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The TC1044 doesn't take 15v though, I was hoping to be able to power a synth filter which needs bipolar 15v

Hi there, does anyone know if the LT1054 will work in the fatpants? It has an operating voltage of up to 15v and the osc frequency is from 15khz to 35khz on 3.5v to 15v so I assume when running at 9v the freq will be out of range? Pin 1 on the LT1054 is different to the MAX1044, where it doubles the osc freq range when connected to pin 8 so its out of hearing range.

from the datasheet about pin 1 on the LT1054

"The feedback/shutdown (FB/SD)  terminal has two functions. Pulling FB/SD below the shutdown threshold
(≈ 0.45 V) puts the device into shutdown.

FB/SD also is the inverting input of the LT1054 error amplifier and, as such, can be used to obtain a regulated output voltage."

Will I need to cut the track between pin 1 and 8 on the iC?

Also will it be the same story with the Roadrage boards?

One more thing, I plan to use a roadrage board with this chip which accepts 15v dc to supply bipolar dc for powering a synth module (vcf) and am wondering if someone can confirm if thats going to work?

All signs point to yes but with my noob brain I can't be sure....


This is the cheapest option for me in NZ, smallbear at 1.70 (MAX1044 from futurlec and smallbear are 3.50 and the LTC1044 from futurlec are 3.90)

cheers
Andy

I'm thinking of saturation in the style of driving tape too hard, but being able to control what frequency this happens at, so if you had a 3 band tone control / eq before a tape machine you could choose which band overdrives the tape, so either the bass, mids, or trebles can be overdriven and the rest of the signal remains relatively unaffected. At the same time this overdrive compress the rest of the frequency range a little so becomes more attenuated.

Drum machines tend to sound a bit thin when running them direct, but the same could be said for any digital signal, so an overdrive or saturation with compression helps fatten the sound and make them punchier in a way that is very endearing to the drum machine or standard or percievably thin sounding signal.

So without having to take a reel to reel, which are usually quite heavy, to gigs I am wondering if this can be 'emulated' in a similar way to what heaps of VST plugins have done digitally, but with an analog circuit. (VST's which do this well, which are all free, are the Acrobatics Rombo, Digital Fish Phones Blockfish, and the AtomSplitter Audio Distroyr).

Maybe a sweepable tone control would be the way here, they needn't be separate, but some method of choosing which freq range the saturation would occur, possibly for the pre eq, and for the post, ideally more of 3 band type, but a tone control could suffice if it was 'wide-band' enough. I'm all for use-ablity so if single tone controls could do it...

Does the Serendipity behave in this way?

I feel like it would be a popular device especially if it could be built or had for less than the units which are currently availble go for. AFAIK units include the Emperical Labs Fatso, Anamod ATS-Analog Tape Simulator
Hi-Fi dirt boxes in a way. With so many people wanting analog 'warmth' and old school A/D conversion from old MPC's for instance for 'fat' drum sounds, I imagine something like this (mono though, but full bandwidth) would be in demand from DIYer's.

The Fatpants I've build and modified to be a little darker has this effect of fattening and warming drum sounds / loops, but is a little limited and maybe cuts a little too much out of the very bottom end, although that seems to be the key to fat drums, that roll off of the very low bass frequencies (<50, 60hz)

Andy

Roughly in that order... Is there an overdrive project anyone knows of that has a similar signal flow to this?

I'm after lots of 2nd order harmonics (I think) and a sort of adjustable saturation frequency control. There's a VST plugin called "Blockfish" which I'm always in danger of over-using, which is a compressor (amount and response (attack decay) controls) and saturator and am wondering if this sort of thing can be made into an analog hardware unit.

I want something that kindof warbles on the low frequency stuff rather than distoring, something that would make a drum machine wish it was married to.

Tape's not an option, but from my limited knowledge I'm thinking FETS, compander, germanium.

Is this sort of effect already available on one of the existing boards? It's kindof a dream effect for me, aside from some sort of glorious delay incarnation

Andy

Awesome work man! This is great news

What do you think is the best way to implement this into the 'box'? A portion of proto-board?

I'm about to order some parts so may as well 2 birds... (actually probably about 6)

this thread too

http://www.diystompboxes.com/smfforum/index.php?topic=68582.0

sorry if you've been there already..

"One buffered 4047 drives 4 x MN 3005 in my Yamaha E1010"

You must have read this thread?

http://www.diystompboxes.com/smfforum/index.php?topic=87831.0

My guess is if we were using 2 3005's and an mn3102, it would sound much cleaner.

"The Yamaha E1010 delay which uses 4 x MN3005, has a low pass filter after each bbd, and each bbd has it's own bias trim. The clock to each bbd is also buffered by it's own TC4049, wired as 2 x 3 inverters in parallel."

It seems both 4047 and 4049 have been used as clock chips

http://www.4shared.com/file/30199724/5425cbd6/1010a.html
http://www.4shared.com/file/30199692/5f70dd1f/1010b.html

I've used v3102 (wouldn't know how or where to use anything else....)

Josh did you try a voltage regulator at R19?

Yes, 2 out of 3 that I've made, that seem to work properly (as good as can be), are very dirty but its not a bad sounding dirt, the filters take the harshness off nicely. Its a different league compared to the AD150 I have (300ms MN3005 running on 18volts) which is almost impossible to overdrive.

The most recent one I've made isn't quite working properly, not sure at all about it... is very dark and overdriven, sounds like an overdrive pedal, which in the right hands can sound pretty cool, but its not subtle. Still a work in progress that one!

I'm in the same boat here, there is more headroom in a pt2399 echo base I've made which is running on 5v. I have 2 more of these to make with the ddt boards so appreciate your research efforts.

Perhaps interestingly, I've read the mpsa18 is quite a high gain transistor and have read suggestions of peeps using (mostly reported in making wah pedals sound more vintage) bc109c and bc550 which have lower hfe? values resulting in a softer and perhaps noisier but less edgy sound. Grain of salt though because the circuit may not accept different values, and so may or may not help. I will know in a couple of weeks, Brian maybe know. I'm going to try an OPA2134 in one of these too

Andy

I think the Phasor II is half a Bi-Phase, so would an idea be to make a Phasor II which is modular or connectable in a way where you can build 2 and have yourself a Bi-Phase?


Andy

Just a wire connection to the lugs of the delay pot, or to the board where the pot is wired too, has the same effect. The wire is connected to the dome, and you touch it.

I don't really know how or why it works, only that it does, and sounds cool!

The interval you get from touching one of the lugs also depends on where you have the trimpot set for delay time. There's a 4th on the new one I've built, and the older one a bit less than a 3rd.

Is the long short switch you have from this post?

http://www.freestompboxes.org/viewtopic.php?f=7&t=8376&hilit=aquapuss+clone&start=160#p104487

Hey thanks for your suggestions. The rhodes is perfect for revealing any distortion because the signal is almost a sine wav and its def not going into the delay too hot. As far as trimpots go, I'm absolutely sure they're dialed in, I mean my ear is a lot more sensitive than my hand holding a screw driver.

I think I was after a technical solution. I've tried replacing 2 of the 220n green mylar caps with wima box and no difference there. I've added a 2.2k resistor to the 1.5k at R19 to giving about 900ohms which *seemed* to clear it up, but only slightly

I've tried a 10k at R15, should be 100k, but it didn't affect the distortion, just the amount of feedback. It seems slightly quieter (just listening to the wet signal with feedback dialed down) but the distortion is still at the same level.

I'm also thinking maybe I should put in 4 new mpsa18 incase any of them were damaged during my previous swapping, or they are faulty? I think someone else experienced this too?

here's another example with the same sample at the same level going through the *questionable* delay, then the one that works well, all with the same settings; wet only signal, level on full, modulation off,

http://littlemp3.com/c632a29

Andy

Here are some voltages, maybe be a better picture

v3205 x 2 DDT mod board (pretty much the same for both)

1. 0 (2nd chip)
2. 3.35
3. 3.95 (4.24)
4. 4     (4.25)
5. 7.4
6. 3.38
7. 3.7
8. 6.35

This from a previous version I've built which is cleaner (very similar in cap choice (green mylar for large values and an assortment for smaller values)

1. 0   (2nd chip)
2. 3.38
3. 4.08  (4.54)
4. 4.11  (4.52)
5. 7.35
6. 3.36
7. 3.65 (4)
8. 6.3

The only thing funky on both of them is a 120pf instead of 100pf at C21 after the clock. The cleaner version also has a 47k at R3 instead of 475k, doesn't seem to make any difference somehow... Also on this version I had the diodes swapped, one for the other, and it worked and sounded pretty good (they are switch to spec now though)

Here are some audio comparisons, cleaner older version then newer darker version

http://littlemp3.com/daf48c7

http://littlemp3.com/b09750c

http://littlemp3.com/e8b8f72

http://littlemp3.com/d2e661e

http://littlemp3.com/76d4eb8

So obviously the new one is voiced darker, but I was trying to disguise the overdriven sound. The darker one has alot more bottom end content even when playing higher notes

Am I just imagining that is sounds bad?

Andy

Hi, I've just built another version and am having what sounds like the same problem with the signal going to the chips too hot.

I've tried replacing R15 with a smaller and larger value which has no effect for me. Swapped out all transistors and all chips, checked all resistor values and caps. Have adjusted all the trimpots for optimimum too. I've got 1.5k at R19 and I'm using green caps for all the large values 47n up and a mix of box caps and mylar for the smaller, tone shaping values

The only thing I haven't tried is jumpering out C15 and am wondering if its possible do that leaving it in the circuit and bridgeing the connections?

I feel like a cap is faulty or one of the diodes, somehow, and there is too much current flowing and/or the chips are being overdriven. I think it would sound ok if played aggresively, on a guitar, but its not as nice or subtle as the other versions I've made and as soon you play chords into it it becomes quite obviously overdriven.

Are there any other components before the delay chips I can check?

Andy

I was wondering wether the clock chip could somehow be 'programmed' to change the delay time in a stepped pitch fashion. One of the best delay sounds, I reckon, is having a switch for long and short times and adjusting the time so the step between results in an interval. A 4th works really well (more notes stay 'in'), but it would be amazing to be able to choose which interval the delay time and subsequently which pitch the feedback would change to.

I imagine this would be easier to do with a digital chip but if its possible with the analog it'd sound so much better.

With the domes its quite hard to control, one is a bit less than a 3rd, the other does nothing but both together shorts the pot out I think..

Maybe a rotary switch with different resistors attached? I guess that would be the easiest way to get something close. But I was kind of thinking along the lines of somehow making the clock adjust the time in semitone steps, that way the pitch change would always be relative, musically speaking (western)

Just thinking, out loud.