Ok. I've been working with Arek at Khozmo and he recommends the Khozmo Shunt type RCA 64 steps with relays and remote. It requires 120 V AC to power its PSU. He says I can pull from the AC at the IEC. My question is can I wire off of the hot and ground at the IEC to power this?
I've mapped out what I'm thinking in the attached files:
As always, thanks.
Attachments
Can I play too? 
I receive this shunt attenuator as a gift from dear old brother. I've been sitting on it for more than a decade. Actually I had it in a crack headphone amp until I sold it. The khozmo did NOT get sold with the amp. So, it's been patiently waiting for a preamp project since then. It will be happy days when it comes back into use.
I receive this shunt attenuator as a gift from dear old brother. I've been sitting on it for more than a decade. Actually I had it in a crack headphone amp until I sold it. The khozmo did NOT get sold with the amp. So, it's been patiently waiting for a preamp project since then. It will be happy days when it comes back into use. Always happy to have company in my confusion. Can I run wires to two separate components from the same IEC or do I need some sort of interim bridge to direct the current two ways?Can I play too?
View attachment 1022126
You can connect your power supply directly to the IEC. It's no different than plugging into another outlet in an extension cord. If your IEC does not have a fuse and if your power supply does not have a fuse, then you need to add a fuse in the live line between the IEC and power supply.
If your power supply does not have an on-off switch, it will be always on. You can insert a switch in the live line.
Or your other choice is to hook it to your soft start circuit, assuming that you do not exceed its current capacity.
If your power supply does not have an on-off switch, it will be always on. You can insert a switch in the live line.
Or your other choice is to hook it to your soft start circuit, assuming that you do not exceed its current capacity.
Ben,
Thanks much for your counsel. I am using the soft start circuit. I'd like to use the 5Vdc from it for the Khozmo but it requires linear power supply, not SMPS. Can I run the power out to the Khozmo from P1D and P1N? That would be great as the Khozmo would now be included in the switch. I understand now that if I wire it from the IEC, it would always be on, as I rely on the soft start switch. If so, I guess that shouldn't be an issue for the Khozmo.
This is really helpful.
Chip
Hello,
hope you all had a pleasant Sunday, here I am with a bunch of some other dumb questions.
Would I go for the dual mono route I will need two linear supply power boards, one per channel to then feed the BA-3 board, question being, is there a significant difference between the many PS boards I can see being used and which ones would you advise to use or be simpler to get considering I am in Italy/EU (dunno if commercial links can be added on the forum, if not please some good soul can send a direct message, grazie).
Is there a preferred PS board and its bill of materials?
Transformers, to pick them I am asked how many output VA, output voltage and mounting pad, basically this is the options list which ones_
Grazie and have a good evening
hope you all had a pleasant Sunday, here I am with a bunch of some other dumb questions.
Would I go for the dual mono route I will need two linear supply power boards, one per channel to then feed the BA-3 board, question being, is there a significant difference between the many PS boards I can see being used and which ones would you advise to use or be simpler to get considering I am in Italy/EU (dunno if commercial links can be added on the forum, if not please some good soul can send a direct message, grazie).
Is there a preferred PS board and its bill of materials?
Transformers, to pick them I am asked how many output VA, output voltage and mounting pad, basically this is the options list which ones_
Grazie and have a good evening
Chip,
Looking at Mark Johnson's post re: H9KPXG (https://www.diyaudio.com/community/...ncludes-soft-start-h9kpxg.354971/post-6216476) it looks like you can connect to P1D and P1N as the H9KPXG can handle a reasonable amount of inrush current. To be sure, you can do the math. Example calculations from Mark's post:
(optional tech info): MORE ABOUT INRUSH LIMITER JOULE RATING
The Ametherm ICL I have recommended in the Parts List, is rated for 125 Joules. Is this too little? Too much? Just right? Let's look at a couple typical scenarios.
Example 1: a chipamp with plus/minus 36V supply rails, using a diyAudio Universal Power Supply, whose PCB has a total of eight electrolytic capacitors. Each capacitor is 15,000 microfarads with a 50V voltage rating. Four of these capacitors filter the +36V supply, and four of them filter the -36V supply.
The energy stored in each of the four V+ capacitors, is 0.5 * C * V * V. Plugging in numbers, (0.5 * 1.5E-2 * (+36) * (+36)) = 9.72 Joules. Since there are four V+ capacitors, that's a total of 39 Joules for V+
Similarly the energy stored in each of the four V- capacitors is 9.72 Joules. {why? because (+36) times (+36) equals (-36) times (-36)} The total for V- is also 39 Joules.
Adding them together, the total energy stored in the PSU is 78 Joules. Which is comfortably below the 125J rating of the Ametherm ICL.
To do the calculation you need determine the amount of capacitance for the power supply capacitors in the BA-3 supply and the Khozmo supply and also the output voltage of each supply, and do the calculation for each supply, add up the total energy, and it needs to be less than 125 Joules. Note that 1 uF = 0.000 001 F.
Looking at Mark Johnson's post re: H9KPXG (https://www.diyaudio.com/community/...ncludes-soft-start-h9kpxg.354971/post-6216476) it looks like you can connect to P1D and P1N as the H9KPXG can handle a reasonable amount of inrush current. To be sure, you can do the math. Example calculations from Mark's post:
(optional tech info): MORE ABOUT INRUSH LIMITER JOULE RATING
The Ametherm ICL I have recommended in the Parts List, is rated for 125 Joules. Is this too little? Too much? Just right? Let's look at a couple typical scenarios.
Example 1: a chipamp with plus/minus 36V supply rails, using a diyAudio Universal Power Supply, whose PCB has a total of eight electrolytic capacitors. Each capacitor is 15,000 microfarads with a 50V voltage rating. Four of these capacitors filter the +36V supply, and four of them filter the -36V supply.
The energy stored in each of the four V+ capacitors, is 0.5 * C * V * V. Plugging in numbers, (0.5 * 1.5E-2 * (+36) * (+36)) = 9.72 Joules. Since there are four V+ capacitors, that's a total of 39 Joules for V+
Similarly the energy stored in each of the four V- capacitors is 9.72 Joules. {why? because (+36) times (+36) equals (-36) times (-36)} The total for V- is also 39 Joules.
Adding them together, the total energy stored in the PSU is 78 Joules. Which is comfortably below the 125J rating of the Ametherm ICL.
To do the calculation you need determine the amount of capacitance for the power supply capacitors in the BA-3 supply and the Khozmo supply and also the output voltage of each supply, and do the calculation for each supply, add up the total energy, and it needs to be less than 125 Joules. Note that 1 uF = 0.000 001 F.
I know its just tongue and cheek, but there are no dumb questions here.
These are the regulators that I use. (Not saying they are the best, or perfect, but they work well for me.)
Can be had built, or as a kit from several suppliers on E-bay.
https://www.ebay.co.uk/itm/122121355586
Fed from 18v transformers they will output about 21 volts regulated. Go much beyond that and they stop regulating.
This (21v) sounds fine in my system.
Can be had built, or as a kit from several suppliers on E-bay.
https://www.ebay.co.uk/itm/122121355586
Fed from 18v transformers they will output about 21 volts regulated. Go much beyond that and they stop regulating.
This (21v) sounds fine in my system.
Ciao Colin and thanks for your feedback,
as far as I understand first thing first is about to decide the output voltage/current to feed to the BA-3 board, once that is established (somebody suggested to go as high as 30V but I will have to go back a few posts to read again) it will be about looking for the proper boards, there seem to be many, what I'd anyways prefer is to have screw connections for the leads coming off the transformers leads as to keep soldering to the minimum.
One more question re transformers, for dual mono build I need 230AC in XXCC out single output, is that correct?
Grazie e buon lunedì
So both transformers have to have dual output in the +/- desired DC voltage to feed the two PS boards, correct?
Grazie
Hello Giovanni1968,
for my a BA-3-preamp I used transformers with primary input 1x 230 V AC (or 2x 115 V AC connected in series) and secondary output at
2x 18V AC or 2x24 V AC.
The transformers with 2x 18 V AC sec. will have an outputvoltage after a CRC-filter of around 2x 24 up to 2x 28V DC (without any load).
The transformers with 2x 24 V AC sec. will go up to approximately 2x 32 V DC to 2x 34 V DC (after a CRC-filter). Perhaps a little bit higher
without load.
I don't know what voltages you will get with the classA-parallel-regulated-supply you showed in your pic? But You will have for sure some losses
in the voltage-output.
I most often use series regulated powersupplies. with the 'old' LM317/LM337 or LT1085/LT1033-regulators. There are very good lowdropout-regulators available today.
For a real dual - mono - BA-3-preamp you would need 2 completely seperated PSUs for the left and right channel. This means:
I have no idea what voltages you will get with that ClassA-PSU in your last post?
I hope this helps?
Cheers
Dirk
for my a BA-3-preamp I used transformers with primary input 1x 230 V AC (or 2x 115 V AC connected in series) and secondary output at
2x 18V AC or 2x24 V AC.
The transformers with 2x 18 V AC sec. will have an outputvoltage after a CRC-filter of around 2x 24 up to 2x 28V DC (without any load).
The transformers with 2x 24 V AC sec. will go up to approximately 2x 32 V DC to 2x 34 V DC (after a CRC-filter). Perhaps a little bit higher
without load.
I don't know what voltages you will get with the classA-parallel-regulated-supply you showed in your pic? But You will have for sure some losses
in the voltage-output.
I most often use series regulated powersupplies. with the 'old' LM317/LM337 or LT1085/LT1033-regulators. There are very good lowdropout-regulators available today.
For a real dual - mono - BA-3-preamp you would need 2 completely seperated PSUs for the left and right channel. This means:
- 2 trafos with symmetrical output (BA-3 wants a symmetrical voltage at around +24 up to +32 V/ and a negative voltage at around -24 up to -32V.
- 4 cap banks ( if you use a CRC-filter = 8 caps; if you want to go with a CRCRC-filter = 12 caps)
- you will have 4 voltages (for 2 channels / dual mono) = 4 regulators (if you want to use them)
I have no idea what voltages you will get with that ClassA-PSU in your last post?
I hope this helps?
Cheers
Dirk
And in addition, and that probably goes for both the BA-1 and 3, they have the gain/swing to drive an F4, and the BA-3 OS (being the same as an F4 sans input buffer), to full output.
Giovanni mentioned F4 are being built so I suggested slightly higher rail voltage for the BA3 preamp to so that even
at the max output required for the F4, the BA3 preamp would not start clipping. Also the higher rails give a slightly
lower distortion overall but that's just bonus.
With the PS board linked previously, the obvious limit comes from the 25V caps limiting the input voltage.
at the max output required for the F4, the BA3 preamp would not start clipping. Also the higher rails give a slightly
lower distortion overall but that's just bonus.
With the PS board linked previously, the obvious limit comes from the 25V caps limiting the input voltage.
Buongiorno Dirk,Hello Giovanni1968,
for my a BA-3-preamp I used transformers with primary input 1x 230 V AC (or 2x 115 V AC connected in series) and secondary output at
2x 18V AC or 2x24 V AC.
The transformers with 2x 18 V AC sec. will have an outputvoltage after a CRC-filter of around 2x 24 up to 2x 28V DC (without any load).
The transformers with 2x 24 V AC sec. will go up to approximately 2x 32 V DC to 2x 34 V DC (after a CRC-filter). Perhaps a little bit higher
without load.
I don't know what voltages you will get with the classA-parallel-regulated-supply you showed in your pic? But You will have for sure some losses
in the voltage-output.
I most often use series regulated powersupplies. with the 'old' LM317/LM337 or LT1085/LT1033-regulators. There are very good lowdropout-regulators available today.
For a real dual - mono - BA-3-preamp you would need 2 completely seperated PSUs for the left and right channel. This means:
You can run a BA-3-preamp easily up to +-30 V DC on the rails. I also used/tested up to +-32V DC without any problems. But then it starts to become 'dangerous' for the JFets.
- 2 trafos with symmetrical output (BA-3 wants a symmetrical voltage at around +24 up to +32 V/ and a negative voltage at around -24 up to -32V.
- 4 cap banks ( if you use a CRC-filter = 8 caps; if you want to go with a CRCRC-filter = 12 caps)
- you will have 4 voltages (for 2 channels / dual mono) = 4 regulators (if you want to use them)
I have no idea what voltages you will get with that ClassA-PSU in your last post?
I hope this helps?
Cheers
Dirk
first and foremost thank you for your detailed reply which helps me starting to understand how it works which is fundamental to me as I don't want just to put parts together but also to get how and why it works the way it is supposed to.
So if I get it right I would have an output off the PSU of approx 1.4x input VDC off the transformers so, as you mention above, whatever in the 18-20V DC should fit the bill and as by @Dennis .Hui suggestion, if I wanna raise in the 28-30VDC range I need a 20-24VDC output and also raise the caps value at the same or higher value to match (if the whole Super Regulated boards meet the specs of desired 30VDC output).
Bill of materials for dual mono would then be:
- 2 x trafos (learning acronyms at least ) with symmetrical output (+/- 20 or 24 VDC)
- 2 x PS boards (whichever you suggest, I still can't tell with my knowledge (no laughs!!!) if the Super Regulator ones would but I guess so) to have 2 positive DC outputs and 2 negative ones
- cap banks, here I go trouble, CRC vs CRCRC vs PS boards, need to understand the difference between CRC and CRCRC and if the above boards fit whatever the choice
It helps a lot Dirk, thanks to you all
No. Not always. As an example - the first PSU you linked had a voltage drop of ~9VDC. So, you need the 25VAC secondaries (or ~27VAC to go with Dennis's excellent suggestion of running slightly higher rails). It looks like a nice regulated / quiet design, but the price you pay is extra heat and a loss of "usable" voltage. It just gets 'used up' by the PSU.
So, for each PSU, you need to know what the expected AC input voltage is to provide the output voltage you require. You also need to be sure that the PSU is rated for the voltage and current you require. For a pre-amp, current is likely not going to be an issue, but it's important to check. Note Dennis mentioned 25V caps in one design. Won't work for you. Also, you are in a 220VAC country vs. 230VAC. So, you also need to adjust a bit for that depending on how your transformer is specified.
See also my previous post. I linked two options for you (assuming you wanted to use the PSU you linked.
Transformers do not output DC. Those are AC voltages. IMO, the best option with the most versatility is what would be called a dual secondary transformer.Bill of materials for dual mono would then be:
- 2 x trafos (learning acronyms at least
It would be noted as 2 x 25VAC. The 25VAC is dependent on the input voltage (your home's line voltage) along with the load or how 'hard you make it work'. So with a 220VAC line voltage, you will get less than 25VAC output vs. 230VAC.The VA rating is how much total power it can put out without too much voltage sag, getting too hot or humming etc.. We tend to be very conservative here. 2, 20VA transformers is plenty for dual mono.
Which super regulators? If you link to them, we can help. If they're the ones you previously linked... Yes. Two of them.
The previous ones you linked do not need any additional filtering.
You guys are amazing, didn't I write that yet?No. Not always. As an example - the first PSU you linked had a voltage drop of ~9VDC. So, you need the 25VAC secondaries (or ~27VAC to go with Dennis's excellent suggestion of running slightly higher rails). It looks like a nice regulated / quiet design, but the price you pay is extra heat and a loss of "usable" voltage. It just gets 'used up' by the PSU.
So, for each PSU, you need to know what the expected AC input voltage is to provide the output voltage you require. You also need to be sure that the PSU is rated for the voltage and current you require. For a pre-amp, current is likely not going to be an issue, but it's important to check. Note Dennis mentioned 25V caps in one design. Won't work for you. Also, you are in a 220VAC country vs. 230VAC. So, you also need to adjust a bit for that depending on how your transformer is specified.
See also my previous post. I linked two options for you (assuming you wanted to use the PSU you linked.
Transformers do not output DC. Those are AC voltages. IMO, the best option with the most versatility is what would be called a dual secondary transformer.
The VA rating is how much total power it can put out without too much voltage sag, getting too hot or humming etc.. We tend to be very conservative here. 2, 20VA transformers is plenty for dual mono.
Which super regulators? If you link to them, we can help. If they're the ones you previously linked... Yes. Two of them.
The previous ones you linked do not need any additional filtering.
Whatever happens I am learning which is a great start.
The boards I mentioned are the ones from the DIY Audio Store and whilst cooking (yes, Italian and from the South, what did you expect us to do in the spare time?) I gave a check at the often mentioned Sigma 22 and off the more complete description I found out, as you outlined, the voltage drop of about 9V.
Let's see if I start to get things right, tension out of transformer is still alternated, my bad, once though what we call "ponte a diodi" which is your "rectifier" the half negative wave of the AC gets rectified and we have DC, caps + rectifiers are responsible for that 1.4 multiply factor (a quick search and read got me this).
With your suggested calculations to reach 30VDC on the BA-3 board it would need about 28V off the transformer (+/- 28VAC), [(28*1.4)-9]=30.2
Let's leave out the transformers bit for a little while as otherwise it gets too many informations to process at once (women would be smiling at a man who can't do two things at once but, hey, cooking and zapping through caps and transformers is no easy task!), I wanna get down to the BOM so the Toshiba MOSFETs should be set, next is the BA-3 board which I will get through the DIY Audio Store and next step being choosing the PS boards.
The Sigma one specs say it can deliver <=1.2A or use bigger heatsinks on the transistors and the max voltage supplied to the board to not exceed 35VAC, be it the Sigma or whichever one you suggest these specs should fit the bill, correct?
As you guessed right I am totally open to suggestion, this thing is gonna take a while, I am in no rush so whatever any suggestion is welcome
I am ordering parts for a BA-3. I wanted to see if this would be a good power supply to use:
https://glass-ware.stores.yahoo.net/dulv.html
For 24V DC output, would an antec AS-0520 - 50va 20v be good or should I go higher?
I am looking for a simple solution for the power supply. I have Gaz's helios bipolar supply board but It seems to only be good for around 18v. I want to go a little higher than that.
Thanks!
https://glass-ware.stores.yahoo.net/dulv.html
For 24V DC output, would an antec AS-0520 - 50va 20v be good or should I go higher?
I am looking for a simple solution for the power supply. I have Gaz's helios bipolar supply board but It seems to only be good for around 18v. I want to go a little higher than that.
Thanks!
The GlassWare Audio power supply looks good.
50VA transformer is good.
20V may be borderline as the LM317 regulators in the power supply will drop a minimum of 3VDC for good regulation. That is in addition to the usual drops in a CRC power supply, and variations in the wall AC voltage may also drop the available voltage.
I would go with a 22V transformer.
50VA transformer is good.
20V may be borderline as the LM317 regulators in the power supply will drop a minimum of 3VDC for good regulation. That is in addition to the usual drops in a CRC power supply, and variations in the wall AC voltage may also drop the available voltage.
I would go with a 22V transformer.