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 Jul 20, 2009 1:38 pm Post subject:
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numbertalk wrote: | Another question - I have decided to go with balanced inputs and outputs. I am unclear on how (or if) I could add an input attenuator. The first thing that comes to mind is a 4-gang pot, but even if I could find one, I've read that using pots with balanced signals is discouraged for risk of disrupting the balance of the signal. Do you have any suggestions? Sounds like shunt attenuators are recommended but the only DIY one I could find is very expensive. Not a huge deal if I can't include one - the only reason I'm being a little stubborn about it is I had a panel made that has a hole drilled and labeled for an input attenuator (oops).
Thanks. |
Why do you want attenuators?
The companders allow a big dynamic range without level adjustment ...
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: Mon Jul 20, 2009 3:00 pm Post subject:
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Ah good to know - too bad I didn't realize this before having the panel made. Thanks.
jhaible wrote: | numbertalk wrote: | Another question - I have decided to go with balanced inputs and outputs. I am unclear on how (or if) I could add an input attenuator. The first thing that comes to mind is a 4-gang pot, but even if I could find one, I've read that using pots with balanced signals is discouraged for risk of disrupting the balance of the signal. Do you have any suggestions? Sounds like shunt attenuators are recommended but the only DIY one I could find is very expensive. Not a huge deal if I can't include one - the only reason I'm being a little stubborn about it is I had a panel made that has a hole drilled and labeled for an input attenuator (oops).
Thanks. |
Why do you want attenuators?
The companders allow a big dynamic range without level adjustment ...
JH. |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Sun Aug 02, 2009 2:21 pm Post subject:
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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. |
Would you ever consider designing an expansion add-on board to incorporate a Juno chorus mode with this project? |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Sun Aug 02, 2009 10:53 pm Post subject:
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numbertalk wrote: | 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. |
Would you ever consider designing an expansion add-on board to incorporate a Juno chorus mode with this project? |
I encourage you, or others, to experiment with this, while I'm going on to design the Flanger, Vocoder, and other new stuff.
Seriously: All you need is the BBD board and a set of trimpots for VC Rate and VC depth, and a switch for (Modulation) Phase. Still, the BBDs are longer than in the Juno 6, so it may not be 100% the same. (Check if shorter BBDs are pin-compatible or not!)
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: Mon Aug 03, 2009 7:14 am Post subject:
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jhaible wrote: | numbertalk wrote: | 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. |
Would you ever consider designing an expansion add-on board to incorporate a Juno chorus mode with this project? |
I encourage you, or others, to experiment with this, while I'm going on to design the Flanger, Vocoder, and other new stuff.
Seriously: All you need is the BBD board and a set of trimpots for VC Rate and VC depth, and a switch for (Modulation) Phase. Still, the BBDs are longer than in the Juno 6, so it may not be 100% the same. (Check if shorter BBDs are pin-compatible or not!)
JH. |
I'm probably not the right person to do this but definitely interested if anyone else works on it and would like to share their work. |
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whomper
Joined: Dec 15, 2007 Posts: 201 Location: Israel
Audio files: 2
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Posted: Fri Aug 07, 2009 2:11 am Post subject:
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Hi,
In my dual Dim-D (well, dual BBD that is) module, one of the boards has some clicking sound at every cycle. When replacing the 13600 between the two boards, the clicking sound is present in the other board, which brings me to think it is a matter of the 13600.
I have tried to replace it with a 13700, but it does not work (i.e. no chorus effect) and it gets somewhat hot.
Is the 13700 a replacement for the 13600? Is there any modification needed on the board to accept the 13700? _________________ Erez Yaary
Home Page: http://www.yaary.com
Buy my CDs at http://www.mellowjet.de |
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diablojoy
Joined: Sep 07, 2008 Posts: 809 Location: melbourne australia
Audio files: 11
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Posted: Fri Aug 07, 2009 3:04 am Post subject:
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don't suppose you still have any boards left at this late stage ?
missed this one completely. |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Fri Aug 07, 2009 8:43 am Post subject:
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diablojoy wrote: | don't suppose you still have any boards left at this late stage ?
missed this one completely. |
Sure have! As long as they are listed here, they are still avaialble:
http://electro-music.com/forum/post-245197.html#245197
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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lexvortex
Joined: May 14, 2008 Posts: 155 Location: Toronto
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Posted: Sun Aug 09, 2009 12:37 am Post subject:
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Hi JH,
I finished the DimD and it sounds great!! My only concern is the output volume, When I put a 10Vpp standard MOTM osc into it I get a bit less than line level output, and when I put a line level input into it the output is very quiet (I would need a mic amp to bring it to the right level). I built it using the modern opamp and unbalanced output/input. I also included 100k input pots to attenuate the input because I thought the modular would have too hot a signal into the DimD but I don't seem to have a problem with the modulars level being too high even when the pots are fully open, is all this behaviour normal? What should I check for the low level output?
Thanks,
Dave |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Sun Aug 09, 2009 3:07 am Post subject:
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lexvortex wrote: | Hi JH,
I finished the DimD and it sounds great!! My only concern is the output volume, When I put a 10Vpp standard MOTM osc into it I get a bit less than line level output, and when I put a line level input into it the output is very quiet (I would need a mic amp to bring it to the right level). I built it using the modern opamp and unbalanced output/input. I also included 100k input pots to attenuate the input because I thought the modular would have too hot a signal into the DimD but I don't seem to have a problem with the modulars level being too high even when the pots are fully open, is all this behaviour normal? What should I check for the low level output?
Thanks,
Dave |
When everything is ok, the output level should be approximately the same as the input level.
If it is not, trace the signal with a scope, stage by stage, from input to output ...
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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electang
Joined: Dec 20, 2007 Posts: 15 Location: fr
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Posted: Mon May 10, 2010 2:43 am Post subject:
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I finished the DimD and audio and mono stereo switch seem to work but there is no modulation sound, presets don't do nothing, by-pass switch has no effect
After checking the usual suspects I found that on both boards I used BF245 C instead of BF245 A. Is the use of BF245 A critical and do I have to replace all BF245 C before checking elsewhere?
Thanks for your help
M |
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haima
Joined: Jul 25, 2008 Posts: 40 Location: Melbourne, Australia
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Posted: Mon May 10, 2010 3:02 am Post subject:
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do you have a "signal tracer probe"?
i.e. some way to follow the audio signal starting at one end to see where your problem might be?
the unit does pass audio though? just no chorus effect? probably a silly question, BUT it is a SUBTLE effect, just want to rule out that you just aren't noticing the effect it's easier to hear on pure tones than on full mixes.
I don't know about the BF245A vs C question - it is possible that the A version is required for the FET switches to work.... but someone with more EE knowledge will have to chime in.
good luck! |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Mon May 10, 2010 3:59 am Post subject:
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I haven't tried a BF245C, but I specified a BF245A for a reason: The threshold voltages are vastly different.
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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electang
Joined: Dec 20, 2007 Posts: 15 Location: fr
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Posted: Mon May 10, 2010 3:03 pm Post subject:
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"I haven't tried a BF245C, but I specified a BF245A for a reason: The threshold voltages are vastly different."
So I went to the shop bought some A's, had to remove 13 C's, soldered 13 A's and ...
everything went fine
thanks Jurgen, next time I will follow the BOM
"the unit does pass audio though? just no chorus effect? probably a silly question, BUT it is a SUBTLE effect, just want to rule out that you just aren't noticing the effect Smile it's easier to hear on pure tones than on full mixes. "
You 're right ! Now that it's working I can tell it s a very subtle fx but I like it a lot..... |
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haima
Joined: Jul 25, 2008 Posts: 40 Location: Melbourne, Australia
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Posted: Sun May 23, 2010 6:14 am Post subject:
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glad that fixed it!
yes it is a beautiful, subtle effect. i can't wait to put mine in a case and take it to the studio... it's been in a working state on my bench for about a month now - so busy i haven't had time to box it up |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Sun Aug 08, 2010 4:24 pm Post subject:
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Hi JH,
When I was considering putting an input attenuator on my circuit you said that I shouldn't need it, that this unit should have a lot of headroom with the compander in the circuit (I'm paraphrasing). I'm noticing, though, that when feeding it the "high" output of my Minimoog D, with all 3 VCOs on 10, I have to back off of the final output level of my mini to about 4 to get it to not distort/be a bit noisy when feeding into my Dim-TD. Is this normal? Not sure offhand what the output level of the mini is offhand, but I'm guessing, for example, that this unit is not geared toward taking in a full 10Vp-p signal straight from a modular, so maybe the high output of the mini with all 3 VCOs cranked is a little too hot for it as well? |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Wed Aug 11, 2010 8:02 pm Post subject:
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Hi JH. Not sure if you missed my previous post but after further investigation it appears there is a problem with my chorus. There's a slight high frequency noise of some sort, in both Dim-D and T modes. I'm going to start debugging tomorrow and in anticipation dug up the documentation and only now noticed the warning not to short pin 2 of the balanced outputs to ground. Well I wired up TRS jacks here and have many times connected TS jacks here. What damage could this have done, if any? Could it be the source of my problem? I built the 'vintage' version. |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Wed Aug 11, 2010 10:18 pm Post subject:
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numbertalk wrote: | Hi JH. Not sure if you missed my previous post but after further investigation it appears there is a problem with my chorus. There's a slight high frequency noise of some sort, in both Dim-D and T modes. I'm going to start debugging tomorrow and in anticipation dug up the documentation and only now noticed the warning not to short pin 2 of the balanced outputs to ground. Well I wired up TRS jacks here and have many times connected TS jacks here. What damage could this have done, if any? Could it be the source of my problem? I built the 'vintage' version. |
Input attenuation:
It will work with many kinds of studio / signal processing levels without level adjustment. For extremely high levels, fro msome synthesizers, just use a resitor divider or a potentiometer.
The noise you described is not normal. This thing should be quiet.
Hard to say if you have damaged anything (I haven't tested mine to destruction), but it seems quite possible.
The output stage of the "vintage" version is just that: a faithful reproduction of the vintage circuit, for those who want it exactly like the original. Personally, I would not design an output stage like this, powerful output stages with just signal inversion (and no auto-balancing). I'd go for short-circuit protected opamp outputs (my unexpensive version), or a transformer output, or an electronic transformer.
If you have damaged that output stage, replacing the power transistors and opamps and the small valued resistors should fix it. Or simply discard the vintage option and go for opamps only.
Can't say if your HF noise has its origin here, though.
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 Aug 12, 2010 5:18 am Post subject:
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Thanks JH. The more I think about it I would describe it as a distortion of the high frequencies of the signal, rather than a static noise. Going to dig around tonight.
So with the vintage set-up, is it ok to have the TRS balanced outputs and to use a TS cable there/connect to an unbalanced input elsewhere sometimes, or with this setup would I always have to have balanced cable at the output to a balanced input elsewhere?
jhaible wrote: | numbertalk wrote: | Hi JH. Not sure if you missed my previous post but after further investigation it appears there is a problem with my chorus. There's a slight high frequency noise of some sort, in both Dim-D and T modes. I'm going to start debugging tomorrow and in anticipation dug up the documentation and only now noticed the warning not to short pin 2 of the balanced outputs to ground. Well I wired up TRS jacks here and have many times connected TS jacks here. What damage could this have done, if any? Could it be the source of my problem? I built the 'vintage' version. |
Input attenuation:
It will work with many kinds of studio / signal processing levels without level adjustment. For extremely high levels, fro msome synthesizers, just use a resitor divider or a potentiometer.
The noise you described is not normal. This thing should be quiet.
Hard to say if you have damaged anything (I haven't tested mine to destruction), but it seems quite possible.
The output stage of the "vintage" version is just that: a faithful reproduction of the vintage circuit, for those who want it exactly like the original. Personally, I would not design an output stage like this, powerful output stages with just signal inversion (and no auto-balancing). I'd go for short-circuit protected opamp outputs (my unexpensive version), or a transformer output, or an electronic transformer.
If you have damaged that output stage, replacing the power transistors and opamps and the small valued resistors should fix it. Or simply discard the vintage option and go for opamps only.
Can't say if your HF noise has its origin here, though.
JH. |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Thu Aug 12, 2010 8:58 am Post subject:
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numbertalk wrote: |
So with the vintage set-up, is it ok to have the TRS balanced outputs and to use a TS cable there/connect to an unbalanced input elsewhere sometimes, |
Quoting from my web page:
"CAUTION: XLRs are not floating balanced outputs - do not connect to unbalanced inputs!"
Certainly using TRS jacks instead of XLRs cries for trouble, as plugging ordinary cables into them already shorts ring to sleeve.
BTW, the drawing how to connect unbalanced cables to the vintage version is here:
http://www.jhaible.de/subtle_chorus/sc_audio_balanced.pdf
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 Aug 12, 2010 3:12 pm Post subject:
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Thanks - looks like it was as simple as the output jacks. Change to TS/unbalanced output and sounds much better. Not a lot (or any until now) with balanced audio in DIY projects - was hoping for the case with some of the newer pro gear that I have where the inputs and outputs don't mind either balanced or unbalanced via TRS jacks.
Also, I wanted to check, the Dim T mode will be pretty noisy, right, in the same way that the Tau is, with the APF ladder? |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Fri Aug 13, 2010 12:18 am Post subject:
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numbertalk wrote: | Thanks - looks like it was as simple as the output jacks. Change to TS/unbalanced output and sounds much better. Not a lot (or any until now) with balanced audio in DIY projects - was hoping for the case with some of the newer pro gear that I have where the inputs and outputs don't mind either balanced or unbalanced via TRS jacks.
Also, I wanted to check, the Dim T mode will be pretty noisy, right, in the same way that the Tau is, with the APF ladder? |
"Modern" balanced outputs are either electronically balanced in a way that they behave like a transformer (tie one output to GND, and the other output will double its voltage!), or, more often, they are very simple and cheap, balancing only the output impedance: that is, just connecting the ring to GND with the same resistor value you find between the tip and the (unbalanced) output amp. The former is great (at least as long as it doesn't clip), the latter is not really a balanced output if you're asking me; it's just an unbalanced output providing balnced impedance for a balanced input making the best of the connection to an unbalanced output.
What Roland did in the Dimension D is a real balanced output, driving the two wires with opposite polarity - but not like a transformer, i. e. not allowing a short of one end of the output. This is why Roland had separate jacks for balanced and unbalanced outputs. And if you're looking at my schemos, I suggest doing the same, for the "vintage" version.
My "modern" version is less critical by far. Same topology as Roland, but no power output stage to drive 600 Ohm loads. Series resistors large enough to allow a short without damage, and still strong enough to drive modern 10kOhm or higher inputs. It's still not recommended to short these outputs, but it won't cause much harm.
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 Aug 13, 2010 6:47 am Post subject:
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Thanks for all of the info - good stuff to know.
Also again, wanted to just verify, there will be some noise from the Dim-T chorus, right, just like there is in the Tau Pipe module, from the APF ladder?
jhaible wrote: | numbertalk wrote: | Thanks - looks like it was as simple as the output jacks. Change to TS/unbalanced output and sounds much better. Not a lot (or any until now) with balanced audio in DIY projects - was hoping for the case with some of the newer pro gear that I have where the inputs and outputs don't mind either balanced or unbalanced via TRS jacks.
Also, I wanted to check, the Dim T mode will be pretty noisy, right, in the same way that the Tau is, with the APF ladder? |
"Modern" balanced outputs are either electronically balanced in a way that they behave like a transformer (tie one output to GND, and the other output will double its voltage!), or, more often, they are very simple and cheap, balancing only the output impedance: that is, just connecting the ring to GND with the same resistor value you find between the tip and the (unbalanced) output amp. The former is great (at least as long as it doesn't clip), the latter is not really a balanced output if you're asking me; it's just an unbalanced output providing balnced impedance for a balanced input making the best of the connection to an unbalanced output.
What Roland did in the Dimension D is a real balanced output, driving the two wires with opposite polarity - but not like a transformer, i. e. not allowing a short of one end of the output. This is why Roland had separate jacks for balanced and unbalanced outputs. And if you're looking at my schemos, I suggest doing the same, for the "vintage" version.
My "modern" version is less critical by far. Same topology as Roland, but no power output stage to drive 600 Ohm loads. Series resistors large enough to allow a short without damage, and still strong enough to drive modern 10kOhm or higher inputs. It's still not recommended to short these outputs, but it won't cause much harm.
JH. |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Fri Aug 13, 2010 7:34 am Post subject:
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The Tau is less noisy than BBDs, but the BBD board has heavy companding going on, so the Dim D is less noisy than the Dim T.
I don't recommend the Dim T version on vocals anyway. It's great for CS80-like synthesizer pads, though, IMO.
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 Aug 13, 2010 7:44 am Post subject:
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jhaible wrote: | The Tau is less noisy than BBDs, but the BBD board has heavy companding going on, so the Dim D is less noisy than the Dim T.
I don't recommend the Dim T version on vocals anyway. It's great for CS80-like synthesizer pads, though, IMO.
JH. |
Makes sense. Thanks. |
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