someone upped this on "another" forum...worth a look!!!!!

[slacker]

This thread right here is what the internet is for 

[R.G.]

It will fit in a Hammond 1590DD if you use e-switch 100 series DPDT toggle switches and round pots, as well as a remote rocker pedal.

From Mouser current prices in ones, this costs over $60 for the box, switches, pots, and jacks, exclusive of the PCBs, PCB mounted parts, wiring, knobs, and remote rocker pedal.

It's likely that cost of parts by the time you're done is going to be about $100.

Now I remember why they call economics "the dismal science".

[Keppy]

It will fit in a Hammond 1590DD if you use e-switch 100 series DPDT toggle switches and round pots, as well as a remote rocker pedal.

At the moment, I'm planning to use a 1590D. Same size, but deeper. Better safe than sorry...

I'm gonna poke around on Mouser and see if I can find any 4x5 photosensitized boards so I can etch this in one piece. If anyone has a link to save me some searching, let me know!

[Keppy]

Found 'em. This will make it easier on me. For the one size he sells, though, Steve beats Mouser's price by half!

http://www.mouser.com/Search/Refine.aspx?Keyword=presensitized

[digi2t]

I've been day dreaming of late of a 1U rack unit. Highly Liquid MIDI decoders to control the switching, and pots. Then I can use my FCB1010 to control it.

Dreeeeeeeamer, silly little dreeeeeeeamer.....

[Keppy]

Here is the quick story for you.
Dick Schory worked for Ludwig.  He had some pull in the company because of the Dick Schory Percussion Ensemble which traveled the country on behalf of Ludwig.
He was in a meeting at Ludwig and basically said at some point everyone in the country is going to own a drum and it is time to move into another area.  This actually got the Ludwigs thinking.
So Dick had an electronics guy who designed this unit (I'm getting his name) and instead of the Ludwigs outsourcing the eletronics work they decided to do it all in-house.
They devoted an entire 1/2 floor in the factoy, made it dust free and made all of the components in-house.  Welding the electronics and making the unit.
Bill Ludwig remembers either 500 or 1000 were made and they ended up being to expensive because of the way they were manufactured. They were drum makers not electronics makers.
It ended up costing $450 and they could not sell them.  Once they realized they did not sell, they gave the salesman a few to travel with and if a dealer was mad or unhappy of drum shipments the salesman would give them one of these units.
It was designed with the lights so on stage you knew what it was doing.   He remembers it was also was easy to pack up for travel.
Bill Ludwig III is going to call Dick Schory for me and see i he has any of the schematics or other history.
I have a bunch here, but not handy.  When I start looking I sometimes can spend hours digging through it.
I will do it for you, it might take some time.

The originals cost $450? Adjusting for inflation, you got a steal, Dino!

[Keppy]

Anyone check the taper of the pots yet?

[digi2t]

Anyone check the taper of the pots yet?

Oh... good question. I'm assuming they're linear.

Get it? Slide pot.... linear.....  oh I just kill me!

OK, a bit of decorum now. Seriously, I didn't check, but they should be all linear. When I was measuring the resistances, I didn't notice any humps in the readings. Then again, I wasn't looking for them. The only one that may not be, could be the Bypass Balance pot, but I would think that's linear as well. I mean, considering the application. What do you think guys?

Yeah... 450$, according to the CPI Inflation calculator, that's 2608$ in 2011 money. Not including taxes. Or mojo.

[pinkjimiphoton]

i couldn't tell a linear taper pot if it made me walk a straight line....

most of the pots i was familiar would kinda creep up on ya, does that mean audio taper?

seriously, i wouldn't know the answer...if someone could enlighten me, that would be hip.

i bet rg will say to read the secret life of pots, which i have read and revisited...i think i'm like kelly bundy tho, can only fit in so much info before preceeding info is lost..

[R.G.]

i couldn't tell a linear taper pot if it made me walk a straight line....

most of the pots i was familiar would kinda creep up on ya, does that mean audio taper?

seriously, i wouldn't know the answer...if someone could enlighten me, that would be hip.

i bet rg will say to read the secret life of pots, which i have read and revisited...i think i'm like kelly bundy tho, can only fit in so much info before preceeding info is lost..

Let's try it more simply. A linear pot is just that - linear. Put 9V across a linear pot, turn it to the middle of its rotation, you get (about) 4.5V. Turn it 1/4 of the way, 2.25V.

An audio taper pot  is designed to be the reverse of the human ear's sensitivity. The human ear hears quiet sounds very sensitively, but gets less and less sensitive as the sounds get louder. So to get a knob that produces about equal changes in perceived loudness in the ear per unit of pot turn, you have to have the pot put out very little, increasing slowly in the first part of its rotation where the ear is most sensitive to changes in sound, then come on strong later after the pot reaches "crossover" where the ear is getting less sensitive.

If you put 9V on an audio (also called log) taper pot, turn it to 1/2 way, the output is about 0.9V. You reach 10% of voltage at about half travel.

A reverse log pot does the reverse: at 1/2 the turn, it is already at 90% of the voltage. This is useful in setting oscillator frequency especially.

Did that help?

[pinkjimiphoton]

yes it did indeed. thank you! that was described in a way even my prefrontallobotomized brain could comprehend!!

[pinkjimiphoton]

man, dino, can't wait to hear if your new friend can come up with more documentation!

i'm putting everything i can find on the phase II into a folder, when all is said and done, i'll make it into a zip file and have it hosted somewhere for posterity.

[digi2t]

Yeah, it's gonna be interesting.

In the meantime, I was missing a cable strain grommet on the fall plate, for the harness that goes through the transfo then up to the console. After some research this one works perfect, and looks identical to the other as well; Mouser P/N 836-1517

It's made by Heyco. Got them today, and just installed it, and it looks stock. The only thing left now cosmetically, are the footswitch caps, one handle knob, and the plastic handle trims.

[Keppy]

Does the Bypass Balance pot set the volume of the buffered signal when the effect is bypassed, or am I reading the wiring diagram wrong? Also, is it worth building the stereo out since that's just buffered dry signal?

Here's what I'm thinking of doing:
-Replace Bypass Balance pot with a Master Volume pot
-Leave out stereo jack/switch
-Leave out Lo Z input
-True bypass

I wanted to run these ideas by you guys before making any changes to the design, since I'm the guinea pig and all. Jimi and Dino, do you think these changes will affect the character of the unit as you know it? Would you miss the stereo out or the Lo Z input if they were gone? Do you wish it had a master volume?

[Keppy]

Jimi and Dino, have either of you measured the AC voltage off the transformer yet, or measured the DC voltage at console pad 17? I'm getting ready to order parts for this, and I'd like to know if your units are really running at the stated voltage before I order a power supply.

On the power supply, I've been thinking about that. For a clone, a DC-output wall plug would be a whole lot better. Not knowing how much current it eats until/unless it gets measured on a real or clone, it's hard to design a charge pump to work right. If the current's high, it may be hard to get a charge pump to get to 35V.

I like the idea of running it from a 24Vdc nominal output wall wart. These are cheap and easy to find, and usually have an output that is larger than the stated. I just bought a couple for another project. They put out 31.1V unloaded. The other option is to use a 15-18V AC output wall wart and use diodes and caps to double it to over 35V. Lots of options, not much real information. Mouser stocks 48Vdc output wall warts. That should be OK for the raw power. There's a regulator on the PCB anyway. Just have to make sure it doesn't burn out with 48Vdc in.

Given that the circuit is already laid out for AC power, could we just use a transformer like in the original units? Or would mounting that in the enclosure cause too much hum? Also, what AC voltage would rectify to +36v DC using the existing power scheme?

[Keppy]

http://www.amazon.com/Genuine-LITEON-2100mA-ADAPTER-KODAK/dp/B0050GD7DQ/ref=sr_1_16?ie=UTF8&qid=1307694711&sr=8-16

[Keppy]

This one's cheaper, but I'd have to replace the plug.
http://www.amazon.com/Electric-Scooter-Battery-Charger-Adapter/dp/B004DH15OQ/ref=sr_1_22?ie=UTF8&qid=1307695736&sr=8-22

[Keppy]

Funny, I never noticed until tonight that the note in this picture reveals the model of one of the transistors. Whether TIP29 is the original or the replacement I'm not sure. Does this tell you anything, R.G.?

Datasheet:
http://www.datasheetcatalog.org/datasheet/fairchild/TIP29.pdf

And I promise that's the last post for tonight!

[digi2t]

I will measure the AC and DC voltages tonight. One thing that strikes me as peculiar is that one drawing says +36, and the other +35. But, then again, there are two "Lo Z" pads as well, so I'm assuming it's a typo.

Personally, I'm not quite sure what the Hi Z does yet, but I would retain it, just in case. I run my rig in stereo, so yes, I would keep the stereo. I often run two different signals left/right.

Master volume? DUDE... you're reading my mind. I was messing with it last night, and I was thinking how nice a master volume would be. But, I think that MV and TB would be best left as DIY mods that one could do themselves. There are not complex mods. We could just publish the procedure, and let them decide.

As for the TIP29, loks like a repair note to me.

[R.G.]

Jimi and Dino, have either of you measured the AC voltage off the transformer yet, or measured the DC voltage at console pad 17? I'm getting ready to order parts for this, and I'd like to know if your units are really running at the stated voltage before I order a power supply.

Given that the circuit is already laid out for AC power, could we just use a transformer like in the original units? Or would mounting that in the enclosure cause too much hum?

I recommend putting at least the AC transformer outside the box. This is kind of a moot point, as our political heros have effectively made simple wall transformers illegal. Only switching wall warts are still being made. But it makes good sense to get the AC power outside the box.

Also, what AC voltage would rectify to +36v DC using the existing power scheme?

It has to rectify to more than 36V. The 36V is the zener voltage for the regulator. To be an effective regulator, the raw DC power has to be from a few to several volts higher than that; moreover, the raw DC when it sags down on ripple in the incoming filter has to never get below maybe 38-40V. I can't figure out enough from the circuit to peg the voltage exactly, but I suspect that the peak DC voltage after the rectifiers is in the range of 42-50V. Knowing the transformer volts would clean up a lot of this.

Just looking at the power supplies you show and the circuits, you're going a lot of overkill on power supply current with either one of those. This thing doesn't use much current. Once I know the transformer output voltages, I can do a better job of suggesting a power supply.

Funny, I never noticed until tonight that the note in this picture reveals the model of one of the transistors. Whether TIP29 is the original or the replacement I'm not sure. Does this tell you anything, R.G.?

I think it's a repair note too. It also tells me that my suspicions about the nature of the regulator are right - it's under a fair amount of stress if it's been replaced.  Overall, the power section of this thing looks amateurish, or done for lowest cost. Anything that results in a quiet 35V where the emitter of Q6 is will work OK. I've been holding off suggesting anything more elaborate or different until we find out if the circuits work as shown. The whole console board is fairly simple to replace with modern circuitry, perhaps as little as one CD4049 and one dual opamp.

All of this can be done more compactly and elegantly now, with the advantage of nearly half a century of advances in electronics under our belts. I just populated the boards for my IC version of the modulated filters yesterday. They get tested in the next few days as I have time. It's on a board that's roughly 2x3" and fits an existing rocker pedal.

I will measure the AC and DC voltages tonight. One thing that strikes me as peculiar is that one drawing says +36, and the other +35. But, then again, there are two "Lo Z" pads as well, so I'm assuming it's a typo.

It's not. The circuit is a DC emitter follower to regulate the incoming DC. They went cheap on the main filter cap. That is C11, and it's only 100uF. That means a fairly large ripple voltage from the rectification. So they used a 36V zener as a reference voltage tied to the base of an NPN, Q6. That makes the emitter of the NPN about 0.7V lower, and they called that "35V". There is some tolerance on the zener voltage as well, so rounding to the nearest volt makes sense there for service literature.

Personally, I'm not quite sure what the Hi Z does yet

The Hi-Z and Lo-Z inputs are just that - separate amplifiers with different input impedances. They're all mixed right into the same signal path again after the input amplifiers. I haven't messed with how much gain, speed, response, etc. yet. With the advantage of that half-century I was talking about, the input amplifiers become fairly quaint, as well. The Hi-Z isn't that high, but it's where you'd put a guitar to avoid treble loss. Lo-Z was probably meant for putting a microphone into this, although I can't imagine wanting to do that musically.

But, I think that MV and TB would be best left as DIY mods that one could do themselves. There are not complex mods. We could just publish the procedure, and let them decide.

There's lots of cleanup and modification that would better suit modern use, once it's clear that the filters and modulation as shown work.