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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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 Posted: Wed May 07, 2008 2:06 pm Post subject:
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| Peake wrote: | Hi, thanks again for the project.
I'll take it that any AC voltage at and above 18V will be fine to power these (power sections fully installed)? |
Well, not exactly any voltage.
The upper limit is the peak voltage after the rectifier, which must stay below 35V.
theat means AC_voltage * 1.4142 - 1.2V must be smaller than 35V under all circumstances. Like, your AC voltage being higher than the nominal voltage because of overvoltage on the 230V (or 115V) side, or because of an oversized transformer which sees less than its nominal load. In other words, th eopper limit is complicated.
If I start with 18V nominal AC, and calculate 10% for low transformer loading, and another 10% for mains overvoltage, I get 21.78V AC.
Feeding the above equation with this, I get a peak voltage after rectifier of 29.6V. That's still below the limit of 35V, but not that much.
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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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Wed May 07, 2008 2:14 pm Post subject:
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| loopcycle wrote: | yesterday, at the primate's request  i measured the current draw on the +15v and -15v rails between the tau and the psu. i came up with the following results:
~29mA draw on -15v
~34mA draw on +15v
hope thats useful (and correct)  |
Thank you for measuring this!
You really saved me some time and cutting copper traces.
Now, for anybody looking for a current consumption specification, I'd say roughly double these figures, just to be save. (Your opamp specimens my draw more current, you may have a different load, higher temperature, and so on.)
So, from measuring the above, I'd specify +/-15V @ < 60mA.
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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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Wed May 07, 2008 2:24 pm Post subject:
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| Stavros wrote: | I am thinking of using a 16Volt AC one that I have already available, with larger than the 470uf capacitors. From my reading on PSUs, I believe even a 15Volt AC transformer of adequate Amps, and larger capacitors should be OK. Is it correct?
Best Regards and many thanks
Stavros |
16V AC is fine, without changing any capacitors.
(I even had my prototype running from a 14V AC wallwart - but that's only because it's rated for 500mA, so the actual voltage is higher than 14V when loaded lightly.)
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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PrimateSynthesis
Joined: May 02, 2008
Posts: 69
Location: U.S.A.
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| Posted: Wed May 07, 2008 2:57 pm Post subject:
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| loopcycle wrote: | yesterday, at the primate's request i measured the current draw on the +15v and -15v rails between the tau and the psu. i came up with the following results:
~29mA draw on -15v
~34mA draw on +15v
hope thats useful (and correct) |
Yes, very useful, and much less current than I thought.
Thank you very much  |
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PrimateSynthesis
Joined: May 02, 2008
Posts: 69
Location: U.S.A.
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| Posted: Wed May 07, 2008 5:07 pm Post subject:
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| jhaible wrote: | | In other words, the upper limit is complicated. |
I had this great book from the 80's on how to build power supplies, but unfortunately, I no longer have it, so I'm not sure how to calculate the voltage rise due to transformer regulation with a capacitive load. While my daughterboards are likely to draw as much current as the phaser board, I still wonder if 36CT 12VA transformer would be too much.
So if anyone has any good links that would be helpful.
| jhaible wrote: | | Thank you for measuring this! |
Ditto
| jhaible wrote: | Now, for anybody looking for a current consumption specification, I'd say roughly double these figures, just to be save. (Your opamp specimens my draw more current, you may have a different load, higher temperature, and so on.)
So, from measuring the above, I'd specify +/-15V @ < 60mA. |
Afaik, running half-wave the available current is only .28 times the rated current , so an 18V wall-wart should be rated at about 4 VA. |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Wed May 07, 2008 11:11 pm Post subject:
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| PrimateSynthesis wrote: |
I had this great book from the 80's on how to build power supplies, but unfortunately, I no longer have it, so I'm not sure how to calculate the voltage rise due to transformer regulation with a capacitive load. While my daughterboards are likely to draw as much current as the phaser board, I still wonder if 36CT 12VA transformer would be too much.
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Go for it.
Just make sure your regulators won't get too hot. (use little heatsinks ...)
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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PrimateSynthesis
Joined: May 02, 2008
Posts: 69
Location: U.S.A.
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| Posted: Thu May 15, 2008 11:32 am Post subject:
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Here is a comparison from Drew Neumann (www.droomusic.com) between
between the SSM2210 and the CA3086:
http://matrixsynth.blogspot.com/2008/05/jh-tau-phaser-samples.html
I was planning on using CA3046. Any thoughts??
Has anyone else tried more than one transistor array to hear how it sounds?? |
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Stavros
Joined: Oct 30, 2007
Posts: 36
Location: Athens-Greece
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| Posted: Thu May 15, 2008 12:41 pm Post subject:
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Could someone please confirm...when using a dual 18V AC power supply (Non CT) the connections to the 5 pin connector would be to pins 1 and 2 for the one and 4 and 5 for the other?
Thanks in advance for your help
Stavros
Stavros |
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PrimateSynthesis
Joined: May 02, 2008
Posts: 69
Location: U.S.A.
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| Posted: Thu May 15, 2008 1:14 pm Post subject:
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| Stavros wrote: | | Could someone please confirm...when using a dual 18V AC power supply (Non CT) the connections to the 5 pin connector would be to pins 1 and 2 for the one and 4 and 5 for the other? |
What do you mean dual 18V AC power supply that is not CT?? Do you mean a 36V secondary with four leads, or an 18V secondary with four leads?? In other words, in theory, if you were two connect the two center leads together putting the secondaries in series, would the nominal voltage between the two outside leads be 18V or 36V?? You want to look that up, not measure it, as you should not run a power transformer without a load. |
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blue hell
Site Admin
Joined: Apr 03, 2004
Posts: 24456
Location: The Netherlands, Enschede
Audio files: 297
G2 patch files: 320
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| Posted: Thu May 15, 2008 1:48 pm Post subject:
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| PrimateSynthesis wrote: | | as you should not run a power transformer without a load. |
Erm .. why not? I mean there may be good reasons that I don't know of, but I've survived it many times 
_________________
Jan
also .. could someone please turn down the thermostat a bit.
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Thu May 15, 2008 2:52 pm Post subject:
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| Stavros wrote: | Could someone please confirm...when using a dual 18V AC power supply (Non CT) the connections to the 5 pin connector would be to pins 1 and 2 for the one and 4 and 5 for the other?
Thanks in advance for your help
Stavros
Stavros |
Right.
Pin 2 and 4 are connected on the PCB, so you're creating a 36V CT configuration from two separate 18V windings.
(You have to check for the right polarity, i.e. 36V (and not 0V) between Pin 1 and 5.)
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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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Thu May 15, 2008 2:54 pm Post subject:
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| Blue Hell wrote: | | PrimateSynthesis wrote: | | as you should not run a power transformer without a load. |
Erm .. why not? I mean there may be good reasons that I don't know of, but I've survived it many times |
I don't know any reasons not to, either.
Just keep in mind that the voltage can be considerably higher without load.
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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Peake
Joined: Jun 29, 2007
Posts: 1113
Location: Loss Angeles
Audio files: 3
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| Posted: Thu May 15, 2008 3:49 pm Post subject:
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The 2210 sounds a bit better. Neither sound quite like the original unit, but are within 75% or so (there's a weirdness in the timbre evident when it's in the slowing-down cycle of the LFO).
I'm going for the 3046. |
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PrimateSynthesis
Joined: May 02, 2008
Posts: 69
Location: U.S.A.
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| Posted: Thu May 15, 2008 4:08 pm Post subject:
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| jhaible wrote: | | Blue Hell wrote: | | PrimateSynthesis wrote: | | as you should not run a power transformer without a load. |
Erm .. why not? I mean there may be good reasons that I don't know of, but I've survived it many times |
I don't know any reasons not to, either.
Just keep in mind that the voltage can be considerably higher without load. |
The reason is that any measurement would be almost meaningless, and would not properly identify the secondary. |
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blue hell
Site Admin
Joined: Apr 03, 2004
Posts: 24456
Location: The Netherlands, Enschede
Audio files: 297
G2 patch files: 320
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| Posted: Thu May 15, 2008 4:50 pm Post subject:
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| PrimateSynthesis wrote: | | The reason is that any measurement would be almost meaningless, and would not properly identify the secondary. |
You are being a bit vague here, the open voltage measured would be a bit on the high side, but meaningless (even when almost but not quite) is such a big word. Maybe you are referring to other measurements?
What do you mean by "properly identifying the secondary"? Distinguish the secondary from the primary?
_________________
Jan
also .. could someone please turn down the thermostat a bit.
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PrimateSynthesis
Joined: May 02, 2008
Posts: 69
Location: U.S.A.
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| Posted: Thu May 15, 2008 6:02 pm Post subject:
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| Blue Hell wrote: | | You are being a bit vague here, the open voltage measured would be a bit on the high side, but meaningless (even when almost but not quite) is such a big word. Maybe you are referring to other measurements? What do you mean by "properly identifying the secondary"? Distinguish the secondary from the primary? |
All I'm saying is measuring the voltage across the secondary without a load will not tell you its nominal voltage, as they are rated for a certain load. It can be way more than "a bit on the high side". While I don't know for sure that a 18V CT could measure closer to 36V without a load, it seems possible. For example, a filament winding intended to drive a large load at a small voltage could be so far off you might think it's for a plate voltage |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Fri May 16, 2008 2:12 am Post subject:
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| PrimateSynthesis wrote: | | Blue Hell wrote: | | You are being a bit vague here, the open voltage measured would be a bit on the high side, but meaningless (even when almost but not quite) is such a big word. Maybe you are referring to other measurements? What do you mean by "properly identifying the secondary"? Distinguish the secondary from the primary? |
All I'm saying is measuring the voltage across the secondary without a load will not tell you its nominal voltage, as they are rated for a certain load. It can be way more than "a bit on the high side". While I don't know for sure that a 18V CT could measure closer to 36V without a load, it seems possible. For example, a filament winding intended to drive a large load at a small voltage could be so far off you might think it's for a plate voltage |
The reason why the unloaded voltage is higher, is the copper resistance of the windings. This, and the load, form a voltage divider, and the voltage is specified for the voltage being divided down by the rated (= maximum!) load.
If the unloaded voltage would actually be twice as high as the loaded voltage, that would mean you'd have as much power loss in the transformer (under nominal load), as you can draw from it!
If you measure plate voltage range on a filament winding, that's probably due to capacitive coupling. (And probably a common mode voltage - measured to earth ground - , not a voltage across the winding.)
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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PrimateSynthesis
Joined: May 02, 2008
Posts: 69
Location: U.S.A.
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| Posted: Fri May 16, 2008 10:13 am Post subject:
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It's more likely due to my not being entirely serious (plate voltages are most often a step up). It's just that I've seen people try to specify transformers by measuring their no load output and ending up with the wrong voltages after they hooked them up.
So I went and wired a little 24V transformer to the mains and measured 30V across the secondary, which is enough of a difference to be misleading.
Anyway, I didn't mean to turn this into the transformer forum... |
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PrimateSynthesis
Joined: May 02, 2008
Posts: 69
Location: U.S.A.
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| Posted: Fri May 16, 2008 10:24 am Post subject:
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| Peake wrote: | The 2210 sounds a bit better. Neither sound quite like the original unit, but are within 75% or so (there's a weirdness in the timbre evident when it's in the slowing-down cycle of the LFO).
I'm going for the 3046. |
From http://www.bridechamber.com/bridechamber.com/Hard%202%20Find%20ICs.html :
CA3046 $ .80
CA3086 $ 1.00
SSM2210 $ 5.00
Imho, the difference in price between the the 3046 and 3086 is negligible, so I might as well pick which of the two is better, but at five times the cost, I wonder if the 2210 is worth it. |
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blue hell
Site Admin
Joined: Apr 03, 2004
Posts: 24456
Location: The Netherlands, Enschede
Audio files: 297
G2 patch files: 320
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| Posted: Fri May 16, 2008 2:38 pm Post subject:
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| PrimateSynthesis wrote: | | Anyway, I didn't mean to turn this into the transformer forum... |
No lets not do that, I read your points, and I consider a 30 to 24 V drop to be very well possible for a small transformer going from no load to full load. I just consider that to be not so dramatic
Thanks for your explanations.
_________________
Jan
also .. could someone please turn down the thermostat a bit.
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loopcycle
Joined: Nov 06, 2006
Posts: 101
Location: California
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| Posted: Sat May 17, 2008 1:29 pm Post subject:
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ive posted this elsewhere already, so apologies.
heres another audio demo of my ca3046-based tau:
http://share.ovi.com/media/consumed.sound/consumed.10033
i think im going to try out the smooth switch and see if it has any significant bearing on the phaser set to kill...or, erm at high resonance. |
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bridechamber
Joined: Oct 06, 2007
Posts: 64
Location: Saint Paul, MN
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Floppy
Joined: May 09, 2008
Posts: 66
Location: Berlin
Audio files: 2
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| Posted: Mon Jun 02, 2008 1:16 pm Post subject:
myReichelt |
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i just searched myreichelt for the parts of tau phaser.
for most of the ingredients i get 2 very simmilar matches and i cant tell whats the difference between them or if they would both be ok...
reichelt has this function to export the warenkorb so i thought maybe somebody who was shopping there before could send me his warenkorb.txt.
regards
F32 |
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StephenGiles
Joined: Apr 17, 2006
Posts: 507
Location: England
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funkyfarm
Joined: Jan 21, 2007
Posts: 583
Location: France
Audio files: 3
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| Posted: Sat Jun 28, 2008 9:34 am Post subject:
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(everybody can see my awfull and temporary setup in Photos of what you've built with JH PCBs thread...)
I have a stupid question about LFO RATE Leds (green/red) and clicks in audio path...
What makes the clicks audible ?
putting some LEDs onto frontpanel ?
or LFO circuitry itself (lying next to audio circuit) ?
I mean : if no LED, no click ?
thank you,
ff |
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