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 Forum index » DIY Hardware and Software » MusicFromOuterSpace.com designs by Ray Wilson
mfos 10step vs. 16 step sequencer advice
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wallace



Joined: Mar 24, 2011
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PostPosted: Sat Dec 24, 2011 6:03 pm    Post subject: mfos 10step vs. 16 step sequencer advice Reply with quote  Mark this post and the followings unread

Hi everyone, I recently finished putting together a soundlab, which was my first synth project. I'm not very experienced with electronics, but I finished the soundlab with no problems. Just wondering how big a jump it would be to take on the 16 step. Think I should play it safe and get some more experience building the ten step?
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RF



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PostPosted: Sat Dec 24, 2011 7:30 pm    Post subject: Reply with quote  Mark this post and the followings unread

No reason to settle - If you did a soundlab, You can do the 16 step sequencer...
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inlifeindeath



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PostPosted: Sun Dec 25, 2011 6:59 pm    Post subject: Reply with quote  Mark this post and the followings unread

after the soundlab, i went with the 10 step and regret not doing the 16 all the time. I wish I could use an external clock, which isn't available on the 10. I'd say go for it! if you have the will, you'll get it done!
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ashleym



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PostPosted: Wed Dec 28, 2011 7:59 am    Post subject: Reply with quote  Mark this post and the followings unread

Well done for finishing the Soundlab as you first project.

Go for the 16 step sequencer, you will be able to build it. I am building one at the moment. It is a little bit more complicated than the 10 step seq but easier than the Soundlab.

Think how music divides in bars, 16 steps work for all the common 4/4 and related but you can also set it to 12 steps for 3/4 etc.

I am also building the quantiser at the same time and I am combining the two. I am doing this so when I use the sequencer to play melodies I dont have to worry about the exact tuning of each step. If I am using the sequencer to control filter cut off or something similar I dont have to use the quantiser. Please ask if you need to know more.
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wallace



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PostPosted: Tue Jan 03, 2012 8:04 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks for the advice guys, guess I'll go for it!

Man, this has gotta be the most helpful forum on the web, and possibly the only one devoid of bs attitudes!

Are you all using a power supply with this thing? yet another realm I have no experience with yet
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loydb



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PostPosted: Tue Jan 03, 2012 9:11 am    Post subject: Reply with quote  Mark this post and the followings unread

MFOS's wall-wart power supplies are fast, easy builds.
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wallace



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PostPosted: Tue Jan 03, 2012 3:11 pm    Post subject: Reply with quote  Mark this post and the followings unread

Cool, I'm ordering the parts for the power supply now. There don't seem to be any AC power jacks on Jameco or Mouser, just DC. Is that the thing to use?

The actual science of all this is a bit over my head. Hope I don't electrocute myself!
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prgdeltablues



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PostPosted: Mon Jan 09, 2012 5:58 am    Post subject: Reply with quote  Mark this post and the followings unread

You need AC output NOT DC.

Mouser UK part no: 553-WAU12-1500 is the sort of thing (listed under Power/Plug-In AC adapters.) 12V AC output, rated at 1 or 1.5 A.
Ideally you want a linear rather than switching wall-wart, but that will get you started.

Peter
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jukingeo



Joined: Oct 24, 2007
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PostPosted: Sat Sep 07, 2013 8:47 am    Post subject: Reply with quote  Mark this post and the followings unread

Hello All,

I know this is an older post, but since I have the same question, I figured why clutter the forum up with another thread, right?

Anyway, I am looking to put together a sequencer to go with the DIY Synth Experimenter board I purchased a little while back.

I had been eyeing the 16 step sequencer for the longest time, but I am concerned that the sheer number of parts might make this build a very expensive proposition.

Turning my attention to the 10 step sequencer there are a few things missing and most I could initially live without, but the one thing that does bother me is the fact that there is no reverse count as you cannot make the CD4017 count backwards (the only thing really bad about this IC). Another disadvantage that is less obvious to the newbie, but more apparent to the person with musical knowledge (me) is that 10 is a bad number to work with since music measures work mostly in 4/4 time. So at best you can go 4-8 with the 10 step sequencer, but you can go 4,8,12,16 with the 16 step.

Circuit board wise, there is really no difference in the price (which I figured the 10 step sequencer should be much cheaper). But since the cost of the PCB's is $35 for the 16 step and $30 for the 10 step there isn't too much of a cost savings here.

So overall it would seem that going with the 16 step would be a no-brainer. However, the extra controls and extra chips needed has me wondering what the overall final build cost would be.

To cut costs, this is what I thought of nixing, but I would like to hear the opinions of others, so feel free to chime in:

1) I thought of just getting the 16 step boards and just building what I need. For one, since I have a sample and hold board, I don't think I would be needing the randomize feature. So that saves a switch and a bunch of chips right there.

2) I am fine with one step button, so I wouldn't need the step down button and it's associated circuit. So that is another switch saved.

3) I think the biggest cost savings would be to nix the fine controls as that would be 16 knobs not needed. However, this is where I am mostly asking for input. Is the fine control really that necessary? Other options I thought of would be to build out just to 8 channels (both course and fine controls) but later go full 16 as time/money permits, since with the 10 step sequencer I rarely see taking it out to the full 10 steps as 8 steps is more musical.

As for the argument that there is no sync output on the 10 step sequencer, well, I had noticed that there is a point marked CLK on the schematics for the 10 step sequencer. That point is at the junction of the internal clock and the step button. Wouldn't it make sense that that could be your Clock In/Out point for external clock use? So that would kind of negate the negative on not having a clock In/Out on the 10 step sequencer. As such, with setting up a common clock output, you COULD link two 10 step sequencers together to make a large 20 step sequencer. BUT that is really only one more measure (in 4/4 time), not really such a great advantage considering the cost of materials for TWO 10 channel sequencers would now be over the cost of one 16 channel (fully built) sequencer.

So as it stands, I think I am still better off with the 16 channel sequencer boards, but just leave out the unneeded circuits to drive down the build cost.

So I am open to your ideas and opinions on this.

EDIT: Since I can't get a direct Mouser BOM for either sequencer, I am curious, what ARE the costs to build either the 16 step or 10 step sequencers (in full).

Thank You,

Geo

Last edited by jukingeo on Sat Sep 07, 2013 9:03 am; edited 1 time in total
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elmegil



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PostPosted: Sat Sep 07, 2013 8:57 am    Post subject: Reply with quote  Mark this post and the followings unread

Saving chips won't save you much money, none of this CMOS stuff is very expensive, nor are the TL082 op amps. Sockets could be more expensive, but if you're reasonably careful you shouldn't need them--nothing here is so rare or touchy as to need an easy way to swap out. I think your biggest expenses will be the pots, knobs, and jacks, which is true for most DIY synth projects. Dropping the fine controls seems like a good plan to save money there.

I would say you very likely want the 16 step version. I built a Baby-8 (because I couldn't see going to 10 steps, as you said, doesn't divide easily) and having only 8 steps makes it disappointing sometimes.
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jukingeo



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PostPosted: Sat Sep 07, 2013 9:21 am    Post subject: Reply with quote  Mark this post and the followings unread

Hello,

Wow! That was a fast response. I was editing my post when you responded already. I basically just added that I wanted to know really how much it costs to build either the 16 step sequencer or the 10 step sequencer. On some of the BOMs on the MFOS site are directly linked to Mouser so you can get an idea of the total costs before hand instead of sitting there plugging everything into shopping cart one by one manually. But the sequencers don't have such a BOM.


elmegil wrote:
Saving chips won't save you much money, none of this CMOS stuff is very expensive, nor are the TL082 op amps. Sockets could be more expensive, but if you're reasonably careful you shouldn't need them--nothing here is so rare or touchy as to need an easy way to swap out.


True, I don't think that the CMOS control IC's would be a high candidate to blow up on you. But it might be prudent to have a socket for the larger IC's and the op amps that are on the input and outputs as it is easy to make a mistake and blow one of these to Kingdom Come. Then it is nice to know it is on a socket and can be easily swapped out. But the IC's that are 'deeper' into the circuit probably would never go bad.

Quote:

I think your biggest expenses will be the pots, knobs, and jacks, which is true for most DIY synth projects. Dropping the fine controls seems like a good plan to save money there.


That is what I thought as well. The jacks and controls do drive up the price considerably, especially if you want good pots (which I DO want). I don't want the pots to get scratchy and skip after only a few months of use (which I have seen with the cheap Chinese controls). The good news is that with the 16 channel sequencer, I could drop the fine controls now, but then add them later.

Quote:

I would say you very likely want the 16 step version. I built a Baby-8 (because I couldn't see going to 10 steps, as you said, doesn't divide easily) and having only 8 steps makes it disappointing sometimes.


LOL, yeah, I thought of that myself. If I was going to go REALLY cheap to go with the 10 step sequencer, but only take it out to 8 steps. But the cost savings are very minor in this case. As I said, there isn't much savings in the PCB's (only a $5 difference) I think it would STILL be better off to go with the 16 channel sequencer and only take that out to 8 steps. But there would be no regrets should I want more steps...I could just fully build out to 16 channels at any time.

Yeah, I think that is the better way the more I think about it. Just get the 16 channel sequencer board and build it out as needed, leave out what I don't need. In fact heeding your advice, I probably will build the boards out fully (with the exception of the randomize circuit as I don't think I would ever use that), but put the cost savings by eliminating some controls. This way in the event I want to add something later it would be as simple as adding the controls later on.

Ok, so I will get the 16 channel boards and then I can always make the decision later on if I want to go 16 channels full, no fine controls, 8 channels full, or even 8 channels no fine controls.

Thank You for your input.

Geo
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jukingeo



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PostPosted: Sat Sep 07, 2013 9:41 am    Post subject:   Reply with quote  Mark this post and the followings unread

Hello All,

I was just looking at sites such as Mouser, Jameco, & MCM and it seems like the larger 24 pin IC's appear to be becoming obsolete. They have smaller (thinner) 24 pin replacements of those IC's, but they will not fit the PCB. Jameco does have the 4067 in the old 'wide' format, but not the 4514. I know I could get the chips from MFOS, but for nearly twice the price Shocked. Would anyone know of a good source that still has these wider ic's?

Thanx,

Geo
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elmegil



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PostPosted: Sat Sep 07, 2013 9:55 am    Post subject: Reply with quote  Mark this post and the followings unread

I would check out tayda electronics, unicorn electronics, smallbear electronics, mammoth electronics.

I don't know for sure that they'd have them, but the first two are where I go for CMOS most of the time.
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elmegil



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PostPosted: Sat Sep 07, 2013 9:56 am    Post subject: Reply with quote  Mark this post and the followings unread

jukingeo wrote:

LOL, yeah, I thought of that myself. If I was going to go REALLY cheap to go with the 10 step sequencer, but only take it out to 8 steps. But the cost savings are very minor in this case. As I said, there isn't much savings in the PCB's (only a $5 difference) I think it would STILL be better off to go with the 16 channel sequencer and only take that out to 8 steps. But there would be no regrets should I want more steps...I could just fully build out to 16 channels at any time.

Yeah, I think that is the better way the more I think about it. Just get the 16 channel sequencer board and build it out as needed, leave out what I don't need. In fact heeding your advice, I probably will build the boards out fully (with the exception of the randomize circuit as I don't think I would ever use that), but put the cost savings by eliminating some controls. This way in the event I want to add something later it would be as simple as adding the controls later on.

Ok, so I will get the 16 channel boards and then I can always make the decision later on if I want to go 16 channels full, no fine controls, 8 channels full, or even 8 channels no fine controls.

Thank You for your input.

Geo


I think that's a great idea, I hadn't even thought of that.
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ashleym



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PostPosted: Sun Sep 08, 2013 11:53 am    Post subject: Reply with quote  Mark this post and the followings unread

As I mentioned I have the 16 channel seq. I dont have the fine controls but my way round this was to have a switchable range. Instead of just having (I cant remember the details without looking but I hope you get my drift) the standard 5v or 5 octave range I put a switch in the circuit with a couple of resistors. This gives me something like 2.5v, 5 and 7.5v range options. With the 2.5v scale you instantly have twice the resolution for the control rotation.

My advice is to get the chips for all the options and then you only need to add the controls and panel space later. They are the expensive parts.

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jukingeo



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PostPosted: Fri Sep 13, 2013 8:56 pm    Post subject: Reply with quote  Mark this post and the followings unread

elmegil wrote:
jukingeo wrote:

..Ok, so I will get the 16 channel boards and then I can always make the decision later on if I want to go 16 channels full, no fine controls, 8 channels full, or even 8 channels no fine controls.

Thank You for your input.

Geo


I think that's a great idea, I hadn't even thought of that.


It kind of just popped in my head as I thought if I was only going to take the 10 step sequencer out to 8, I certainly could do that with the 16 step one AND get the other features I want. Then I can always add the fine controls and the remaining 8 channels later on.

ashleym wrote:
As I mentioned I have the 16 channel seq. I dont have the fine controls but my way round this was to have a switchable range. Instead of just having (I cant remember the details without looking but I hope you get my drift) the standard 5v or 5 octave range I put a switch in the circuit with a couple of resistors. This gives me something like 2.5v, 5 and 7.5v range options. With the 2.5v scale you instantly have twice the resolution for the control rotation.


I guess that would be a good option too, especially if the switch is cheaper than a pot. Since you need a knob for a pot that could certainly be so.

Quote:

My advice is to get the chips for all the options and then you only need to add the controls and panel space later. They are the expensive parts.


Sounds good to me.

Thanx,

Geo
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ashleym



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PostPosted: Tue Sep 17, 2013 1:09 pm    Post subject: Reply with quote  Mark this post and the followings unread

As an aside, dont forget the experimenter board VCOs arent geared up for v/oct tracking. From Ray's notes +5 to -5 v will give a range of 20 to 10,000Hz. I think it will be tricky to get musical scales from a sequencer- that is, of course, if you want musical scales.
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jukingeo



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PostPosted: Tue Sep 17, 2013 8:15 pm    Post subject: Reply with quote  Mark this post and the followings unread

ashleym wrote:
As an aside, dont forget the experimenter board VCOs arent geared up for v/oct tracking. From Ray's notes +5 to -5 v will give a range of 20 to 10,000Hz. I think it will be tricky to get musical scales from a sequencer- that is, of course, if you want musical scales.


From what I read in other posts the 1v per octave is not really necessary with sequencers as you can use the knobs to dial in the pitch you want. More guesswork and using your ears rather than set mathematics. But I can see that. However, using a keyboard and keeping in tune with other instruments would be a different story and there you definitely need the more accurate VCOs
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ashleym



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PostPosted: Wed Sep 18, 2013 5:35 am    Post subject: Reply with quote  Mark this post and the followings unread

Yes, sequencers do allow a sweep of voltage/frequencies and you set the exact level/pitch by ear. This is why I have combined my seq with a quantiser.

But usually VCOs have a limited range and the seq is scaled to match that. TO me a musically useful scale is something like 5 octaves (or 5V) and on top of that you have the tuning ability of the VCOs to move a further 3 or so octaves. The experimenter VCOs have a 10 octave range. Imagine this spread over the same range on each seq control, a rough calculate gives 10 octaves x 12 notes= 120 notes for the travel of the control. 270 degrees of rotation, 270/120= 2.25 degrees of movement per note if all responses are linear and they arent.........This isnt me trying to pick holes, Shocked Shocked I am just trying to point out that you are using a sequencer on a VCO that isnt designed to be played by a sequencer. It will work but it might not be as easy as you think to get a melody out of the combination.

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jukingeo



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PostPosted: Thu Sep 19, 2013 9:28 pm    Post subject: Reply with quote  Mark this post and the followings unread

ashleym wrote:
Yes, sequencers do allow a sweep of voltage/frequencies and you set the exact level/pitch by ear. This is why I have combined my seq with a quantiser.

But usually VCOs have a limited range and the seq is scaled to match that. TO me a musically useful scale is something like 5 octaves (or 5V) and on top of that you have the tuning ability of the VCOs to move a further 3 or so octaves. The experimenter VCOs have a 10 octave range. Imagine this spread over the same range on each seq control, a rough calculate gives 10 octaves x 12 notes= 120 notes for the travel of the control. 270 degrees of rotation, 270/120= 2.25 degrees of movement per note if all responses are linear and they arent.........This isnt me trying to pick holes, Shocked Shocked I am just trying to point out that you are using a sequencer on a VCO that isnt designed to be played by a sequencer. It will work but it might not be as easy as you think to get a melody out of the combination.


Couldn't you limit the range on the VCO?
Probably wouldn't be a good idea to skip the fine controls on the sequencer then.

Thanx,

Geo
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Mongo1



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PostPosted: Sun Sep 22, 2013 10:22 am    Post subject: Reply with quote  Mark this post and the followings unread

First thing, If I built my 16 step again, I would leave off the Fine pots. I literally never use them.

The second thing - Having the full voltage sweep is pretty pointless really. If you put a voltage divider on the output, you can cut the range down to 2 or 3 octaves. That will make the 'coarse' knob easier to tune with, and you probably won't ever want a sequence that needs a wider range than that.

Third - If I were going to build another 16 step, I would go whole-hog and get that variable time board (or whatever it's called). That thing is uber awesome.

Just my $.02

Gary
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jukingeo



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PostPosted: Wed Sep 25, 2013 6:39 pm    Post subject: Reply with quote  Mark this post and the followings unread

Mongo1 wrote:
First thing, If I built my 16 step again, I would leave off the Fine pots. I literally never use them.


Really? That is interesting to know. I could save a bundle right there.

Quote:

The second thing - Having the full voltage sweep is pretty pointless really. If you put a voltage divider on the output, you can cut the range down to 2 or 3 octaves. That will make the 'coarse' knob easier to tune with, and you probably won't ever want a sequence that needs a wider range than that.


THAT is a fantastic idea! I could install a single RANGE switch that would allow you to select the whole range (for making noise) and a voltage divider for music. Having one range switch on the ENTIRE bank of knobs would in effect be a go between for full range and fine range. THAT would save a chunk of change on knobs AND also add some flexibility. Do you have a picture or schematic of this?

Quote:

Third - If I were going to build another 16 step, I would go whole-hog and get that variable time board (or whatever it's called). That thing is uber awesome.


Hmmm, I CAN see that for making music and if you have the tuned VCO's. But I am just starting out and I am going to interface the sequencer with the experimenter's board.

But the idea of changing the voltage range on the coarse dials is a GREAT idea. I definitely will experiment with that.

Quote:

Just my $.02

Gary


Thanx a bunch. I believe you came up with a great idea AND saved me a chunk of change in the process.

Geo

Last edited by jukingeo on Wed Sep 25, 2013 7:11 pm; edited 1 time in total
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jukingeo



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PostPosted: Wed Sep 25, 2013 6:46 pm    Post subject: Reply with quote  Mark this post and the followings unread

ashleym wrote:
As I mentioned I have the 16 channel seq. I dont have the fine controls but my way round this was to have a switchable range. Instead of just having (I cant remember the details without looking but I hope you get my drift) the standard 5v or 5 octave range I put a switch in the circuit with a couple of resistors. This gives me something like 2.5v, 5 and 7.5v range options. With the 2.5v scale you instantly have twice the resolution for the control rotation.

My advice is to get the chips for all the options and then you only need to add the controls and panel space later. They are the expensive parts.


I don't know if you meant having a range switch on EACH channel or globally. For some reason the way Gary worded his response, it sounded more global and I thought it was a great idea. But then I recalled your response and you mentioned something about a switch too. But for some reason I mistook it for having a switch on each channel and naturally I thought that while it is cheaper than having a control on each channel, it doesn't save much.

But now that I am reading your reply again, I am curious if you meant a global range switch or individual? If so, then it is similar to what Gary wrote. I guess just with his reply it just clicked in my head and hit me like a ton of bricks that changing the voltage across the pots to a more usable range would be like having a finer control pot without the expense of wiring in additional controls on each channel.

So I am sorry if I misunderstood you. BTW, they say a picture is worth 1000 words. Do you have a schematic of this? Then things would be a whole lot clearer.

Geo
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ashleym



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PostPosted: Sat Sep 28, 2013 4:43 am    Post subject: Reply with quote  Mark this post and the followings unread

Dont worry, I am sure I am the one not being very clear.

I have a switch to set the overall voltage range. I wired the switch to the analogue board. Look around VS1 that sets the control voltage into U1-A of the TL084. It has the usual two resistors R25 and R26, 200 and 100k respectively. A quick calculate

Amplification, voltage= (R25+R26)/R26 or (200+100)/100

gives you the 3x gain for the 2.5v source= 7.5 volts Ray mentions.

So if you switch one of these resistors, I used R25, between 10K, 100K & 200k, you roughly get unity gain with the 10K (2.5v ish), 2x gain with the 100K (5v) or the existing 3x gain with 200k (7.5v).

On the circuit diagram, dont connect R25. Put one end of a lead in position 1 of R25. The other end of the lead goes to the in of a 3 way rotary switch. Wire the 10/100/200K resistors to each of the outs of the switch. Tie all the ends of the resistors together and solder into position 2 of R25.

I hope that helps.

Quote:
U1-A in conjunction with VS1 (LM336-2.5V 2.5 volt precision voltage reference) create a 7.5 volt source to which one side of all of the pots are connected. The precision voltage source applies a very clean 2.5V to the non-inverting input of U1-A. Feedback resistor R25 (200K) and gain set resistor R26 (100K) set the gain around U1-A to 3 which is how we get 7.5V from the 2.5V reference.

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Mongo1



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PostPosted: Sat Sep 28, 2013 7:37 am    Post subject: Reply with quote  Mark this post and the followings unread

Sorry I didn't get back to you earlier - It sounds like you've got it sussed out though.

I originally did the range modification on the hexinverter sympleSeq. On that one it's a breeze - There's an output resistor between the op-amp and the jack, so you just need to solder another resistor between the output jack and the ground. It makes a voltage divider, and it works great.

Gary
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