, and how it came to be part of the US. Many guidebooks have some history info, and here are some good wiki articles:
It's not a pretty story. It's good to understand a little bit about native Hawaiian culture and where they are coming from to appreciate many of the historic sites around the island and the issues that linger today.

Open Discussion / Re: Just Saying -- the soapbox thread
« on: January 30, 2019, 01:13:34 AM »

Brian, I found some inspiration for the next Moodring revision. Skip to the tunnel section.

That demands a new pedal design - the Plug'ole.

Also, getting close to the edge of that thing, NOPE.

Open Discussion / Re: TSV808
« on: January 30, 2019, 12:46:30 AM »
Hmm, Looks like it's bufferless. Wont that detract from some of the 808'ness

"The TSV808 employs a refined version of the original Tube Screamer circuit: Instead of four stages like the Tube Screamer (buffer -> overdrive -> tone -> buffer), the TSV808 contains three stages (overdrive -> tone -> +7dB gain boost). The end result is an ultra-smooth drive that retains the Tube Screamer’s trademark mid bump; however, it opens it up with the full-range clarity of the Jan Ray."

Bufferless TS -> Son of Screamer and Hermida Zendrive family of circuits.

Open Discussion / Re: Ultimate GW score. Wish it were mine
« on: January 27, 2019, 11:56:40 PM »
That's awesome. I have mooned after the JC-120 since seeing one in a music store in the 80s. They are way too big and loud for someone of my playing ability, but fantastic amps.

The Goodwill auction site is a little dangerous in a time wasting sense. You can spend a lot of time on it and find bargains, or sometimes partially broken junk. I live in Arizona too and the local Goodwill auctions all the good stuff, but they won't ship overly big or fragile things, which seems reasonable - I mean it's a little weird how we're shipping each other's castoffs around the country. Luckily, that means I was able to win a decent synth (nothing incredible, a DX21) relatively cheaply.

Open Discussion / Re: Strat body built out of 1200 colored pencils
« on: January 08, 2019, 08:47:30 PM »
It has laminated wood ... and glue ... Oh noes its's a plywood guitar!  It's a Teisco burn it!

Nice video of the build, some clever fixturing in there.

EBK, many Danelectros had a Masonite top and back over a wood frame - that's close to MDF, but possibly somewhat harder than MDF.

Open Discussion / Re: Me = Super Dumb
« on: December 14, 2018, 12:48:18 PM »
lars -- Boss used tip-ground power because you can get sleeve-switching power jacks (for the battery to disconnect from circuit when external power is used), but tip-switching jacks are a bit more uncommon.

Yes.  Back in the 80s, say, lots of people used 9V batteries in pedals (many people also owned just a few pedals), and the battery power had to be switched off by the usual input jack arrangement of using the sleeve and ring connections.  That switched the ground. In order to lift the battery from the circuit when a wallwart was used, the positive connection had to be broken. If you look at how a barrel jack works, it's a lot easier to push the outside connection away to break the sleeve connection, so the sleeve became positive. I think this design drove Boss to use a negative tip adaptor, that is I think the negative tip adaptor started with the classic Boss mini pedal series and did not exist before, but I could be wrong.

Also back in the 70s or 80s, wallwarts were more expensive and people had fewer devices/gizmos, so one really didn't have a lot of wallwarts and the chance of grabbing the wrong one was probably smaller.

Open Discussion / Re: Just Saying -- the soapbox thread
« on: November 22, 2018, 01:10:19 PM »
I look up how to do simple programming tasks on stack overflow all the time (partly because I have to proficient in more than one language and get the methodology of simple things confused, plus python2 -> 3, etc). However, it's because I have years of programming experience that I can translate the stack overflow answers into an efficient application to my problem. If one only copies, one won't learn nearly as much. This is the essence of homework - by definition, you're doing something that has already been solved, somewhere. That may be tedious at times but it's necessary for practice, like playing scales, or building a Fuzz Face before you tackle a Lovetone.

P.S. Happy American Thanksgiving, everybody!

General Questions / Re: Hotcake project?
« on: November 20, 2018, 02:59:48 PM »
A bit of circuit discussion: There are some more threads on freestompboxes, including one quoting a letter discussing the circuit from Paul Crowther, the original designer.

Open Discussion / Re: Just Saying -- the soapbox thread
« on: November 19, 2018, 09:26:13 PM »
And beware of German owned supermarkets, and supermarkets in Germany in general. For some strange reason German grundlichkeit does not seem to apply to maintaining as many open registers for their customers as possible, but as few as they can get away with.

Don't get behind me in the self checkout line of a European supermarket!  I will have managed to screw up pre-weighing my produce at the separate weigh station, cause a nuisance because I'm trying to buy wine and need to be ID'ed or it's the wrong day or God only knows what, and generally fail to understand what is going on even though I nominally speak a little bit of the language. I'm better off taking my chances with the cashier and only half-understanding the conversation.

Also, after being conditioned (by Germany and maybe Italy) that shops, restaurants etc prefer cash and paying with a credit card is a big production that you only pull out at the department store, I was then a bit stunned to find out that it's not unusual for shops in the Netherlands to be cash-free. Is this really a major cultural difference between the countries or more a rapidly evolving generational thing?

Open Discussion / Re: Understanding Ring Modulators (Physics article)
« on: November 17, 2018, 04:56:21 PM »
Oh god, imagine the Klon snobs if it comes out that THE perfect mystery diode sound can be found at 78 kelvin.


What the world needs now is the Cryobender. It's time for someone to use a microcontroller to thermally regulate a germanium-transistor pedal for consistent performance.

As I write this, I'm surprised that it hasn't already happened.

Open Discussion / Re: Understanding Ring Modulators (Physics article)
« on: November 16, 2018, 12:03:44 PM »
Huh, we never got to do anything so pedal-worthy in physics lab!  (We did fry several op-amps, learn breadboarding and some electronics, which I have been coasting on ever since ...)

The voltage drop (band gap) of a semiconductor gets larger as it gets colder, for ex, so as you immerse your clipping diodes in LN2, your circuit should get louder and cleaner.

LN2 is a nuisance to deal with, but a thermoelectric cooler can get you well below zero with care. Be the first pedal maker on your block to put a heatsink the size of a 125B on your pedal board.

Open Discussion / Re: Sunn Beta from FSB
« on: November 12, 2018, 09:40:57 PM »
There is also a vero layout at tagboardeffects:

Open Discussion / Re: Long term memory - WTF
« on: November 10, 2018, 04:19:55 PM »
Otherwise, I'd be more inclined to file that in the "getting old sucks" bin, which I am all too familiar with!

In case you are interested, here is a recent interview I did on why we forget names:

That and your line of work are very cool.

I feel that there are certain areas where I have very vivid memories, and often, I think, these were formed during a heightened state of attention.  For me a lot of the time that has to do with outdoor activity (cycling, hiking, climbing type of things). Because I like what I'm doing, but also, I think, because it requires a lot of attention at the moment the memory is being formed. Like everyone, I also sometimes forget people's names immediately after introduction, or which of my friends told me  a story or which I told a story to, and I think that's related to distractions and not paying as much attention in the moment.

General Questions / Re: Phase 90 dominant pole compensation
« on: November 08, 2018, 02:57:34 PM »
The Tractor Beam schematic is kind of spaghetti ... but the relevant parts are decipherable.

It uses the zener as a sort of poor man's voltage regulator to provide a Vbias. The large electro cap across the zener should stabilize Vbias. The intent is possibly to reduce noise in Vbias from either power supply noise or LFO ticking.

The TB output mixer stage is different from the Phase 90 because it uses a mix pot, some mixing resistors, and a Level trimpot to adjust the gain of a typical op-amp amplifier. It probably would work with any "modern" op-amp, not just an OPA2134. By "modern" I mean anything from a 741/1458 onward. These op-amps all have tiny internal compensating capacitors to decrease gain at high frequencies (well above the audio range). The LM308 was designed before semiconductor fab could squeeze these little capacitors onto a chip, so it needs an external compensating cap, which serves a function sort of like that cap across the base and collector of the transistor.

Whether this feedback cap rolls off the audible highs of the P90 would depend on the value, and it's something one might have to experiment with to adjust to taste.

The Miller effect refers to the phenomenon that a capacitor in the feedback loop effectively has its capacitance increased by the gain of the amplifier:

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