What "chipset" would you like to see in a Dim D PCB |
Original chips. They are still out there. |
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76% |
[ 39 ] |
Low voltage BBDs - easier to get, probably more noisy. Takes longer to design. |
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5% |
[ 3 ] |
Make a PCB that allows both options. Will be more expensive (more PCB area required!), and will take the longest to design. |
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13% |
[ 7 ] |
Not interested. (Who needs a Dim D? And isn't there another Dim D project on the way?!) |
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3% |
[ 2 ] |
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Total Votes : 51 |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Mon Jun 22, 2009 11:27 pm Post subject:
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numbertalk wrote: | Hi JH,
The only trimmer I don't see any instructions on how to calibrate is the LFO Offs trimmer on the BBD board - what is this one exactly and how is this one set?
Thanks! |
This is for a symmetrical LFO shape at pin 7 of U14.
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Tue Jun 23, 2009 4:17 am Post subject:
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Thanks!
jhaible wrote: | numbertalk wrote: | Hi JH,
The only trimmer I don't see any instructions on how to calibrate is the LFO Offs trimmer on the BBD board - what is this one exactly and how is this one set?
Thanks! |
This is for a symmetrical LFO shape at pin 7 of U14.
JH. |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Thu Jun 25, 2009 6:25 am Post subject:
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Oops, I see one more - the Tau Mod trimmer. You said for the Tau Bias to set by ear for pleasant sound in Dim T mode but what about the Tau Mod? Do these need to both be set together somehow?
Thanks! |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Thu Jun 25, 2009 9:55 am Post subject:
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numbertalk wrote: | Oops, I see one more - the Tau Mod trimmer. You said for the Tau Bias to set by ear for pleasant sound in Dim T mode but what about the Tau Mod? Do these need to both be set together somehow?
Thanks! |
One trimmer sets the modulation amplitude, the other the bias (i.e. DC shift).
Set the such that the TAU modules get what they normally get - a positive modulation signal with about +10V maximum (peak) and 0V minimum (valley). Then fine tune by ear to your taste.
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Thu Jun 25, 2009 10:03 am Post subject:
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jhaible wrote: | One trimmer sets the modulation amplitude, the other the bias (i.e. DC shift).
Set the such that the TAU modules get what they normally get - a positive modulation signal with about +10V maximum (peak) and 0V minimum (valley). Then fine tune by ear to your taste.
JH. |
We measure this at the Tau CVs pads on the Main Board or the Osc Level pad on the Tau boards, right?
Thanks! |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Thu Jun 25, 2009 12:06 pm Post subject:
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numbertalk wrote: | jhaible wrote: | One trimmer sets the modulation amplitude, the other the bias (i.e. DC shift).
Set the such that the TAU modules get what they normally get - a positive modulation signal with about +10V maximum (peak) and 0V minimum (valley). Then fine tune by ear to your taste.
JH. |
We measure this at the Tau CVs pads on the Main Board or the Osc Level pad on the Tau boards, right?
Thanks! |
Right.
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Fri Jun 26, 2009 2:09 pm Post subject:
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A few more questions as I'm plugging along on this project:
1) I'm building a Dim-TD version and definitely want the preset modes. In addition I'd like to include the second on-board LFO shown in the "Option A" document. Just want to make sure I understand from what I read earlier in the thread - to switch this 2nd LFO in and out of the signal to get back and forth to and from the strictly preset mode, it sounds like it's just a matter of dialing up the "depth" pot connection for the BBD board LFO, right? So as you said you could wire up a switch between the wiper of the depth pot and the board to break this connection? And to disconnect the presets would you only break the connection on the LFO wire between the Main board and BBD board, or would you break both that wire as well as the SW wire at the same connector?
2) I populated the entire BBD board, including Option B components (minus off-board panel components). Will this have any effect on the signal this way? If I leave the swA/swB and 0LR pads unconnected will it leave this section of the circuit disconnected from the signal chain?
3) On the Main Board, what are the following connections exactly:
Interf
LSW
4) I'd like to include the "phase" switch so I could get Juno style chorus sounds as well. What would be the best approach to dial this kind of sound in - for example, in conjunction with which mode, or with the bonus controllable BBD board LFO, etc...?
5) I just re-read the thread and saw this:
jhaible wrote: | (You can easily replace the output stage with modern opamps that don't need extra power transistors, though.)
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I had asked you about this before, but before I solder in the op-amps (I have and was planning to use HA1457W with the 620R series resistors), do I need the extra power transistors (because I don't have them)? If i *do*, would this be the case for all of them or just some of them? If just some of them (for the output stage, for instance), which ones exactly might I be better off using TL072s or TL071s for if not using the power transistors?
Thanks! |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Fri Jun 26, 2009 10:55 pm Post subject:
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numbertalk wrote: | to switch this 2nd LFO in and out of the signal to get back and forth to and from the strictly preset mode, it sounds like it's just a matter of dialing up the "depth" pot connection for the BBD board LFO, right? So as you said you could wire up a switch between the wiper of the depth pot and the board to break this connection? |
Yes!
Quote: | And to disconnect the presets would you only break the connection on the LFO wire between the Main board and BBD board, or would you break both that wire as well as the SW wire at the same connector? |
Both
Quote: | 2) I populated the entire BBD board, including Option B components (minus off-board panel components). Will this have any effect on the signal this way? If I leave the swA/swB and 0LR pads unconnected will it leave this section of the circuit disconnected from the signal chain?
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Won't have any effec besides drawing a few milliamps. I have it in my prototype, too.
Quote: | 3) On the Main Board, what are the following connections exactly:
Interf
LSW |
Level switching, mono-stero switching, bypass switching.
PDFs like these show how to connect them:
http://www.jhaible.de/subtle_chorus/sc_audio_unbalanced.pdf
http://www.jhaible.de/subtle_chorus/sc_wiring_mode_switch_and_bypass.jpg
Quote: | 4) I'd like to include the "phase" switch so I could get Juno style chorus sounds as well. What would be the best approach to dial this kind of sound in - for example, in conjunction with which mode, or with the bonus controllable BBD board LFO, etc...? |
Juno style chorus would be a separate BBD board.
You certainly *could* find a way to do it with the same board as the dim D and a million switches, but that would be messy.
Quote: | 5) I just re-read the thread and saw this:
jhaible wrote: | (You can easily replace the output stage with modern opamps that don't need extra power transistors, though.)
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I had asked you about this before, but before I solder in the op-amps (I have and was planning to use HA1457W with the 620R series resistors), do I need the extra power transistors (because I don't have them)? If i *do*, would this be the case for all of them or just some of them? If just some of them (for the output stage, for instance), which ones exactly might I be better off using TL072s or TL071s for if not using the power transistors?
Thanks! |
What I have built are two versions:
HA + transistors, and TL without transistors.
You can certainly use HA without transistors (see schemos, and wire them like any ordinary opamp), but then that's neither vintage nor unexpensive ...
The transistors are rather cheap, btw.
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Sat Jun 27, 2009 7:23 am Post subject:
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Of course. Thought I'd looked closely at all the docs before posting but did miss that these connections were on these 2 docs.
jhaible wrote: |
Juno style chorus would be a separate BBD board.
You certainly *could* find a way to do it with the same board as the dim D and a million switches, but that would be messy.
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So is there any value in wiring up the Phase switch with just the Dim TD boards? Is it still possible to get a nice/interesting Chorus even if it's not like the Juno chorus?
jhaible wrote: |
What I have built are two versions:
HA + transistors, and TL without transistors.
You can certainly use HA without transistors (see schemos, and wire them like any ordinary opamp), but then that's neither vintage nor unexpensive ...
The transistors are rather cheap, btw. |
All good points. I think the last time I really explored this was before the BOM was up and I was looking at the original transistors, which were either not cheap or I was not able to find. Will grab these others that are in the BOM now.
Thanks for all the help! |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Mon Jun 29, 2009 1:54 pm Post subject:
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Do we need to solder any of the SMD bypass caps for the 2 Tau boards for the Dim-TD version? |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Mon Jun 29, 2009 3:28 pm Post subject:
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numbertalk wrote: | Do we need to solder any of the SMD bypass caps for the 2 Tau boards for the Dim-TD version? |
Yes of course!
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Tue Jun 30, 2009 8:26 pm Post subject:
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jhaible wrote: | numbertalk wrote: | Do we need to solder any of the SMD bypass caps for the 2 Tau boards for the Dim-TD version? |
Yes of course!
JH. |
Thanks. Thought I'd make sure since if it saved me from saving any SMDs that wouldn't have been a bad thing. I've gotten pretty good at it at this point so not a big deal. |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Tue Jun 30, 2009 11:45 pm Post subject:
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numbertalk wrote: | jhaible wrote: | numbertalk wrote: | Do we need to solder any of the SMD bypass caps for the 2 Tau boards for the Dim-TD version? |
Yes of course!
JH. |
Thanks. Thought I'd make sure since if it saved me from saving any SMDs that wouldn't have been a bad thing. I've gotten pretty good at it at this point so not a big deal. |
About the bypass caps in general: I'm pretty sure you could get away with half of them, on all my projects, without amplifiers starting to oscillate. But it's much easier to solder them all in, than to check which ones you really need.
And I could *not* find out for you, because it would be different on each board, depending on what manufacturer's opamps you use. I even had ICs from the same manufacturer, but different date code, an one burst into RF oscillation, and the other was perfectly quiet, under the same outward conditions. Semiconductor companies change their design process over the life cycle of a chip, without an obligation to tell anybody, as long as they keep the specs they guarantee in their data sheets. So the worst you can do as a designer is to rely on a unspecified feature. You may get away with it now, but it may cause trouble later on. So I keep providing plenty of pads for SMD bypass caps (the pads cost nothing), and I recommend to use them (the capacitors cost next to nothing).
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Thu Jul 02, 2009 7:53 am Post subject:
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That all makes sense and I'm all about being safe and not sorry later on. Namely when it's really not such a big deal to just solder them all in. Just takes a little practice to get good at it.
jhaible wrote: | numbertalk wrote: | jhaible wrote: | numbertalk wrote: | Do we need to solder any of the SMD bypass caps for the 2 Tau boards for the Dim-TD version? |
Yes of course!
JH. |
Thanks. Thought I'd make sure since if it saved me from saving any SMDs that wouldn't have been a bad thing. I've gotten pretty good at it at this point so not a big deal. |
About the bypass caps in general: I'm pretty sure you could get away with half of them, on all my projects, without amplifiers starting to oscillate. But it's much easier to solder them all in, than to check which ones you really need.
And I could *not* find out for you, because it would be different on each board, depending on what manufacturer's opamps you use. I even had ICs from the same manufacturer, but different date code, an one burst into RF oscillation, and the other was perfectly quiet, under the same outward conditions. Semiconductor companies change their design process over the life cycle of a chip, without an obligation to tell anybody, as long as they keep the specs they guarantee in their data sheets. So the worst you can do as a designer is to rely on a unspecified feature. You may get away with it now, but it may cause trouble later on. So I keep providing plenty of pads for SMD bypass caps (the pads cost nothing), and I recommend to use them (the capacitors cost next to nothing).
JH. |
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JoeMorris
Joined: Apr 26, 2009 Posts: 161 Location: Brighton
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Posted: Thu Jul 02, 2009 9:26 am Post subject:
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hold them down with the tip of a small screwdriver is my 'tip' |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Thu Jul 02, 2009 1:10 pm Post subject:
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JH, any suggestions for the best way to get power to the 2 Tau boards? I see in your prototype photo on your site that you're using the 3-pad power connections between the Main board and the BBD board, but I can't quite tell where your Tau boards are getting power from. I'm building with this with AC power of course, using a transformer and power cord inlet, not a wall wart.
Would soldering wires from the MOTM and dotcom pads on the Main board to the Tau boards work ok, since those pads will otherwise go unused? Any better suggestions?
Thanks. |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Thu Jul 02, 2009 3:09 pm Post subject:
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numbertalk wrote: | JH, any suggestions for the best way to get power to the 2 Tau boards? I see in your prototype photo on your site that you're using the 3-pad power connections between the Main board and the BBD board, but I can't quite tell where your Tau boards are getting power from. I'm building with this with AC power of course, using a transformer and power cord inlet, not a wall wart.
Would soldering wires from the MOTM and dotcom pads on the Main board to the Tau boards work ok, since those pads will otherwise go unused? Any better suggestions?
Thanks. |
I used the same connectors that bring the +/-15V from main board to BBD board, daisy-chained to the two Tau boards.
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Sat Jul 04, 2009 2:44 pm Post subject:
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Could you verify that using a 100K Log pot to attenuate audio input levels and 100K Linear pots to attenuate the LFO Depth & Rate CV inputs would be good choices here?
Thanks for all the help. I have all 4 boards soldered now, minus a few parts I'm still waiting on. Then I just need to get the panel made and wire it up! It's been a while since I built my Tau module - I'd forgotten how the pads for the SMD caps are much smaller on that board. It was a little trickier to get them in - having larger pads for those make a big difference, at least to me. |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Sat Jul 04, 2009 11:05 pm Post subject:
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numbertalk wrote: | Could you verify that using a 100K Log pot to attenuate audio input levels and 100K Linear pots to attenuate the LFO Depth & Rate CV inputs would be good choices here?
Thanks for all the help. I have all 4 boards soldered now, minus a few parts I'm still waiting on. Then I just need to get the panel made and wire it up! It's been a while since I built my Tau module - I'd forgotten how the pads for the SMD caps are much smaller on that board. It was a little trickier to get them in - having larger pads for those make a big difference, at least to me. |
Rate yes, Depth no.
See values of R114 vs. R112 and it's all clear.
(http://www.jhaible.de/subtle_chorus/jh_subtle_chorus_BBD_Board_sch_page2.pdf)
I would go for 10k ... 22k lin.
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Sun Jul 05, 2009 6:43 am Post subject:
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jhaible wrote: | numbertalk wrote: | Could you verify that using a 100K Log pot to attenuate audio input levels and 100K Linear pots to attenuate the LFO Depth & Rate CV inputs would be good choices here?
Thanks for all the help. I have all 4 boards soldered now, minus a few parts I'm still waiting on. Then I just need to get the panel made and wire it up! It's been a while since I built my Tau module - I'd forgotten how the pads for the SMD caps are much smaller on that board. It was a little trickier to get them in - having larger pads for those make a big difference, at least to me. |
Rate yes, Depth no.
See values of R114 vs. R112 and it's all clear.
(http://www.jhaible.de/subtle_chorus/jh_subtle_chorus_BBD_Board_sch_page2.pdf)
I would go for 10k ... 22k lin.
JH. |
Ah, I see. Thanks. In that case I'll double check that for the Rate & Depth manual control pots B100K is ok for both (that's what I read earlier in the thread but just making sure).
Also would B25K be ok for the Depth CV pot? I happen to have one. |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Sun Jul 05, 2009 7:01 am Post subject:
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B25k = 25k lin = 22k lin
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Sun Jul 05, 2009 7:14 am Post subject:
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jhaible wrote: | B25k = 25k lin = 22k lin
JH. |
Yep, I know B = Linear, was just making sure using a pot at the higher end was ok and that I wouldn't be better off with something smaller. Don't think I've ever come across something asking for a 22K pot but realizing that I sub 50K for 47K pots all the time I should have realized it would be fine.
Thanks. |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Sun Jul 05, 2009 7:19 am Post subject:
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These pots have high tolerances.
Also, you *could* of course use a 100k lin, but the sensitivity would be warped a lot towards to last bit of the roation.
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Sun Jul 05, 2009 9:20 am Post subject:
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jhaible wrote: | These pots have high tolerances.
Also, you *could* of course use a 100k lin, but the sensitivity would be warped a lot towards to last bit of the roation.
JH. |
Makes sense. I'll go with the 25K linear Thanks! |
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JoeMorris
Joined: Apr 26, 2009 Posts: 161 Location: Brighton
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Posted: Tue Jul 07, 2009 12:14 pm Post subject:
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So I explored the Dim D with my DIY audio probe, and as stated in my comapct phasing post, it turns out the main problem lay with how I'd wired up the jacks. Once I'd sorted this out I got sound coming through fine... which is a big result.
However, the wet sound isn't very different to the bypassed sound at all...
slightly warmer is about all... and the rotary switch seems to have no noticeable effect... Am I right in thinking that turning the switch should make quite a noticeable difference?
I traced the sound across the boards and it makes it to the BBD board OK....
The MN3007 pins seem to make a mental bubbling sound, is this right?
Any ideas about where this could be going wrong, as I presume somethings not right?
So close but yet so far!! |
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